Oracle Undocumented Underscore Startup Parameters
Version 18.3

General Information
Library Note Morgan's Library Page Header
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Purpose The "undocumented" underscore parameters are parameters officially undocumented and unsupported by Oracle but that may be utilized, after receiving permission from Oracle Support to address specific issues such as bugs.
Query for undocumented initialization parameters set pagesize 35
set linesize 150
col NAME format a40
col VALUE format a20
col DESCRIPTION format a60
set pause on
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SELECT x.ksppinm NAME, y.ksppstvl VALUE, x.ksppdesc DESCRIPTION
FROM x$ksppi x, x$ksppcv y
WHERE x.inst_id = userenv('Instance')
AND y.inst_id = userenv('Instance')
AND x.indx = y.indx
AND SUBSTR(LOWER(x.ksppinm),1,1) = '_'
ORDER BY 1;
Page Index
 
Adaptive Queries
_OPTIMIZER_ADAPTIVE_CURSOR_SHARING
Default: TRUE
Optimizer adaptive cursor sharing
_optimizer_adaptive_cursor_sharing=TRUE
_OPTIMIZER_ADAPTIVE_PLANS
Obsolete
Enable adaptive plans
_optimizer_adaptive_plans=TRUE
_OPTIMIZER_ADAPTIVE_PLAN_CONTROL
Default: 0
Internal controls for adaptive plans
_optimizer_adaptive_plan_control=0
_OPTIMIZER_ADAPTIVE_RANDOM_SEED
Default: 0
Random seed for adaptive plans
_optimizer_adaptive_random_seed=0
_OPTIMIZER_NLJ_HJ_ADAPTIVE_JOIN
Default: TRUE
Allow adaptive NL Hash joins
_optimizer_nlj_hj_adaptive_join=TRUE
_OPTIMIZER_STRANS_ADAPTIVE_PRUNING
Default: TRUE
Enables adaptive pruning of star transformation bitmap trees, https://www.slideshare.net/pachot/nl-2014-4adaptivebitmappruning
_optimizer_strans_adaptive_pruning=TRUE
_ADAPTIVE_DIRECT_READ
Default: TRUE
Adaptive Direct Read
 
_ADAPTIVE_DIRECT_WRITE
Default: TRUE
Adaptive Direct Write
 
_ADAPTIVE_FETCH_ENABLED
Default: TRUE
Enable/disable adaptive fetch in parallel group by
 
_ADAPTIVE_LOG_FILE_SYNC_HIGH_SWITCH_FREQ_THRESHOLD
Default: 3
Threshold for frequent log file sync mode switches (per minute)
 
_ADAPTIVE_LOG_FILE_SYNC_POLL_AGGRESSIVENESS
Default: 0
Polling interval selection bias (conservative=0, aggressive=100)
 
_ADAPTIVE_LOG_FILE_SYNC_SAMPLING_COUNT
Default: 128
Evaluate post/wait versus polling every N writes
 
_ADAPTIVE_LOG_FILE_SYNC_SAMPLING_TIME
Default: 3
Evaluate post/wait versus polling every N seconds
 
_ADAPTIVE_LOG_FILE_SYNC_SCHED_DELAY_WINDOW
Default: 60
Window (in seconds) for measuring average scheduling delay
 
_ADAPTIVE_LOG_FILE_SYNC_USE_POLLING_THRESHOLD
Default: 200
Ratio of redo synch time to expected poll time as a percentage
 
_ADAPTIVE_LOG_FILE_SYNC_USE_POSTWAIT_THRESHOLD
Default: 50
Percentage of foreground load from when post/wait was last used
 
_ADAPTIVE_LOG_FILE_SYNC_USE_POSTWAIT_THRESHOLD_AGING
Default: 1001
Permille of foreground load from when post/wait was last used
 
_ADAPTIVE_SCALABLE_LOG_WRITER_DISABLE_WORKER_THRESHOLD
Default: 90
Percentage of overlap across multiple outstanding writes
 
_ADAPTIVE_SCALABLE_LOG_WRITER_ENABLE_WORKER_AGING
Default: 999900
Per million of redo gen rate when LGWR workers were last used
 
_ADAPTIVE_SCALABLE_LOG_WRITER_ENABLE_WORKER_THRESHOLD
Default: 200
Increase in redo generation rate as a percentage
 
_ADAPTIVE_SCALABLE_LOG_WRITER_SAMPLING_COUNT
Default:: 128
Evaluate single versus scalable LGWR every N writes
 
_ADAPTIVE_SCALABLE_LOG_WRITER_SAMPLING_TIME
Default:: 3
Evaluate single versus scalable LGWR every N seconds
 
_ADAPTIVE_WINDOW_CONSOLIDATOR_ENABLED
Default:: TRUE
Enable/disable adaptive window consolidator PX plan
 
  _BSLN_ADAPTIVE_THRESHOLDS_ENABLED TRUE Adaptive Thresholds Enabled
 
  _DB_DW_SCAN_ADAPTIVE_COOLING FALSE if TRUE, enable adaptive DW scan cooling
 
  _DB_DW_SCAN_MAX_SHADOW_COUNT 5 DW Scan adaptive cooling max shadow count
 
  _DISABLE_ADAPTIVE_SHRUNK_AGGREGATION FALSE adaptive shrunk aggregation
 
 
ADDM
_ADDM_AUTO_ENABLE
Default:: TRUE
Governs whether ADDM gets run automatically after every AWR snapshot
 
_ADDM_SKIPRULES
Default: None Defined
Comma-separated list of ADDM nodes to skip
TBD
_ADDM_VERSION_CHECK
Default:: TRUE
Governs whether ADDM checks the input AWR snapshot version
 
 
Advanced Queuing (AQ) & Streams
_AQSHARDED_CACHE_LIMIT
Default: 0
Limit for cached enqueue/dequeue operations
 
_AQ_ADDPT_BATCH_SIZE
Default: 1
Add PT batch size
 
_AQ_DQ_PREFETCH_SIZ
Default: 5
AQ PT DQ prefech size
 
_AQ_DROPPT_BATCH_SIZE
Default: 5
Drop PT batch Size
 
_AQ_INIT_SHARDS
Default: 5
Minimum enqueue shards per queue at an instance
 
_AQ_IPC_MAX_SLAVE
Default: 10
Maximum number of slaves for knlpipcm
 
_AQ_LATENCY_ABSOLUTE_THRESHOLD
Default: 100
Absolute threshold greater than average latency
 
_AQ_LATENCY_RELATIVE_THRESHOLD
Default: 30
Relative threshold of average latency
 
_AQ_LB_CYCLE
Default: 120
Time(seconds) between consecutive AQ load balancing efforts
 
_AQ_LB_STATS_COLLECT_CYCLE
Default: 120
Time(seconds) between consecutive AQ load statistics collection
 
_AQ_LOOKBACK_SIZE
Default: 30
AQ PT look back size
 
_AQ_MAX_SCAN_DELAY
Default: 1500
Maximum allowable scan delay for AQ indexes and IOTs
 
_AQ_PT_PROCESSES
Default: 15
Partition background processes
 
_AQ_PT_SHRINK_FREQUENCY
Default: 30
PT shrink window size
 
_AQ_PT_STATISTICS_WINDOW
Default: 30
PT statistics sample window size
 
_AQ_QT_PREFETCH_SIZE
Default: 5
AQ PT QT prefech size
 
_AQ_SHARD_BITMAP_CHILD_LATCHES
Default: 32
bitmap child latches
 
_AQ_SHARD_CHILD_LATCHES
Default: 512
Shard child latches
 
_AQ_SHARD_PRTY_LATCHES
Default: 16
Shard priority child latches
 
_AQ_SHARD_RETRY_CHILD_LATCHES
Default: 32
Retry child latches
 
_AQ_SHARD_SUB_CHILD_ELEM_LATCHES
Default: 1024
Subscriber element child latches
 
_AQ_SHARD_SUB_CHILD_LATCHES
Default: 512
Subscriber child latches
 
_AQ_SHARD_TXN_CHILD_LATCHES
Default: 128
Txn child latches
 
_AQ_STOP_BACKGROUNDS
Default: FALSE
Stop all AQ background processes
 
_AQ_STREAMING_THRESHOLD
Default: 10485760
Large payload threshold size
 
_AQ_SUBSHARDS_PER_DQPARTITION
Default: 1
SubShards Per Deq Partition
 
_AQ_SUBSHARDS_PER_QPARTITION
Default: 1
SubShards Per Q Partition
 
_AQ_SUBSHARD_SIZE
Default: 20000
Sub Shard Size
 
_AQ_TM_DEQCOUNTINTERVAL
Default: 0
Dequeue count interval for Time Managers to cleanup DEQ IOT BLOCKS
 
_AQ_TM_SCANLIMIT
Default: 0
Scan limit for Time Managers to clean up IOT
 
_AQ_TM_STATISTICS_DURATION
Default: 0
Statistics collection window duration
 
_AQ_TRUNCPT_BATCH_SIZE
Default: 1
Trunc PT batch Size
 
_AQ_TXN_HT_SZ
Default: 1024
Message cache transaction hash table size
 
_AQ_X_MSG_SIZE
Default: 32768
AQ cross single message buffer size
 
_DISABLE_STREAMS_DIAGNOSTICS
Default: 0
Streams diagnostics
_disable_streams_diagnostics=0
_DISABLE_STREAMS_POOL_AUTO_TUNING
Default: FALSE
Disable streams pool auto tuning
_disalbe_streams_pool_auto_tuning=TRUE
_STREAMS_POOL_MAX_SIZE
Default:
Streams pool maximum size when auto SGA enabled
_streams_pool_max_size=4M
__STREAMS_POOL_SIZE
Default:
Actual size in bytes of streams pool
__streams_pool_size=4M
 
ANSI Compliance
   
 
 
Archive Logging
  _ARCH_COMPRESSION TRUE archive compression enabled
 
  _ARCH_COMPRESS_CHECKSUMS FALSE enable/disable row checksums for archive compressed blocks
 
  _ARCH_COMP_DEC_BLOCK_CHECK_DUMP 1 decompress archive compression blocks for checking and dumping
 
_arch_comp_dbg_scan

Default: 0
archive compression scan debug
 
  _ARCH_IO_SLAVES 0 ARCH I/O slaves
 
  _ARCH_SIM_MODE 0 Change behavior of local archiving
 
 
ASH Reporting
_ASH_COMPRESSION_ENABLE

Default: TRUE
To enable or disable string compression in ASH
Range of values: {TRUE | FALSE}
_ash_compression_enable=TRUE
_ASH_DISK_FILTER_RATIO

Default: 10
Ratio of the number of in-memory samples to the number of samples actually written to disk
_ash_disk_filter_ratio=10
_ASH_DISK_WRITE_ENABLE

Default: TRUE
To enable or disable Active Session History flushing
Range of values: {TRUE | FALSE}
_ash_disk_write_enable=TRUE
_ASH_DUMMY_TEST_PARAM

Default: 0
Oracle internal dummy ASH parameter used ONLY for testing!
_ash_dummy_test_param=0
_ASH_EFLUSH_TRIGGER

Default: 66
The percentage above which if the in-memory ASH is full the emergency flusher will be triggered
_ash_eflush_trigger=66
_ASH_ENABLE

Default: TRUE
To enable or disable Active Session sampling and flushing
Range of values: {TRUE | FALSE}
_ash_enable=FALSE
_ASH_MIN_MMNL_DUMP

Default: 90
Minimum Time interval passed to consider MMNL Dump
_ash_min_mmnl_dump=90
_ASH_SAMPLE_ALL

Default: FALSE
To enable or disable sampling every connected session including ones waiting for idle waits
Range of values: {TRUE | FALSE}
_ash_sample_all=TRUE
_ASH_SAMPLING_INTERVAL 1000 Time interval between two successive Active Session samples in millisecs
_ash_sampling_interval=2000
_ASH_SIZE
Default: 1048618
To set the size of the in-memory Active Session History buffers
 
 
ASM
_ASMSID
Default: asm
ASM instance id
TBD
_ASM_ACCESS
Default: AUTO
ASM File access mechanism
 
_ASM_ACD_CHUNKS
Default: 1
Initial ACD chunks created
 
_ASM_ADMIN_WITH_SYSDBA
Default: FALSE
Does the sysdba role have administrative privileges on ASM?
 
_ASM_ALLOWDEGENERATEMOUNTS
Default: FALSE
Allow force-mounts of DGs w/o proper quorum
 
_ASM_ALLOW_APPLIANCE_DROPDISK_NOFORCE
Default: FALSE
Allow DROP DISK/FAILUREGROUP NOFORCE on ASM Appliances
 
_ASM_ALLOW_DANGEROUS_UNPROTECTED_VOLUMES
Default: FALSE
Disable checking for unprotected volumes in mirrored disk groups
 
_ASM_ALLOW_LVM_RESILVERING
Default: TRUE
Enable disk resilvering for external redundancy
 
_ASM_ALLOW_ONLY_RAW_DISKS
Default: TRUE
Discovery only raw devices
 
_ASM_ALLOW_SMALL_MEMORY_TARGET
Default: FALSE
Allow a small memory_target for ASM instances
 
_ASM_ALLOW_SYSTEM_ALIAS_RENAME
Default: FALSE
If system alias renaming is allowed
 
_ASM_ALLOW_UNSAFE_RECONNECT
Default: TRUE
attempt unsafe reconnect to ASM
 
_ASM_APPLIANCE_CONFIG_FILE
Default: Appliance
Configuration file name
 
_ASM_APPLIANCE_IGNORE_OAK
Default: FALSE
Ignore OAK appliance library
 
_ASM_APPLIANCE_SLOT_FROM_PATH
Default: FALSE
Get appliance disk slot from disk path
 
_ASM_AUSIZE
Default: 1048576
Allocation unit size
 
_ASM_AUTOMATIC_REZONE
Default: TRUE
Automatically rebalance free space across zones
 
_ASM_AVOID_PST_SCANS
Default: TRUE
Avoid PST Scans
 
_ASM_BLKSIZE
Default: 4096
Metadata block size
 
_ASM_CHECK_FOR_MISBEHAVING_CF_CLIENTS
Default: FALSE
Check for misbehaving CF-holding clients
 
_ASM_COMPATIBILITY
Default: 10.1
Default ASM compatibility level
 
_ASM_DBA_BATCH
Default: 500000
ASM Disk Based Allocation Max Batch Size
 
_ASM_DBA_SPCCHK_THLD
Default: 100000
ASM Disk Based Allocation Space Check Threshold
 
_ASM_DBA_THRESHOLD
Default: 0
ASM Disk Based Allocation Threshold
 
_ASM_DBMSDG_NOHDRCHK
Default: FALSE
dbms_diskgroup.checkfile does not check block headers
 
_ASM_DIAG_DEAD_CLIENTS
Default: FALSE
Diagnostics for dead clients
 
_ASM_DIRECT_CON_EXPIRE_TIME
Default: 120
Expire time for idle direct connection to ASM instance
 
_ASM_DISABLE_AMDU_DUMP
Default: FALSE
Disable AMDU dump
 
_ASM_DISABLE_ASYNC_MSGS
Default: FALSE
Disable async intra-instance messaging
 
_ASM_DISABLE_DANGEROUS_FAILGROUP_CHECKING
Default: FALSE
Disable checking for dubious failgroup configurations
 
_ASM_DISABLE_MULTIPLE_INSTANCE_CHECK
Default: FALSE
Disable checking for multiple ASM instances on a given node
 
_ASM_DISABLE_PROFILEDISCOVERY
Default: FALSE
Disable profile query for discovery
 
_ASM_DISABLE_SMR_CREATION
Default: FALSE
Do not create smr: Now if only I knew what "smr" was
 
_ASM_DISABLE_UFGMEMBERKILL
Default: FALSE
Disable ufg member kill
 
_ASM_DISABLE_UFG_DUMP
Default: FALSE
Disable terminated umbilicus diagnostic
 
_ASM_DISKERR_TRACES
Default: 2
Number of read/write errors per disk a process can trace
 
_ASM_DISKGROUPS2
Default: None Defined
Disk groups to mount automatically set 2
TBD
_ASM_DISKGROUPS3
Default: None Defined
Disk groups to mount automatically set 3
TBD
_ASM_DISKGROUPS4
Default: None Defined
Disk groups to mount automatically set 4
TBD
_ASM_DISK_REPAIR_TIME
Default: 14400
Seconds to wait before dropping a failing disk
 
_ASM_EMULATE_NFS_DISK
Default: FALSE
Emulate NFS disk test event
 
_ASM_EMULMAX
Default: 10000
Max number of concurrent disks to emulate I /O errors
 
_ASM_EMULTIMEOUT
Default: 0
Timeout before emulation begins (in 3s ticks)
 
_ASM_ENABLE_XROV
Default: FALSE
Enable XROV capability
 
_ASM_EVENREAD
Default: 2
ASM Even Read level
 
_ASM_EVENREAD_ALPHA
Default: 0
ASM Even Read Alpha
 
_ASM_EVENREAD_ALPHA2
Default: 0
ASM Even Read Second Alpha
 
_ASM_EVENREAD_FASTSTART
Default: 0
ASM Even Read Fast Start Threshold
 
_ASM_FAIL_RANDOM_RX
Default: FALSE
Randomly fail some RX enqueue gets
 
_ASM_FD_CLN_IDLE_SESS_TWAIT
Default: 60000000
Idle session time wait to run ASM FD cleanup
 
_ASM_FD_CLN_ON_FG
Default: FALSE
ASM stale FD cleanup on foregrounds
 
_ASM_FOB_TAC_FREQUENCY
Default: 9
Timeout frequency for FOB cleanup
 
_ASM_FORCE_QUIESCE
Default: FALSE
Force diskgroup quiescing
 
_ASM_FORCE_VAM
Default: FALSE
Force VAM for external redundancy
 
_ASM_GLOBAL_DUMP_LEVEL
Default: 267
System state dump level for ASM asserts
 
_ASM_HBEATIOWAIT
Default: 120
Number of secs to wait for PST Async Hbeat IO return
 
_ASM_HBEATWAITQUANTUM
Default: 2
Quantum used to compute time-to-wait for a PST Hbeat check
 
_ASM_HEALTHCHECK_TIMEOUT
Default: 180
Seconds until health check takes action
 
_ASM_IMBALANCE_TOLERANCE
Default: 3
Hundredths of a percentage of inter-disk imbalance to tolerate
 
_ASM_INSTLOCK_QUOTA
Default: 0
ASM Instance Lock Quota
 
_ASM_IOSTAT_LATCH_COUNT
Default: 31
ASM I/O statistics latch count
 
_ASM_KFDPEVENT
Default: 0
KFDP event
 
_ASM_KILL_UNRESPONSIVE_CLIENTS
Default: TRUE
Kill unresponsive ASM clients
 
_ASM_LIBRARIES
Default: ufs
Library search order for discovery
 
_ASM_LOG_SCALE_REBALANCE
Default: FALSE
Rebalance power uses logarithmic scale
 
_ASM_LSOD_BUCKET_SIZE
Default: 67
ASM lsod bucket size
 
_ASM_MAXIO
Default: 1048576
Maximum size of individual I/O request
 
_ASM_MAX_COD_STRIDES
Default: 5
Maximum number of COD strides
 
_ASM_MAX_PARALLELIOS
Default: 256
Maximum simultaneous outstanding IOs
 
_ASM_MAX_REDO_BUFFER_SIZE
Default: 2097152
ASM maximum redo buffer size
 
_ASM_NETWORKS
Default: ASM
Network subnet addresses
 
_ASM_NETWORK_TIMEOUT
Default: 1
Keepalive timeout for ASM network connections
 
_ASM_NODEKILL_ESCALATE_TIME
Default: 180
Secs until escalating to nodekill if fence incomplete
 
_ASM_NOEVENREAD_DISKGROUPS
Default: None Defined
List of disk groups having even read disabled
 
_ASM_OFFLOAD_ALL
Default: FALSE
Offload all write operations to Exadata cells, when supported
 
_ASM_PARTNER_TARGET_DISK_PART
Default: 8
Target maximum number of disk partners for repartnering
 
_ASM_PARTNER_TARGET_FG_REL
Default: 4
Target maximum number of failure group relationships for repartnering
 
_ASM_PRIMARY_LOAD
Default: 1
Number of cycles/extents to load for non-mirrored files
 
_ASM_PRIMARY_LOAD_CYCLES
Default: TRUE
True if primary load is in cycles, false if extent counts
 
_ASM_PROCS_TRACE_DISKERR
Default: 5
Number of processes allowed to trace a disk failure
 
_ASM_PROXY_STARTWAIT
Default: 60
Maximum time to wait for ASM proxy connection
 
_ASM_RANDOM_ZONE
Default: FALSE
Random zones for new files
 
_ASM_READ_CANCEL
Default: AUTO
Read cancel timeout in milliseconds
 
_ASM_READ_CANCEL_BACK_OUT
Default: 5000
Time period in milliseconds when no reads are issued to a disk after a read is cancelled
 
_ASM_REBALANCE_PLAN_SIZE
Default: 120
Maximum rebalance work unit
 
_ASM_REBALANCE_SPACE_ERRORS
Default: 4
Number of out of space errors allowed before aborting rebalance
 
_ASM_RELOCATION_IGNORE_HARD_FAILURE
Default: 0
Ignore HARD for relocation
 
_ASM_RELOCATION_TRACE
Default: FALSE
Enable extent relocation tracing
 
_ASM_REMOTE_CLIENT_TIMEOUT
Default: 300
Timeout before killing disconnected remote clients
 
_ASM_REPAIRQUANTUM
Default: 60
Quantum (in 3s) used to compute elapsed time for disk drop
 
_ASM_RESERVE_SLAVES
Default: TRUE
Reserve ASM slaves for CF txns
 
_ASM_RESYNCCKPT
Default: 1024
Number of extents to resync before flushing checkpoint
 
_ASM_ROOT_DIRECTORY
Default: ASM
ASM default root directory
 
_ASM_RUNTIME_CAPABILITY_VOLUME_SUPPORT
Default: FALSE
Runtime capability for volume support returns supported
 
_ASM_SCRUB_LIMIT
Default: AUTO
ASM disk scrubbing power
 
_ASM_SCRUB_UNMATCHED_DBA
Default: 3
Scrub maximum number of blocks with unmatched DBA
 
_ASM_SECONDARY_LOAD
Default: 10000
Number of cycles/extents to load for mirrored files
 
_ASM_SECONDARY_LOAD_CYCLES
Default: FALSE
True if secondary load is in cycles, false if extent counts
 
_ASM_SERIALIZE_VOLUME_REBALANCE
Default: FALSE
Serialize volume rebalance
 
_ASM_SHADOW_CYCLE
Default: 3
Inverse shadow cycle requirement
 
_ASM_SKIP_DBFILE_IOS
Default: FALSE
Skip I/Os to database files (do only ASM metadata I/O)
 
_ASM_SKIP_DISKVAL_CHECK
Default: FALSE
Skip client side discovery for disk revalidate
 
_ASM_SKIP_RENAME_CHECK
Default: FALSE
Skip the checking of the clients for s/w compatibility for rename
 
_ASM_SKIP_RESIZE_CHECK
Default: FALSE
Skip the checking of the clients for s/w compatibility for resize
 
_ASM_STORAGEMAYSPLIT
Default: FALSE
PST Split Possible
 
_ASM_STRIPESIZE
Default: 131072
ASM file stripe size
 
_ASM_STRIPEWIDTH
Default: 8
ASM file stripe width
 
_ASM_SYNC_REBALANCE
Default: FALSE
Rebalance uses sync I/O
 
_ASM_TRACE_LIMIT_TIMEOUT
Default: 30000
Time-out in milliseconds to reset the number of traces per disk and the number of processes allowed to trace
 
_ASM_USD_BATCH
Default: 64
ASM USD Update Max Batch Size
 
_ASM_WAIT_TIME
Default: 18
Max/imum time to wait before asmb exits
 
_ASM_WRITE_CANCEL
Default: AUTO
Write timeout in milliseconds
 
_ASM_XROV_NSTATS
Default: 0
Specify number of IOs before stats
 
_ASM_XROV_NVIOS
Default: 4
Specify number of VIO processes
 
_ASM_XROV_RSNMOD
Default: 1
Specify reason mode
 
_ASM_XROV_SINGLE
Default: TRUE
Enable single issues of IOs
 
 
AWR Reporting
_AWR_CDBPERF_THRESHOLD

Default: 21
Setting for AWR CDBPERF Threshold
_awr_cdbperf_threshold=21
_AWR_CORRUPT_MODE

Default: FALSE
AWR Corrupt Mode
Range of values: {TRUE | FALSE}
_awr_corrupt_mode=TRUE
_AWR_DISABLED_FLUSH_TABLES Disable flushing of specified AWR tables
TBD
_AWR_DISABLED_PURGE_TABLES Disable purging of specified AWR tables
TBD
_AWR_FLUSH_THRESHOLD_METRICS

Default TRUE
Enable/Disable Flushing AWR Threshold Metrics
Range of values: {TRUE | FALSE}
_awr_flush_threshold_metrics=TRUE
_AWR_FLUSH_WORKLOAD_METRICS

Default: FALSE
Enable/Disable Flushing AWR Workload Metrics
Range of values: {TRUE | FALSE}
_awr_flush_workload_metrics=TRUE
_AWR_MMON_CPUUSAGE

Default: TRUE
Enable/disable AWR MMON CPU Usage Tracking
Range of values: {TRUE | FALSE}
_awr_mmn_cpuusage=TRUE
_AWR_MMON_DEEP_PURGE_ALL_EXPIRED

