Oracle X$ Structures
Version 12.1.0.1

General Information
Library Note Morgan's Library Page Footer
The Library is currently in the process of being upgraded from Oracle Database Version 11.2.0.3 to 12.1.0.1. Demos are being upgraded to reflect the new Container paradigm as well as EBR (Edition Based Redefinition) and may contain references to CDBs, PDBs, and other objects you may not be familiar with such as CDB_OBJECTS_AE: Welcome to 12c.
Purpose This page is a work in progress. As I find demos and descriptions of X$ structures this page will continue to be enhanced.

Assignments on this page are based on research, white papers, and wild guesses based on naming conventions: Some may well be incorrect.

If you have any information that might further expand these contents please forward them to me. Thank you. Morgan
Dependencies
V$FIXED_TABLE V$FIXED_VIEW_DEFINITION V$INDEXED_FIXED_COLUMN
List X$ Arrays and related information conn / as sysdba

desc v$fixed_table

desc v$fixed_view_definition

desc v$indexed_fixed_column

SELECT kqftanam
FROM x$kqfta
ORDER BY 1;

SELECT t.kqftanam "Table Name"
FROM x$kqfta t, x$kqfco c
WHERE t.indx = c.kqfcotab
AND c.kqfconam like '%SID%'
INTERSECT
SELECT DISTINCT t.kqftanam "Table Name"
FROM x$kqfta t, x$kqfco c
WHERE t.indx = c.kqfcotab
AND c.kqfconam like '%NAM%';
Morgan's brute-force code for collecting the names of X$ objects. It ain't pretty but it gets the job done.

Adding additional loops allows for brute force construction of arbitrarily sized X$ objects.
CREATE TABLE xdollar (
file_name VARCHAR2(30),
numrows   NUMBER);

CREATE OR REPLACE PROCEDURE xdollarproc IS
 rindex  BINARY_INTEGER;
 slno    BINARY_INTEGER;
 sofar   NUMBER(6,2);
 twork   NUMBER;

 pfix CONSTANT VARCHAR2(23) := 'SELECT COUNT(*) FROM X$';
 str1 VARCHAR2(128);
 str2 VARCHAR2(128);
 str3 VARCHAR2(128);
 str4 VARCHAR2(128);
 str5 VARCHAR2(128);
 xstr VARCHAR2(128);
 n xdollar.numrows%TYPE;
BEGIN
  rindex := dbms_application_info.set_session_longops_nohint;
/*
  -- one
  twork := ((95-65)+1)**1;
  FOR a IN 65 .. 95 LOOP
    sofar := (a-65);
    dbms_application_info.set_session_longops(rindex,slno,'1',0,0,sofar,twork,'');

    str1 := pfix || CHR(a);
    BEGIN
      xstr := str1;
      EXECUTE IMMEDIATE xstr INTO n;
      INSERT INTO xdollar (file_name,numrows) VALUES ('X$' || CHR(a),n);
    EXCEPTION
      WHEN others THEN
    NULL;
    END;
  END LOOP;
  COMMIT;

  -- two
  twork := ((95-65)+1)**2;
  FOR a IN 65 .. 95 LOOP
    str1 := pfix || CHR(a);
    FOR b IN 65 .. 95 LOOP
      sofar := (a-65)*(b-65);
      dbms_application_info.set_session_longops(rindex,slno,'2',0,0,sofar,twork,'');

      str2 := str1 || CHR(b);
      BEGIN
        xstr := str2;
        EXECUTE IMMEDIATE xstr INTO n;
        INSERT INTO xdollar (file_name, numrows) VALUES ('X$' || CHR(a) || CHR(b),n);
      EXCEPTION
        WHEN others THEN
          NULL;
      END;
    END LOOP;
  END LOOP;
  COMMIT;

  -- three
  twork := ((95-65)+1)**3
  FOR a IN 65 .. 95 LOOP
    str1 := pfix || CHR(a);
    FOR b IN 65 .. 95 LOOP
      str2 := str1 || CHR(b);
      FOR c IN 65 .. 95 LOOP
        sofar := (a-65)*(b-65)*(c-65);
        dbms_application_info.set_session_longops(rindex,slno,'3',0,0,sofar,twork,'');

        str3 := str2 || CHR(c);
        BEGIN
          xstr := str3;
          EXECUTE IMMEDIATE xstr INTO n;
          INSERT INTO xdollar (file_name,numrows) VALUES ('X$'||CHR(a)||CHR(b)||CHR(c),n);
        EXCEPTION
          WHEN others THEN
            NULL;
        END;
      END LOOP;
    END LOOP;
  END LOOP;
  COMMIT;

  -- four
  totwork := ((95-65)+1)**4
  FOR a IN 65 .. 95 LOOP
    str1 := pfix || CHR(a);
    FOR b IN 65 .. 95 LOOP
      str2 := str1 || CHR(b);
      FOR c IN 65 .. 95 LOOP
        str3 := str2 || CHR(c);
        FOR d IN 65 .. 95 LOOP
          sofar := (a-65)*(b-65)*(c-65)*(d-65);
         dbms_application_info.set_session_longops(rindex,slno,'4',0,0,sofar,twork,'');

          str4 := str3 || CHR(d);
          BEGIN
            xstr := str4;
            EXECUTE IMMEDIATE xstr INTO n;
            INSERT INTO xdollar (file_name,numrows) VALUES ('X$' || CHR(a) || CHR(b) || CHR(c) || CHR(d),n);
          EXCEPTION
            WHEN others THEN
              NULL;
          END;
        END LOOP;
      END LOOP;
    END LOOP;
  END LOOP;
  COMMIT;
*/
  -- five
  FOR a IN 65 .. 95 LOOP
    str1 := pfix || CHR(a);
    FOR b IN 65 .. 95 LOOP
      str2 := str1 || CHR(b);
      FOR c IN 65 .. 95 LOOP
        str3 := str2 || CHR(c);
        FOR d IN 65 .. 95 LOOP
          str4 := str3 || CHR(d);
          FOR e IN 65 .. 95 LOOP
            str5 := str4 || CHR(e);
            BEGIN
              xstr := str5;
              EXECUTE IMMEDIATE xstr INTO n;
              INSERT INTO xdollar (file_name,numrows) VALUES ('X$' || CHR(a) || CHR(b) || CHR(c) || CHR(d) || CHR(e),n);
            EXCEPTION
              WHEN others THEN
                NULL;
            END;
          END LOOP;
        END LOOP;
      END LOOP;
    END LOOP;
  END LOOP;
  COMMIT;
END xdollarproc;
/
X$ Naming Notes -- see the kernel subsystems link at page bottom for more hints on X$ naming