Default: FALSE
Allows deep purge to purge AWR data for all expired snapshots
Range of values: {TRUE | FALSE}
_awr_mmon_deep_purge_all_expired=TRUE
_AWR_MMON_DEEP_PURGE_EXTENT

Default: 7
Set extent of rows to check each deep purge run
_awrmmon_deep_purge_extent=7
_AWR_MMON_DEEP_PURGE_INTERVAL

Default: 7
Set interval for deep purge of AWR contents
_awr_mmon_deep_purge_interval=7
_AWR_MMON_DEEP_PURGE_NUMROWS

Default: 5000
Set max number of rows per table to delete each deep purge run
_awr_mmon_deep_purge_numrows=5000
_AWR_PARTITION_INTERVAL

Default: 0
Setting for AWR Partition Interval
_awr_partition_interval=0
_AWR_PDB_REGISTRATION_ENABLED

Default: FALSE
Parameter to enable/disable AWR PDB Registration
Range of values: {TRUE | FALSE}
_awr_pdb_registration_enabled=TRUE
_AWR_RESTRICT_MODE

Default: FALSE
AWR Restrict Mode
Range of values: {TRUE | FALSE}
_awr_restrict_mode=TRUE
_AWR_SNAPSHOT_LEVEL

Default: BESTFIT
Set Default AWR snapshot level
_awr_snapshot_level=BESTFIT
_AWR_SQL_CHILD_LIMIT

Default: 200
Setting for AWR SQL Child Limit
_awr_sql_child_limit=100
_FLUSH_PLAN_IN_AWR_SQL

Default: 0
Plan is being flushed from an AWR flush SQL
_flush_plan_in_awr_sql=0
_REMOTE_AWR_ENABLED

Default: FALSE
Enable/disable Remote AWR Mode
_remote_awr_enabled=TRUE
_AWR_CDBPERF_THRESHOLD
Default: 21
Setting for AWR CDBPERF Threshold
 
_AWR_CORRUPT_MODE
Default: FALSE
AWR Corrupt Mode
 
_AWR_DISABLED_FLUSH_TABLES
Default: None
Disable flushing of specified AWR tables
TBD
_AWR_DISABLED_PURGE_TABLES
Default: None Defined
Disable purging of specified AWR tables
 
_AWR_FLUSH_THRESHOLD_METRICS
Default: TRUE
Enable/Disable Flushing AWR Threshold Metrics
 
_AWR_FLUSH_WORKLOAD_METRICS
Default: FALSE
Enable/Disable Flushing AWR Workload Metrics
 
_AWR_MMON_CPUUSAGE
Default: TRUE
Enable/disable AWR MMON CPU Usage Tracking
 
_AWR_MMON_DEEP_PURGE_ALL_EXPIRED
Default: FALSE
Allows deep purge to purge AWR data for all expired snapshots
 
_AWR_MMON_DEEP_PURGE_EXTENT
Default: 7
Set extent of rows to check each deep purge run
 
_AWR_MMON_DEEP_PURGE_INTERVAL
Default: 7
Set interval for deep purge of AWR contents
 
_AWR_MMON_DEEP_PURGE_NUMROWS
Default: 5000
Set max number of rows per table to delete each deep purge run
 
_AWR_PARTITION_INTERVAL
Default: 0
Setting for AWR Partition Interval
 
_AWR_PDB_REGISTRATION_ENABLED
Default: FALSE
Parameter to enable/disable AWR PDB Registration
 
_AWR_REMOTE_TARGET_DBLINK
Default: AWR
Remote Target DBLink for Flushing
 
_AWR_RESTRICT_MODE
Default: FALSE
By default the value is FALSE which indicates that AWR snapshots will not be made when the database is in restricted mode.
See the DBMS_WORKLOAD_REPOSITORY.CONTROL_RESTRICTED_SNAPSHOT Demo using the link at page bottom
_AWR_SNAPSHOT_LEVEL
Default: 'BESTFIT'
Set Default AWR snapshot level
 
_AWR_SQL_CHILD_LIMIT
Default: 200
Setting for AWR SQL Child Limit
 
_FLUSH_PLAN_IN_AWR_SQL
Default: 0
Plan is being flushed from an AWR flush SQL
 
 
Backup and Restore
_BACKGROUND_PROCESS_OPTS
Default: 0
Misc BG procs parameter
 
_BACKUP_ALIGN_WRITE_IO
Default: TRUE
Align backup write I/Os
 
_BACKUP_APPLIANCE_ENABLED
Default: FALSE
Backup Appliance Enabled
 
_BACKUP_AUTOMATIC_RETRY
Default: 10
Automatic retry on backup write errors
 
_BACKUP_BOOL_SPARE1
Default: FALSE
Backup bool spare1
 
_BACKUP_BOOL_SPARE2
Default: FALSE
Backup bool spare2
 
_BACKUP_BOOL_SPARE3
Default: FALSE
Backup bool spare3
 
_BACKUP_BOOL_SPARE4
Default: FALSE
Backup bool spare4
 
_BACKUP_DISK_BUFCNT
Default: 0
Number of buffers used for DISK channels
 
_BACKUP_DISK_BUFSZ
Default: 0
Size of buffers used for DISK channels
 
_BACKUP_DISK_IO_SLAVES
Default: 0
Backup Disk I/O slaves
 
_BACKUP_DYNAMIC_BUFFERS
Default: TRUE
Dynamically compute backup/restore buffer sizes
 
_BACKUP_ENCRYPT_OPT_MODE
Default: 4294967294
Specifies encryption block optimization mode
 
_BACKUP_FILE_BUFCNT
Default: 0
Number of buffers used for file access
 
_BACKUP_FILE_BUFSZ
Default: 0
Size of buffers used for file access
 
_BACKUP_INT_SPARE1
Default: 4294967294
Backup int spare1
 
_BACKUP_INT_SPARE2
Default: 4294967294
Backup int spare2
 
_BACKUP_INT_SPARE3
Default: 4294967294
Backup int spare3
 
_BACKUP_INT_SPARE4
Default: 4294967294
Backup int spare4
 
_BACKUP_IO_POOL_SIZE
Default: 1048576
Memory to reserve from the large pool
 
_BACKUP_KGC_SCHEME
Default: ZLIB
Specifies compression scheme
 
_BACKUP_KSFQ_BUFCNT
Default: 0
Number of buffers used for backup/restore
 
_BACKUP_KSFQ_BUFMEM_MAX
Default: 268435456
Maximum amount of memory (in bytes) used for buffers for backup/restore
 
_BACKUP_KSFQ_BUFSZ
Default: 0
Size of buffers used for backup/restore
 
_BACKUP_MAX_GAP_SIZE
Default: 4294967294
Largest gap in an incremental/optimized backup buffer, in bytes
 
_BACKUP_MIN_CT_UNUSED_OPTIM
Default: 2097152
Mimimun size in bytes of change tracking to apply unused space optimuzation
 
_BACKUP_SEQ_BUFCNT
Default: 0
Number of buffers used for non-DISK channels
 
_BACKUP_SEQ_BUFSZ
Default: 0
Size of buffers used for non-DISK channels
 
_BACKUP_TEXT_SPARE1
Default: None Defined
Backup text spare1
TBD
_BACKUP_TEXT_SPARE2
Default: None Defined
Backup text spare2
TBD
_BACKUP_TEXT_SPARE3
Default: None Defined
Backup text spare3
TBD
_BACKUP_TEXT_SPARE4
Default: None Defined
Backup text spare4
TBD
 
Block Change Tracking
_BCT_BITMAPS_PER_FILE
Default: 8
Number of bitmaps to store for each datafile
_bct_bitmaps_per_file=12
_BCT_BUFFER_ALLOCATION_MAX
Default: 104857600
maximum size of all change tracking buffer allocations, in bytes
TBD
_BCT_BUFFER_ALLOCATION_MIN_EXTENTS
Default: 1
mininum number of extents to allocate per buffer alloca
_bct_buffer_allocation_min_extents=2
_BCT_BUFFER_ALLOCATION_SIZE
Default: 2097152
size of one change tracking buffer allocation, in bytes
TBD
_BCT_CHUNK_SIZE
Default: 0
change tracking datafile chunk size, in bytes
TBD
_BCT_CRASH_RESERVE_SIZE
Default: 262144
change tracking reserved crash recovery SGA space, in bytes
_bct_crash_reserve_size=393216
_BCT_FILE_BLOCK_SIZE
Default: 0
block size of change tracking file, in bytes
_bct_file_block_size=8192
_BCT_FILE_EXTENT_SIZE
Default: 0
extent size of change tracking file, in bytes
_bct_file_extent_size=65536
_BCT_FIXTAB_FILE
Default: NULL
change tracking file for fixed tables
_bct_fixtab_file='/u01/oradata/flash_recovery_area/bct/bctfile.bct';
_BCT_HEALTH_CHECK_INTERVAL
Default: 60
CTWR health check interval (seconds), zero to disable
_bct_health_check_interval=0
_BCT_INITIAL_PRIVATE_DBA_BUFFER_SIZE
Default: 0
initial number of entries in the private change tracking dba buffers
_bct_initial_private_dba_buffer_size=8192
_BCT_MRP_TIMEOUT
Default: 600
CTWR MRP wait timeout (seconds), zero to wait forever
_bct_mrp_timeout=900
_BCT_PUBLIC_DBA_BUFFER_DYNRESIZE
Default: 2
Allow dynamic resizing of public dba buffers, zero to disable
_bct_public_dba_buffer_dynresize=2
_BCT_PUBLIC_DBA_BUFFER_MAXSIZE
Default: 0
Max buffer size permitted for public dba buffers, in bytes
_bct_public_dba_buffer_maxsize=0
_BCT_PUBLIC_DBA_BUFFER_SIZE
Default: 0
total size of all public change tracking dba buffers, in bytes
_bct_public_dba_buffer_size=104857600
 
Buffer Cache and I/O
   
 
 
Compression
_ADVANCED_INDEX_COMPRESSION_OPTIONS
Default: 0
Advanced index compression options
 
_ADVANCED_INDEX_COMPRESSION_OPTIONS_VALUE
Default: 20
Advanced index compression options_value
 
_ADVANCED_INDEX_COMPRESSION_TRACE
Default: 0
Advanced index compression trace
 
 
Cursors and Library Cache
   
 
 
Data Guard
_ACTIVE_STANDBY_FAST_RECONFIGURATION
Default: TRUE
If TRUE optimize dlm reconfiguration for active/standby OPS
_active_standby_fast_reconfiguration=TRUE
_ADG_DISTRIBUTED_LOCKMASTER
Default: FALSE
Standby runs under ADG distributed lockmaster mode
_adg_distributed_lockmaster=FALSE
_ADG_INSTANCE_RECOVERY
Default: TRUE
Enable ADG instance recovery
_adg_instance_recovery=TRUE
_ADG_PARSELOCK_TIMEOUT
Default: 0
Timeout for parselock get on ADG in centiseconds
_adg_parse_lockout_timeout=0
_ADG_PARSELOCK_TIMEOUT_SLEEP
Default: 100
Sleep duration after a parselock timeout on ADG in milliseconds
_adg_parselock_timeout_sleep=100
_DG_BROKER_TRACE_LEVEL
Default: None Defined
Data Guard Broker trace level
TBD
_DG_CF_CHECK_TIMER
Default: 15
Data Guard controlfile check timer
_dg_cf_check_timer=15
_DG_CORRUPT_REDO_LOG
Default: 0
Corrupt redo log validation during archivals
_dg_corrupt_redo_log=0
 
Database / Instance / Identification
   
 
 
DB Block
  _DB_BLOCK_ADJCHECK TRUE adjacent cache buffer checks - low blkchk overwrite parameter
_DB_BLOCK_ADJCHK_LEVEL 0 adjacent cache buffer check level
_DB_BLOCK_ALIGN_DIRECT_READ TRUE Align Direct Reads
_DB_BLOCK_BAD_WRITE_CHECK FALSE enable bad write checks
_DB_BLOCK_BUFFERS 218337 Number of database blocks cached in memory: hidden parameter
_DB_BLOCK_CACHE_HISTORY_LRU FALSE buffer header tracing for lru operations
_DB_BLOCK_CACHE_PROTECT FALSE protect database blocks (true only when debugging)
_DB_BLOCK_CACHE_PROTECT_INTERNAL 0 protect database blocks (for strictly internal use only)
_DB_BLOCK_CHECK_FOR_DEBUG FALSE Check more and dump block before image for debugging
_DB_BLOCK_CHECK_OBJTYP TRUE check objd and typ on cache disk read
_DB_BLOCK_CHUNKIFY_NCMBR FALSE chunkify noncontig multi block reads
_DB_BLOCK_CORRUPTION_RECOVERY_THRESHOLD 5 threshold number of block recovery attempts
_DB_BLOCK_DO_FULL_MBREADS FALSE do full block read even if some blocks are in cache
_DB_BLOCK_HASH_BUCKETS 524288 Number of database block hash buckets
_DB_BLOCK_HASH_LATCHES 16384 Number of database block hash latches
_DB_BLOCK_HEADER_GUARD_LEVEL 0 number of extra buffer headers to use as guard pages
_DB_BLOCK_HI_PRIORITY_BATCH_SIZE 0 Fraction of writes for high priority reasons
_DB_BLOCK_KNOWN_CLEAN_PCT 2 Initial Percentage of buffers to maintain known clean
_DB_BLOCK_LRU_LATCHES 32 number of lru latches
_DB_BLOCK_MAX_CR_DBA 6 Maximum Allowed Number of CR buffers per dba
_DB_BLOCK_MAX_SCAN_PCT 40 Percentage of buffers to inspect when looking for free
_DB_BLOCK_MED_PRIORITY_BATCH_SIZE 0 Fraction of writes for medium priority reasons
_DB_BLOCK_PREFETCH_FAST_LONGJUMPS_ENABLED TRUE Batched IO enable fast longjumps
_DB_BLOCK_PREFETCH_LIMIT 0 Prefetch limit in blocks
_DB_BLOCK_PREFETCH_OVERRIDE 0 Prefetch force override in blocks
_DB_BLOCK_PREFETCH_PRIVATE_CACHE_ENABLED TRUE Batched IO enable private cache
_DB_BLOCK_PREFETCH_QUOTA 10 Prefetch quota as a percent of cache size
_DB_BLOCK_PREFETCH_SKIP_READING_ENABLED TRUE Batched IO enable skip reading buffers
_DB_BLOCK_PREFETCH_WASTED_THRESHOLD_PERC 2 Allowed wasted percent threshold of prefetched size
_DB_BLOCK_TABLE_SCAN_BUFFER_SIZE 4194304 Size of shared table scan read buffer
_DB_BLOCK_TEMP_REDO FALSE generate redo for temp blocks
_DB_BLOCK_TRACE_PROTECT FALSE trace buffer protect calls
_DB_BLOCK_VLM_CHECK FALSE check of rvlm mapping leaks (for debugging)
_DB_BLOCK_VLM_LEAK_THRESHOLD 4 Threshold for allowable vlm leaks
 
 
DB Cache
zzyzx _DB_CACHE_ADVICE_HASH_LATCH_MULTIPLE 16 cache advisory hash latch multiple
_DB_CACHE_ADVICE_MAX_SIZE_FACTOR 2 cache advisory maximum multiple of current size to similate
_DB_CACHE_ADVICE_SAMPLE_FACTOR 4 cache advisory sampling factor
_DB_CACHE_ADVICE_SANITY_CHECK FALSE cache simulation sanity check
_DB_CACHE_BLOCK_READ_STACK_TRACE 0 dump short call stack for block reads
_DB_CACHE_CRX_CHECK FALSE check for costly crx examination functions
_DB_CACHE_MISS_CHECK_LES FALSE check LEs after cache miss
_DB_CACHE_MMAN_LATCH_CHECK FALSE check for wait latch get under MMAN ops in kcb
_DB_CACHE_PRE_WARM TRUE Buffer Cache Pre-Warm Enabled : hidden parameter
_DB_CACHE_PROCESS_CR_PIN_MAX 2147483647 maximum number of cr pins a process may have
_DB_CACHE_WAIT_DEBUG 0 trace new kslwaits
 
 
Diagnostics and ADR
_DIAG_ADR_AUTO_PURGE
Default: TRUE
Enable/disable ADR MMON Auto Purging
 
_DIAG_ADR_ENABLED
Default: TRUE
Parameter to enable/disable Diag ADR
 
_DIAG_ADR_TEST_PARAM
Default: 0
Test parameter for Diagnosability
 
_DIAG_ADR_TRACE_DEST
Default: None Defined
Diagnosability trace directory path
 
_DIAG_ARB_BEFORE_KILL
Default: FALSE
Dump diagnostics before killing unresponsive ARBs
 
_DIAG_BACKWARD_COMPAT
Default: TRUE
Backward Compatibility for Diagnosability
 
_DIAG_CC_ENABLED
Default: TRUE
Parameter to enable/disable Diag Call Context
 
_DIAG_CONF_CAP_ENABLED
Default: TRUE
Parameter to enable/disable Diag Configuration Capture
 
_DIAG_CRASHDUMP_LEVEL
Default: 10
Parameter for systemstate dump level, used by DIAG during crash
 
_DIAG_DAEMON
Default: TRUE
Start DIAG daemon
 
_DIAG_DDE_ASYNC_AGE_LIMIT
Default: 300
Diag dde async actions: message age limit (in seconds)
 
_DIAG_DDE_ASYNC_CPUTIME_LIMIT
Default: 300
Diag dde async actions: action cputime limit (in seconds)
 
_DIAG_DDE_ASYNC_MODE
Default: 1
Diag dde async actions: dispatch mode
 
_DIAG_DDE_ASYNC_MSGS
Default: 50
Diag dde async actions: number of preallocated message buffers
 
_DIAG_DDE_ASYNC_MSG_CAPACITY
Default: 1024
Diag dde async actions: message buffer capacity
 
_DIAG_DDE_ASYNC_PROCESS_RATE
Default: 5
Diag dde async actions: message processing rate - per loop
 
_DIAG_DDE_ASYNC_RUNTIME_LIMIT
Default: 900
Diag dde async actions: action runtime limit (in seconds)
 
_DIAG_DDE_ASYNC_SLAVES
Default: 5
Diag dde async actions: max number of concurrent slave processes
 
_DIAG_DDE_ENABLED
Default: TRUE
Enable DDE handling of critical errors
 
_DIAG_DDE_FC_ENABLED
Default: TRUE
Parameter to enable/disable Diag Flood Control
 
_DIAG_DDE_FC_IMPLICIT_TIME
Default: 0
Override Implicit Error Flood Control time parameter
 
_DIAG_DDE_FC_MACRO_TIME
Default: 0
Override Macro Error Flood Control time parameter
 
_DIAG_DDE_INC_PROC_DELAY
Default: 1
The minimum delay between two MMON incident sweeps (minutes)
 
_DIAG_DIAGNOSTICS
Default: TRUE
Turn off diag diagnostics
 
_DIAG_DUMP_REQUEST_DEBUG_LEVEL
Default: 1
DIAG dump request debug level (0-2)
 
_DIAG_DUMP_TIMEOUT
Default: 30
Timeout parameter for SYNC dump
 
_DIAG_ENABLE_STARTUP_EVENTS
Default: FALSE
Enable events in instance startup notifiers
 
_DIAG_HM_RC_ENABLED
Default: TRUE
Parameter to enable/disable Diag HM Reactive Checks
 
_DIAG_HM_TC_ENABLED
Default: FALSE
Parameter to enable/disable Diag HM Test(dummy) Checks
 
_DIAG_PATCH_CAP_ENABLED
Default: TRUE
Parameter to enable/disable Diag Patch Configuration Capture
 
_DIAG_PROC_ENABLED
Default: TRUE
Enable hung process diagnostic API
 
_DIAG_PROC_MAX_TIME_MS
Default: 30000
Hung process diagnostic API max wait time in milliseconds
 
_DIAG_PROC_STACK_CAPTURE_TYPE
Default: 1
Hung process diagnostic API stack capture type
 
_DIAG_TEST_SEG_REINC_MODE
Default: FALSE
Sets trace segmentation to be in reincarnation mode
 
_DIAG_UTS_CONTROL
Default: 0
UTS control parameter
 
_DIAG_VERBOSE_ERROR_ON_INIT
Default: 0
Allow verbose error tracing on diag init
 
_DIAG_XM_ENABLED
Default: FALSE
If TRUE, DIAG allows message exchanges across DB/ASM boundary
 
 
Distributed Replication
   
 
 
Exadata Storage Server
_ALLOW_CELL_SMART_SCAN_ATTR
Default: TRUE
Allow checking smart_scan_capable Attr
_allow_cell_smart_scan_attr=TRUE
_AUTO_MANAGE_EXADATA_DISKS
Default: TRUE
Automate Exadata disk management
_auto_manage_exadata_disks=TRUE
_CELL_FAST_FILE_CREATE
Default: TRUE
Allow optimized file creation path for Cells
_cell_fast_file_create=TRUE
_CELL_FAST_FILE_RESTORE
Default: TRUE
Allow optimized rman restore for cells
_cell_fast_file_restore=TRUE
_CELL_FILE_FORMAT_CHUNK_SIZE
Default: 0
Cell file format chunk size in MB
_cell_file_format_chunk_size=8192
_CELL_INDEX_SCAN_ENABLED
Default: TRUE
Enable cell processing of index FFS
_cell_index_scan_enabled=TRUE
_CELL_MATERIALIZE_ALL_EXPRESSIONS
Default: FALSE
Force materialization of all offloadable expressions on the cells
_cell_materialize_all_expressions=TRUE
_CELL_MATERIALIZE_VIRTUAL_COLUMNS
Default: TRUE
Enable offload of expressions underlying virtual columns to cells
_cell_materialize_virtual_columns=TRUE
_CELL_OBJECT_EXPIRATION_HOURS
Default: 24
Flashcache object expiration timeout
_cell_object_expiration_hours=12
_CELL_OFFLOAD_BACKUP_COMPRESSION
Default: TRUE
Enable offload of backup compression to cells
_cell_offload_backup_compression=FALSE
_CELL_OFFLOAD_CAPABILITIES_ENABLED
Default: 1
Specifies capability table to load
_cell_offload_capabilities_enabled=1
_CELL_OFFLOAD_COMPLEX_PROCESSING
Default: TRUE
Enable complex SQL processing offload to cells
_cell_offload_complex_processing=FALSE
_CELL_OFFLOAD_EXPRESSIONS
Default: TRUE
Enable offload of expressions to cells
_cell_offload_expressions=FALSE
_CELL_OFFLOAD_HYBRIDCOLUMNAR
Default: TRUE
Query offloading of hybrid columnar compressed tables to exadata
_cell_offload_hybridcolumnar=FALSE
_CELL_OFFLOAD_PREDICATE_REORDERING_ENABLED
Default: FALSE
Enable out-of-order SQL processing offload to cells
_cell_offload_predicate_reordering_enabled=TRUE
_CELL_OFFLOAD_SYS_CONTEXT
Default: TRUE
Enable offload of SYS_CONTEXT evaluation to cells
_cell_offload_sys_context=FALSE
_CELL_OFFLOAD_TIMEZONE
Default: TRUE
Enable timezone related SQL processing offload to cells
_cell_offload_timezone=FALSE
_CELL_OFFLOAD_VIRTUAL_COLUMNS
Default: TRUE
Enable offload of predicates on virtual columns to cells
_cell_offload_virtual_columns=FALSE
_CELL_RANGE_SCAN_ENABLED
Default: TRUE
Enable CELL processing of index range scans
_cell_range_scan_enabled=TRUE
_CELL_STORIDX_MINMAX_ENABLED
Default: TRUE
Cell storage index mode
_cell_storidx_minmax_enabled=FALSE
_CELL_STORIDX_MODE
Default: EVA
Cell storage index mode
_cell_storidx_mode='EVA'
_CONTROLFILE_CELL_FLASH_CACHING
Default: 3
Flash cache hint for control file accesses
_controlfile_cell_flash_caching=3
_DB_CHECK_CELL_HINTS
Default: FALSE
Undocumented
_db_check_cell_hints=TRUE
_DISABLE_CELL_OPTIMIZED_BACKUPS
Default: FALSE
Disable cell optimized backups
_disable_cell_optimized_backups=FALSE
_KCFIS_CELL_PASSTHRU_DATAONLY
Default: TRUE
Allow dataonly passthru for smart scan
_kcfis_cell_passthru_dataonly=TRUE
_KCFIS_CELL_PASSTHRU_ENABLED
Default: FALSE
Do not perform smart IO filtering on the cell
_kcfis_cell_passthru_enabled=FALSE
_KCFIS_CELL_PASSTHRU_FROMCPU_ENABLED
Default: TRUE
Enable automatic passthru mode when cell CPU util is too high
_kcfis_cell_passthru_fromcpu_enabled=TRUE
_KCFIS_CELLOFLSRV_PASSTHRU_ENABLED
Default: FALSE
Enable offload server usage for passthru operations
_kcfis_celloflsrv_passthru_enabled=FALSE
_KCFIS_CELLOFLSRV_USAGE_ENABLED
Default: TRUE
Enable offload server usage for offload operations
_kcfis_celloflsrv_usage_enabled=TRUE
_KCFIS_KEPT_IN_CELLFC_ENABLED
Default: TRUE
Enable usage of cellsrv flash cache for kept objects
_kcfis_kept_in_cellfc_enabled=TRUE
_KCFIS_NONKEPT_IN_CELLFC_ENABLED
Default: FALSE
Enable use of cellsrv flash cache for non-kept objects
_kcfis_nonkept_in_cellfc_enabled=TRUE
 
File Locations, Names, and Sizes
   
 
 
Flashback
_DB_FLASHBACK_IOBUF_SIZE
Default: 1
Flashback IO Buffer Size
 
_DB_FLASHBACK_LOG_MIN_SIZE
Default: 16777216
Minimum flashback database log size in bytes
 
_DB_FLASHBACK_LOG_MIN_TOTAL_SPACE
Default: 0
Minimum flashback database log total space in bytes
 
_DB_FLASHBACK_NUM_IOBUF 64 Flashback Number of IO buffers
 
_DROP_FLASHBACK_LOGICAL_OPERATIONS_ENQ
Default: FALSE
Drop logical operations enqueue immediately during flashback marker generation
 
  _FBDA_BUSY_PERCENTAGE 0 flashback archiver busy percentage
 
  _FBDA_DEBUG_ASSERT 0 flashback archiver debug assert for testing
 
  _FBDA_DEBUG_MODE 0 flashback archiver debug event for testing
 
  _FBDA_GLOBAL_BSCN_LAG 0 flashback archiver global barrier scn lag
 
  _FBDA_INLINE_PERCENTAGE 0 flashback archiver inline percentage
 
  _FBDA_RAC_INACTIVE_LIMIT 0 flashback archiver rac inactive limit
 
_FLASHBACK_ALLOW_NOARCHIVELOG
Default: FALSE
Allow enabling flashback on noarchivelog database
 
_FLASHBACK_ARCHIVER_PARTITION_SIZE
Default: 0
Flashback archiver table partition size
 
_FLASHBACK_BARRIER_INTERVAL
Default: 1800
Flashback barrier interval in seconds
 
_FLASHBACK_COPY_LATCHES
Default: 10
Number of flashback copy latches
 
_FLASHBACK_DATABASE_TEST_ONLY
Default: FALSE
Run Flashback Database in test mode
 
_FLASHBACK_DELETE_CHUNK_MB
Default: 128
Amount of flashback log (in MB) to delete in one attempt
 
_FLASHBACK_DYNAMIC_ENABLE
Default: TRUE
Enable flashback enable code path
 
_FLASHBACK_DYNAMIC_ENABLE_FAILURE
Default: 0
Simulate failures during dynamic enable
 
_FLASHBACK_ENABLE_RA
Default: TRUE
Flashback enable read ahead
 
_FLASHBACK_FORMAT_CHUNK_MB
Default: 4
Chunk mega-bytes for formatting flashback logs using sync write
 
_FLASHBACK_FORMAT_CHUNK_MB_DWRITE
Default: 16
Chunk mega-bytes for formatting flashback logs using delayed write
 
_FLASHBACK_FUZZY_BARRIER
Default: TRUE
Use flashback fuzzy barrier
 
_FLASHBACK_GENERATION_BUFFER_SIZE
Default: 16777216
Flashback generation buffer size
 
_FLASHBACK_HINT_BARRIER_PERCENT
Default: 20
Flashback hint barrier percent
 
_FLASHBACK_LOGFILE_ENQUEUE_TIMEOUT
Default: 600
Flashback logfile enqueue timeout for opens
 
_FLASHBACK_LOG_IO_ERROR_BEHAVIOR
Default: 0
Specify Flashback log I/O error behavior
 
_FLASHBACK_LOG_MIN_SIZE
Default: 100
Minimum flashback log size
 
_FLASHBACK_LOG_RAC_BALANCE_FACTOR
Default: 10
Flashback log rac balance factor
 
_FLASHBACK_LOG_SIZE
Default: 1000
Flashback log size
 
_FLASHBACK_MARKER_CACHE_ENABLED
Default: TRUE
Enable flashback database marker cache
 
_FLASHBACK_MARKER_CACHE_SIZE
Default: 328
Size of flashback database marker cache
 
_FLASHBACK_MAX_LOG_SIZE
Default: 0
Maximum flashback log size in bytes (OS limit)
 
_FLASHBACK_MAX_N_LOG_PER_THREAD
Default: 2048
Maximum number of flashback logs per flashback thread
 
_FLASHBACK_MAX_STANDBY_SYNC_SPAN
Default:300
Maximum time span between standby recovery sync for flashback
 
_FLASHBACK_N_LOG_PER_THREAD
Default: 128
Desired number of flashback logs per flashback thread
 
_FLASHBACK_PREPARE_LOG
Default: TRUE
Prepare Flashback logs in the background
 
_FLASHBACK_SIZE_BASED_ON_REDO
Default: TRUE
Size new flashback logs based on average redo log size
 
_FLASHBACK_STANDBY_BARRIER_INTERVAL
Default: 1
Flashback standby barrier interval in seconds
 
_FLASHBACK_VALIDATE_CONTROLFILE
Default: FALSE
Validate flashback pointers in controlfile for 11.2.0.2 database. Looks to be irrelevant going forward
 
_FLASHBACK_VERBOSE_INFO
Default: FALSE
Print verbose information about flashback database
 
_FLASHBACK_WRITE_MAX_LOOP
Default: 10
Flashback writer loop limit before it returns
 
 
Group By
_GBY_HASH_AGGREGATION_ENABLED
Default: TRUE
Enable group-by and aggregation using hash scheme
_gby_hash_aggregation_enabled=TRUE
_gby_onekey_enabled
Default: TRUE
Enable use of one comparison of all group by keys
_gby_onekey_enabled=TRUE
_gby_vector_aggregation_enabled
Default: TRUE
Enable group-by and aggregation using vector scheme
_gby_vector_aggregation_enabled=TRUE
_GROUPBY_NOPUSHDOWN_CUT_RATIO

Default: 3
Group by nopushdown cut ratio
_groupby_nopushdown_cut_ratio=3
_GROUPBY_ORDERBY_COMBINE

Default: 5000
Group By/Order By don't combine threshold
_groupby_orderby_combine=5000
_OPTIMIZER_AGGR_GROUPBY_ELIM

Default: TRUE
Group-By and aggregation elimination
Range of values: {TRUE | FALSE}
_optimizer_aggr_groupby_elim=TRUE
_OPTIMIZER_GROUP_BY_PLACEMENT

Default: TRUE
Consider group-by placement optimization
Range of values: {TRUE | FALSE}
_optimizer_group_by_placement=TRUE
_OPTIMIZER_REDUCE_GROUPBY_KEY

Default: TRUE
Group-By key reduction
Range of values: {TRUE | FALSE}
_optimizer_reduce_groupby_key=TRUE
_PX_GROUPBY_PUSHDOWN_FORCE

Default: ON
Perform group-by pushdown for parallel query
Range of values: {ON | OFF}
_px_groupby_pushdown_force=ON
 
Hang Manager
xx _HANG_ANALYSIS_NUM_CALL_STACKS 3 hang analysis num call stacks
_HANG_BASE_FILE_COUNT 5 Number of trace files for the normal base trace file
_HANG_BASE_FILE_SPACE_LIMIT 20000000 File space limit for current normal base trace file
_HANG_BOOL_SPARE1 TRUE Hang Management 1
_HANG_CROSS_BOUNDARY_HANG_DETECTION_ENABLED TRUE Hang Management Cross Boundary detection
_HANG_DELAY_RESOLUTION_FOR_LIBCACHE TRUE Hang Management delays hang resolution for library cache
_HANG_DETECTION_ENABLED TRUE Hang Management detection
_HANG_HANG_ANALYZE_OUTPUT_HANG_CHAINS TRUE if TRUE hang manager outputs hang analysis hang chains
_HANG_HILOAD_PROMOTED_IGNORED_HANG_COUNT 2 Hang Management high load or promoted ignored hang count
_HANG_HIPRIOR_SESSION_ATTRIBUTE_LIST Hang Management high priority session attribute list
_HANG_IGNORED_HANGS_INTERVAL 300 Time in seconds ignored hangs must persist after verification
_HANG_IGNORED_HANG_COUNT 1 Hang Management ignored hang count
_HANG_INT_SPARE2 FALSE Hang Management 2
_HANG_LOG_VERIFIED_HANGS_TO_ALERT FALSE Hang Management log verified hangs to alert log
_HANG_LONG_WAIT_TIME_THRESHOLD 0 Long session wait time threshold in seconds
_HANG_LWS_FILE_COUNT 5 Number of trace files for long waiting sessions
_HANG_LWS_FILE_SPACE_LIMIT 20000000 File space limit for current long waiting session trace file
 
xx _HANG_MONITOR_ARCHIVING_RELATED_HANG_INTERVAL 300 Time in seconds ignored hangs must persist after verification
_HANG_MSG_CHECKSUM_ENABLED TRUE enable hang graph message checksum
_HANG_RESOLUTION_ALLOW_ARCHIVING_ISSUE_TERMINATION TRUE Hang Management hang resolution allow archiving issue termination
_HANG_RESOLUTION_CONFIDENCE_PROMOTION FALSE Hang Management hang resolution confidence promotion
_HANG_RESOLUTION_GLOBAL_HANG_CONFIDENCE_PROMOTION FALSE Hang Management hang resolution global hang confidence promotion
_HANG_RESOLUTION_PERCENT_HUNG_SESSIONS_THRESHOLD 300 Hang Manager hang resolution percent hung sessions threshold
_HANG_RESOLUTION_POLICY HIGH Hang Management hang resolution policy
_HANG_RESOLUTION_PROMOTE_PROCESS_TERMINATION FALSE Hang Management hang resolution promote process termination
_HANG_RESOLUTION_SCOPE PROCESS Hang Management hang resolution scope
_HANG_SHORT_STACKS_OUTPUT_ENABLED FALSE if TRUE hang manager outputs short stacks
_HANG_SIGNATURE_LIST_MATCH_OUTPUT_FREQUENCY 10 Hang Signature List matched output frequency
_HANG_STATISTICS_COLLECTION_INTERVAL 15 Hang Management statistics collection interval in seconds
_HANG_STATISTICS_COLLECTION_MA_ALPHA 30 Hang Management statistics collection moving average alpha
_HANG_STATISTICS_HIGH_IO_PERCENTAGE_THRESHOLD 25 Hang Management statistics high IO percentage threshold
_HANG_TERMINATE_SESSION_REPLAY_ENABLED FALSE Hang Management terminates sessions allowing replay
_HANG_VERIFICATION_INTERVAL 46 Hang Management verification interval in seconds
 
 
In-Memory
  _INMEMORY_64K_PERCENT 30 percentage of in-memory area for 64k pools
 
  _INMEMORY_ANALYZER_OPTIMIZE_FOR 0 inmemory analyzer optimize for
 
  _INMEMORY_AUTODIST_2SAFE FALSE If true, enable auto distribute with 2safe
 
  _INMEMORY_AUTO_DISTRIBUTE TRUE If true, enable auto distribute
 
  _INMEMORY_BUFFER_WAITTIME 100 wait interval for one SMU or IMCU to be freed
 
  _INMEMORY_CHECKSUM FALSE If true, checksums in-memory area to detect stray writes
 
   
 
  _INMEMORY_CHECK_PROT_META FALSE If true, marks SMU area read only to prevent stray writes
 
  _INMEMORY_CUDROP_TIMEOUT 1000 maximum wait time for IMCU to be freed during drop
 
  _INMEMORY_CU_TIMEOUT 100 maximum wait time for one IMCU to be freed
 
  _INMEMORY_DBG_SCAN 0 In-memory scan debugging
 
  _INMEMORY_DEFAULT_FLAGS 8459 Default flags based on inmemory_clause_default
 
  _INMEMORY_DEFAULT_NEW FALSE Force in-memory on new tables
_INMEMORY_DISTRIBUTE_ONDEMAND_TIMEOUT 300 On demand timeout for redistribute
_INMEMORY_DISTRIBUTE_TIMEOUT 300 If true, enable auto distribute with 2safe
_INMEMORY_ENABLE_POPULATION_VERIFY 1 verify in-memory population
_INMEMORY_ENABLE_STAT_ALERT FALSE dump in-memory stats in alert log file
 
   
 
  _INMEMORY_ENABLE_SYS FALSE enable in-memory on system tablespace with sys user
_INMEMORY_EXCLTO_TIMEOUT 1000 maximum wait time to pin SMU for cleanout
_INMEMORY_FORCE_FS FALSE in-memory faststart force
_INMEMORY_FORCE_FS_TBS SYSAUX in-memory faststart force tablespace
_INMEMORY_FORCE_FS_TBS_SIZE 1073741824 in-memory faststart force tablespace size
 
   
 
  _INMEMORY_FORCE_NON_ENGINEERED FALSE force non-engineered systems in-memory behavior on RAC
_INMEMORY_FS_BLK_INV_BLKCNT in-memory faststart CU invalidation threshold(blocks)
_INMEMORY_FS_BLK_INV_BLK_PERCENT 20 in-memory faststart CU invalidation threshold(blocks)
_INMEMORY_FS_ENABLE FALSE in-memory faststart enable
_INMEMORY_FS_ENABLE_BLK_LVL_INV TRUE in-memory faststart enable block level invalidation
 
   
 
  _INMEMORY_FS_NODML FALSE in-memory faststart assumes no dmls while populating
_INMEMORY_FS_RAISE_ERROR FALSE in-memory faststart raise error
_INMEMORY_FS_VERIFY FALSE in-memory faststart verify
_INMEMORY_IMCO_CYCLE 120 IMCO cycle in seconds (sleep period)
_INMEMORY_IMCU_ALIGN TRUE Enforce 8M IMCU alignment
 
   
 
  _INMEMORY_IMCU_POPULATE_MINBYTES 5242880 minimum free space in IMA for populating IMCU
_INMEMORY_IMCU_SOURCE_ANALYZE_BYTES 134217728 number of source analyze bytes per IMCU
_INMEMORY_IMCU_SOURCE_BLOCKS 0 number of source blocks per IMCU
_INMEMORY_IMCU_SOURCE_EXTENTS 0 number of source extents per IMCU
_INMEMORY_IMCU_SOURCE_MAXBYTES 536870912 IMCU maximum source size in bytes
 
   
 
  _INMEMORY_IMCU_SOURCE_MINBYTES 1048576 number of minimum source bytes per IMCU
_INMEMORY_IMCU_TARGET_BYTES 0 IMCU target size in bytes
_INMEMORY_IMCU_TARGET_MAXROWS 8388608 IMCU maximum target number of rows
_INMEMORY_IMCU_TARGET_ROWS 1048576 IMCU target number of rows
_INMEMORY_INCREMENTAL_REPOPULATION FALSE If true, incremental repopulation of IMCU will be attempted
 
   
 
  _INMEMORY_INVALIDATE_CURSORS TRUE In-memory populate enable cursor invalidations
_INMEMORY_JOURNAL_CHECK 0 Depending on value does one of the DML verifications
_INMEMORY_JOURNAL_ROW_LOGGING FALSE If true, log the entire row into the in-memory journal
_INMEMORY_JSCAN 0 inmemory jscan enable
_INMEMORY_LOCK_FOR_SMUCREATE FALSE take object lock during smu creation
 
   
 
  _INMEMORY_LOG_LEVEL 1 in-memory log level
_INMEMORY_MAX_POPULATE_RETRY 3 IM populate maximum number of retry
_INMEMORY_MAX_QUEUED_TASKS 0 Maximum queued populating tasks on the auxiliary queue
_INMEMORY_MEMPROT TRUE enable or disable memory protection for in-memory
_INMEMORY_MIN_IMA_DEFERSIZE 0 Defer in-memory area allocation beyond this size
 
   
 
  _INMEMORY_NUM_HASH_LATCHES 256 Maximum number of latches for IM buffers
_INMEMORY_PCT_INV_BLOCKS_INVALIDATE_IMCU 100 In-memory percentage invalid blocks for IMCU invalidation
_INMEMORY_PCT_INV_ROWS_INVALIDATE_IMCU 50 In-memory percentage invalid rows for IMCU invalidation
_INMEMORY_PGA_PER_SERVER 536870912 minimum pga needed per inmemory populate server
_INMEMORY_PIN_HIST_MODE 16 settings for IM pinned buffer history
 
   
 
  _INMEMORY_POPULATE_FG FALSE populate in foreground
_INMEMORY_POPULATE_WAIT FALSE wait for population to complete
_INMEMORY_POPULATE_WAIT_MAX 600 maximum wait time in seconds for segment populate
_INMEMORY_PREPOPULATE TRUE Enable inmemory populate by IMCO
_INMEMORY_PREPOPULATE_FG 0 Force prepopulate of in-memory segment in foreground
 
   
 
  _INMEMORY_PRIVATE_JOURNAL_NUMBKTS 512 Number of priv jrnl ht bkts
_INMEMORY_PRIVATE_JOURNAL_NUMGRAN 128 Number of granules per HT node
_INMEMORY_PRIVATE_JOURNAL_QUOTA 100 quota for transaction in-memory private journals
_INMEMORY_PRIVATE_JOURNAL_SHAREDPOOL_QUOTA 20 quota for transaction in-memory objects
_INMEMORY_PRUNING ON In-memory pruning
 
   
 
  _INMEMORY_QUERY_CHECK 0 In-memory query checking
_INMEMORY_QUERY_FETCH_BY_ROWID FALSE In-memory fetch-by-rowid enabled
_INMEMORY_QUERY_SCAN TRUE In-memory scan enabled
_INMEMORY_REPOPULATE_DISABLE FALSE disable In-memory repopulate
_INMEMORY_REPOPULATE_INVALIDATE_RATE_PERCENT 100 In-memory repopulate invalidate rate percent
 
   
 
  _INMEMORY_REPOPULATE_PRIORITY_SCALE_FACTOR 100 In-memory repopulate priority threshold scale factor
_INMEMORY_REPOPULATE_PRIORITY_THRESHOLD_BLOCK 40 In-memory repopulate priority threshold block
_INMEMORY_REPOPULATE_PRIORITY_THRESHOLD_ROW 20 In-memory repopulate priority threshold row
_INMEMORY_REPOPULATE_THRESHOLD_BLOCKS In-memory repopulate threshold number of modified blocks
_INMEMORY_REPOPULATE_THRESHOLD_BLOCKS_PERCENT 10 In-memory repopulate threshold blocks invalid percentage
 
   
 
  _INMEMORY_REPOPULATE_THRESHOLD_MINTIME 0 In-memory repopulate minimum interval (millisec)
_INMEMORY_REPOPULATE_THRESHOLD_MINTIME_FACTOR 5 In-memory repopulate minimum interval (N*timetorepop)
_INMEMORY_REPOPULATE_THRESHOLD_ROWS In-memory repopulate threshold number of modified rows
_INMEMORY_REPOPULATE_THRESHOLD_ROWS_PERCENT 5 In-memory repopulate threshold rows invalid percentage
_INMEMORY_REPOPULATE_THRESHOLD_SCANS 0 In-memory repopulate threshold number of scans
 
   
 
  _INMEMORY_ROWS_CHECK_INTERRUPT 1000 Number of rows buffered before interrupt check
_INMEMORY_SCAN_OVERRIDE FALSE In-memory scan override
_INMEMORY_SCAN_THRESHOLD_PERCENT_NOSCAN 50 In-memory scan threshold maximum percent dirty no scan
_INMEMORY_SERVERS_THROTTLE_PGALIM_PERCENT 55 In-memory populate servers throttling pga limit percentage
 
   
 
  _INMEMORY_SMALL_SEGMENT_THRESHOLD 65536 In-memory small segment threshold (must be larger for in-memory)
_INMEMORY_STRDLXID_TIMEOUT 0 max time to determine straddling transactions
_INMEMORY_SUPPRESS_VSGA_IMA FALSE Suppress inmemory area in v$sga
_INMEMORY_TEST_VERIFICATION 0 In-memory verification testing
_INMEMORY_TRICKLE_REPOPULATE TRUE Enable inmemory trickle repopulate
 
   
 
  _INMEMORY_TRICKLE_REPOPULATE_FG 0 Trickle Repopulate in the Foreground
 
  _INMEMORY_TRICKLE_REPOPULATE_MIN_INTERVAL 300 IMCO Trickle Repopulate Interval
 
  _INMEMORY_TRICKLE_REPOPULATE_THRESHOLD_DIRTY_RATIO 0 IMCO Trickle Repopulate threshold dirty ratio
 
  _INMEMORY_TXN_CHECKSUM 0 checksum for SMUs and private journals
 
  _INMEMORY_VALIDATE_FETCH FALSE If true, validate single-row fetch between in-memory and disk
 
  _IN_MEMORY_TBS_SEARCH TRUE FALSE - disable fast path for alter tablespace read only
 
  _IN_MEMORY_UNDO TRUE Make in memory undo for top level transactions
 
_IN_MEMORY_UNDO
Default: TRUE
Enables in memory undo for top level transactions
_in_memory_undo=FALSE
_OPTIMIZER_INMEMORY_ACCESS_PATH
Default: TRUE
Optimizer access path costing for in-memory
_optimizer_inmemory_access_pathy=TRUE
_OPTIMIZER_INMEMORY_AUTODOP
Default: TRUE
Optimizer autoDOP costing for in-memory
_optimizer_inmemory_autodop=TRUE
_OPTIMIZER_INMEMORY_BLOOM_FILTER
Default: TRUE
Controls serial bloom filter for in-memory tables
_optimizer_inmemory_bloom_filter=TRUE
_OPTIMIZER_INMEMORY_GEN_PUSHABLE_PREDS
Default: TRUE
Optimizer generate pushable predicates for in-memory
_optimizer_inmemory_gen_pushable_preds=TRUE
_OPTIMIZER_INMEMORY_MINMAX_PRUNING
Default: TRUE
Controls use of min/max pruning for costing in-memory tables
_optimizer_inmemory_minmax_pruning=TRUE
_OPTIMIZER_INMEMORY_PRUNING_RATIO_ROWS
Default: 100
In-memory pruning ratio for # rows (% of rows remaining after pruning)
_optimizer_inmemory_pruning_ratio_rows=TRUE
_OPTIMIZER_INMEMORY_QUOTIENT
Default: 0
In-memory quotient (% of rows in in-memory format)
_optimizer_inmemory_quotient=TRUE
_OPTIMIZER_INMEMORY_TABLE_EXPANSION
Default: TRUE
Optimizer in-memory awareness for table expansion
_optimizer_inmemory_table_expansion=TRUE
 
I/O
_AIOWAIT_TIMEOUTS
Default: 100
Number of aiowait timeouts before error is reported
_aiowait_timeouts=100
  _IOSLAVE_BATCH_COUNT 1 Per attempt IOs picked
 
  _IOSLAVE_ISSUE_COUNT 500 IOs issued before completion check
 
  _IO_INTERNAL_TEST 0 I/O internal testing parameter
 
  _IO_OSD_PARAM 1 OSD specific parameter
 
  _IO_OUTLIER_THRESHOLD 500 Latency threshold for io_outlier table
 
  _IO_RESOURCE_MANAGER_ALWAYS_ON FALSE io resource manager always on
 
  _IO_SHARED_POOL_SIZE 4194304 Size of I/O buffer pool from SGA
 
  _IO_SLAVES_DISABLED FALSE Do not use I/O slaves
 
  _IO_STATISTICS TRUE if TRUE, ksfd I/O statistics are collected
 
 
Memory Management
_ASSM_DEFAULT
Default: TRUE
ASSM default
_assm_default=TRUE
_ASSM_FORCE_FETCHMETA
Default: FALSE
Enable metadata block fetching in ASSM segment scan
_assm_force_fetchmeta=TRUE
_ASSM_HIGH_GSP_THRESHOLD
Default: 11024
Number of blocks rejected before growing segment
_assm_high_gsp_threshold=11024
_ASSM_LOW_GSP_THRESHOLD
Default: 10000
Number of blocks rejected before collecting stats
_assm_low_gsp_threshold=10000
_ASSM_TEST_FORCE_REJ
Default: 0
ASSM min number of blocks to cbk-reject
_assm_test_force_rej=0
_ASSM_TEST_FORCE_REJ2
Default: 0
ASSM min number of blocks to kdt-reject
_assm_test_force_rej2=0
_ASSM_TEST_REENTRANT_GSP
Default: FALSE
ASSM test reentrant gsp
_assm_test_reentrant_gsp=FALSE
__DB_CACHE_SIZE
Default: None Defined
Actual size of DEFAULT buffer pool for standard block size buffers
Not settable
__JAVA_CACHE_SIZE
Default: None Defined
Actual size in bytes of java pool
Not settable
__LARGE_POOL_SIZE
Default: None Defined
Actual size in bytes of large pool
Not settable
__ORACLE_BASE
Default: None Defined
ORACLE_BASE
Not settable
__PGA_AGGREGATE_TARGET
Default: None Defined
Current target size for the aggregate PGA memory consumed
Not settable
__SGA_TARGET
Default: None Defined
 Actual size of SGA
Not settable
__SHARED_IO_POOL_SIZE
Default: None Defined
Actual size of shared IO pool
Not settable
__SHARED_POOL_SIZE
Default: None Defined
 Actual size in bytes of shared pool
Not settable
 
Miscellaneous
_JOB_QUEUE_INTERVAL
Default: 5
Wakeup interval in seconds for job queue coordinator
_job_queue_interval=60
_ORACLE_SCRIPT
Default: FALSE
Running an Oracle-supplied script
_oracle_script=TRUE
_SYSTEM_TRIG_ENABLED
Default: TRUE
If set to FALSE system triggers will not fire
alter session set "_system_trig_enabled"=FALSE;
   
 
 
Network & Connections Parameters
   
 
 