ALO = allocate
RLs = release
 
X$ Objects By Category
Active Session History
Object Name Notes
X$ASH Maps to V$ACTIVE_SESSION_HISTORY
Advanced Queuing
Object Name Notes
X$AQ_SUBSCRIBER_LOAD -
X$BUFFERED_QUEUES -
X$BUFFERED_SUBSCRIBERS -
X$MESSAGE_CACHE SELECT queue_name, schema_name, enqueued_msgs, used_memory_size, state
FROM x$message_cache;
X$PERSISTENT_QUEUES SELECT queue_schema, queue_name
FROM x$persistent_queues;

-- in 11gR2

QUEUE_SCHEMA                   QUEUE_NAME
------------------------------ -------------
SYSMAN                         MGMT_TASK_Q

-- in 12cR1 no rows are returned
X$PERSISTENT_PUBLISHERS -
X$PERSISTENT_SUBSCRIBERS -
X$UNFLUSHED_DEQUEUES -
Alert Log
Object Name Notes
X$DBGALERTEXT In memory copy of ADR alert log. Effectively indexed by date. Source for v$diag_alert_ext
Archived Redo Logs
Object Name Notes
X$KCCAL SQL> SELECT alnam
2 FROM x$kccal
3 WHERE alnam IS NOT NULL;

ALNAM
-----------------------------------------------------------
C:\ORACLE\FAST_RECOVERY_AREA\ORABASE\ARCHIVELOG\2011_10_09\ O1_MF_1_198_79451QF5_.ARC
Audit
Object Name Notes
X$AUD_DPAPI_ACTIONS -
X$AUD_DP_ACTIONS -
X$AUD_DV_OBJ_EVENTS -
X$AUD_OBJ_ACTIONS -
X$AUD_OLS_ACTIONS -
X$AUD_XS_ACTIONS -
X$DIR col os_path format a55

SELECT con_id, obj#, audit$, os_path
FROM x$dir
ORDER BY 1,2;

ALNAM
-----------------------------------------------------------
C:\ORACLE\FAST_RECOVERY_AREA\ORABASE\ARCHIVELOG\2011_10_09\ O1_MF_1_198_79451QF5_.ARC
X$UNIFIED_AUDIT_RECORD_FORMAT -
X$UNIFIED_AUDIT_TRAIL -
Automatic Diagnostic Repository (ADR)
Object Name Notes
X$DBKRUN Health management runs
X$DIAG_ADR_CONTROL ADR homes, paths, purge times, and similar administrative data
X$DIAG_ADR_INVALIDATION no rows when checked
X$DIAG_ALERT_EXT Text portions of the XML version of the Alert Log
X$DIAG_AMS_XACTION -
X$DIAG_DDE_USER_ACTION contains incident_id
X$DIAG_DDE_USER_ACTION_DEF -
X$DIAG_DDE_USR_ACT_PARAM -
X$DIAG_DDE_USR_ACT_PARAM_DEF -
X$DIAG_DDE_USR_INC_ACT_MAP -
X$DIAG_DDE_USR_INC_TYPE -
X$DIAG_DFW_CONFIG_CAPTURE -
X$DIAG_DFW_CONFIG_ITEM -
X$DIAG_DIAGV_INCIDENT -
X$DIAG_DIR_EXT -
X$DIAG_EM_DIAG_JOB -
X$DIAG_EM_TARGET_INFO -
X$DIAG_EM_USER_ACTIVITY -
X$DIAG_HM_FDG_SET -
X$DIAG_HM_FINDING -
X$DIAG_HM_INFO -
X$DIAG_HM_MESSAGE -
X$DIAG_HM_RECOMMENDATION -
X$DIAG_HM_RUN -
X$DIAG_INCCKEY -
X$DIAG_INCIDENT -
X$DIAG_INCIDENT_FILE Lists incident files
X$DIAG_INC_METER_CONFIG -
X$DIAG_INC_METER_IMPT_DEF -
X$DIAG_INC_METER_INFO -
X$DIAG_INC_METER_PK_IMPTS -
X$DIAG_INC_METER_SUMMARY -
X$DIAG_INFO ADR equivalent to the database instance's V$PARAMETER
X$DIAG_IPS_CONFIGURATION -
X$DIAG_IPS_FILE_COPY_LOG -
X$DIAG_IPS_FILE_METADATA -
X$DIAG_IPS_PACKAGE -
X$DIAG_IPS_PACKAGE_FILE -
X$DIAG_IPS_PACKAGE_HISTORY -
X$DIAG_IPS_PACKAGE_INCIDENT -
X$DIAG_IPS_PKG_UNPACK_HIST -
X$DIAG_IPS_PROGRESS_LOG -
X$DIAG_IPS_REMOTE_PACKAGE -
X$DIAG_LOG_EXT 0 rows
X$DIAG_PICKLEERR -
X$DIAG_PROBLEM -
X$DIAG_RELMD_EXT -
X$DIAG_SWEEPERR -
X$DIAG_VEM_USER_ACTLOG -
X$DIAG_VEM_USER_ACTLOG1 -
X$DIAG_VHM_RUN -
X$DIAG_VIEW -
X$DIAG_VIEWCOL -
X$DIAG_VINCIDENT -
X$DIAG_VINCIDENT_FILE -
X$DIAG_VINC_METER_INFO -
X$DIAG_VIPS_FILE_COPY_LOG -
X$DIAG_VIPS_FILE_METADATA -
X$DIAG_VIPS_PACKAGE_FILE -
X$DIAG_VIPS_PACKAGE_HISTORY -
X$DIAG_VIPS_PACKAGE_MAIN_INT -
X$DIAG_VIPS_PACKAGE_SIZE -
X$DIAG_VIPS_PKG_FILE -
X$DIAG_VIPS_PKG_INC_CAND -
X$DIAG_VIPS_PKG_INC_DTL -
X$DIAG_VIPS_PKG_INC_DTL1 -
X$DIAG_VIPS_PKG_MAIN_PROBLEM -
X$DIAG_VNOT_EXIST_INCIDENT -
X$DIAG_VPROBLEM -
X$DIAG_VPROBLEM1 -
X$DIAG_VPROBLEM2 -
X$DIAG_VPROBLEM_BUCKET -
X$DIAG_VPROBLEM_BUCKET1 -
X$DIAG_VPROBLEM_BUCKET_COUNT -
X$DIAG_VPROBLEM_INT -
X$DIAG_VPROBLEM_LASTINC -
X$DIAG_VSHOWCATVIEW -
X$DIAG_VSHOWINCB -
X$DIAG_VSHOWINCB_I -
X$DIAG_VTEST_EXISTS -
X$DIAG_V_ACTINC -
X$DIAG_V_ACTPROB -
X$DIAG_V_INCCOUNT -
X$DIAG_V_INCFCOUNT -
X$DIAG_V_INC_METER_INFO_PROB -
X$DIAG_V_IPSPRBCNT -
X$DIAG_V_IPSPRBCNT1 -
X$DIAG_V_NFCINC -
X$DIAG_V_SWPERRCOUNT -
Backup & Recovery
Object Name Notes
X$ESTIMATED_MTTR Estimated Mean Time To Recovery
X$KCCBI SQL> SELECT bitsm, bimdt, bidun
   2 FROM x$kccbi;