NLS Parameters
_ADD_TRIM_FOR_NLSSORT
Default:: TRUE
Add trimming for fixed char semantics
 
 
NUMA
  _DB_BLOCK_NUMA 1 Number of NUMA nodes
 
  _ENABLE_NUMA_INTERLEAVE TRUE Enable NUMA interleave mode
 
  _ENABLE_NUMA_OPTIMIZATION FALSE Enable NUMA specific optimizations
 
  _ENABLE_NUMA_SUPPORT FALSE Enable NUMA support and optimizations
 
 
Optimizer
_ALWAYS_ANTI_JOIN
Default: CHOOSE
Always use this method for anti-join when possible
_always_anti_join='CHOOSE'
_ALWAYS_SEMI_JOIN
Default: CHOOSE
Always use this method for semi-join when possible
_always_semi_join='CHOOSE'
_ALWAYS_STAR_TRANSFORMATION
Default: FALSE
Always favor use of star transformation
_always_star_transforamtion=FALSE
_ALWAYS_VECTOR_TRANSFORMATION
Default: FALSE
Always favor use of vector transformation
_always_vector_transforamtion=FALSE
_OPTIMIZER_ADJUST_FOR_NULLS
Default: TRUE
Adjust selectivity for null values
_optimizer_adjust_for_nulls=TRUE
_OPTIMIZER_ADS_MAX_TABLE_COUNT
Default: 0
Maximum number of tables in a join under ADS
_optimizer_ads_max_table_count=0
_OPTIMIZER_ADS_TIME_LIMIT
Default: 0
Maximum time limit (seconds) under ADS
_optimizer_ads_time_limit=0
_OPTIMIZER_ADS_USE_PARTIAL_RESULTS
Default: FALSE
Use partial results of ADS queries
_optimizer_ads_use_partial_results=TRUE
_OPTIMIZER_AGGR_GROUPBY_ELIM
Default: TRUE
Group-by and aggregation elimination
_optimizer_aggr_groupby_elim=TRUE
_OPTIMIZER_ANSI_JOIN_LATERAL_ENHANCE
Default: TRUE
Optimization of left/full ansi-joins and lateral views
_optimizer_ansi_join_lateral_enhance=TRUE
_OPTIMIZER_ANSI_REARCHITECTURE
Default: TRUE
Re-architecture of ANSI left, right, and full outer joins
_optimizer_ansi_rearchitecture=TRUE
_OPTIMIZER_AUTOSTATS_JOB
Default: TRUE
Enable/disable auto stats collection job
_optimizer_autostats_job=TRUE
_OPTIMIZER_AW_JOIN_PUSH_ENABLED
Default: TRUE
Enables AW Join Push optimization
_optimizer_aw_join_push_enabled=FALSE
_OPTIMIZER_AW_STATS_ENABLED
Default: TRUE
Enables statistcs on AW olap_table table function
_optimizer_aw_stats_enabled=FALSE
_OPTIMIZER_BATCH_TABLE_ACCESS_BY_ROWID
Default: TRUE
Enable table access by ROWID IO batching
_optimizer_batch_table_access_by_rowid=TRUE
_OPTIMIZER_BETTER_INLIST_COSTING
Default: ALL
Enable improved costing of index access using in-list(s)
_optimizer_better_inlist_costing='ALL'
_OPTIMIZER_BLOCK_SIZE
Default: 8192
Standard block size used by optimizer
_optimizer_block_size=8192
_OPTIMIZER_CACHE_STATS
Default: FALSE
Cost with cache statistics
_optimizer_cache_stats=TRUE
_OPTIMIZER_CARTESIAN_ENABLED
Default: TRUE
Optimizer cartesian join enabled
_optimizer_cartesian_enabled=TRUE
_OPTIMIZER_CBQT_FACTOR
Default: 50
Cost factor for cost-based query transformation
_optimizer_cbqt_no_size_restriction=50
_OPTIMIZER_CBQT_NO_SIZE_RESTRICTION
Default: TRUE
Disable cost based transformation query size restriction
_optimizer_cbqt_no_size_restriction=TRUE
_OPTIMIZER_CEIL_COST
Default: TRUE
CEIL cost in CBO
_optimizer_ceil_cost=TRUE
_OPTIMIZER_CLUSTER_BY_ROWID
Default: TRUE
Enable/disable the cluster by rowid feature
_optimizer_cluster_by_rowid=TRUE
_OPTIMIZER_CLUSTER_BY_ROWID_BATCHED
Default: TRUE
Enable/disable the cluster by rowid batching feature
_optimizer_cluster_byu_rowid_batched=TRUE
_OPTIMIZER_CLUSTER_BY_ROWID_BATCH_SIZE
Default: 100
Sorting batch size for cluster by rowid feature
_optimizer_cluster_by_rowid_batch_size=100
_OPTIMIZER_CLUSTER_BY_ROWID_CONTROL
Default: 129
Internal control for cluster by rowid feature mode
_optimizer_cluster_by_rowid_control=129
_OPTIMIZER_COALESCE_SUBQUERIES
Default: TRUE
Consider coalescing of subqueries optimization
_optimizer_coalesce_subqueries=TRUE
_OPTIMIZER_COMPLEX_PRED_SELECTIVITY
Default: TRUE
Enable selectivity estimation for builtin functions
_optimizer_complex_pred_selectivity=TRUE
_OPTIMIZER_COMPUTE_INDEX_STATS
Default: TRUE
Force index stats collection on index creation/rebuild
_optimizer_compute_index_stats=TRUE
_OPTIMIZER_CONNECT_BY_CB_WHR_ONLY
Default: FALSE
Use cost-based transformation for whr clause in connect by
_optimizer_connect_by_cb_whr_only=FALSE
_OPTIMIZER_CONNECT_BY_COMBINE_SW
Default: TRUE
Combine no filtering connect by and start with
_optimizer_connect_by_combine_sw=TRUE
_OPTIMIZER_CONNECT_BY_COST_BASED
Default: TRUE
Use cost-based transformation for connect by
_optimizer_connect_by_cost_based=TRUE
_OPTIMIZER_CONNECT_BY_ELIM_DUPS
Default: TRUE
Allow connect by to eliminate duplicates from input
_optimizer_connect_by_elim_dups=TRUE
_OPTIMIZER_CORRECT_SQ_SELECTIVITY
Default: TRUE
Force correct computation of subquery selectivity
_optimizer_correct_sq_selectivity=TRUE
_OPTIMIZER_COST_BASED_TRANSFORMATION
Default: LINEAR
Enables cost-based query transformation
_optimizer_cost_based_transformation='LINEAR'
_OPTIMIZER_COST_FILTER_PRED
Default: FALSE
Enables costing of filter predicates in IO cost model
_optimizer_cost_filter_pred=TRUE
_OPTIMIZER_COST_HJSMJ_MULTIMATCH
Default: TRUE
Add cost of generating result set when #rows per key > 1
_optimizer_cost_hjsmj_multimatch=TRUE
_OPTIMIZER_COST_MODEL
Default: CHOOSE
Optimizer cost model
_optimizer_cost_model='CHOOSE'
_OPTIMIZER_CUBE_JOIN_ENABLED
Default: TRUE
Enable cube join
_optimizer_cube_join_enabled=TRUE
_OPTIMIZER_DEGREE
Default: 0
Force the optimizer to use the same degree of parallelism
_optimizer_degree=0
_OPTIMIZER_DIM_SUBQ_JOIN_SEL
Default: TRUE
Use join selectivity in choosing star transformation dimensions
_optimizer_dim_subq_join_sel=TRUE
_OPTIMIZER_DISABLE_STRANS_SANITY_CHECKS
Default: 0
Disable star transformation sanity checks
_optimizer_disable_strans_sanity_checks=0
_OPTIMIZER_DISTINCT_AGG_TRANSFORM
Default: TRUE
Transforms Distinct Aggregates to non-distinct aggregates
_optimizer_distinct_agg_transform=TRUE
_OPTIMIZER_DISTINCT_ELIMINATION
Default: TRUE
Eliminates redundant SELECT DISTNCTs
_optimizer_distinct_elimination=TRUE
_OPTIMIZER_DISTINCT_PLACEMENT
Default: TRUE
Consider distinct placement optimization
_optimizer_distinct_placement=TRUE
_OPTIMIZER_DSDIR_USAGE_CONTROL
Default: 126
Controls optimizer usage of dynamic sampling directives
_optimizer_dsdir_usage_control=126
_OPTIMIZER_DYN_SMP_BLKS
Default: 32
Number of blocks for optimizer dynamic sampling
_optimizer_dyn_smp_blks=28
_OPTIMIZER_ELIMINATE_FILTERING_JOIN
Default: TRUE
Optimizer filtering join elimination enabled
_optimizer_eliminate_filtering_join=TRUE
_OPTIMIZER_ENABLE_DENSITY_IMPROVEMENTS
Default: TRUE
Use improved density computation for selectivity estimation
_optimizer_enable_density_improvements=TRUE
_OPTIMIZER_ENABLE_EXTENDED_STATS
Default: TRUE
Use extended statistics for selectivity estimation
_optimizer_enable_extended_stats=TRUE
_OPTIMIZER_ENABLE_TABLE_LOOKUP_BY_NL
Default: TRUE
Consider table lookup by nl transformation
_optimizer_complex_pred_selectivity=TRUE
_OPTIMIZER_ENHANCED_FILTER_PUSH
Default: TRUE
Push filters before trying cost-based query transformation
_optimizer_enhanced_filter_push=TRUE
_OPTIMIZER_EXTENDED_CURSOR_SHARING
Default: UDO;
Optimizer extended cursor sharing
_optimizer_extended_cursor_sharing=UDO
_OPTIMIZER_EXTENDED_CURSOR_SHARING_REL
Default: SIMPLE
SIMPLE optimizer extended cursor sharing for relational operators
_optimizer_extended_cursor_sharing_rel=SIMPLE
_OPTIMIZER_EXTENDED_STATS_USAGE_CONTROL
Default: 192
Controls the optimizer usage of extended stats
_optimizer_extended_stats_usage_control=192
_OPTIMIZER_EXTEND_JPPD_VIEW_TYPES
Default: TRUE
Join pred pushdown on group-by, distinct, semi-/anti-joined view
_optimizer_extend_jppd_view_types=TRUE
_OPTIMIZER_EXTENDED_CURSOR_SHARING
Default: UDO
Optimizer extended cursor sharing
_optimizer_extended_cursor_sharing='UDO'
_OPTIMIZER_EXTENDED_CURSOR_SHARING_REL
Default: SIMPLE
Optimizer extended cursor sharing for relational operators
_optimizer_extended_cursor_sharing_rel='SIMPLE'
_OPTIMIZER_EXTENDED_STATS_USAGE_CONTROL
Default: 192
Controls the optimizer usage of extended stats
_optimizer_extended_stats_usage_control=224
_OPTIMIZER_FALSE_FILTER_PRED_PULLUP
Default: TRUE
Optimizer false predicate pull up transformation
_optimizer_false_filter_pred_pullup=TRUE
_OPTIMIZER_FAST_ACCESS_PRED_ANALYSIS
Default: TRUE
Use fast algorithm to traverse predicates for physical optimizer
_optimizer_fast_access_pred_analysis=TRUE
_OPTIMIZER_FAST_PRED_TRANSITIVITY
Default: TRUE
Use fast algorithm to generate transitive predicates
_optimizer_fast_pred_transitivity=TRUE
_OPTIMIZER_FEEDBACK_CONTROL
Default: None Defined
Controls the optimizer feedback framework
_optimizer_feedback_control=TRUE
_OPTIMIZER_FILTER_PRED_PULLUP
Default: TRUE
Use cost-based flter predicate pull up transformation
_optimizer_filter_pred_pullup=TRUE
_OPTIMIZER_FILTER_PUSHDOWN
Default: TRUE
Enable/disable filter predicate pushdown
_optimizer_filter_pushdown=TRUE
_OPTIMIZER_FKR_INDEX_COST_BIAS
Default: 10
Optimizer index bias over FTS/IFFS under first K rows mode
_optimizer_fkr_index_cost_bias=10
_OPTIMIZER_FORCE_CBQT
Default: No Default Value
Force CBQT transformation regardless of cost
TBD
_OPTIMIZER_FREE_TRANSFORMATION_HEAP
Default: TRUE
Free transformation subheap after each transformation
_optimizer_free_transformation_heap=TRUE
_OPTIMIZER_FULL_OUTER_JOIN_TO_OUTER
Default: TRUE
Enable/disable full outer to left outer join conversion
_optimizer_full_outer_join_to_outer=TRUE
_OPTIMIZER_GATHER_FEEDBACK
Default: TRUE
Optimizer gather feedback
_optimizer_gather_feedback=TRUE
_OPTIMIZER_GATHER_STATS_ON_LOAD
Default: TRUE
Enable/disable online statistics gathering
_optimizer_gather_stats_on_load=TRUE
_OPTIMIZER_GENERATE_TRANSITIVE_PRED
Default: TRUE
Optimizer generate transitive predicates
_optimizer_generate_transitive_pred=TRUE
_OPTIMIZER_GROUP_BY_PLACEMENT
Default: TRUE
Consider group-by placement optimization
_optimizer_group_by_placement=TRUE
_OPTIMIZER_HLL_ENTRY
Default: 4096
Number of entries in hll hash table
_optimizer_hll_entry=TRUE
_OPTIMIZER_HYBRID_FPWJ_ENABLED
Default: TRUE
Enable hybrid full partition-wise join when TRUE
_optimizer_hybrid_fpwj_enabled=TRUE
_OPTIMIZER_IGNORE_HINTS
Obsolete
Enables the embedded hints to be ignored
_optimizer_ignore_hints=TRUE
_OPTIMIZER_IMPROVE_SELECTIVITY
Default: TRUE
Improve table and partial overlap join selectivity computation
_optimizer_improve_selectivity=TRUE
_OPTIMIZER_INSTANCE_COUNT
Default: 0
Force the optimizer to use the specified number of instances
_optimizer_instance_count=0
_OPTIMIZER_INTERLEAVE_JPPD
Default: TRUE
Interleave join predicate pushdown during CBQT
_optimizer_interleave_jppd=TRUE
_OPTIMIZER_INVALIDATION_PERIOD
Default: 18000
Time window for invalidation of cursors of analyzed objects
_optimizer_invalidate_period=16000
_OPTIMIZER_JOIN_ELIMINATION_ENABLED
Default: TRUE
Optimizer join elimination enabled
_optimizer_join_elimination_enabled=TRUE
_OPTIMIZER_JOIN_FACTORIZATION
Default: TRUE
Use join factorization transformation
_optimizer_join_factorization=TRUE
_OPTIMIZER_JOIN_ORDER_CONTROL
Default: 3
Controls the optimizer join order search algorithm
_optimizer_join_order_control=3
_OPTIMIZER_JOIN_SEL_SANITY_CHECK
Default: TRUE
Enable/disable sanity check for multi-column join selectivity
_optimizer_join_sel_sanity_check=TRUE
_OPTIMIZER_KEY_VECTOR_AGGR_FACTOR
Default: 75
The required aggregation between IJK and DGK
_optimizer_key_vector_aggr_factor=TRUE
_OPTIMIZER_MAX_PERMUTATIONS
Default: 2000
Optimizer maximum join permutations per query block
_optimizer_max_permutations=2000
_OPTIMIZER_MIN_CACHE_BLOCKS 10
Default: 10
Set minimum cached blocks
_optimizer_min_cache_blocks=12
_OPTIMIZER_MJC_ENABLED
Default: TRUE
Enable merge join cartesian
_optimizer_mjc_enabled=TRUE
_OPTIMIZER_MODE_FORCE
Default: TRUE
Force setting of optimizer mode for user recursive SQL also
_optimizer_mode_force=TRUE
_OPTIMIZER_MULTIPLE_CENV
Default: TRUE
Generate and run plans using several compilation environments
_optimizer_multiple_cenv=TRUE
_OPTIMIZER_MULTIPLE_CENV_REPORT
Default: TRUE
Result control what to report in trace file when run in multi-plan mode
_optimizer_multiple_cenv_report=TRUE
_OPTIMIZER_MULTIPLE_CENV_STMT
No Default
Query control the types of statements that are run in multi-plan mode
TBD
_OPTIMIZER_MULTI_LEVEL_PUSH_PRED
Default: TRUE
Consider join-predicate pushdown that requires multi-level pushdown to base table
_optimizer_multi_level_push_pred=TRUE
_OPTIMIZER_MULTI_TABLE_OUTERJOIN
Default: TRUE
Allows multiple tables on the left of outerjoin
_optimizer_multi_tale_outerjoin=TRUE
_OPTIMIZER_NATIVE_FULL_OUTER_JOIN
Default: FORCE
execute full outer join using native implementaion
_optimizer_native_full_outer_join='FORCE'
_OPTIMIZER_NESTED_ROLLUP_FOR_GSET
Default: 100
Number of groups above which we use nested rollup exec for gset
_optimizer_nested_rollup_for_gset=80
_OPTIMIZER_NEW_JOIN_CARD_COMPUTATION
Default: TRUE
Compute join cardinality using non-rounded input values
_optimizer_new_join_card_computation=TRUE
_OPTIMIZER_NULL_ACCEPTING_SEMIJOIN
Default: TRUE
Enables null-accepting semijoin
_optimizer_null_accepting_semijoin=TRUE
_OPTIMIZER_NULL_AWARE_ANTIJOIN
Default: TRUE
Null-aware antijoin parameter
_optimizer_null_aware_antijoin=TRUE
_OPTIMIZER_ORDER_BY_ELIMINATION_ENABLED
Default: TRUE
Eliminates order bys from views before query transformation
_optimizer_order_by_elimination_enabled=TRUE
_OPTIMIZER_OR_EXPANSION
Default: DEPTH
Control or expansion approach used
_optimizer_or_expansion='DEPTH'
_OPTIMIZER_OR_EXPANSION_SUBHEAP
Default: TRUE
Use subheap for optimizer or-expansion
_optimizer_or_expansion_subheap=TRUE
_OPTIMIZER_OUTER_JOIN_TO_INNER
Default: TRUE
Enable/disable outer to inner join conversion
_optimizer_outer_join_to_inner=TRUE
_OPTIMIZER_OUTER_TO_ANTI_ENABLED
Default: TRUE
Enable transformation of outer-join to anti-join if possible
_optimizer_outer_to_anti_enabled=TRUE
_OPTIMIZER_PARTIAL_JOIN_EVAL
Default: TRUE
Partial join evaluation parameter
_optimizer_partial_join_eval=TRUE
_OPTIMIZER_PERCENT_PARALLEL
Default: 101
Optimizer percent parallel
_optimizer_percent_parallel=99
_OPTIMIZER_PERFORMANCE_FEEDBACK
Default: OFF
Controls the performance feedback
_optimizer_performance_feedback=ON
_OPTIMIZER_PROC_RATE_LEVEL
Default: BASIC
Control the level of processing rates
_optimizer_proc_rate_level=BASIC
_OPTIMIZER_PROC_RATE_SOURCE
Default: DEFAULT
Control the source of processing rates
_optimizer_proc_rate_source=DEFAULT
_OPTIMIZER_PURGE_STATS_ITERATION_ROW_COUNT
Default: 10000
Number of rows to be deleted at each iteration of the statspurging process
_optimizer_purge_stats_iteration_row_count=TRUE
_OPTIMIZER_PUSH_DOWN_DISTINCT
Default: 0
Push down distinct from query block to table
_optimizer_push_down_distinct=0
_OPTIMIZER_PUSH_PRED_COST_BASED
Default: TRUE
Use cost-based query transformation for push pred optimization
_optimizer_push_pred_cost_based=TRUE
_OPTIMIZER_RANDOM_PLAN
Default: 0
Optimizer seed value for random plans
_optimizer_random_plan=TRUE
_OPTIMIZER_REDUCE_GROUPBY_KEY
Default: TRUE
Group-by key reduction
_optimizer_reduce_groupby_key=TRUE
_OPTIMIZER_REUSE_COST_ANNOTATIONS
Default: TRUE
Reuse cost annotations during cost-based query transformation
_optimizer_reuse_cost_annotations=TRUE
_OPTIMIZER_ROWNUM_BIND_DEFAULT
Default: 10
Default value to use for rownum bind
_optimizer_rownum_bind_default=10
_OPTIMIZER_ROWNM_PRED_BASED_FKR
Default: TRUE
Enable the use of first K rows due to rownum predicate
_optimizer_rownum_pred_based_fkr=TRUE
_OPTIMIZER_SAVE_STATS
Default: TRUE
Enable/disable saving old versions of optimizer stats
_optimizer_save_stats=TRUE
_OPTIMIZER_SEARCH_LIMIT
Default: 5
Optimizer search limit
_optimizer_search_limit=6
_OPTIMIZER_SELF_INDUCED_CACHE_COST
Default: FALSE
Account for self-induced caching
_optimizer_self_induced_cache_cost=TRUE
_OPTIMIZER_SKIP_SCAN_ENABLED
Default: TRUE
Enable/disable index skip scan
_optimizer_skip_scan_enabled=TRUE
_OPTIMIZER_SKIP_SCAN_GUESS
Default: FALSE
Consider index skip scan for predicates with guessed selectivity
_optimizer_skip_scan_guess=TRUE
_OPTIMIZER_SORTMERGE_JOIN_ENABLED
Default: TRUE
Enable/disable sort-merge join method
_optimizer_sortmerge_join_enabled=TRUE
_OPTIMIZER_SORTMERGE_JOIN_INEQUALITY
Default: TRUE
Enable/disable sort-merge join using inequality predicates
_optimizer_sortmerge_join_inequality=TRUE
_OPTIMIZER_SQU_BOTTOMUP
Default: TRUE
Enables unnesting of subquery in a bottom-up manner
_optimizer_squ_bottomup=TRUE
_OPTIMIZER_STARPLAN_ENABLED
Default: TRUE
Optimizer star plan enabled
_optimizer_starplan_enabled=TRUE
_OPTIMIZER_STAR_TRANS_MIN_COST
Default: 0
Optimizer star transformation minimum cost
_optimizer_star_trans_min_cost=0
_OPTIMIZER_STAR_TRANS_MIN_RATIO
Default: 0
Optimizer star transformation minimum ratio
_optimizer_star_trans_min_ratio=0
_OPTIMIZER_STAR_TRAN_IN_WITH_CLAUSE
Default: TRUE
Enable/disable star transformation in with clause queries
_optimizer_star_tran_in_with_clause=TRUE
_OPTIMIZER_SYNOPSIS_MIN_SIZE
Default: 2
Minimal synopsis size (kb)
_optimizer_synopsis_min_size=2
_OPTIMIZER_SYSTEM_STATS_USAGE
Default: TRUE
System statistics usage
_optimizer_system_stats_usage=TRUE
_OPTIMIZER_TABLE_EXPANSION
Default: TRUE
Consider table expansion transformation
_optimizer_table_expansion=TRUE
_OPTIMIZER_TRACE
Default: None
Optimizer trace parameter
_optimizer_trace=NONE
_OPTIMIZER_TRANSITIVITY_RETAIN
Default: TRUE
Retain equi-join pred upon transitive equality pred generation
_optimizer_transitivity_retain=TRUE
_OPTIMIZER_TRY_ST_BEFORE_JPPD
Default: TRUE
Try Star Transformation before Join Predicate Push Down
_optimizer_try_st_before_jppd=TRUE
_OPTIMIZER_UNDO_CHANGES
Default: FALSE
Undo changes to query optimizer
_optimizer_undo_changes=TRUE
_OPTIMIZER_UNDO_COST_CHANGE
Default: '12.1.0.2'
Optimizer undo cost change
_optimizer_undo_cost_change='12.1.0.2'
_OPTIMIZER_UNNEST_ALL_SUBQUERIES
Default: TRUE
Enables unnesting of every type of subquery
_optimizer_unnest_all_subqueries=TRUE
_OPTIMIZER_UNNEST_CORR_SET_SUBQ
Default: TRUE
Unnesting of correlated set subqueries (TRUE/FALSE)
_optimizer_unnest_corr_set_subq=TRUE
_OPTIMIZER_UNNEST_DISJUNCTIVE_SUBQ
Default: TRUE
Unnesting of disjunctive subqueries (TRUE/FALSE)
_optimizer_unnest_disjunctive_subq=TRUE
_OPTIMIZER_UNNEST_SCALAR_SQ
Default: TRUE
Enables unnesting of of scalar subquery
_optimizer_unnest_scalar_sq=TRUE
_OPTIMIZER_USE_CBQT_STAR_TRANSFORMATION
Default: TRUE
Use rewritten star transformation using cbqt framework
_optimizer_use_cbqt_star_transformation=TRUE
_OPTIMIZER_USE_FEEDBACK
Default: TRUE
Optimizer use feedback
_optimizer_use_feedback=TRUE
_OPTIMIZER_USE_GTT_SESSION_STATS
Default: TRUE
Use GTT session private statistics
_optimizer_use_ftt_session_stats=TRUE
_OPTIMIZER_USE_HISTOGRAMS
Default: TRUE
Enable/disable the usage of histograms by the optimizer
_optimizer_use_historgrams=TRUE
_OPTIMIZER_USE_SUBHEAP
Default: TRUE
Enables physical optimizer subheap
_optimizer_use_subheap=TRUE
_OPTIMIZER_VECTOR_COST_ADJ
Default: 100
Cost adjustment for vector aggregation processing estimates
_optimizer_vector_cost_adj=100
_OPTIMIZER_VECTOR_FACT_DIM_RATIO
Default: 10
Cost based vector transform dimension to fact ratio
_optimizer_vector_fact_dim_ratio=10
_OPTIMIZER_VECTOR_MIN_FACT_ROWS
Default:
10000000
Min number of rows required for vector aggregation transform
_optimizer_vector_min_fact_rows=10000000
_OPTIMIZER_VECTOR_TRANSFORMATION
Default: TRUE
Perform vector transform
_optimizer_vector_transformation=TRUE
_NEW_SORT_COST_ESTIMATE
Default: TRUE
Enables the use of new cost estimate for sort
_new_sort_cost_estimate=FALSE
_NLJ_BATCHING_ENABLED
Default: 1
Enable batching of the RHS IO in NLJ
_nlj_batching_enabled=1
_OPTIM_ADJUST_FOR_PART_SKEWS
Default: TRUE
Adjust stats for skews across partitions
_optim_adjust_for_part_skews=TRUE
_OPTIM_DICT_STATS_AT_DB_CR_UPG
Default: TRUE
Enable/disable dictionary stats gathering at db create/upgrade
_optim_dictstats_at_db_cr_upg=TRUE
_OPTIM_ENHANCE_NNULL_DETECTION
Default: TRUE
TRUE to enable index [fast] full scan more often
_optim_enhance_nnull_detection=TRUE
_OPTIM_NEW_DEFAULT_JOIN_SEL
Default: TRUE
Improves the way default equijoin selectivity are computed
_optim_new_default_join_sel=TRUE
_OPTIM_PEEK_USER_BINDS
Default: TRUE
Enable peeking of user binds
_optim_peek_user_binds=TRUE
_MINIMAL_STATS_AGGREGATION
Default: TRUE
Prohibit stats aggregation at compile/partition maintenance time
_minimal_stats_aggregation=TRUE
_MMV_QUERY_REWRITE_ENABLED
Default: TRUE
Allow rewrites with multiple MVs and/or base tables
_mmv_query_rewrite_enabled=TRUE
_NEW_INITIAL_JOIN_ORDERS
Default: TRUE
Enable initial join orders based on new ordering heuristics
_new_initial_join_orders=TRUE
_NEWSORT_ENABLED
Default: TRUE
controls whether new sorts can be used as system sort
alter session set "_newsort_enabled"=TRUE;
_NEWSORT_ORDERED_PCT
Default: 63
Controls when new sort avoids sorting ordered input
_newsort_ordered_pct=70
_NEWSORT_TYPE
Default: 0
Specifies options for the new sort algorithm
TBD
_ORDERED_NESTED_LOOP
Default: TRUE
Enable ordered nested loop costing
_ordered_nested_loop=TRUE
_OR_EXPAND_NVL_PREDICATE
Default: TRUE
Enable OR expanded plans for NVL/DECODE predicate
_or_expand_nvl_predicate=TRUE
BROADCAST_ENABLED
Default: TRUE
Enable broadcasting of small inputs to hash and sort merge joins
_parallel_broadcast_enabled=TRUE
_PARTITION_VIEW_ENABLED
Default: TRUE
enable/disable partitioned views
_partition_view_enabled=TRUE
_PIVOT_IMPLEMENTATION_METHOD
Default: 'CHOOSE'
Pivot implementation method
_pivot_implementation_method='CHOOSE'
_PRE_REWRITE_PUSH_PRED
Default: TRUE
Push predicates into views before rewrite
_pre_rewrite_push_pred=TRUE
_PRED_MOVE_AROUND
Default: TRUE
Enables predicate move-around
_pred_move_around=TRUE
_PUSH_JOIN_PREDICATE
Default: TRUE
Enable pushing join predicate inside a view
_push_join_predicate=TRUE
_PUSH_JOIN_UNION_VIEW
Default: TRUE
Enable pushing join predicate inside a union all view
_push_join_union_view=TRUE
_PUSH_JOIN_UNION_VIEW2
Default: TRUE
Enable pushing join predicate inside a union view
_push_join_union_view2=TRUE
_PX_MINUS_INTERSECT
Default: TRUE
Enables pq for minus/interect operators
_px_minus_intersect=TRUE
_PX_PWG_ENABLED
Default: TRUE
Parallel partition wise group by enabled
_px_pwg_enabled=TRUE
_PX_UAL_SERIAL_INPUT
Default: TRUE
Enables new pq for UNION operators
_px_ual_serial_input=TRUE
_QUERY_REWRITE_SETOPGRW_ENABLE
Default: TRUE
Perform general rewrite using set operator summaries
_query_rewrite_setopgrw_enable=TRUE
_RECURSIVE_IMU_TRANSACTIONS
Default: FALSE
Enables recursive SQL to use In-Memory Undo (IMU)
_recursive_imu_transactions=TRUE
_REMOVE_AGGR_SUBQUERY
Default: TRUE
Enables removal of subsumed aggregated subquery
_remove_aggr_subquery=TRUE
_RIGHT_OUTER_HASH_ENABLED
Default: TRUE
Right outer/semi/anti hash enabled
_right_outer_hash_enable=TRUE
_SELFJOIN_MV_DUPLICATES
Default: TRUE
Control rewrite self-join algorithm
_selfjoin_mv_duplicates=TRUE
_SQLTUNE_CATEGORY_PARSED
Default: 'DEFAULT'
Parsed category qualifier for applying hintsets
_sqltune_category_parsed='DEFAULT'
_SUBQUERY_PRUNING_ENABLED
Default: TRUE
Enable the use of subquery predicates to perform pruning
_subquery_pruning_enabled=TRUE
_SUBQUERY_PRUNING_MV_ENABLED
Default: FALSE
Enable the use of subquery predicates with MVs to perform pruning
_subquery_pruning_mv_enabled=FALSE
_TABLE_SCAN_COST_PLUS_ONE
Default: TRUE
Bump estimated full table scan and index ffs cost by one
_table_scan_cost_plus_one=TRUE
_UNION_REWRITE_FOR_GS
Default: YES_GSET_MVS
Expands queries with GSets into UNIONs for rewrite
_union_rewrite_for_gs='YES_GSET_MVS'
_UNNEST_SUBQUERY
Default: TRUE
Enables unnesting of complex subqueries
EXPLAIN PLAN FOR
SELECT srvr_id
FROM servers
WHERE srvr_id IN (
  SELECT srvr_id
  FROM serv_inst);

SELECT * FROM TABLE(dbms_xplan.display);

alter session set "_unnest_subquery"=FALSE;

EXPLAIN PLAN FOR
SELECT srvr_id
FROM servers
WHERE srvr_id IN (
  SELECT srvr_id
  FROM serv_inst);

SELECT * FROM TABLE(dbms_xplan.display);
_USE_COLUMN_STATS_FOR_FUNCTION Enable the use of column statistics for DDP functions
 
 
PL/SQL
  _CLOSE_CACHED_OPEN_CURSORS FALSE close cursors cached by PL/SQL at each commit
 
  _DISABLE_FAST_VALIDATE FALSE disable PL/SQL fast validation
 
  _INLINE_SQL_IN_PLSQL FALSE inline SQL in PL/SQL
 
_PARALLEL_SYSPLS_OBEY_FORCE
Default: TRUE
TRUE to obey force parallel query/dml/ddl under System PL/SQL
_parallel_syspls_obey_force=TRUE
_SQL_MODEL_UNFOLD_FORLOOPS
Default = 'RUN_TIME'
Specifies compile-time unfolding of sql model for loops
_sql_model_unfold_forloops='RUN_TIME'
 
Pluggable/Container Database
_CDB_SPFILE_INHERIT
Default: FALSE
Inherit CDB Spfile enabled/disabled in a PDB
 
_ENABLE_PDB_CLOSE_ABORT
Default: FALSE
Enable PDB shutdown abort (close abort)
 
 
Real Application Clusters
_ACTIVE_INSTANCE_COUNT
Default: None Defined
Number of active instances in the cluster database
TBD
  _GCS__cluster_flash_cache_mode 0 cluster flash cache mode
 
  _GCS__DISABLE_remote_handles FALSE disable remote client/shadow handles
 
  _GCS__DISABLE_skip_close_remastering FALSE if TRUE, disable skip close optimization in remastering
 
  _GCS__dynamic_slaves TRUE if TRUE, it enables dynamic adjustment of the number of gcs slaves
 
  _GCS__fast_reconfig TRUE if TRUE, enable fast reconfiguration for gcs locks
 
  _GCS__flash_cache_mode 0 flash cache mode
 
  _GCS__latches 0 number of gcs resource hash latches to be allocated per LMS process
 
  _GCS__min_slaves 0 if non zero, it enables the minimum number of gcs slaves
 
  _GCS__pkey_history 4000 number of pkey remastering history
 
  _GCS__process_in_recovery TRUE if TRUE, process gcs requests during instance recovery
 
  _GCS__res_hash_buckets number of gcs resource hash buckets to be allocated
 
  _GCS__res_per_bucket 4 number of gcs resource per hash bucket
 
  _GCS__reserved_resources 400 allocate the number of reserved resources in reconfiguration
 
  _GCS__reserved_shadows 400 allocate the number of reserved shadows in reconfiguration
 
  _GCS__resources number of gcs resources to be allocated
 
  _GCS__shadow_locks number of pcm shadow locks to be allocated
 
  _GCS__testing 0 GCS testing parameter
 
  _GC_AFFINITY_LOCKING TRUE if TRUE, enable object affinity
 
  _GC_AFFINITY_LOCKS TRUE if TRUE, get affinity locks
 
  _GC_AFFINITY_RATIO 50 dynamic object affinity ratio
 
  _GC_ASYNC_SEND FALSE send blocks asynchronously
 
  _GC_BYPASS_READERS TRUE if TRUE, modifications bypass readers
 
  _GC_CHECK_BSCN TRUE if TRUE, check for stale blocks
 
  _GC_COALESCE_RECOVERY_READS TRUE if TRUE, coalesce recovery reads
 
  _GC_CPU_TIME FALSE if TRUE, record the gc cpu time
 
  _GC_CR_SERVER_READ_WAIT TRUE if TRUE, cr server waits for a read to complete
 
  _GC_DEFER_PING_INDEX_ONLY TRUE if TRUE, restrict deferred ping to index blocks only
 
  _GC_DEFER_TIME 0 how long to defer pings for hot buffers in microseconds
 
  _GC_DISABLE_S_LOCK_BRR_PING_CHECK TRUE if TRUE, disable S lock BRR ping check for lost write protect
 
  _GC_DOWN_CONVERT_AFTER_KEEP TRUE if TRUE, down-convert lock after recovery
 
  _GC_DUMP_REMOTE_LOCK TRUE if TRUE, dump remote lock
 
  _GC_ELEMENT_PERCENT 120 global cache element percent
 
  _GC_FG_MERGE TRUE if TRUE, merge pi buffers in the foreground
 
  _GC_FG_SPIN_TIME 0 foreground msgq spin time
 
  _GC_FLUSH_DURING_AFFINITY TRUE if TRUE, flush during affinity
 
  _GC_FUSION_COMPRESSION 1024 compress fusion blocks if there is free space
 
  _GC_GLOBAL_CHECKPOINT_SCN TRUE if TRUE, enable global checkpoint scn
 
  _GC_GLOBAL_LRU AUTO turn global lru off, make it automatic, or turn it on
 
  _GC_GLOBAL_LRU_TOUCH_COUNT 5 global lru touch count
 
  _GC_GLOBAL_LRU_TOUCH_TIME 60 global lru touch time in seconds
 
  _GC_INTEGRITY_CHECKS 1 set the integrity check level
 
  _GC_KEEP_RECOVERY_BUFFERS TRUE if TRUE, make single instance crash recovery buffers current
 
  _GC_LATCHES 8 number of latches per LMS process
 
  _GC_LOG_FLUSH TRUE if TRUE, flush redo log before a current block transfer
 
  _GC_MAX_DOWNCVT 256 maximum downconverts to process at one time
 
  _GC_MSGQ_BUFFERS 128 number of MSGQ buffers
 
  _GC_NO_FAIRNESS_FOR_CLONES TRUE if TRUE, no fairness if we serve a clone
 
  _GC_OBJECT_QUEUE_MAX_LENGTH 0 maximum length for an object queue
 
  _GC_OVERRIDE_FORCE_CR TRUE if TRUE, try to override force-cr requests
 
  _GC_PERSISTENT_READ_MOSTLY TRUE if TRUE, enable persistent read-mostly locking
 
  _GC_POLICY_MINIMUM 2400 dynamic object policy minimum activity per minute
 
  _GC_POLICY_RM_DIRTY_PERCENT 1 percent of cache which can be dirty for readmostly
 
  _GC_POLICY_TIME 10 how often to make object policy decisions in minutes
 
  _GC_READ_MOSTLY_FLUSH_CHECK FALSE if TRUE, optimize flushes for read mostly objects
 
  _GC_READ_MOSTLY_LOCKING TRUE if TRUE, enable read-mostly locking
 
  _GC_SANITY_CHECK_CR_BUFFERS FALSE if TRUE, sanity check CR buffers
 
  _GC_SAVE_CLEANOUT TRUE if TRUE, save cleanout to apply later
 
  _GC_SERVE_FROM_FLASH_CACHE FALSE if TRUE, try to serve a flash cache buffer
 
  _GC_STATISTICS TRUE if TRUE, kcl statistics are maintained
 
  _GC_TEMP_AFFINITY FALSE if TRUE, enable global temporary affinity
 
  _GC_TRACE_FREELIST_EMPTY TRUE if TRUE, dump a trace when we run out of lock elements
 
  _GC_TRANSFER_RATIO 2 dynamic object read-mostly transfer ratio
 
  _GC_TRY_TO_SKIP_IMC_FLUSH TRUE if TRUE, try to skip an imc populate flush
 
  _GC_UNDO_AFFINITY TRUE if TRUE, enable undo affinity
 
_GC_UNDO_BLOCK_DISK_READS
Default: TRUE
If TRUE, enable undo block disk reads
 
_GC_VECTOR_READ TRUE
Default: TRUE
If TRUE, vector read current buffers
 
_CDB_RAC_AFFINITY TRUE
Default: ???
RAC affinity for parallel cdb operations
 
_INTERCONNECT_CHECKSUM
Default: TRUE
If TRUE, checksum interconnect blocks
_interconnect_checksum=TRUE
 
Result Cache
_CDB_VIEW_RC_SHELFLIFE
Default: 30
Result Cache Shelflife for a CDB view query
 
_CLIENT_RESULT_CACHE_BYPASS
Default: FALSE
bypass the client result cache
 
_DISABLE_CDB_VIEW_RC_INVALIDATION
Default: FALSE
Disable Result Cache invalidation for CDB View results
 
_OPTIMIZER_ADS_RESULT_CACHE_LIFE
Default: 3600
Result cache shelf life for ADS queries
_optimizer_ads_result_cache_life=1800
_OPTIMIZER_ADS_USE_RESULT_CACHE
Default: TRUE
Use result cache for ADS queries
_optimizer_ads_use_result_cache=TRUE
 
Security
  _CLEAR_BUFFER_BEFORE_REUSE FALSE Always zero-out buffer before reuse for security
 
  _CLIENT_ENABLE_AUTO_UNREGISTER FALSE enable automatic unregister after a send fails with timeout
 
_DBMS_SQL_SECURITY_LEVEL
Default: 1
Security level in DBMS_SQL
 
_FUSION_SECURITY
Default: TRUE
Enable Fusion Security
 
 
Tracing
_DBWR_TRACING
Default: 0
Enable dbwriter tracing
 
_TRACE_FILES_PUBLIC
Default: FALSE
Create publicly accessible trace files by setting the file protection mask to 644
alter session set "_trace_files_public"=TRUE;
_TRACE_TEMP
Default: FALSE
Enable trace tempspace management
alter session set "_trace_temp"=TRUE;
 
Transactions
   
 
 
Undo Tablespace
_CLEANUP_ROLLBACK_ENTRIES
Defaul: 100
no. of undo entries to apply per transaction cleanup
 
_UNDO_AUTOTUNE
Default: TRUE
Enable auto tuning of undo_retention: appears to apply segment compression to undo blocks
_undo_autotune=TRUE;
_UNDO_BLOCK_COMPRESSION
Default: TRUE
Enable undo block compression
_undo_block_compression=TRUE;
_UNDO_DEBUG_MODE
Default: 0
Debug flag for undo related operations
_undo_debug_mode=0;
_UNDO_DEBUG_USAGE
Default: 0
Invokes undo usage functions for testing
_undo_debug_usage=0;
 
Undocumented
_ABORT_ON_MRP_CRASH
Default: FALSE
Abort database instance when MRP crashes
_abort_on_mrp_crash=FALSE
_ABORT_RECOVERY_ON_JOIN
Default: FALSE
If TRUE, abort recovery on join reconfigurations
_abort_recovery_on_join=FALSE
_ACCEPT_VERSIONS
Default: None Defined
List of parameters for rolling operation
TBD
_ACTIVE_SESSION_IDLE_LIMIT
Default: 5
Active session idle limit
_active_session_idle_limit=5
_ACTIVE_SESSION_LEGACY_BEHAVIOR
Default: FALSE
Active session legacy behavior
_active_session_legacy_behavior=FALSE
_AC_ENABLE_DSCN_IN_RAC
Default: FALSE
Enable Dependent Commit SCN tracking
 
_AC_STRICT_SCN_CHECK
Default: FALSE
Enforce strict SCN check for AC replay across DG failover
 
_ADD_COL_OPTIM_ENABLED TRUE Allows new add column optimization
 
_ADD_NULLABLE_COLUMN_WITH_DEFAULT_OPTIM
Default:: TRUE
Allows add of a nullable column with default optimization
 
_ADD_STALE_MV_TO_DEPENDENCY_LIST
Default:: TRUE
Add stale mv to dependency list
 
_ADJUST_LITERAL_REPLACEMENT
Default:: FALSE
If TRUE, we will adjust the SQL/PLUS output
 
_ADR_MIGRATE_RUNONCE
Default:: TRUE
Enable/disable ADR Migrate Runonce action
 
  _AFD_DISABLE_FENCE FALSE Disable AFD fencing
 
  _AFFINITY_ON TRUE enable/disable affinity at run time
 
  _AGED_OUT_CURSOR_CACHE_TIME 300 number of seconds an aged out session cached cursor stay in cache
 
  _AGGREGATION_OPTIMIZATION_SETTINGS 0 settings for aggregation optimizations
 
  _ALERT_EXPIRATION 604800 seconds before an alert message is moved to exception queue
 
  _ALERT_MESSAGE_CLEANUP 1 Enable Alert Message Cleanup
 
  _ALERT_MESSAGE_PURGE 1 Enable Alert Message Purge
 
  _ALERT_POST_BACKGROUND 1 Enable Background Alert Posting
 
  _ALLOCATE_CREATION_ORDER FALSE should files be examined in creation order during allocation
 
  _ALLOCATION_UPDATE_INTERVAL 3 interval at which successful search in L1 should be updated
 
  _ALLOW_CELL_SMART_SCAN_ATTR TRUE Allow checking smart_scan_capable Attr
 
  _ALLOW_COMMUTATIVITY TRUE allow for commutativity of +, * when comparing expressions
 
  _ALLOW_COMPATIBILITY_ADV_W_GRP FALSE allow advancing DB compatibility with guaranteed restore points
 
  _ALLOW_CONVERT_TO_STANDBY FALSE allow convert to standby to go through
 
  _ALLOW_DROP_SNAPSHOT_STANDBY_GRSP FALSE Allow dropping snapshot standby guaranteed restore point
 
  _ALLOW_DROP_TS_WITH_GRP FALSE Allow drop Tablespace with guaranteed restore points
 
  _ALLOW_ERROR_SIMULATION FALSE Allow error simulation for testing
 
  _ALLOW_FILE_1_OFFLINE_ERROR_1245 FALSE don't signal ORA-1245 due to file 1 being offline
 
  _ALLOW_LEVEL_WITHOUT_CONNECT_BY FALSE allow level without connect by
 
  _ALLOW_READ_ONLY_CORRUPTION FALSE allow read-only open even if database is corrupt
 
  _ALLOW_RESETLOGS_CORRUPTION FALSE allow resetlogs even if it will cause corruption
 
  _ALLOW_TERMINAL_RECOVERY_CORRUPTION FALSE Finish terminal recovery even if it may cause corruption
 
  _ALL_SHARED_DBLINKS treat all dblinks as shared
 
  _ALTERNATE_IOT_LEAF_BLOCK_SPLIT_POINTS TRUE enable alternate index-organized table leaf-block split-points
 
  _ALTER_UPGRADE_SIGNATURE_ONLY FALSE alter table upgrade only sets signature
 
  _AND_PRUNING_ENABLED TRUE allow partition pruning based on multiple mechanisms
 
  _APPQOS_CDB_SETTING 0 QoSM CDB Performance Class Setting
 
  _APPQOS_PO_MULTIPLIER 1000 Multiplier for PC performance objective value
 
  _APPQOS_QT 10 System Queue time retrieval interval
 
  _APPROX_CNT_DISTINCT_GBY_PUSHDOWN choose perform group-by pushdown for approximate distinct count query
 
  _APPROX_CNT_DISTINCT_OPTIMIZATION 0 settings for approx_count_distinct optimizations
 
  _ARRAY_CDB_VIEW_ENABLED TRUE array mode enabled for CDB views
 
  _ARRAY_UPDATE_VECTOR_READ_ENABLED FALSE Enable array update vector read
 
  _ASYNC_RECOVERY_CLAIMS TRUE if TRUE, issue recovery claims asynchronously
 
  _ASYNC_RECOVERY_READS TRUE if TRUE, issue recovery reads asynchronously
 
  _ASYNC_RTA_BROADCAST FALSE asynchronously broadcast RTA boundary
 
  _ASYNC_TS_THRESHOLD 1 check tablespace thresholds asynchronously
 
  _AUTO_ASSIGN_CG_FOR_SESSIONS
 
  _AUTO_BMR enabled enable/disable Auto BMR
 
  _AUTO_BMR_BG_TIME 3600 Auto BMR Process Run Time
 
  _AUTO_BMR_FC_TIME 60 Auto BMR Flood Control Time
 
  _AUTO_BMR_MAX_ROWNO 1024 x$krbabrstat Max number of rows
 
  _AUTO_BMR_PUB_TIMEOUT 10 Auto BMR Publish Timeout
 
  _AUTO_BMR_REQ_TIMEOUT 60 Auto BMR Requester Timeout
 
  _AUTO_BMR_SESS_THRESHOLD 30 Auto BMR Request Session Threshold
 
  _AUTO_BMR_SYS_THRESHOLD 100 Auto BMR Request System Threshold
 
  _AUTO_MANAGE_ENABLE_OFFLINE_CHECK TRUE perodically check for OFFLINE disks and attempt to ONLINE
 
  _AUTO_MANAGE_INFREQ_TOUT 0 TEST: Set infrequent timeout action to run at this interval, unit is seconds
 
  _AUTO_MANAGE_IOCTL_BUFSZ 8192 oss_ioctl buffer size, to read and respond to cell notifications
 
  _AUTO_MANAGE_MAX_ONLINE_TRIES 3 Max. attempts to auto ONLINE an ASM disk
 
  _AUTO_MANAGE_NUM_PIPE_MSGS 1000 Max. number of out-standing msgs in the KXDAM pipe
 
  _AUTO_MANAGE_NUM_TRIES 2 Num. tries before giving up on a automation operation
 
_AUTO_MANAGE_ONLINE_TRIES_EXPIRE_TIME
Default: 86400
Allow Max. attempts to auto ONLINE an ASM disk after lapsing this time (unit in seconds)
 
_AUTOMATIC_MAINTENANCE_TEST
Default: 0
Enable AUTOTASK Test Mode
 
  _AUTOMEMORY_BROKER_INTERVAL 3 memory broker statistics gathering interval for auto memory
 
  _AUTOTASK_MAX_WINDOW 480 Maximum Logical Maintenance Window Length in minutes
 
  _AUTOTASK_MIN_WINDOW 15 Minimum Maintenance Window Length in minutes
 
  _AUTOTASK_TEST_NAME N/A Name of current Autotask Test (or test step)
 
  _AUTOTUNE_GTX_IDLE_TIME 600 idle time to trigger auto-shutdown a gtx background process
 
  _AUTOTUNE_GTX_INTERVAL 5 interval to autotune global transaction background processes
 
  _AUTOTUNE_GTX_THRESHOLD 60 auto-tune threshold for degree of global transaction concurrency
 
  _AUX_DFC_KEEP_TIME 1440 auxiliary datafile copy keep time in minutes
 
  _AVAILABLE_CORE_COUNT 0 number of cores for this instance
 
_BG_SPAWN_DIAG_OPTS
Default: 0
Background processes spawn diagnostic options
 
_BIGDATA_EXTERNAL_TABLE
Default: FALSE
Enables use of ORACLE_HIVE and ORACLE_HDFS access drivers
 
_BITMAP_OR_IMPROVEMENT_ENABLED
Default: TRUE
Controls extensions to partition pruning for general predicates
 
_BLOCKING_SESS_GRAPH_CACHE_SIZE
Default: None Defined
Blocking session graph cache size in bytes
TBD
_BLOCKS_PER_CACHE_SERVER
Default: 16
Number of consecutive blocks per global cache server
 
_BLOCK_LEVEL_OFFLOAD_HIGH_LAT_THRESH
Default: 40000
High Latency Threshold for Block Level Offload operations
 
_BLOCK_SAMPLE_READAHEAD_PROB_THRESHOLD
Default: 10
Controls readahead value during block sampling
 