BITSM                BIMDT                BIDUN
-------------------- -------------------- ---------
12/22/2013 18:43:16  12/22/2013 18:42:06  ORABASE2

SQL> SELECT start_time
   2 FROM v$rman_backup_job_details
   3 ORDER BY 1;
X$KCVFHONL -- from a private communication with Riyaj Shamsudeen:

v$backup is based upon x$kcvfhonl. KCV tables are mapping from file headers.Read from v$backup will show lots of db file sequential reads with block_id=1 and blocks=1, i.e. reading file headers.

WAIT #1: nam='db file sequential read' ela= 942 file#=2 block#=1 blocks=1 obj#=-1 tim=497122949693
WAIT #1: nam='unspecified wait event' ela= 34380 p1=0 p2=0 p3=0 obj#=-1 tim=497122949979
WAIT #1: nam='db file sequential read' ela= 1188 file#=3 block#=1 blocks=1 obj#=-1 tim=497123009270
WAIT #1: nam='unspecified wait event' ela= 58053 p1=0 p2=0 p3=0 obj#=-1 tim=497123009523
WAIT #1: nam='db file sequential read' ela= 736 file#=4 block#=1 blocks=1 obj#=-1 tim=497123052425
WAIT #1: nam='unspecified wait event' ela= 42143 p1=0 p2=0 p3=0 obj#=-1 tim=497123052678
WAIT #1: nam='db file sequential read' ela= 2022 file#=5 block#=1 blocks=1 obj#=-1 tim=497123093842
WAIT #1: nam='unspecified wait event' ela= 39161 p1=0 p2=0 p3=0 obj#=-1 tim=497123094115

Here is the file header update, I was talking about. you can see that backup checkpointed at SCN from thread 6. This is not a problem per se, but other sessions in the remote nodes are not reading the file headers.

Backup Checkpointed at scn:  0x0b26.2cc0c5c8 04/12/2011 18:25:34
 thread:6 rba:(0x69fb.8fa5.10)
 enabled  threads:  00000111 11100000 00000000 00000000 00000000 00000000
  00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
  00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
  00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
Buffer Headers
Object Name Notes
X$BH --commonly used to locate file# and block# when diagnosing cache buffers chains latch contention.

SELECT bh.obj, bh.dbarfil, bh.dbablk
FROM x$bh bh, v$latch_children lc
WHERE bh.hladdr = lc.addr;

-- for the said latch (whose sleeps you think are too high).

-- To determine if a specific buffer has too many clones:


SELECT dbarfil, dbablk, COUNT(*)
FROM x$bh
GROUP BY dbarfil, dbablk
HAVING COUNT(*) > 9;

obj column matches dba_objects.data_object_id
The tch column, touch count, records how many times a particular buffer has been accessed
Tim is time the buffer touch happened
Lru_flag relates to a buffer's hot/cold feature and is often used to find hot blocks
Buffer Pools
Object Name Notes
X$KCBWBPD -
Buffer Working Data Sets
Object Name Notes
X$KCBWDS -
Checkpoint Process
Object Name Notes
X$ACTIVECKPT -
X$CKPTBUF -
Child Cursors
Object Name Notes
X$KGLCURSOR_CHILD SELECT kglfnobj, DECODE(kglobt32, 0,
                       'NONE', 1,
                       'ALL_ROWS', 2,
                       'FIRST_ROWS', 3,
                       'RULE', 4,
                       'CHOOSE', 'UNKNOWN')
FROM x$kglcursor_child
WHERE rownum < 6;
Compilation Layer
Object Name Notes
X$KKAEET -
X$KKCNEREG -
X$KKCNEREGSTAT -
X$KKCNRSTAT all raw/number/timestamp - 3 rows
X$KKKICR -
X$KKOAR_HINT -
X$KKOCS_HISTOGRAM -
X$KKOCS_SELECTIVITY -
X$KKOCS_STATISTICS -
X$KKSAI -
X$KKSBV Cursor Cache Bind Variables - 13,968 rows
X$KKSCS -
X$KKSSQLSTAT SQL plan information- 4,323 rows
X$KKSSRD -
Control Files
Object Name Notes
X$KCCCF SELECT cfnam
FROM x$kcccf;

CFNAM
--------------------------------------------------
C:\ORACLE\ORADATA\ORABASE\CONTROL01.CTL
C:\ORACLE\FAST_RECOVERY_AREA\ORABASE\CONTROL02.CTL
Database Version
Object Name Notes
X$DRC Data Guard Broker
Data Files
Object Name Notes
X$KCVDF

Datafile header information
SELECT df_fhfno, df_fhtnm
FROM x$kcvdf;

DF_FHFNO   DF_FHTNM
---------- ------------------------------
         1 SYSTEM
         2 SYSAUX
         3 UNDOTBS1
         4 USERS
         5 EXAMPLE
         6 UWDATA
X$KCVFH K = kernel, C = cache layer, V = recoVery Component, FH = File Header
The following query will tell you if recovery is complete:

col file# format 99
col status format 9999
col scn format a8
col sequence format 999
col datafile_name format a62

SELECT hxfil FILE#, fhsta STATUS, fhscn SCN, fhrba_seq SEQUENCE,
hxfnm DATAFILE_NAME
FROM x$kcvfh;

FILE# STATUS SCN      SEQUENCE DATAFILE_NAME
----- ------ -------- -------- -------------------------------------------------------------
    1   8196 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\SYSTEM01.DBF
    2      0 2502812        29 C:\APP\ORACLE\ORADATA\ORABASE2\PDBSEED\SYSTEM01.DBF
    3      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\SYSAUX01.DBF
    4      0 2502812        29 C:\APP\ORACLE\ORADATA\ORABASE2\PDBSEED\SYSAUX01.DBF
    5      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\UNDOTBS01.DBF
    6      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\USERS01.DBF
    7      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\ORCL\SYSTEM01.DBF
    8      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\ORCL\SYSAUX01.DBF
    9      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\ORCL\SAMPLE_SCHEMA_USERS01.DBF
   10      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\ORCL\EXAMPLE01.DBF
   11      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\SYSTEM01.DBF
   12      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\SYSAUX01.DBF
   13      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\ORADATA01.DBF
   14      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\UWDATA01.DBF
   15      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\CATTBSP.DBF
   16      4 6844946       132 C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\TBFS.DBF