_BLOOM_FILTER_DEBUG
Default: 0
Debug level for bloom filtering
 
_BLOOM_FILTER_ENABLED
Default: TRUE
Enables or disables bloom filter
_bloom_filter_enabled=TRUE
_BLOOM_FILTER_SIZE
Default: 0
Bloom filter vector size (in KB)
 
_BLOOM_FOLDING_DENSITY
Default: 16
Bloom filter folding density lower bound
 
_BLOOM_FOLDING_ENABLED
Default: TRUE
Enable folding of bloom filter
_bloom_folding_enabled=TRUE
_BLOOM_FOLDING_MIN
Default: 128
Bloom filter folding size lower bound (in KB)
 
_BLOOM_MAX_SIZE 262144 Maximum bloom filter size (in KB)
 
_BLOOM_MINMAX_ENABLED TRUE Enable or disable bloom min max filtering
 
_BLOOM_PREDICATE_ENABLED TRUE Enables or disables bloom filter predicate pushdown
 
_BLOOM_PREDICATE_OFFLOAD TRUE Enables or disables bloom filter predicate offload to cells
 
_BLOOM_PRUNING_ENABLED
Default: TRUE
Enable partition pruning using bloom filtering
_bloom_pruning_enabled=TRUE
  _BLOOM_PUSHING_MAX 512 bloom filter pushing size upper bound (in KB)
_BLOOM_PUSHING_TOTAL_MAX 262144 bloom filter combined pushing size upper bound (in KB)
_BLOOM_RM_FILTER FALSE remove bloom predicate in favor of zonemap join pruning predicate
_BLOOM_SERIAL_FILTER ON enable serial bloom filter on exadata
_BLOOM_SM_ENABLED TRUE enable bloom filter optimization using slave mapping
_BRANCH_TAGGING TRUE enable branch tagging for distributed transaction
_BROADCAST_SCN_MODE 1 broadcast-on-commit scn mode
_BROADCAST_SCN_WAIT_TIMEOUT 10 broadcast-on-commit scn wait timeout in centiseconds
_BT_MMV_QUERY_REWRITE_ENABLED TRUE allow rewrites with multiple MVs and base tables
_BUFFERED_MESSAGE_SPILL_AGE 300 Buffered message spill age
_BUFFERED_PUBLISHER_FLOW_CONTROL_THRESHOLD 0 Flow control threshold for buffered publishers except capture
_BUFFER_BUSY_WAIT_TIMEOUT 100 buffer busy wait time in centiseconds
_BUFQ_STOP_FLOW_CONTROL FALSE Stop enforcing flow control for buffered queues
_BUILD_DEFERRED_MV_SKIPPING_MVLOG_UPDATE TRUE DEFERRED MV creation skipping MV log setup update
_BUMP_HIGHWATER_MARK_COUNT 0 how many blocks should we allocate per free list on advancing HWM
_BWR_FOR_FLUSHED_PI TRUE if TRUE, generate a BWR for a flushed PI
_BYPASS_SRL_FOR_SO_EOR FALSE bypass SRL for S/O EOR logs
_BYPASS_XPLATFORM_ERROR FALSE bypass datafile header cross-platform-compliance errors
 
   
 
_B_TREE_BITMAP_PLANS
Default: TRUE
Enable the use of bitmap plans for tables w. only B-tree indexes
_b_tree_bitmap_plans=TRUE
  _CACHE_ORL_DURING_OPEN ALL cache online logs
_CACHE_STATS_MONITOR FALSE if TRUE, enable cache stats monitoring
_CAPTURE_BUFFER_SIZE 65536 To set the size of the PGA I/O recording buffers
_CAPTURE_PUBLISHER_FLOW_CONTROL_THRESHOLD 0 Flow control threshold for capture publishers
_CASE_SENSITIVE_LOGON TRUE case sensitive logon enabled
_CATALOG_FOREIGN_RESTORE FALSE catalog foreign file restore
_CAUSAL_STANDBY_WAIT_TIMEOUT 20 Causal standby wait timeout
_CDB_COMPATIBLE TRUE CDB Compatible
_CDB_CROSS_CONTAINER 65535 Debug flag for cross container operations
_CDB_VIEW_PARALLEL_DEGREE 65535 Parallel degree for a CDB view query
_CDB_VIEW_PREFETCH_BATCH_SIZE 200 Batch Size for Prefetch for a CDB view query
_CDC_SUBSCRIPTION_OWNER Change Data Capture subscription_owner
_CDMP_DIAGNOSTIC_LEVEL 2 cdmp directory diagnostic level
_CELL_FAST_FILE_CREATE TRUE Allow optimized file creation path for Cells
_CELL_FAST_FILE_RESTORE TRUE Allow optimized rman restore for Cells
_CELL_FILE_FORMAT_CHUNK_SIZE 0 Cell file format chunk size in MB
_CELL_INDEX_SCAN_ENABLED TRUE enable CELL processing of index FFS
_CELL_MATERIALIZE_ALL_EXPRESSIONS FALSE Force materialization of all offloadable expressions on the cells
_CELL_MATERIALIZE_VIRTUAL_COLUMNS TRUE enable offload of expressions underlying virtual columns to cells
_CELL_OBJECT_EXPIRATION_HOURS 24 flashcache object expiration timeout
_CELL_OFFLOAD_BACKUP_COMPRESSION TRUE enable offload of backup compression to cells
_CELL_OFFLOAD_CAPABILITIES_ENABLED 1 specifies capability table to load
_CELL_OFFLOAD_COMPLEX_PROCESSING TRUE enable complex SQL processing offload to cells
_CELL_OFFLOAD_EXPRESSIONS TRUE enable offload of expressions to cells
_CELL_OFFLOAD_HYBRIDCOLUMNAR TRUE Query offloading of hybrid columnar compressed tables to exadata
_CELL_OFFLOAD_PREDICATE_REORDERING_ENABLED FALSE enable out-of-order SQL processing offload to cells
_CELL_OFFLOAD_SYS_CONTEXT TRUE enable offload of SYS_CONTEXT evaluation to cells
_CELL_OFFLOAD_TIMEZONE TRUE enable timezone related SQL processing offload to cells
_CELL_OFFLOAD_VIRTUAL_COLUMNS TRUE enable offload of predicates on virtual columns to cells
_CELL_RANGE_SCAN_ENABLED TRUE enable CELL processing of index range scans
_CELL_STORIDX_MINMAX_ENABLED TRUE enable Storage Index Min/Max optimization on the cells
_CELL_STORIDX_MODE EVA Cell Storage Index mode
_CGS_ALLGROUP_POLL_TIME 20000 CGS DBALL group polling interval in milli-seconds
_CGS_BIG_GROUP_ENABLED FALSE big group membership support
_CGS_COMM_READINESS_CHECK 1 CGS communication readiness check
_CGS_DBALL_GROUP_REGISTRATION local CGS DBALL group registration type
_CGS_DBGROUP_POLL_TIME 600 CGS DB group polling interval in milli-seconds
_CGS_HEALTH_CHECK_IN_RECONFIG FALSE CGS health check during reconfiguration
_CGS_MEMBERKILL_FROM_RIM_INSTANCE FALSE allow a RIM instance to issue a CSS member kill
 
   
 
_CGS_MSG_BATCHING TRUE CGS message batching
 
_CGS_MSG_BATCH_SIZE 4096 CGS message batch size in bytes
 
  _CGS_NODE_KILL_ESCALATION TRUE CGS node kill escalation to CSS
 
  _CGS_NODE_KILL_ESCALATION_WAIT 0 CGS wait time to escalate node kill to CSS in seconds
 
  _CGS_OS_LEVEL_CONNECTION_CHECK 1 allow OS level connection and interface check
 
  _CGS_OS_LEVEL_CONNECTION_REQNO 0 number of ping rqst to process at once, threads created
 
  _CGS_RECONFIG_EXTRA_WAIT 3 CGS reconfiguration extra wait time for CSS in seconds
 
  _CGS_RECONFIG_TIMEOUT 0 CGS reconfiguration timeout interval
 
  _CGS_SEND_TIMEOUT 300 CGS send timeout value
 
  _CGS_SUPPORT_RIM_DISC TRUE rim instance disconnect and reconnect event support
 
  _CGS_TICKETS 1000 CGS messaging tickets
 
  _CGS_TICKET_SENDBACK 50 CGS ticket active sendback percentage threshold
 
  _CGS_ZOMBIE_MEMBER_KILL_WAIT 20 CGS zombie member kill wait time in seconds
 
  _CHANGE_VECTOR_BUFFERS 1 Number of change vector buffers for media recovery
 
  _CHECK_BLOCK_AFTER_CHECKSUM TRUE perform block check after checksum if both are turned on
 
  _CHECK_BLOCK_NEW_INVARIANT_FOR_FLASHBACK FALSE check block new invariant for flashback
 
  _CHECK_COLUMN_LENGTH TRUE check column length
 
  _CHECK_PDBID_IN_REDO FALSE Enable checking of pluggable database ID in redo
 
  _CHECK_TS_THRESHOLD 0 check tablespace thresholds
 
  _CHILD_READ_AHEAD_DBA_CHECK FALSE if TRUE, assert child read ahead dba to be continuous of parent
 
  _CLEANOUT_SHRCUR_BUFFERS TRUE if TRUE, cleanout shrcur buffers
 
  _CLEANUP_TIMEOUT 150 timeout value for PMON cleanup
 
  _CLEANUP_TIMEOUT_FLAGS 0 flags for PMON cleanup timeout
 
  _CLIENT_NTFN_CLEANUP_INTERVAL 2400 interval after which dead client registration cleanup task repeats
 
  _CLIENT_NTFN_PINGINTERVAL 75 time between pings to unreachable notification clients
 
  _CLIENT_NTFN_PINGRETRIES 6 number of times to ping unreachable notification clients
 
  _CLIENT_NTFN_PINGTIMEOUT 30000 timeout to connect to unreachable notification clients
 
  _CLIENT_TSTZ_ERROR_CHECK TRUE Should Client give error for suspect Timestamp with Timezone operations
 
  _CLI_CACHEBKTALLOC 100 Percentage of memory to allocate
 
  _CLONE_ONE_PDB_RECOVERY FALSE Recover ROOT and only one PDB in clone database
 
  _CLOSE_DEQ_BY_COND_CURS FALSE Close Dequeue By Condition Cursors
 
  _CLOUD_NAME gsm cloud name
 
_CLUSTERWIDE_GLOBAL_TRANSACTIONS TRUE Enable/disable clusterwide global transactions
 
_CLUSTER_FLASH_CACHE_SLAVE_FILE
Default: None Defined
Cluster flash cache slave file for default block size
 
_CLUSTER_LIBRARY
Default: clss
Cluster library selection
 
_COLLAPSE_WAIT_HISTORY FALSE Collapse wait history
 
_COLLECT_TEMPUNDO_STATS TRUE Collect Statistics v$tempundostat
 
_COLLECT_UNDO_STATS TRUE Collect Statistics v$undostat
 
_COLUMN_COMPRESSION_FACTOR 0 Column compression ratio
 
_COLUMN_ELIMINATION_OFF FALSE Turn off predicate-only column elimination
 
_COLUMN_TRACKING_LEVEL 1 Column usage tracking
 
_COMMON_DATA_VIEW_ENABLED TRUE Common objects returned through dictionary views
 
_COMMON_USER_PREFIX
Default: C##
Enforce restriction on a prefix of a Common User/Role/Profile name
 
_COMPILATION_CALL_HEAP_EXTENT_SIZE 16384 Size of the compilation call heaps extents
 
_COMPLEX_VIEW_MERGING
Default: TRUE
Enable complex view merging
_complex_view_merging=TRUE
_COMPRESSION_ABOVE_CACHE 0 Number of recompression above cache for sanity check
 
_COMPRESSION_ADVISOR 0 Compression advisor
 
_COMPRESSION_CHAIN 90 Percentage of chained rows allowed for Compression
 
_COMPRESSION_COMPATIBILITY 12.1.0.2.0 Compression compatability
 
_CONCURRENCY_CHOSEN 10 What is the chosen value of concurrency
 
_CONNECTION_BROKER_HOST
Default: None Defined
Localhost connection broker host for listen address
 
_CONNECT_BY_USE_UNION_ALL
Default: TRUE
Use union all for connect by
 
_CONTROLFILE_AUTOBACKUP_DELAY 300 Time delay (in seconds) for performing controlfile autobackups
 
_CONTROLFILE_BACKUP_COPY_CHECK TRUE Enable check of the copied blocks during controlfile backup copy
 
_CONTROLFILE_BLOCK_SIZE 0 Control file block size in bytes
 
_CONTROLFILE_ENQUEUE_DUMP FALSE Dump the system states after controlfile enqueue timeout
 
_CONTROLFILE_ENQUEUE_HOLDING_TIME 120 Control file enqueue max holding time in seconds
 
_CONTROLFILE_ENQUEUE_HOLDING_TIME_TRACKING_SIZE
Default: 10
Control file enqueue holding time tracking size
 
_CONTROLFILE_ENQUEUE_TIMEOUT
Default: 900
Control file enqueue timeout in seconds
 
_CONTROLFILE_SECTION_INIT_SIZE
Default: None Defined
Control file initial section size
 
_CONTROLFILE_SECTION_MAX_EXPAND
Default: 900
Control file max expansion rate
 
_CONTROLFILE_SPLIT_BRAIN_CHECK
Default: TRUE
Check for a split-brain in distributed lock manager domain
 
_CONTROLFILE_UPDATE_CHECK
Default: OFF
Controlfile update sanity check
 
_CONVERT_SET_TO_JOIN
Default: FALSE
Enables conversion of set operator to join
_convert_set_to_join=FALSE
_COORD_MESSAGE_BUFFER
Default: 0
Parallel recovery coordinator side extra message buffer size
 
_CORRUPTED_ROLLBACK_SEGMENTS
Default: TRUE
Marks an undo segment as corrupt so it can be dropped
SQL> select segment_name, tablespace_name, status from dba_rollback_segs;

SEGMENT_NAME                   TABLESPACE_NAME                STATUS
------------------------------ ------------------------------ --------------
SYSTEM                         SYSTEM                         ONLINE
_SYSSMU1_1222867085$           UNDOTBS1                       NEEDS RECOVERY
_SYSSMU20_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU19_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU18_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU17_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU16_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU15_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU14_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU13_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU12_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU11_1235038139$          UNDOTBS2                       ONLINE

SQL> create pfile from spfile;

SQL> shutdown abort

-- edit pfile and add
_corrupted_rollback_segments=('_SYSSMU1_1222867085$')

SQL> create spfile from pfile

SQL> startup

SQL> drop rollback segment "_SYSSMU1_1222867085$";
_COST_EQUALITY_SEMI_JOIN
Default: TRUE
Enables costing of equality semi-join
_cost_equality_semi_join=TRUE
_CP_NUM_HASH_LATCHES
Default: 1
Connection pool number of hash latches
 
_CPU_EFF_THREAD_MULTIPLIER
Default: 'CPU'
Effective thread multiplier
 
_CPU_TO_IO
Default: 0
Divisor for converting CPU cost to I/O cost
_cpu_to_io=0
  _CPU_UTIL_ADJ_FORCE 0 force cpu util adjustment
 
  _CPU_UTIL_ADJ_TARGET 0 cpu utilization adjustment target
 
  _CREATE_STAT_SEGMENT 0 create ilm statistics segment
 
  _CREATE_TABLE_IN_ANY_CLUSTER FALSE allow creation of table in a cluster not owned by the user
 
  _CROSS_CON_ROW_COUNT FALSE use actual row count for cross container views
 
  _CRS_2PHASE bypass crs 2phase
 
  _CR_GRANT_GLOBAL_ROLE TRUE if TRUE, grant lock for CR requests when block is in global role
 
  _CR_GRANT_LOCAL_ROLE AUTO turn 3-way CR grants off, make it automatic, or turn it on
 
  _CR_GRANT_ONLY FALSE if TRUE, grant locks when possible and do not send the block
 
  _CR_SERVER_LOG_FLUSH TRUE if TRUE, flush redo log before serving a CR buffer
 
  _CR_TRC_BUF_SIZE 8192 size of cr trace buffer
 
  _CTX_DOC_POLICY_STEMS FALSE enable ctx_doc.policy_stems api
 
  _CURSOR_BIND_CAPTURE_AREA_SIZE 400 maximum size of the cursor bind capture area
 
  _CURSOR_BIND_CAPTURE_INTERVAL 900 interval (in seconds) between two bind capture for a cursor
 
  _CURSOR_CACHE_TIME 900 number of seconds a session cached cursor stay in cache.
 
  _CURSOR_DB_BUFFERS_PINNED 725 additional number of buffers a cursor can pin at once
 
  _CURSOR_DIAGNOSTIC_NODE_AGEDOUT_COUNT 100 Number of cursor-sharing diagnostic nodes to retain before reuse
 
_CURSOR_FEATURE_ENABLED
Default: 2
Shared cursor features enabled bits
_cursor_feature_enabled=3
_CURSOR_OBSOLETE_THRESHOLD
Default: 1024
Number of cursors per parent before obsoletion. Use if too many obsolete cursors are being created.
-- required
_cursor_feature_enabled
=2048
events= "106001 trace name context forever, level 1024"
-- then

_cursor_obsolete_threshold
=25
  _CURSOR_PLAN_ENABLED TRUE enable collection and display of cursor plans
 
  _CURSOR_PLAN_HASH_VERSION 1 version of cursor plan hash value
 
  _CURSOR_PLAN_UNPARSE_ENABLED TRUE enables/disables using unparse to build projection/predicates
 
  _CURSOR_RELOAD_FAILURE_THRESHOLD 0 Number of failed reloads before marking cursor unusable
 
  _CURSOR_RUNTIMEHEAP_MEMLIMIT 5242880 Shared cursor runtime heap memory limit
 
  _CURSOR_STATS_ENABLED TRUE Enable cursor stats
 
  _CU_ROW_LOCKING 0 CU row level locking
 
  _CVW_ENABLE_WEAK_CHECKING TRUE enable weak view checking
 
  _DATA_TRANSFER_CACHE_BC_PERC_X100 500 Percentange * 100 of buffer cache to transfer to data transfer cache
_DATA_TRANSFER_CACHE_SIZE 0 Size of data transfer cache / Obsolete /
_DATA_WAREHOUSING_SCAN_BUFFERS TRUE if TRUE, enable data warehousing scan buffers
_DATA_WAREHOUSING_SCAN_FLASH_BUFFERS FALSE if TRUE, enable data warehousing scan flash buffers
_DATA_WAREHOUSING_SERIAL_SCAN TRUE if TRUE, enable data warehousing serial scans
_DBFS_MODIFY_IMPLICIT_FETCH TRUE DBFS Link allows implicit fetch on modify - only on SecureFiles
_DBG_PROC_STARTUP FALSE debug process startup
_DBG_SCAN 0 generic scan debug
_DBOP_ENABLED 1 Any positive number enables automatic DBOP monitoring. 0 is disabled
_DBPOOL_NAME gsm database pool name
_DBRM_DYNAMIC_THRESHOLD 33490396 DBRM dynamic threshold setting
_DBRM_NUM_RUNNABLE_LIST 0 Resource Manager number of runnable list per NUMA node
_DBRM_QUANTUM DBRM quantum
_DBRM_RUNCHK 0 Resource Manager Diagnostic Running Thread Check
_DBRM_SHORT_WAIT_US 300 Resource Manager short wait length
_DBWR_ASYNC_IO TRUE Enable dbwriter asynchronous writes
_DBWR_SCAN_INTERVAL 300 dbwriter scan interval
_DBWR_STALL_WRITE_DETECTION_INTERVAL 0 dbwriter stall write detection interval
_DB_16K_FLASH_CACHE_FILE flash cache file for 16k block size
_DB_16K_FLASH_CACHE_SIZE 0 flash cache size for _db_16k_flash_cache_file
_DB_2K_FLASH_CACHE_FILE flash cache file for 2k block size
_DB_2K_FLASH_CACHE_SIZE 0 flash cache size for _db_2k_flash_cache_file
_DB_32K_FLASH_CACHE_FILE flash cache file for 32k block size
_DB_32K_FLASH_CACHE_SIZE 0 flash cache size for _db_32k_flash_cache_file
_DB_4K_FLASH_CACHE_FILE flash cache file for 4k block size
_DB_4K_FLASH_CACHE_SIZE 0 flash cache size for _db_4k_flash_cache_file
_DB_8K_FLASH_CACHE_FILE flash cache file for 8k block size
_DB_8K_FLASH_CACHE_SIZE 0 flash cache size for _db_8k_flash_cache_file
_DB_AGING_COOL_COUNT 1 Touch count set when buffer cooled
_DB_AGING_FREEZE_CR FALSE Make CR buffers always be too cold to keep in cache
_DB_AGING_HOT_CRITERIA 2 Touch count which sends a buffer to head of replacement list
_DB_AGING_STAY_COUNT 0 Touch count set when buffer moved to head of replacement list
_DB_AGING_TOUCH_TIME 3 Touch count which sends a buffer to head of replacement list
_DB_ALWAYS_CHECK_SYSTEM_TS TRUE Always perform block check and checksum for System tablespace
 
   
 
_DB_ALWAYS_CHECK_SYSTEM_TS
Default: TRUE
When set to FALSE stops Oracle from check for corrupt blocks in the SYSTEM tablespace during startup
SQL> ALTER SYSTEM SET "_db_always_check_system_ts" = FALSE;
SQL> ALTER SYSTEM SET db_block_checksum = FALSE;
  _DB_CHANGE_NOTIFICATION_ENABLE TRUE enable db change notification
_DB_CHECK_CELL_HINTS FALSE
_DB_DISABLE_TEMP_ENCRYPTION FALSE Disable Temp Encryption for Spills
_DB_DISCARD_LOST_MASTERKEY FALSE discard lost masterkey handles
_DB_DUMP_FROM_DISK_AND_EFC 0 dump contents from disk and efc
_DB_DW_SCAN_OBJ_COOLING_FACTOR 500 DW Scan object cooling factor to cool all temperatures
_DB_DW_SCAN_OBJ_COOLING_INTERVAL 100 DW Scan object cooling interval in number of scans, seconds, ct of cache size
_DB_DW_SCAN_OBJ_COOLING_POLICY CACHE_SIZE DW scan objtect cooling policy
_DB_DW_SCAN_OBJ_WARMING_INCREMENT 1000 DW Scan object warming increment when an object is scanned
_DB_FAST_OBJ_CHECK FALSE enable fast object drop sanity check
_DB_FAST_OBJ_CKPT TRUE enable fast object checkpoint
_DB_FAST_OBJ_TRUNCATE TRUE enable fast object truncate
_DB_FILE_DIRECT_IO_COUNT 1048576 Sequential I/O buf size
_DB_FILE_EXEC_READ_COUNT 128 multiblock read count for regular clients
_DB_FILE_FORMAT_IO_BUFFERS 4 Block formatting I/O buf count
_DB_FILE_NONCONTIG_MBLOCK_READ_COUNT 11 number of noncontiguous db blocks to be prefetched
_DB_FILE_OPTIMIZER_READ_COUNT 8 multiblock read count for regular clients

_DB_FLASH_CACHE_DISABLE_WRITE_BATCHSIZE 4096 Flash cache disable writes processing batchsize
_DB_FLASH_CACHE_FORCE_REPLENISH_LIMIT 8 Flash cache force replenish lower limit in buffers
_DB_FLASH_CACHE_KEEP_LIMIT 80 Flash cache keep buffer upper limit in percentage
_DB_FLASH_CACHE_MAX_LATENCY 400 Flash cache maximum latency allowed in 10 milliseconds
_DB_FLASH_CACHE_MAX_OUTSTANDING_WRITES 32 Flash cache maximum outstanding writes allowed
_DB_FLASH_CACHE_MAX_READ_RETRY 3 Flash cache max read retry
_DB_FLASH_CACHE_MAX_SLOW_IO 3 Flash cache maximum slow io allowed
_DB_FLASH_CACHE_WRITE_LIMIT 1 Flash cache write buffer upper limit in percentage
_DB_FULL_CACHING TRUE enable full db implicit caching
_DB_FULL_DB_CACHE_DIFF_PCT 5 Cache at least this % larger than DB size for full db caching
_DB_GENERATE_DUMMY_MASTERKEY FALSE if TRUE, use old havior and generate dummy master key
_DB_HANDLES 3000 System-wide simultaneous buffer operations
_DB_HANDLES_CACHED 10 Buffer handles cached each process
_DB_HOT_BLOCK_TRACKING FALSE track hot blocks for hash latch contention
_DB_INDEX_BLOCK_CHECKING TRUE index block checking override parameter
_DB_INITIAL_CACHESIZE_CREATE_MB 256 size of cache created at startup
_DB_L2_TRACING 0 flash cache debug tracing
_DB_LARGE_DIRTY_QUEUE 25 Number of buffers which force dirty queue to be written
_DB_LOST_WRITE_CHECKING 2 Enable scn based lost write detection mechanism
_DB_LOST_WRITE_CORRUPT_BLOCK FALSE allow corruption for lost write
_DB_LOST_WRITE_TRACING FALSE Enable _db_lost_write_checking tracing
_DB_MTTR_ADVICE ON MTTR advisory
_DB_MTTR_PARTITIONS 0 number of partitions for MTTR advisory
_DB_MTTR_SAMPLE_FACTOR 64 MTTR simulation sampling factor
_DB_MTTR_SIM_TARGET MTTR simulation targets
_DB_MTTR_SIM_TRACE_SIZE 256 MTTR simulation trace size
_DB_MTTR_TRACE_TO_ALERT FALSE dump trace entries to alert file
_DB_NOARCH_DISBLE_OPTIM FALSE Image redo logging (NOARCHIVEMODE)
_DB_NUM_EVICT_WAITEVENTS 64 number of evict wait events
_DB_NUM_GSM 0 database number in gsm dbpool
_DB_OBJ_ENABLE_KSR TRUE enable ksr in object checkpoint/reuse
_DB_PERCENT_HOT_DEFAULT 50 Percent of default buffer pool considered hot
_DB_PERCENT_HOT_KEEP 0 Percent of keep buffer pool considered hot
_DB_PERCENT_HOT_RECYCLE 0 Percent of recycle buffer pool considered hot
_DB_PERCPU_CREATE_CACHESIZE 2 size of cache created per cpu in deferred cache create
_DB_PREFETCH_HISTOGRAM_STATISTICS FALSE maintain prefetch histogram statistics in x$kcbprfhs
_DB_RECOVERY_TEMPORAL_FILE_DEST default database recovery temporal file location
_DB_REQUIRED_PERCENT_FAIRSHARE_USAGE 10 percent of fairshare a processor group should always use
_DB_ROW_OVERLAP_CHECKING TRUE row overlap checking override parameter for data/index blocks
_DB_TODEFER_CACHE_CREATE TRUE buffer cache deferred create
_DB_WRITER_CHUNK_WRITES 0 Number of writes DBWR should wait for
_DB_WRITER_COALESCE_AREA_SIZE 4194304 Size of memory allocated to dbwriter for coalescing writes
_DB_WRITER_COALESCE_ENCRYPTED_BUFFERS TRUE Coalecsing for encrypted buffers
_DB_WRITER_COALESCE_WRITE_LIMIT 131072 Limit on size of coalesced write
_DB_WRITER_HISTOGRAM_STATISTICS FALSE maintain dbwr histogram statistics in x$kcbbhs
_DB_WRITER_MAX_WRITES 0 Max number of outstanding DB Writer IOs
_DB_WRITER_NOMEMCOPY_COALESCE FALSE Enable DBWR no-memcopy coalescing
_DB_WRITER_VERIFY_WRITES FALSE Enable lost write detection mechanism
 