-- during beta the following was observed
Status = 0: The datafile is consistent
Status = 1: The datafile needs more recovery
Status = 4: The datafile is in a fuzzy state-poss bad backup
Status = 8192: ?
Status = 8196: ?
X$KCVFHTMP -
Data Guard
Object Name Notes
X$VERSION -
Distributed Execution Layer - 2PC handling
Object Name Notes
X$K2GTE -- kernel 2-phase commit, global transaction entry. Find sessions coming from or going to a remote database

SELECT /*+ ordered */
  SUBSTR(s.ksusemnm,1,10)||'-'|| SUBSTR(s.ksusepid,1,10) origin,
  SUBSTR(g.k2gtitid_ora,1,35) gtxid,
  SUBSTR(s.indx,1,4)||'.'|| SUBSTR(s.ksuseser,1,5) lsession,
  s.ksuudlna username, SUBSTR(
    DECODE(BITAND(ksuseidl,11), 1,'ACTIVE', 0,
    DECODE(BITAND(ksuseflg,4096), 0,'INACTIVE','CACHED'),
    2,'SNIPED', 3,'SNIPED', 'KILLED'),1,1)
  status, e.kslednam waiting
FROM x$k2gte g, x$ktcxb t, x$ksuse s, x$ksled e
WHERE g.k2gtdxcb=t.ktcxbxba
AND g.k2gtdses = t.ktcxbses
AND s.addr = g.k2gtdses
AND e.indx=s.ksuseopc;

x$k2gte.k2gtdses matches v$session.saddr
k2gtdxcb matches v$transaction.addr.

It's better than checking for DX locks for outgoing sessions (since a DX lock only shows up in v$lock for the current distributed transaction session). x$k2gte2 is the same as x$k2gte except on k2gtetyp which may show 2 for 'TIGHTLY COUPLED' instead of 0 for 'FREE'. One use of x$k2gte[2] is the clearly translated global transaction ID in k2gtitid_ora as opposed to the hex numbers in v$global_transaction.globalid.
X$K2GTE2 kernel 2-phase commit, global transaction entry: See above entry.
DNFS
Object Name Notes
X$DNFS_CHANNELS -
X$DNFS_FILES -
X$DNFS_HIST -
X$DNFS_META -
X$DNFS_SERVERS -
X$DNFS_STATS -
DUAL
Object Name Notes
X$DUAL SELECT * FROM x$dual;

ADDR           INDX    INST_ID DUMMY
-------- ---------- ---------- -----
069D450C          0          1 X

SQL> select * from dual;

DUMMY
-----
X
Exadata Cells
Object Name Notes
X$CELL_NAME -
X$KCFISOSS Cellname
X$KCFISOSSN Cellname / wait
X$KCFISOSST Cellname
Heterogeneous Services
Object Name Notes
X$HS_SESSION Heterogeneous services data base link users, hosts, and SIDs
Incident Repair
Object Name Notes
X$IR_MANUAL_OPTION -
X$IR_REPAIR_OPTION -
X$IR_REPAIR_STEP -
X$IR_RS_PARAM -
X$IR_WF_PARAM -
X$IR_WORKING_FAILURE_SET -
X$IR_WORKING_REPAIR_SET -
X$IR_WR_PARAM -
Kernel Cache
Object Name Notes
X$KCBBES -
X$KCBBF According to Jonathan Lewis the number of available buffer handles set at instance start-up, and likely dependent on the number of processes, apparently 5 * processes, although that value five may be related to the fact that the default value for _db_handles_cached is five. These handles appear as the structure x$kcbbf.

SQL> show parameter processes

SELECT COUNT(*)
FROM x$kcbbf;
X$KCBBHS -
X$KCBDBK -
X$KCBDWOBJ -
X$KCBDWS -
X$KCBFCIO -
X$KCBFWAIT Kernel Cache Buffer File Wait used to break down the contents of v$waitstat into per-datafile statistics

SELECT name, count, time
FROM v$datafile df, x$kcbfwait fw
WHERE fw.indx+1 = df.file#;
X$KCBKPFS Kernel Cache Buffer ckpt PreFetch Statistics. Used by the CKPT process to store its wasted prefetch block statistics history. [Link]
X$KCBKWRL -
X$KCBLDRHIST raw/numeric - 1000 rows
X$KCBLSC -
X$KCBMKID -
X$KCBMMAV -
X$KCBOBH Kernel Cache Buffer OBject queue Buffer Header. Contains one row for each buffers in the KCB object queue. [Link]
X$KCBOQH Kernel Cache Buffer Object Queue Header
X$KCBPINTIME -
X$KCBPRFH -
X$KCBSDS -
X$KCBUWHY -
X$KCBSW kernel cache waits
X$KCBTEK -
X$KCBVBL -
X$KCBWAIT kernel cache, block wait
X$KCBWH -
X$KCCACM -
X$KCCADFC -
X$KCCAGF -
X$KCCBF -
X$KCCBL -
X$KCCBLKCOR -
X$KCCBP -
X$KCCBS -
X$KCCCC -
X$KCCCP kernel cache, controlfile checkpoint progress
X$KCCDFHIST -
X$KCCDI -
X$KCCDI2 -
X$KCCDL -
X$KCCFC -
X$KCCFE -
X$KCCFLE -
X$KCCIC -
X$KCCIRT -
X$KCCLE -
X$KCCLH -
X$KCCNRS -
X$KCCOR -
X$KCCPA -
X$KCCPD -
X$KCCPDB -
X$KCCRDI -
X$KCCRL -
X$KCCRM -
X$KCCRS -
X$KCCRSP -
X$KCCRSR -
X$KCCRT -
X$KCCSL -
X$KCCTF -
X$KCCTIR -
X$KCFIO kernel cache, file I/O
X$KCFISOSSL -
X$KCFISCAP -
X$KCFISTCAP -
X$KCFISTSA -
X$KCLCURST -
X$KCLDELTAST -
X$KCFIOFCHIST -
X$KCFIOHIST 20 rows
X$KCFISOSSC -
X$KCFTIO -
X$KCLFX -
X$KCLLS -
X$KCLQN -
X$KCLCRST -
X$KCLCURST -
X$KCLPINGPIN -
X$KCLRCVST -
X$KCMSCN -
X$KCPDBINC -
X$KCPXPL -
X$KCRFDEBUG 1 row
X$KCRFSTRAND -
X$KCRFWS -
X$KCRFX -
X$KCRMF -
X$KCRMT -
X$KCRMX -
X$KCRRARCH -
X$KCRRASTATS -
X$KCRRDSTAT -
X$KCRRLNS -
X$KCRRNHG -
X$KCTICW 1 row
X$KCTLAX 0 rows
Kernel Data Layer
Object Name Notes
X$KDLT 1 row
X$KDLU_STAT 216 rows
X$KDNSSF 472 rows
X$KDXHS Histograms - 16 rows
X$KDXST Stats collection - 0 rows
Kernel eXecution Layer
Object Name Notes
X$KXDBIO_STATS -
X$KXDRS -
X$KXFBBOX -
X$KXFPBS -
X$KXFPCDS Client Dequeue Statistics - 47 rows
X$KXFPCMS Client Messages Statistics - 70 rows
X$KXFPCST -
X$KXFPDP -
X$KXFPIG -
X$KXFPINSTLOAD -
X$KXFPNS -
X$KXFPPFT -
X$KXFPPIG -
X$KXFPREMINSTLOAD -
X$KXFPSDS -
X$KXFPSMS -
X$KXFPSST -
X$KXFPYS -
X$KXFQSROW -
X$KXFRSVCHASH -
X$KXFSOURCE -
X$KXFTASK -
X$KXSBD -
X$KXSCC -
X$KXSREPLAY -
X$KXSREPLAYDATE -
X$KXSREPLAYGUID -
X$KXSREPLAYLOB -
X$KXSREPLAYSEQ -
X$KXSREPLAYTIME -
X$KXTTSTECS -
X$KXTTSTEHS -
X$KXTTSTEIS -
X$KXTTSTETS -
Kernel Generic Heap
Object Name Notes
X$KGHLU kernel generic, heap LRUs: A one-row summary of LRU statistics for the shared pool
X$KGICS -
X$KGLAU -
X$KGLBODY Derived from X$KGLOB (col kglhdnsp = 2) - 208 rows
X$KGLCLUSTER Derived from X$KGLOB (col kglhdnsp = 5) - 27 rows
X$KGLINDEX Derived from X$KGLOB (col kglhdnsp = 4) - 192 rows
X$KGLDP -
X$KGLJMEM -
X$KGLJSIM -
X$KGLLK kernel generic, library cache lock
X$KGLMEM -
X$KGLNA -
X$KGLNA1 -
X$KGLOB kernel generic, library cache object. A direct dependency for DBMS_ALERT.
X$KGLOBXML -
X$KGLPN kernel generic, library cache pin - 0 rows
X$KGLRD -
X$KGLSIM -
X$KGLSN -
X$KGLST kernel generic, library cache status
X$KGLTABLE Derived from X$KGLOB (col kglhdnsp = 1) - 4147 rows
X$KGLTR Library Cache Translation Table entry - 4287 rows
X$KGLTRIGGER Derived from X$KGLOB (col kglhdnsp = 3) - 49 rows
X$KGLXS Library Cache Access - 12,485 rows
X$KGSCC -
X$KGSKASP Active Session Pool
X$KGSKCFT -
X$KGSKCP -
X$KGSKDOPP -
X$KGSKNCFT -
X$KGSKPFT -
X$KGSKPP -
X$KGSKQUEP -
X$KGSKSCS -
X$KGSKTE -
X$KGSKTO -
X$KGSKVFT -
Kernel Lock Manager
Object Name Notes
X$KJAC_CONFIG -
X$KJAC_ID -
X$KJAC_MY_ID -
X$KJBL -
X$KJBLFX -
X$KJBR -
X$KJBRFX -
X$KJCISOT -
X$KJCISPT -
X$KJCTFR -
X$KJCTFRI -
X$KJCTFS -
X$KJDDDEADLOCKS 0 rows
X$KJDDDEADLOCKSES 0 rows
X$KJDRHV -
X$KJDRMAFNSTATS -
X$KJDRMHVSTATS -
X$KJDRMREADMOSTLYSTATS -
X$KJDRMREQ -
X$KJDRPCMHV -
X$KJDRPCMPF -
X$KJFMHBACL 0 rows
X$KJICVT -
X$KJIDT 1 row very slow to load
X$KJILFT -
X$KJILKFT -
X$KJIRFT -
X$KJISFT -
X$KJITRFT -
X$KJKMKGA 0 rows - very interesting
X$KJLEQFP -
X$KJMDDP -
X$KJMSDP -
X$KJPNPX -
X$KJREQFP -
X$KJRTBCFP 0 rows
X$KJR_CHUNK_STATS -
X$KJR_FREEABLE_CHUNKS -
X$KJXM -
X$KJZNCBHANGS -
X$KJZNHANGS -
X$KJZNHANGSES -
X$KJZNHNGMGRSTS -
X$KJZNHNGSTATS -
X$KJZNRSLNRC -
X$KJZNWLMPCRANK -
X$KJZSIWTEVT -
Kernel Query
Object Name Notes
X$KQDPG kernel query, fixed table columns:
X$KQFCO -
X$KQFDT kernel query, fixed tables:
X$KQFOPT -
X$KQFP kernel query, fixed procedures:
X$KQFSZ kernel query, fixed size:
X$KQFTA Kernel Query, Fixed Table: Base table of v$fixed_table, whose object_id (indx of x$kqfta) matches obj# of tab_stats$, the table dbms_stats.gather_fixed_objects_stats inserts stats into.
X$KQFTVRTTST0 -
X$KQFVI Kernel Query, Fixed View: V$ and GV$ dynamic performance views
X$KQFVT Kernel Query, Fixed View Table:
X$KQLFBC -
X$KQLFSQCE Underscore startup/initialization parameters (3308 entries per parameter in my database)
X$KQLFXPL -
X$KQLSET -
X$KQRFP -
X$KQRFS -
X$KQRPD Kernel Query, Rowcache Parent Definition: Column kqrpdosz is size of this parent rowcache object, not exposed in v$rowcache_parent although shown in rowcache dump.
X$KQRSD Kernel Query, Rowcache Subordinate Definition: Column kqrsdosz is size of this subordinate rowcache object, not exposed in v$rowcache_subordinate although shown in rowcache dump.
X$KQRST -
Kernel Security
Object Name Notes
X$KZAHIST 0 rows
X$KZAJOBS 0 rows
X$KZAPARAMS 0 rows
X$KZATS 0 rows
X$KZCKMCS 0 rows
X$KZCKMEK 0 rows
X$KZDOS Represent an OS role as defined by the operating system- 0 rows
X$KZDPSUPSF 3 rows
X$KZEKMENCWAL col wrl_type format a8
col wrl_parameter format a32
col wallet_type format a11

SELECT wrl_type, wrl_parameter, status, wallet_type, wallet_order
FROM x$kzekmencwal;