   
 
_DB_WRITER_FLUSH_IMU
Default: TRUE
If FALSE, DBWR will not downgrade IMU txns for AGING. If TRUE allows Oracle the ability to artificially age a transaction for increased automatic cache management. Required for In-Memory Undo
SQL> ALTER SYSTEM SET "_db_writer_flush_imu" = FALSE;
  _DDE_FLOOD_CONTROL_INIT TRUE Initialize Flood Control at database open
_DD_VALIDATE_REMOTE_LOCKS TRUE GES deadlock detection validate remote locks
_DEADLOCK_DIAGNOSTIC_LEVEL 2 automatic deadlock resolution diagnostics level
_DEADLOCK_RECORD_TO_ALERT_LOG TRUE record resolved deadlocks to the alert log
_DEADLOCK_RESOLUTION_INCIDENTS_ALWAYS FALSE create incidents when resolving any deadlock?
_DEADLOCK_RESOLUTION_INCIDENTS_ENABLED TRUE create incidents during deadlock resolution
_DEADLOCK_RESOLUTION_LEVEL 1 automatic deadlock resolution level
_DEADLOCK_RESOLUTION_MIN_WAIT_TIMEOUT_SECS 60 the minimum wait timeout required for deadlock resolution
_DEADLOCK_RESOLUTION_SIGNAL_PROCESS_THRESH_SECS 60 the amount of time given to process a deadlock resolution signal
_DEAD_PROCESS_SCAN_INTERVAL 60 PMON dead process scan interval (in seconds)
_DEBUG_ENABLE FALSE wait for debug
_DEDICATED_SERVER_POLL_COUNT 10 dedicated server poll count
_DEDICATED_SERVER_POST_WAIT FALSE dedicated server post/wait
_DEDICATED_SERVER_POST_WAIT_CALL FALSE dedicated server post/wait call
_DEFAULT_ENCRYPT_ALG 0 default encryption algorithm
_DEFAULT_NON_EQUALITY_SEL_CHECK TRUE sanity check on default selectivity for like/range predicate
_DEFERRED_CONSTANT_FOLDING_MODE DEFAULT Deferred constant folding mode
_DEFERRED_LOG_DEST_IS_VALID TRUE consider deferred log dest as valid for log deletion (TRUE/FALSE)
_DEFERRED_SEG_IN_SEED TRUE Enable Deferred Segment Creation in Seed
_DEFER_EOR_ORL_ARCH_FOR_SO TRUE defer EOR ORL archival for switchover
_DEFER_LOG_BOUNDARY_CKPT TRUE defer media recovery checkpoint at log boundary
_DEFER_LOG_COUNT 100 Number of log boundaries media recovery checkpoint lags behind
_DEFER_RCV_DURING_SW_TO_SBY FALSE Defer recovery during switchover to standby
_DEFER_SGA_ALLOC_CHUNK_SIZE 1073741824 Chunk size for defer sga allocation
_DEFER_SGA_ENABLED FALSE Enable deferred shared memory allocation for SGA
_DEFER_SGA_MIN_SPSZ_AT_STARTUP 53687091200 Minimum shared pool size at startup with deferred sga enabled
_DEFER_SGA_MIN_TOTAL_DEFER_SEGS_SZ 107374182400 Minimum total deferred segs size for defer sga allocation
_DEFER_SGA_TEST_ALLOC_INTV 0 SA** sleeps for N secs before allocating a deferred segment
_DELAY_INDEX_MAINTAIN TRUE delays index maintenance until after MV is refreshed
_DEQ_EXECUTE_RESET_TIME 30 deq execute reset time
_DEQ_HT_CHILD_LATCHES 8 deq ht child latches
_DEQ_HT_MAX_ELEMENTS 100000 deq ht max elements
_DEQ_LARGE_TXN_SIZE 25000 deq large txn size
_DEQ_LOG_ARRAY_SIZE 10000 deq log array size
_DEQ_MAXWAIT_TIME 0 Change wait times between dequeue calls
_DEQ_MAX_FETCH_COUNT 10 deq max fetch count
_DESIRED_READMEM_RATE 90 The desired percentage of redo reading from memory
 
   
 
_DIMENSION_SKIP_NULL
Default: TRUE
Control dimension skip when null feature
_dimension_skip_null=TRUE
  _DIRECT_IO_SKIP_CUR_SLOT_ON_ERROR TRUE Skip current slot on error
_DIRECT_IO_SLOTS 0 number of slots for direct path I/O
_DIRECT_IO_WSLOTS 0 number of write slots for direct path I/O
_DIRECT_PATH_INSERT_FEATURES 0 disable direct path insert features
_DIRECT_READ_DECISION_STATISTICS_DRIVEN TRUE enable direct read decision based on optimizer statistics
_DIRTY_APPLIANCE_MODE FALSE Enable appliance mode even on non-appliance
_DISABLE_12751 FALSE disable policy timeout error (ORA-12751)
_DISABLE_12CBIGFILE FALSE DIsable Storing ILM Statistics in 12cBigFiles
_DISABLE_ACTIVE_INFLUX_MOVE FALSE disable active influx move during parallel media recovery
_DISABLE_APPLIANCE_CHECK FALSE Disable appliance-specific code
_DISABLE_APPLIANCE_PARTNERING FALSE Disable appliance partnering algorithms
_DISABLE_AUTOTUNE_GTX FALSE disable autotune global transaction background processes
_DISABLE_BLOCK_CHECKING FALSE disable block checking at the session level
_DISABLE_CELL_OPTIMIZED_BACKUPS FALSE disable cell optimized backups
_DISABLE_CPU_CHECK FALSE disable cpu_count check
_DISABLE_CURSOR_SHARING FALSE disable cursor sharing
_DISABLE_DATALAYER_SAMPLING FALSE disable datalayer sampling
_DISABLE_DIRECTORY_LINK_CHECK FALSE Disable directory link checking
_DISABLE_DUPLEX_LINK TRUE Turn off connection duplexing
_DISABLE_DUPLICATE_SERVICE_WARNING FALSE disable listener warning for duplicate service
_DISABLE_FASTOPEN FALSE Do Not Use Fastopen
_DISABLE_FAST_AGGREGATION FALSE fast aggregation
_DISABLE_FBA_QRW 0 disable flashback archiver query rewrite
_DISABLE_FBA_WPR 0 disable flashback archiver wait for prepared transactions
_DISABLE_FILE_LOCKS FALSE disable file locks for control, data, redo log files
_DISABLE_FILE_RESIZE_LOGGING FALSE disable file resize logging to alert log
_DISABLE_FLASHBACK_ARCHIVER 0 disable flashback archiver
_DISABLE_FLASHBACK_RECYCLEBIN_OPT TRUE Don't use the Flashback Recyclebin optimization
_DISABLE_FLASHBACK_WAIT_CALLBACK FALSE Disable flashback wait callback
_DISABLE_FUNCTION_BASED_INDEX FALSE disable function-based index matching
_DISABLE_GVAQ_CACHE FALSE Disable cache
_DISABLE_HEALTH_CHECK FALSE Disable Health Check
_DISABLE_HIGHRES_TICKS FALSE disable high-res tick counter
_DISABLE_IMAGE_CHECK FALSE Disable Oracle executable image checking
_DISABLE_IMPLICIT_ROW_MOVEMENT FALSE disable implicit row movement
_DISABLE_INCREMENTAL_CHECKPOINTS FALSE Disable incremental checkpoints for thread recovery
_DISABLE_INCREMENTAL_RECOVERY_CKPT FALSE Disable incremental recovery checkpoint mechanism
_DISABLE_INDEX_BLOCK_PREFETCHING FALSE disable index block prefetching
_DISABLE_INITIAL_BLOCK_COMPRESSION FALSE disable initial block compression
_DISABLE_INSTANCE_PARAMS_CHECK FALSE disable instance type check for ksp
_DISABLE_INTERFACE_CHECKING FALSE disable interface checking at startup
_DISABLE_KCBHXOR_OSD FALSE disable kcbh(c)xor OSD functionality
_DISABLE_KCBL_FLASHBACK_BLOCKNEW_OPT FALSE Disable KCBL flashback block new optimization
_DISABLE_KCB_FLASHBACK_BLOCKNEW_OPT FALSE Disable KCB flashback block new optimization
_DISABLE_KGGHSHCRC32_OSD FALSE disable kgghshcrc32chk OSD functionality
_DISABLE_LOGGING FALSE Disable logging
_DISABLE_METRICS_GROUP 0 Disable Metrics Group (or all Metrics Groups)
_DISABLE_MODSVC_REFRESH disable modify service cache refresh
_DISABLE_MULTIPLE_BLOCK_SIZES FALSE disable multiple block size support (for debugging)
_DISABLE_NTLOG_EVENTS FALSE Disable logging to NT event log
_DISABLE_ODM FALSE disable odm feature
_DISABLE_ORADEBUG_COMMANDS none disable execution of certain categories of oradebug commands
_DISABLE_PARALLEL_CONVENTIONAL_LOAD FALSE Disable parallel conventional loads
_DISABLE_PRIMARY_BITMAP_SWITCH FALSE disable primary bitmap switch
_DISABLE_READ_ONLY_OPEN_DICT_CHECK FALSE Disable read-only open dictionary check
_DISABLE_REBALANCE_SPACE_CHECK FALSE disable space usage checks for storage reconfiguration
_DISABLE_RECOVERY_READ_SKIP FALSE Disable the read optimization during media recovery
_DISABLE_ROLLING_PATCH 0 Disable Rolling Patch Feature
_DISABLE_SAMPLE_IO_OPTIM FALSE disable row sampling IO optimization
_DISABLE_SAVEPOINT_RESET FALSE disable the fix for bug 1402161
_DISABLE_SELFTUNE_CHECKPOINTING FALSE Disable self-tune checkpointing
_DISABLE_STORAGE_TYPE FALSE Disable storage type checks
_DISABLE_STREAMS_DIAGNOSTICS 0 streams diagnostics
_DISABLE_STREAMS_POOL_AUTO_TUNING FALSE disable streams pool auto tuning
_DISABLE_SYSTEM_STATE 4294967294 disable system state dump
_DISABLE_SYSTEM_STATE_WAIT_SAMPLES FALSE Disable system state dump - wait samples
_DISABLE_TEMP_TABLESPACE_ALERTS FALSE disable tablespace alerts for TEMPORARY tablespaces
_DISABLE_THREAD_INTERNAL_DISABLE FALSE Disable thread internal disable feature
_DISABLE_THREAD_SNAPSHOT TRUE Thread snapshot
_DISABLE_TXN_ALERT 0 disable txn layer alert
_DISABLE_UNDO_TABLESPACE_ALERTS FALSE disable tablespace alerts for UNDO tablespaces
_DISABLE_WAIT_STATE Disable wait state
_DISCARD_CMN_DDL_IN_PDB_ERR FALSE Discard error when Common DDL is attempted in PDB
_DISCRETE_TRANSACTIONS_ENABLED FALSE enable OLTP mode
_DISKMON_PIPE_NAME DiSKMon skgznp pipe name
_DISK_SECTOR_SIZE_OVERRIDE FALSE if TRUE, OSD sector size could be overridden
_DISPATCHER_LISTEN_ON_VIP FALSE Determines if dispatcher listens on VIP if no HOST is supplied
_DISPATCHER_RATE_SCALE scale to display rate statistic (100ths of a second)
_DISPATCHER_RATE_TTL time-to-live for rate statistic (100ths of a second)
_DISTINCT_AGG_OPTIMIZATION_GSETS CHOOSE Use Distinct Aggregate Optimization for Grouping Sets
_DISTINCT_VIEW_UNNESTING FALSE enables unnesting of in subquery into distinct view
_DISTRIBUTED_RECOVERY_CONNECTION_HOLD_TIME 200 number of seconds RECO holds outbound connections open
_DLMTRACE Trace string of global enqueue type(s)
_DML_BATCH_ERROR_LIMIT 0 number or error handles allocated for DML in batch mode
_DML_FREQUENCY_TRACKING FALSE Control DML frequency tracking
_DML_FREQUENCY_TRACKING_ADVANCE TRUE Control automatic advance and broadcast of DML frequencies
_DML_FREQUENCY_TRACKING_SLOTS 4 Number of slots to use for DML frequency tracking
_DML_FREQUENCY_TRACKING_SLOT_TIME 15 Time length of each slot for DML frequency tracking
_DML_MONITORING_ENABLED TRUE enable modification monitoring
_DM_DMF_DETAILS_COMPATIBILITY 12.1.0 set dm dmf details compatibility version
_DM_ENABLE_LEGACY_DMF_OUTPUT_TYPES FALSE revert dmf output types to pre-12.1.0.1
_DM_MAX_SHARED_POOL_PCT 1 max percentage of the shared pool to use for a mining model
_DNFS_RDMA_ENABLE 1 Enable dNFS RDMA transfers
_DNFS_RDMA_MAX 1048576 Maximum size of dNFS RDMA transfer
_DNFS_RDMA_MIN 8192 Minimum size of dNFS RDMA transfer
_DOMAIN_INDEX_BATCH_SIZE 2000 maximum number of rows from one call to domain index fetch routine
_DOMAIN_INDEX_DML_BATCH_SIZE 200 maximum number of rows for one call to domain index dml routines
_DRA_BMR_NUMBER_THRESHOLD 1000 Maximum number of BMRs that can be done to a file
_DRA_BMR_PERCENT_THRESHOLD 10 Maximum percentage of blocks in a file that can be BMR-ed
_DRA_ENABLE_OFFLINE_DICTIONARY FALSE Enable the periodic creation of the offline dictionary for DRA
_DRM_PARALLEL_FREEZE TRUE if TRUE enables parallel drm freeze
_DROP_STAT_SEGMENT 0 drop ilm statistics segment
_DROP_TABLE_GRANULE 256 drop_table_granule
_DROP_TABLE_OPTIMIZATION_ENABLED TRUE reduce SGA memory use during drop of a partitioned table
_DSC_FEATURE_LEVEL 0 controls the feature level for deferred segment creation
_DSKM_HEALTH_CHECK_CNT 20 DiSKMon health check counter
_DSS_CACHE_FLUSH FALSE enable full cache flush for parallel execution
_DS_ENABLE_AUTO_TXN FALSE Dynamic Sampling Service Autonomous Transaction control parameter
_DS_IOCOUNT_IOSIZE 6553664 Dynamic Sampling Service defaults: #IOs and IO Size
_DS_PARSE_MODEL 2 Dynamic Sampling Service Parse Model control parameter
_DTREE_AREA_SIZE 131072 size of Decision Tree Classification work area
_DTREE_BINNING_ENABLED TRUE Decision Tree Binning Enabled
_DTREE_BINTEST_ID 0 Decision Tree Binning Test ID / Obsolete /
_DTREE_COMPRESSBMP_ENABLED TRUE Decision Tree Using Compressed Bitmaps Enabled / Obsolete /
_DTREE_MAX_SURROGATES 1 maximum number of surrogates
_DTREE_PRUNING_ENABLED TRUE Decision Tree Pruning Enabled
_DUMMY_INSTANCE FALSE dummy instance started by RMAN
_DUMP_10261_LEVEL 0 Dump level for event 10261, 1=>minimal dump 2=>top pga dump
_DUMP_COMMON_SUBEXPRESSIONS FALSE dump common subexpressions
_DUMP_CONNECT_BY_LOOP_DATA FALSE dump connect by loop error message into trc file
_DUMP_CURSOR_HEAP_SIZES FALSE dump comp/exec heap sizes to tryace file
_DUMP_INTERVAL_LIMIT 120 trace dump time interval limit (in seconds)
_DUMP_MAX_LIMIT 5 max number of dump within dump interval
_DUMP_QBC_TREE 0 dump top level query parse tree to trace
_DUMP_RCVR_IPC TRUE if TRUE enables IPC dump at instance eviction time
_DUMP_SCN_INCREMENT_STACK Dumps scn increment stack per session
_DUMP_SYSTEM_STATE_SCOPE local scope of sysstate dump during instance termination
_DUMP_TRACE_SCOPE global scope of trace dump during a process crash
_DYNAMIC_RLS_POLICIES TRUE rls policies are dynamic
_DYNAMIC_SHARE_RANGE_FACTOR 2 dynamic share range factor
_DYNAMIC_STATS_THRESHOLD 30 delay threshold (in seconds) between sending statistics messages
 
   
 
_EARLY_FLUSH_DELTA
Default: 0
SCN delta to trigger early log flush
 
_ELIMINATE_COMMON_SUBEXPR
Default: TRUE
Enables elimination of common sub-expressions
_eliminate_common_subexpr=TRUE
  _EMON_MAX_ACTIVE_CONNECTIONS 256 maximum open connections to clients per emon
_EMON_OUTBOUND_CONNECT_TIMEOUT 30000 timeout for completing connection set up to clients
_EMON_POOL_INC 4 increment in EMON slaves per pool type
_EMON_POOL_MAX 16 maximum number of EMON slaves per pool type
_EMON_POOL_MIN 4 minimum number of EMON slaves per pool type
_EMON_REGULAR_NTFN_SLAVES 4 number of EMON slaves doing regular database notifications
_EMON_SEND_TIMEOUT 10000 send timeout after which the client is unregistered
_EMX_CONTROL 0 EM Express control (internal use only)
_EMX_MAX_SESSIONS 128 Maximum number of sessions in the EM Express cache
_EMX_SESSION_TIMEOUT 3600 Session timeout (sec) in the EM Express cache
_ENABLE_12G_BFT TRUE enable 12g bigfile tablespace
_ENABLE_ASYNCVIO FALSE enable asynch vectored I/O
_ENABLE_AUTOMATIC_MAINTENANCE 1 if 1, Automated Maintenance Is Enabled
_ENABLE_AUTOMATIC_SQLTUNE TRUE Automatic SQL Tuning Advisory enabled parameter
_ENABLE_BLOCK_LEVEL_TRANSACTION_RECOVERY TRUE enable block level recovery
_ENABLE_CHECK_TRUNCATE TRUE enable checking of corruption caused by canceled truncate
_ENABLE_COLUMNAR_CACHE 1 Enable Columnar Flash Cache Rewrite
_ENABLE_CSCN_CACHING FALSE enable commit SCN caching for all transactions
_ENABLE_DDL_WAIT_LOCK TRUE use this to turn off ddls with wait semantics
_ENABLE_DEFAULT_AFFINITY 0 enable default implementation of hard affinity osds
_ENABLE_DEFAULT_TEMP_THRESHOLD TRUE Enable Default Tablespace Utilization Threshold for UNDO Tablespaces
_ENABLE_DEFAULT_UNDO_THRESHOLD TRUE Enable Default Tablespace Utilization Threshold for TEMPORARY Tablespaces
_ENABLE_DML_LOCK_ESCALATION TRUE enable dml lock escalation against partitioned tables if TRUE
_ENABLE_EDITIONS_FOR_USERS FALSE enable editions for all users
_ENABLE_EXCHANGE_VALIDATION_USING_CHECK TRUE use check constraints on the table for validation
_ENABLE_FAST_FILE_ZERO TRUE enable fast file zero code path
_ENABLE_FAST_REF_AFTER_MV_TBS FALSE enable fast refresh after move tablespace
_ENABLE_FFW TRUE FAL FORWARDING
_ENABLE_FLASH_LOGGING TRUE Enable Exadata Smart Flash Logging
_ENABLE_FRONT_END_VIEW_OPTIMIZATION 1 enable front end view optimization
_ENABLE_HASH_OVERFLOW FALSE TRUE - enable hash cluster overflow based on SIZE
_ENABLE_HEATMAP_INTERNAL FALSE heatmap related - to be used by oracle dev only
_ENABLE_HWM_SYNC TRUE enable HWM synchronization
 
   
 
  _ENABLE_IEE_STATS TRUE enables IEE stats gathering
 
  _ENABLE_ILM_FLUSH_STATS TRUE Enable ILM Stats Flush
 
  _ENABLE_ILM_TESTFLUSH_STATS FALSE Enable Test ILM Stats Flush
 
  _ENABLE_KERNEL_IO_OUTLIERS FALSE enable kernel I/O outlier feature
 
  _ENABLE_KQF_PURGE TRUE Enable KQF fixed runtime table purge
 
  _ENABLE_LIST_IO FALSE Enable List I/O
 
  _ENABLE_METRICS_ALLPDB TRUE Enable/Disable Metrics for Root and all PDBs if applicable
 
  _ENABLE_METRICS_PDB FALSE Enable/Disable Metrics for this Non-Root PDB
 
  _ENABLE_MIDTIER_AFFINITY TRUE enable midtier affinity metrics processing
 
  _ENABLE_MINSCN_CR TRUE enable/disable minscn optimization for CR
 
  _ENABLE_NATIVENET_TCPIP FALSE Enable skgxp driver usage for native net
_ENABLE_OBJ_QUEUES TRUE enable object queues
_ENABLE_OFFLOADED_WRITES FALSE Enable offloaded writes for Unit Test
_ENABLE_ONLINE_INDEX_WITHOUT_S_LOCKING TRUE Allow online index creation algorithm without S DML lock
 
   
 
  _ENABLE_PLUGGABLE_DATABASE FALSE Enable Pluggable Database
 
  _ENABLE_QUERY_REWRITE_ON_REMOTE_OBJS TRUE mv rewrite on remote table/view
 
  _ENABLE_REDO_GLOBAL_POST FALSE LGWR post globally on write
 
  _ENABLE_REFRESH_SCHEDULE TRUE enable or disable MV refresh scheduling (revert to 9.2 behavior)
 
  _ENABLE_RELIABLE_LATCH_WAITS TRUE Enable reliable latch waits
 
_ENABLE_RENAME_USER
Default: FALSE
Enable RENAME-clause using ALTER USER statement
SQL> ALTER SESSION SET "_enable_rename_user"=TRUE;
Session altered.

SQL> ALTER SYSTEM ENABLE RESTRICTED SESSION;
System altered.

SQL> ALTER USER uwclass RENAME TO uwclass_test IDENTIFIED BY Wi1!ThisW0rK;
User altered.

SQL> ALTER SYSTEM DISABLE RESTRICTED SESSION;
System altered.
SQL> ALTER SESSION SET "_enable_rename_user"=FALSE;
Session altered.

SQL> SELECT username FROM dba_users WHERE username LIKE '%UWCLASS%';

USERNAME
------------------------------
UWCLASS_TEST
_ENABLE_RLB
Default:: TRUE
Enable RLB metrics processing
 
_ENABLE_ROW_SHIPPING
Default: TRUE
Use the row shipping optimization for wide table selects
 
_ENABLE_SCHEMA_SYNONYMS
Default: FALSE
Enable DDL operations (e.g. creation) involving schema synonyms
ALTER SYSTEM SET "_enable_schema_synonyms"=TRUE SCOPE=SPFILE;
-- for examples of schema synonym creation click on the Synonyms link at page bottom
  _ENABLE_SCN_WAIT_INTERFACE TRUE use this to turn off scn wait interface in kta
 
  _ENABLE_SECUREFILE_FLASHBACK_OPT FALSE Enable securefile flashback optimization
 
  _ENABLE_SEPARABLE_TRANSACTIONS FALSE enable/disable separable transactions
 
  _ENABLE_SHARED_POOL_DURATIONS TRUE temporary to disable/enable kgh policy
 
  _ENABLE_SHARED_SERVER_VECTOR_IO FALSE Enable shared server vector I/O
 
  _ENABLE_SPACEBG TRUE enable space management background task
 
  _ENABLE_SPACE_PREALLOCATION 3 enable space pre-allocation
 
  _ENABLE_TABLESPACE_ALERTS TRUE enable tablespace alerts
 
_ENABLE_TYPE_DEP_SELECTIVITY
Default: TRUE
Enable type dependent selectivity estimates
_enable_type_dep_selectivity=TRUE
  _ENDPROT_CHUNK_COMMENT chk 10235 dflt chunk comment for selective overrun protection
_ENDPROT_HEAP_COMMENT hp 10235 dflt heap comment for selective overrun protection
_ENDPROT_SUBHEAPS TRUE selective overrun protection for subeheaps
_ENQUEUE_DEADLOCK_DETECT_ALL_GLOBAL_LOCKS FALSE enable deadlock detection on all global enqueues
_ENQUEUE_DEADLOCK_SCAN_SECS 0 deadlock scan interval
_ENQUEUE_DEADLOCK_TIME_SEC 5 requests with timeout <= this will not have deadlock detection
_ENQUEUE_DEBUG_MULTI_INSTANCE FALSE debug enqueue multi instance
_ENQUEUE_HASH 979 enqueue hash table length
_ENQUEUE_HASH_CHAIN_LATCHES 4 enqueue hash chain latches
_ENQUEUE_LOCKS 5860 locks for managed enqueues
_ENQUEUE_PARANOIA_MODE_ENABLED FALSE enable enqueue layer advanced debugging checks
_ENQUEUE_RESOURCES 2296 resources for enqueues
_ENQUEUE_SYNC_RETRY_ATTEMPTS 3 max number of times the bg process to retry synchronous enqueue open if it failed because master could not allocate memory
 
   
 
  _ENQUEUE_SYNC_SIM_MEM_ERROR FALSE simulate master instance running out of memory when synchronously getting a remotely mastered enqueue
 
  _EVOLVE_PLAN_BASELINE_REPORT_LEVEL typical Level of detail to show in plan verification/evolution report / Obsolete /
 
  _EVT_SYSTEM_EVENT_PROPAGATION TRUE disable system event propagation
 
  _EXPAND_AGGREGATES TRUE expand aggregates
 
  _EXPLAIN_REWRITE_MODE FALSE allow additional messages to be generated during explain rewrite
 
  _EXTENDED_PRUNING_ENABLED TRUE do runtime pruning in iterator if set to TRUE
 
  _EXTERNAL_SCN_LOGGING_THRESHOLD_SECONDS 86400 High delta SCN threshold in seconds
 
  _EXTERNAL_SCN_REJECTION_DELTA_THRESHOLD_MINUTES 0 external SCN rejection delta threshold in minutes
 
  _EXTERNAL_SCN_REJECTION_THRESHOLD_HOURS 24 Lag in hours between max allowed SCN and an external SCN
 
  _EXTERNAL_TABLE_SMART_SCAN HADOOP_ONLY External Table Smart Scan
 
  _FAIRNESS_THRESHOLD 2 number of times to CR serve before downgrading lock
 
  _FAIR_REMOTE_CVT FALSE if TRUE enables fair remote convert
 
  _FASTPIN_ENABLE 1 enable reference count based fast pins
 
  _FAST_CURSOR_REEXECUTE FALSE use more memory in order to get faster execution
 
  _FAST_DUAL_ENABLED TRUE enable/disable fast dual
 
_FAST_FULL_SCAN_ENABLED
Default TRUE
Enable/disable index fast full scan
_fast_full_scan_enabled=TRUE
  _FAST_INDEX_MAINTENANCE TRUE fast global index maintenance during PMOPs
 
  _FAST_PSBY_CONVERSION TRUE Enable fast physical standby conversion
 
  _FG_IORM_SLAVES 1 ForeGround I/O slaves for IORM
 
  _FG_LOG_CHECKSUM TRUE Checksum redo in foreground process
 
  _FG_SYNC_SLEEP_USECS 0 Log file sync via usleep
 
  _FIC_ALGORITHM_SET automatic Set Frequent Itemset Counting Algorithm
 
  _FIC_AREA_SIZE 131072 size of Frequent Itemset Counting work area
 
  _FIC_MAX_LENGTH 20 Frequent Itemset Counting Maximum Itemset Length / Obsolete /
 
  _FIC_MIN_BMSIZE 1024 Frequent Itemset Counting Minimum BITMAP Size
 
  _FIC_OUTOFMEM_CANDIDATES FALSE Frequent Itemset Counting Out Of Memory Candidates Generation / Obsolete /
 
_FILEMAP_DIR
Default: None Defined
FILEMAP Directory
TBD
  _FILE_OFFLINE_SYNC_TIMEOUT 900 Timeout to sync file offline enqueue (secs)
 
  _FILE_SET_ENQUEUE_TIMEOUT 1200 Timeout to acquire file set enqueue (secs)
 
  _FILE_SIZE_INCREASE_INCREMENT 67108864 Amount of file size increase increment, in bytes
 
_FIRST_K_ROWS_DYNAMIC_PRORATION
Default TRUE
Enable the use of dynamic proration of join cardinalities
_first_k_rows_dynamic_proration=TRUE
_FIRST_SPARE_PARAMETER
Default: None Defined
First spare parameter - integer
TBD
_FIX_CONTROL
Default: None Defined
Bug fix control parameter
TBD
_FLUSH_ILM_STATS
Default: 0
Flush ilm stats
 
_FLUSH_REDO_TO_STANDBY
Default: 0
Flush redo to standby test event parameter
 
_FLUSH_UNDO_AFTER_TX_RECOVERY
Default: TRUE
If TRUE, flush undo buffers after TX recovery
 
_FORCE_ARCH_COMPRESS
Default: 0
Archive Compress all newly created compressed tables
 
_FORCE_DATEFOLD_TRUNC
Default: FALSE
Force use of trunc for datefolding rewrite
 
_FORCE_HASH_JOIN_SPILL
Default: FALSE
Force hash join to spill to disk
 
_FORCE_HSC_COMPRESS
Default: FALSE
Compress all newly created tables
 
_FORCE_LOGGING_IN_UPGRADE
Default: TRUE
Force logging during upgrade mode
 
_FORCE_OLTP_COMPRESS
Default: FALSE
OLTP Compress all newly created compressed tables
 
_FORCE_OLTP_UPDATE_OPT
Default: TRUE
OLTP Compressed row optimization on update
 
_FORCE_REWRITE_ENABLE
Default: FALSE
Control new query rewrite features
 
_FORCE_SLAVE_MAPPING_INTRA_PART_LOADS
Default: FALSE
Force slave mapping for intra partition loads
 
_FORCE_SYS_COMPRESS
Default: TRUE
Force SYS_COMPRESS for LOBs
 
_FORCE_TEMPTABLES_FOR_GSETS
Default: FALSE
Executes concatenation of rollups using temp tables
 
_FORCE_TMP_SEGMENT_LOADS
Default: FALSE
Force tmp segment loads
 
_FORWARDED_2PC_THRESHOLD
Default: 10
Auto-tune threshold for two-phase commit rate across RAC instances
 
_FRAME_CACHE_TIME
Default: 0
Number of seconds a cached frame page stay in cache.
 
_FULL_DIAG_ON_RIM
Default: FALSE
Rim nodes have full DIA* function
 
_FULL_PWISE_JOIN_ENABLED
Default: TRUE
Enable full partition-wise join when TRUE
 
  _GCR_CPU_MIN_FREE 10 minimum amount of free CPU to flag an anomaly
 
  _GCR_CSS_GROUP_LARGE size of large CSS group above which query/update disabled
 
  _GCR_CSS_GROUP_QUERY_BOOST allowed number of serial multiple queries
 
  _GCR_CSS_GROUP_TRY_LOCK_DELAY minimum delay between group locking attempts, secs
 
  _GCR_CSS_GROUP_UPDATE2_INTERVAL interval between CSS group updates when busy, secs
 
  _GCR_CSS_GROUP_UPDATE_INTERVAL interval between CSS group updates, secs
 
  _GCR_CSS_USE_2GROUP_LOCK TRUE if FALSE, GCR will not try to lock 2 CSS groups at the same time
 
  _GCR_ENABLE_HIGH_CPU_KILL FALSE if TRUE, GCR may kill foregrounds under high load
 
  _GCR_ENABLE_HIGH_CPU_RM TRUE if TRUE, GCR may enable a RM plan under high load
 
  _GCR_ENABLE_HIGH_CPU_RT TRUE if TRUE, GCR may boost bg priority under high load
 
  _GCR_ENABLE_HIGH_MEMORY_KILL FALSE if TRUE, GCR may kill foregrounds under high memory load
 
  _GCR_ENABLE_NEW_DRM_CHECK FALSE if FALSE, revert to old drm load metric
 
  _GCR_ENABLE_STATISTICAL_CPU_CHECK TRUE if FALSE, revert to old cpu load metric
 
  _GCR_HIGH_CPU_THRESHOLD 10 minimum amount of CPU process must consume to be kill target
 
  _GCR_HIGH_MEMORY_THRESHOLD 10 minimum amount of Memory process must consume to be kill target
 
  _GCR_MAX_RT_PROCS maximum number of RT DLM processes allowed by GCR
 
  _GCR_MEM_MIN_FREE 10 minimum amount of free memory to flag an anomaly
 
  _GCR_TICK duration of time tick used by state machine, centisecs
 
  _GCR_USE_CSS TRUE if FALSE, GCR wont register with CSS nor use any CSS feature
 
_GENERALIZED_PRUNING_ENABLED
Default: TRUE
Controls extensions to partition pruning for general predicates
_generalized_pruning_enabled=TRUE
_GES_DD_DEBUG
Default: 1
If 1 or higher enables GES deadlock detection debug diagnostics
_ges_dd_debug=1
_GES_DEFAULT_LMDS
Default: '*'
Default lmds for enqueue hashing
_ges_default_lmds='*'
_GES_DESIGNATED_MASTER
Defaul TRUE
Designated master for GES and GCS resources
_ges_designated_master=TRUE
_GES_DIAGNOSTICS
Default: TRUE
If TRUE enables GES diagnostics
_ges_diagnostics=TRUE
_GES_DIAGNOSTICS_ASM_DUMP_LEVEL
Default: 11
Systemstate level on global enqueue diagnostics blocked by ASM
_ges_diagnostics_asm_dump_level=11
_GES_DIRECT_FREE
Default: FALSE
If TRUE, free each resource directly to the freelist
_ges_direct_free=FALSE
_GES_DIRECT_FREE_RES_TYPE
Default: CTARAH
String of resource types(s) to directly free to the freelist
_ges_direct_free_res_type='CTARAH'
_GES_DUMP_OPEN_LOCKS
Default: FALSE
If TRUE, dump open locks for the LCK process during shutdown
_ges_dump_open_locks=FALSE
_GES_FGGL
Default: TRUE
DLM fg grant lock on/off
_ges_fggl=TRUE
_GES_FREEABLE_RES_CHUNK_FREE
Default: FALSE
If TRUE, free dynamic resource chunks which are freeable
_ges_freeable_res_chunk_free=FALSE
_GES_FREEABLE_RES_CHUNK_FREE_INTERVAL
Default: 180
Time interval for freeing freeable dynamic resource chunks
_ges_freeable_res_chunk_free_interval=180
_GES_GATHER_RES_REUSE_STATS
Default: FALSE
If TRUE, gather resource reuse statistics
_ges_gather_res_reuse_stats=FALSE
_GES_HASH_GROUPS
Default: *
Enqueue hash table groups
_ges_hash_groups='*'
_GES_HEALTH_CHECK
Default: 0
If greater than 0 enables GES system health check
_ges_health_check=0
_GES_LMD_MAPPING
Default: *
Enqueue to lmd mapping
_ges_lmd_mapping=*
_GES_NRES_DIVIDE
Default: 0
How to divide number of enqueue resources among hash tables
_ges_nres_divide=0
_GES_NUM_BLOCKERS_TO_KILL
Default: 1
Number of blockers to be killed for hang resolution
_ges_num_blockers_to_kill=1
_GES_RESOURCE_MEMORY_OPT
Default: 4
Enable different level of ges res memory optimization
_ges_resource_memory_opt=4
_GES_SERVER_PROCESSES
Default: 1
Number of background global enqueue server processes
_ges_server_processes=1
_GES_VBFREELISTS
Default: 0
Number of valueblock freelists (will be adjusted to power of 2)
_ges_vbfreelists=0
_GLOBALINDEX_PNUM_FILTER_ENABLED
Default: TRUE
Enables filter for global index with partition extended syntax
_globalindex_pnum_filter_enabled=TRUE
_GLOBAL_HANG_ANALYSIS_INTERVAL_SECS
Default: 10
The interval at which global hang analysis is run
_global_hang_analysis_interval_secs=10
_GRANT_READ_INSTEAD_OF_SELECT
Default: FALSE
Grant read privilege instead of select wherever applicable
_grant_Read_instead_of_select=TRUE
_GRANT_SECURE_ROLE
Default: FALSE
Disallow granting of Secure Role to NSR
_grant_secure_role=FALSE
_GROUPBY_NOPUSHDOWN_CUT_RATIO
Default: 3
Group By nopushdown cut ratio
_grouby_nopushdown_cut_ratio=3
_GROUPBY_ORDERBY_COMBINE
Default: 5000
Group By/Order By don't combine threshold
_groupby_orderby_combine=5000
_GS_ANTI_SEMI_JOIN_ALLOWED
Default: TRUE
Enable anti/semi join for the GS query
_gs_anti_semi_join_allowed=TRUE
_GSM
Default: None Defined
GSM Descriptions
TBD
_GSM_CONFIG_VERS
Default: 0
Version of gsm config
_gsm_config_vers=0
_GSM_CPU_THRESH
Default: 75
CPU busy threshold
_gsm_cpu_thresh=75
_GSM_DRV_INTERVAL
Default: 30
Metric derived values interval
_gsm_drv_interval=30
_GSM_MAX_INSTANCES_PER_DB
Default: 8
Maximum number of instances per database in gsm cloud
_gsm_max_instances_per_db=8
_GSM_MAX_NUM_REGIONS
Default: 10
Maximum number of regions in gsm cloud
_gsm_max_num_regions=10
_GSM_REGION_LIST
Default: None Defined
List of GSM Regions
TBD
_GSM_SRLAT_THRESH
Default: 20
Single block read latency threshold
_gsm_srlat_thresh=20
_GSM_THRESH_RESPCT
Default: 50
Threshold resource percentage
_gsm_thresh_respct=50
_GSM_THRESH_ZONE
Default: 10
Threshold zone
_gsm_thresh_zone=10
???
Default: TRUE
_HARD_PROTECTION FALSE if TRUE enable H.A.R.D specific format changes
_???=???
???
Default: TRUE
_HASHOPS_PREFETCH_SIZE 4 maximum no of rows whose relevant memory locations are prefetched
_???=???
???
Default: TRUE
_HASH_JOIN_ENABLED TRUE enable/disable hash join
_???=???
???
Default: TRUE
_HASH_MULTIBLOCK_IO_COUNT 0 number of blocks hash join will read/write at once
_???=???
???
Default: TRUE
_HB_REDO_INTERVAL 1000 generic heartbeat redo frequency
_???=???
???
Default: TRUE
_HB_REDO_MSG_INTERVAL 100 BOC HB redo message interval in ms
_???=???
???
Default: TRUE
_HEATMAP_FORMAT_1BLOCK FALSE heatmap related - to be used by oracle dev only
_???=???
???
Default: TRUE
_HEATMAP_MIN_MAXSIZE 0 Internal testing only
_???=???
???
Default: TRUE
_HEUR_DEADLOCK_RESOLUTION_SECS 0 the heuristic wait time per node for deadlock resolution
_???=???
???
Default: TRUE
_HIGHEST_PRIORITY_PROCESSES VKTM Highest Priority Process Name Mask
_???=???
???
Default: TRUE
_HIGHRES_DRIFT_ALLOWED_SEC 1 allowed highres timer drift for VKTM
_???=???
???
Default: TRUE
_HIGHTHRESHOLD_UNDORETENTION 4294967294 high threshold undo_retention in seconds
_???=???
_HIGH_PRIORITY_PROCESSES
Default: LMS*
High priority process name mask. For More information
_high_priority_processes=LMS*|VKTM
???
Default: TRUE
_HIGH_THRESHOLD_DELTA 65535 high threshold delta
_???=???
???
Default: TRUE
_HJ_BIT_FILTER_THRESHOLD 50 hash-join bit filtering threshold (0 always enabled)
_???=???
???
Default: TRUE
_HM_ANALYSIS_ORADEBUG_SYS_DUMP_LEVEL 0 the oradebug system state level for hang manager hang analysis
_???=???
???
Default: TRUE
_HM_XM_ENABLED TRUE If TRUE, DIA0 allows message exchanges across DB/ASM boundary
_???=???
???
Default: TRUE
_HPK_COMPRESSION_RANGE 5 hpk compression range
_???=???
???
Default: TRUE
_HPK_PROJECT_COST_WEIGHTING 20 hpk project cost weighting
_???=???
???
Default: TRUE
_HPK_THROUGHPUT_RANGE 5 hpk throughput range
_???=???
???
Default: TRUE
_HWM_SYNC_THRESHOLD 10 HWM synchronization threshold in percentage
_???=???
???
Default: TRUE
_IDLE_SESSION_KILL_ENABLED TRUE enables or disables resource manager session idle limit checks
_???=???
???
Default: TRUE
_IDL_CONVENTIONAL_INDEX_MAINTENANCE TRUE enable conventional index maintenance for insert direct load / Obsolete /
_???=???
???
Default: TRUE
_IDXRB_ROWINCR 100000000 proportionality constant for dop vs. rows in index rebuild
_???=???
???
Default: TRUE
_IGNORE_DESC_IN_INDEX FALSE ignore DESC in indexes, sort those columns ascending anyhow
_???=???
???
Default: TRUE
_IGNORE_EDITION_ENABLED_FOR_EV_CREATION FALSE ignore schema's edition-enabled status during EV creation
_???=???
???
Default: TRUE
_IGNORE_FG_DEPS ignore fine-grain dependencies during invalidation
_???=???
???
Default: TRUE
_ILMFLUSH_STAT_LIMIT 0 ILM flush statistics limit - Internal testing only
_???=???
???
Default: TRUE
_ILMSET_STAT_LIMIT 0 ILM set statistics limit - Internal testing only
_???=???
???
Default: TRUE
_ILMSTAT_MEMLIMIT 10 Percentage of shared pool for use by ILM Statistics
_???=???
???
Default: TRUE
_ILM_MEM_LIMIT 10 percentage of the max shared pool heat-map can use - internal
_???=???
???
Default: TRUE
_IMAGE_REDO_GEN_DELAY 0 Image redo generation delay in centi-seconds (direct write mode)
_???=???
???
Default: TRUE
_IMMEDIATE_COMMIT_PROPAGATION TRUE if TRUE, propagate commit SCN immediately
_???=???
_IMPROVED_OUTERJOIN_CARD
Default: TRUE
Improved outer-join cardinality calculation
_improved_outerjoin_card=TRUE
_IMPROVED_ROW_LENGTH_ENABLED
Default: TRUE
Enable the improvements for computing the average row length
_improved_row_length_enabled=TRUE
???
Default: TRUE
_IMR_ACTIVE TRUE Activate Instance Membership Recovery feature
_IMR_AVOID_DOUBLE_VOTING TRUE Avoid device voting for CSS reconfig during IMR
_IMR_CHECK_CSS_INCARNATION_NUMBER TRUE IMR verify the global consistency of CSS incarnation number
_IMR_CONTROLFILE_ACCESS_WAIT_TIME 10 IMR controlfile access wait time in seconds
_IMR_DEVICE_TYPE controlfile Type of device to be used by IMR
_IMR_DISKVOTE_IMPLEMENTATION auto IMR disk voting implementation method
_IMR_DISK_VOTING_INTERVAL 3 Maximum wait for IMR disk voting (seconds)
_IMR_EVICTED_MEMBER_KILL TRUE IMR issue evicted member kill after a wait
_IMR_EVICTED_MEMBER_KILL_WAIT 20 IMR evicted member kill wait time in seconds
_IMR_EXTRA_RECONFIG_WAIT 10 Extra reconfiguration wait in seconds
_IMR_HIGHLOAD_THRESHOLD IMR system highload threshold
_IMR_MAX_RECONFIG_DELAY 75 Maximum Reconfiguration delay (seconds)
_IMR_RR_HOLDER_KILL_TIME 300 IMR max time instance is allowed to hold RR lock in seconds
_IMR_SPLITBRAIN_RES_WAIT 0 Maximum wait for split-brain resolution (seconds)
_IMR_SYSTEMLOAD_CHECK TRUE Perform the system load check during IMR
_???=???
???
Default: TRUE
 
_???=???
_IMU_POOLS
Default: 3
Determines the number of pools used by In-Memory Undo
_imu_pools=5
_INCREMENTAL_RECOVERY_CKPT_MIN_BATCH
Default: 500
Minimum number of writes for incremental recovery ckpt every second
_incremental_recovery_ckpt_min_batch=500
_INDEXABLE_CON_ID
Default: TRUE
Indexing of CON_ID column enabled for X$ tables
_indexable_con_id=TRUE
_INDEX_JOIN_ENABLED
Default: TRUE
Enable the use of index joins
_index_join_enabled=TRUE
???
Default: TRUE
_INDEX_LOAD_BUF_OLTP_SACRIFICE_PCT 10 index load buf oltp sacrifice pct
_INDEX_LOAD_BUF_OLTP_UNDER_PCT 85 index load buf and comp oltp under-estimation pct
_INDEX_MAX_INC_TRANS_PCT 20 max itl expand percentage soft limit during index insert
_INDEX_PARTITION_LARGE_EXTENTS FALSE Enables large extent allocation for partitioned indices
_INDEX_PREFETCH_FACTOR 100 index prefetching factor
_INDEX_SCAN_CHECK_SKIP_CORRUPT FALSE check and skip corrupt blocks during index scans
_INDEX_SCAN_CHECK_STOPKEY FALSE check stopkey during index range scans
_INIT_GRANULE_INTERVAL 10 number of granules to process for deferred cache
_INIT_SQL_FILE %ORACLE_HOME%\RDBMS\ADMIN\SQL. File containing SQL statements to execute upon database creation BSQ
_INJECT_STARTUP_FAULT 0 inject fault in the startup code
_INPLACE_UPDATE_RETRY TRUE inplace update retry for ora1551
_INQUIRY_RETRY_INTERVAL 3 if greater than 0 enables inquiry retry after specified interval
_INSERT_ENABLE_HWM_BROKERED TRUE during parallel inserts high water marks are brokered
_INST_LOCKING_PERIOD 5 period an instance can retain a newly acquired level1 bitmap
_INTRAPART_PDML_ENABLED TRUE Enable intra-partition updates/deletes
_INTRAPART_PDML_RANDOMLOCAL_ENABLED TRUE Enable intra-partition updates/deletes with random local dist
_IOCALIBRATE_INIT_IOS 2 iocalibrate init I/Os per process
_IOCALIBRATE_MAX_IOS 0 iocalibrate max I/Os per process
_IOQ_FANIN_MULTIPLIER 2 IOQ miss count before a miss exception
_IORM_TOUT 1000 IORM scheduler timeout value in msec
_IOR_SERIALIZE_FAULT 0 inject fault in the ior serialize code
_IPC_CONFIG_OPTS_DYN 0 Dyn config for ipclw startup
_IPC_CONFIG_OPTS_STAT 0 static config for ipclw startup
_IPDDB_ENABLE TRUE Enable IPD/DB data collection
_???=???
???
Default: TRUE
 
_???=???
_KSB_RESTART_POLICY_TIMES
Default: '0, 60, 120, 240'
Process restart policy times in seconds
_ksb_restart_policy_times='0'
_ksb_restart_policy_times
='60'
_ksb_restart_policy_times='120'
_ksb_restart_policy_times='240' # internal update to set default
_LEFT_NESTED_LOOPS_RANDOM
Default: TRUE
Enable random distribution method for left of nestedloops
_left_nested_loops_random=TRUE
_LOCAL_COMMUNICATION_COSTING_ENABLED
Default: TRUE
Enable local communication costing when TRUE
_local_communication_costing_enabled=TRUE
_LOG_IO_SIZE
Obsolete
Automatically initiate log write if this many redo blocks in buffer
_log_io_size=60
_MEMORY_BROKER_STAT_INTERVAL
Default: 30
Sets the interval between AMM checks to resize the SGA. The range of values is 1 to 999 seconds
_minimal_stats_aggregation=90
 
Backup Appliance
_BA_CF_TRACE_BUFFER_SIZE
Default: 131072
Size of per-process I/O KBC trace buffer
 
_BA_CONTAINER_FILESYSTEM_AUSIZE
Default: 4194304
Allocation unit size for Backup Appliance containers
 
_BA_MAX_CONTAINERS
Default: 0
Maximum number of Backup Appliance containers
 
_BA_MAX_GROUPS
Default: 0
Maximum number of Backup Appliance container groups
 
_BA_MAX_SEG_BYTES
Default: 4000
Maximum number of bytes per array segment
 
_BA_TIMEOUTS_ENABLED
Default: TRUE
Enable timeouts
 
   
 
 

Related Topics
DBMS_WORKLOAD_REPOSITORY
Init.ora & SPFILE
Synonyms
What's New In 18c
What's New In 19c

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