WRL_TYPE WRL_PARAMETER                    STATUS WALLET_TYPE WALLET_ORDER
-------- -------------------------------- ------ ----------- ------------
FILE     c:\oracle\admin\orabase2\wallet      64 UNKNOWN                0
X$KZEKMFVW 0 rows
X$KZPOPR -- appears to be an intersection between object privileges and object_types

SELECT privilege_name, object_type_name
FROM x$kzpopr;
X$KZRTPD - 0 rows
X$KZSPR - 393 rows
X$KZSRO kernel security, system role

SELECT * FROM x$kzsro;

ADDR                   INDX    INST_ID     CON_ID   KZSROROL
---------------- ---------- ---------- ---------- ----------
0000000000000000          0          1          0          1
0000000000000008          1          1          0          0
X$KZSRT 0 rows
Kernel Service
Object Name Notes
X$KSBDD -
X$KSBDP -
X$KSBDPNEEDED -
X$KSBFT -
X$KSBSRVDT 124 rows

col ksbsrvdfile format a14
col ksbsrvddesc format a35

SELECT ksbsrvdfile, ksbsrvddesc
FROM x$ksbsrvdt;
X$KSBTABACT -
X$KSDAF -
X$KSDAFT -
X$KSFDFTYP -
X$KSFDKLL -
X$KSFDSSCLONEINFO -
X$KSFDSTBLK Block level stats- 0 rows
X$KSFDSTCG -
X$KSFDSTCMP -
X$KSFDSTFILE -
X$KSFDSTHIST -
X$KSFDSTLL -
X$KSFDSTTHIST -
X$KSFMCOMPL -
X$KSFMELEM -
X$KSFMEXTELEM -
X$KSFMFILE -
X$KSFMFILEEXT -
X$KSFMIOST -
X$KSFMLIB -
X$KSFMSUBELEM -
X$KSFQDVNT -
X$KSFQP -
X$KSFVQST -
X$KSFVSL -
X$KSFVSTA -
X$KSIMAT -
X$KSIMAV -
X$KSIMSI -
X$KSIPC_INFO -
X$KSIPC_PROC_STATS -
X$KSIRESTYP -
X$KSIRGD -
X$KSIRPINFO -
X$KSI_REUSE_STATS -
X$KSKPLW -
X$KSKQDFT -
X$KSKQVFT -
X$KSLCS -
X$KSLECLASS -
X$KSLED -
X$KSLEI -
X$KSLEMAP Kernel Service, Latch Event Map: Maps events to a small number of useful classes like I/O waits
X$KSLEPX -
X$KSLES -
X$KSLHOT -
X$KSLLCLASS -
X$KSLLD -
X$KSLLTR -
X$KSLLW -
X$KSLPO -
X$KSLSCS -
X$KSLSESHIST -
X$KSLWH -
X$KSLWSC -
X$KSLWT -
X$KSMDD -
X$KSMDUT1 -
X$KSMFS Kernel Services: memory fixed SGA
X$KSMFSV Kernel Services: memory fixed SGA vectors
X$KSMGE -
X$KSMHP -
X$KSMJCH -
X$KSMJS Kernel Services: memory java_pool summary
X$KSMLRU Kernel Services: memory LRU
X$KSMLS Kernel Services: memory large_pool summary
X$KSMMEM Kernel Services: memory
X$KSMNIM -
X$KSMNS -
X$KSMPGDP -
X$KSMPGDST -
X$KSMPGST -
X$KSMPP Kernel Services: memory process pool
X$KSMSD Kernel Services: memory SGA definition
X$KSMSGMEM -
X$KSMSP Kernel Services: memory shared pool - 166197 rows
X$KSMSPR Kernel Services: memory shared pool reserved
X$KSMSP_DSNEW -
X$KSMSP_NWEX -
X$KSMSS Kernel Services: memory shared_pool summary - 1261 rows
X$KSMSSINFO -
X$KSMSST -
X$KSMSTRS -
X$KSMUP Kernel Services: memory user pool
X$KSOLSFTS -
X$KSOLSSTAT -
X$KSOLTD -
X$KSO_SCHED_DELAY_HISTORY -
X$KSPPCV -
X$KSPPCV2 -
X$KSPPI -
X$KSPPO -
X$KSPPSV -
X$KSPPSV2 -
X$KSPSPFH -
X$KSPSPFILE -- strongly suspect one row for each documented and undocumented startup parameter as it returns 3342 rows.

col kspspfftctxspname format a25
col kspspfftctxspvalue format a25
col kspspfftctxspdvalue format a25

SELECT kspspfftctxspname, kspspfftctxspvalue, kspspfftctxspdvalue
FROM x$kspspfile
WHERE kspspfftctxspvalue IS NOT NULL
AND rownum < 11
ORDER BY 1;
X$KSPVLD_VALUES -
X$KSQDN Global database name - 1 row

SQL> SELECT inst_id, con_id, ksqdngdn, ksqdngln, ksqdngun, ksqdngunid
2 FROM x$ksqdn;

INST_ID CON_ID KSQDNGDN KSQDNGLN KSQDN
---------- ---------- --------- ------------------------------- -----
1 0 ORABASE2 ORABASE2 oraba

SQL> col ksqdngln format a10
SQL> col ksqdngun format a10

INST_ID CON_ID KSQDNGDN  KSQDNGLN  KSQDNGUN  KSQDNGUNID
------- ------ --------- --------- --------- ----------
      1      0 ORABASE2  ORABASE2  orabase2  3232374927
X$KSQEQ -
X$KSQEQTYP -
X$KSQRS -
X$KSQST Kernel Services: enqueue status, Gets and waits for different types of enqueues - 419 rows
X$KSRCCTX -
X$KSRCDES -
X$KSRCHDL -
X$KSRMPCTX -
X$KSRMSGDES -
X$KSRMSGO -
X$KSRPCIOS -
X$KSTEX -
X$KSUCF Cost function for each Kernel Profile - 10 rows
X$KSUCLNDPCC -
X$KSUCPUSTAT -
X$KSUINSTSTAT -
X$KSULL -
X$KSULV Kernel Services: user locale value
X$KSUMYSTA -
X$KSUNETSTAT -
X$KSUPDBSES -
X$KSUPGP -
X$KSUPGS -
X$KSUPL Resource Limit for each Kernel Profile - 10 rows
X$KSUPR Kernel Services: user process
X$KSUPRLAT -
X$KSURLMT -
X$KSURU Resource Usage for each Kernel Profile - 4,720 rows
X$KSUSD -
X$KSUSE See Demo At Page Bottom
X$KSUSECON -
X$KSUSECST -
X$KSUSESTA -
X$KSUSEX -
X$KSUSGIF -
X$KSUSGSTA -
X$KSUSIO -
X$KSUSM -
X$KSUTM -
X$KSUVMSTAT -
X$KSUXSINST -
X$KSWSAFTAB -
X$KSWSASTAB -
X$KSWSCLSTAB -
X$KSWSCRSSVCTAB -
X$KSWSCRSTAB -
X$KSWSEVTAB -
X$KSXAFA -
X$KSXM_DFT -
X$KSXPCLIENT -
X$KSXPIA -
X$KSXPIF -
X$KSXPPING -
X$KSXPTESTTBL -
X$KSXP_STATS -
X$KSXRCH -
X$KSXRCONQ -
X$KSXRMSG -
X$KSXRREPQ -
X$KSXRSG -
Kernel Transaction Layer
Object Name Notes
X$KTADM -
X$KTATL -
X$KTATRFIL -
X$KTATRFSL -
X$KTCNCLAUSES -
X$KTCNINBAND -
X$KTCNQROW -
X$KTCNQUERY -
X$KTCNREG -
X$KTCNREGQUERY -
X$KTCSP -
X$KTCXB -
X$KTFBFE -
X$KTFBHC -
X$KTFBNSTAT -
X$KTFBUE -
X$KTFSAN -
X$KTFSBI -
X$KTFSIMSTAT -
X$KTFSRI -
X$KTFSTAT -
X$KTFTBTXNGRAPH -
X$KTFTBTXNMODS -
X$KTFTHC -
X$KTFTME -
X$KTIFB -
X$KTIFF -
X$KTIFV -
X$KTPRHIST -
X$KTPRXRS -
X$KTPRXRT -
X$KTRSO -
X$KTSKSTAT -
X$KTSLCHUNK -
X$KTSPSTAT -
X$KTSSO -
X$KTSSPU -
X$KTSTFC -
X$KTSTSSD -
X$KTSTUSC -
X$KTSTUSG -
X$KTSTUSS -
X$KTTEFINFO -
X$KTTETS -
X$KTTVS Possibly relates to tablespaces that have valid save undo segments - 5 rows
X$KTUCUS -
X$KTUGD -
X$KTUMASCN -
X$KTUQQRY -
X$KTURD -
X$KTURHIST -
X$KTUSMST -
X$KTUSMST2 -
X$KTUSUS -
X$KTUTST -
X$KTUXE -
Kernel Variables
Object Name Notes
X$KVII Internal instance parameters set at instance initialization

col kviitag format a24
col kviidsc format a54

SELECT kviival, kviitag, kviidsc
FROM x$kvii;

 KVIIVAL   KVIITAG                KVIIDSC
-------- ------------------------ -----------------------------------------------------
    1566 kslnbe                   # of base events
     447 kslnbesess               # of base events in session
     703 kslltl                   number of latches
   39952 kslerb                   event range base
       4 ksbcpurawthrcnt_startup  initial number of raw CPU threads in the system
       4 ksbcpueffthrcnt_startup  initial number of effective CPU threads in the system
    4096 kcbswc                   DBWR max outstanding writes
       1 kcbnwp                   number of DBWR processes
     204 kcbscw                   DBWR write chunk
       1 kctsat                   true if Statically Allocated Thread
       1 kctthr                   THRead mounted by this instance - zero if none
       1 ktsinm                   sga shadow value of instance_number
X$KVIS Oracle Data Block (size_t type) variables - 0 rows
X$KVIT Instance internal flags, variables and parameters that can change during the life of an instance

col kvittag format a17
col kvitdsc format a60

SELECT kvitval, kvittag, kvitdsc
FROM x$kvit;

 KVITVAL KVITTAG           KVITDSC
-------- ----------------- ------------------------------------------------------------
       4 ksbcpurawthrcnt   number of raw CPU threads in the system used by Oracle
       4 ksbcpueffthrcnt   number of effective CPU threads in the system used by Oracle
       2 ksbcpucore        number of physical CPU cores in the system used by Oracle
       1 ksbcpusocket      number of physical CPU sockets in the system used by Oracle
       4 ksbcpu_hwm        high water mark of number of CPUs used by Oracle
       2 ksbcpucore_hwm    high water mark of number of CPU cores on system
       1 ksbcpusocket_hwm  high water mark of number of CPU sockets on system
       4 ksbcpu_actual     number of available CPUs in the system
       1 ksbcpu_dr         CPU dynamic reconfiguration supported
  190799 kcbnbh            number of buffers
      25 kcbldq            large dirty queue if kcbclw reaches this
      40 kcbfsp            Max percentage of LRU list foreground can scan for free
       2 kcbcln            Initial percentage of LRU list to keep clean
    3000 kcbnbf            number buffer objects
       0 kcbwst            Flag that indicates recovery or db suspension
       0 kcteln            Error Log Number for thread open
       0 kcvgcw            SGA: opcode for checkpoint cross-instance call
       0 kcvgcw            SGA:opcode for pq checkpoint cross-instance call
Large Objects (LOB)
Object Name Notes
X$ABSTRACT_LOB -
X$KEWX_LOBS -
X$LOBSEGSTAT LOB Segment Stats
X$LOBSTAT LOB Stats
X$LOBSTATHIST LOB Stat History
X$TEMPORARY_LOB_REFCNT -
Locks
Object Name Notes
X$LE Lock Element : each PCM lock that is used by the buffer cache (gc_db_locks)
If a buffer is locked maps to v$lock_element - 0 rows
Log Buffers
Object Name Notes
X$LOGBUF_READHIST Log buffer read history
Log Miner
Object Name Notes
X$LOGMNR_ATTRCOL$ -
X$LOGMNR_ATTRIBUTE$ -
X$LOGMNR_CALLBACK -
X$LOGMNR_CDEF$ Log Miner Column Definitions
X$LOGMNR_CLU$ Log Miner Clusters
X$LOGMNR_COL$ Log Miner Columns
X$LOGMNR_COLTYPE$ Log Miner Column Types
X$LOGMNR_CONTENTS -
X$LOGMNR_DICTIONARY -
X$LOGMNR_DICTIONARY_LOAD -
X$LOGMNR_ENC$ -
X$LOGMNR_ENCRYPTED_OBJ$ Log Miner Encrypted Objects
X$LOGMNR_ENCRYPTION_PROFILE$ -
X$LOGMNR_FILE$ Log Miner Data and Temp Files
X$LOGMNR_IND$ Log Miner Indexes
X$LOGMNR_INDCOMPART$ -
X$LOGMNR_INDPART$ Log Miner Index Partitions
X$LOGMNR_INDSUBPART$ Log Miner Index Subpartitions
X$LOGMNR_KOPM$ -
X$LOGMNR_KTFBUE -
X$LOGMNR_LATCH Log Miner Latches
X$LOGMNR_LOB$ Log Miner Large Objects
X$LOGMNR_LOBFRAG$ -
X$LOGMNR_LOG -
X$LOGMNR_LOGFILE Log Miner Log Files
X$LOGMNR_LOGS -
X$LOGMNR_NTAB$ -
X$LOGMNR_OBJ$ Log Miner Objects
X$LOGMNR_OPQTYPE$ Log Miner Opaque Types
X$LOGMNR_PARAMETERS Log Miner Parameters
X$LOGMNR_PARTOBJ$ -
X$LOGMNR_PROCESS -
X$LOGMNR_PROPS$ -
X$LOGMNR_REFCON$ -
X$LOGMNR_REGION -
X$LOGMNR_ROOT$ -
X$LOGMNR_SEG$ Log Miner Segments
X$LOGMNR_SESSION Log Miner Sessions
X$LOGMNR_SUBCOLTYPE$ -
X$LOGMNR_TAB$ Logminer Tables
X$LOGMNR_TABCOMPART$ -
X$LOGMNR_TABPART$ Log Miner Table Partitions
X$LOGMNR_TABSUBPART$ Log Miner Table Subpartitions
X$LOGMNR_TS$ Log Miner Tablespaces
X$LOGMNR_TYPE$ Log Miner Data Types
X$LOGMNR_UET$ -
X$LOGMNR_UNDO$ Log Miner Undo
X$LOGMNR_USER$ Log Miner Users
Long Operations
Object Name Notes
X$KSULOP Kernel Services: user long operation
X$XSLONGOPS Maps to v$session_longops
Mutexes
Object Name Notes
X$MUTEX_SLEEP -
X$MUTEX_SLEEP_HISTORY -
NLS Parameters
Object Name Notes
X$NLS_PARAMETERS -- set NLS database parameters

SELECT parameter, value
FROM x$nls_parameters;

SELECT *
FROM v$nls_parameters;
NFS Mount
Object Name Notes
X$NFSCLIENTS NFS Clients
X$NFSLOCKS NFS Locks
X$NFSOPENS -
Physical Files
Object Name Notes
X$KCCFN col fnnam format a62

SELECT fnnam
FROM x$kccfn;

FNNAM
--------------------------------------------------------------
C:\APP\ORACLE\ORADATA\ORABASE2\REDO03.LOG
C:\APP\ORACLE\ORADATA\ORABASE2\REDO02.LOG
C:\APP\ORACLE\ORADATA\ORABASE2\REDO01.LOG
C:\APP\ORACLE\ORADATA\ORABASE2\USERS01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\UNDOTBS01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\SYSAUX01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\SYSTEM01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\TEMP01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\PDBSEED\SYSTEM01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\PDBSEED\SYSAUX01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\PDBSEED\PDBSEED_TEMP01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\ORCL\SYSTEM01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\ORCL\SYSAUX01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\ORCL\ORCL_TEMP01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\ORCL\SAMPLE_SCHEMA_USERS01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\ORCL\EXAMPLE01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\SYSTEM01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\SYSAUX01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\PDBSEED_TEMP01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\ORADATA01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\UWDATA01.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\CATTBSP.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\CATTEMP.DBF
C:\APP\ORACLE\ORADATA\ORABASE2\PDBDEV\TBFS.DBF
C:\TEMP\PART01.DBF
C:\TEMP\PART02.DBF
C:\TEMP\PART03.DBF
C:\TEMP\PART04.DBF
Processes and Process Messages
Object Name Notes
X$MESSAGES -- background process messages

col description format a70
col dest format a10

SELECT dest, description
FROM x$messages
ORDER BY 1,2;
RDA
Object Name Notes
X$KCCDC 6 rows
Real Application Clusters
Object Name Notes
X$INSTANCE_CACHE_TRANSFER SELECT inst_id, lost, lost_time, cr_2hop_time, cr_3hop_time, cr_busy_time, cr_congested_time
FROM x$instance_cache_transfer;
X$KCBSC I/O
Redo and Undo
Object Name Notes
X$KCRFSTRAND Redo pool descriptor
X$KTIFP In-Memory Undo
Rules and Rule Sets
Object Name Notes
X$RULE -- rule WHERE clause & metrics - 1 row

col rule_owner format a10
col rule_condition format a80

SELECT rule_set_object_id RSOID, rule_owner, rule_condition, true_hits, maybe_hits
FROM x$rule;
Tablespaces
Object Name Notes
X$KCCTS SELECT con_id, tsnam
FROM x$kccts;

    CON_ID TSNAM
--------- -------------
         1 SYSTEM
         1 SYSAUX
         1 UNDOTBS1
         1 USERS
         1 TEMP
         2 SYSTEM
         2 SYSAUX
         2 TEMP
         3 SYSTEM
         3 SYSAUX
         3 TEMP
         3 USERS
         3 EXAMPLE
         4 SYSTEM
         4 SYSAUX
         4 TEMP
         4 ORADATA
         4 UWDATA
         4 CATTBSP
         4 CATTEMP
         4 TBFS
         4 PART1
         4 PART2
         4 PART3
         4 PART4
Time Zone
Object Name Notes
X$TIMEZONE_FILE -- timezone file current in use

SELECT filename, version
FROM x$timezone_file;

FILENAME                VERSION
-------------------- ----------
timezlrg_18.dat              18
X$TIMEZONE_NAMES Timezones

col tzname format a30

SELECT tzname, tzabbrev
FROM x$timezone_names;
Wait Interface
Object Name Notes
X$KCBSH raw/numeric - 21,960 rows
X$KSDHNG_CHAINS Blockers and waits- 0 rows
X$DB Objects
Object Name Notes
X$DBGDIREXT -
X$DBGLOGEXT -
X$DBGRICX -
X$DBGRIFX -
X$DBGRIKX -
X$DBGRIPX -
X$DBKECE -
X$DBKEFAFC 7 rows

SELECT "ACTION ID", "ACTION NAME"
FROM x$dbkefafc;
X$DBKEFDEAFC 0 rows

SELECT "ACTION ID",  "PROBLEM KEY"
FROM x$dbkefdeafc;
X$DBKEFEFC -
X$DBKEFIEFC -
X$DBKFDG -
X$DBKFSET -
X$DBKH_CHECK -
X$DBKH_CHECK_PARAM -
X$DBKINCMETCFG -
X$DBKINCMETINFO -
X$DBKINCMETSUMMARY -
X$DBKINFO -
X$DBKRECO -
X$KE Objects
Object Name Notes
X$KEACMDN -
X$KEAFDGN -
X$KEAOBJT -
X$KECPDENTRY -
X$KECPRT -
X$KEHECLMAP -
X$KEHETSX -
X$KEHEVTMAP -
X$KEHF -
X$KEHOSMAP -
X$KEHPRMMAP -
X$KEHR -- lookup table with 82 rows: possibly ADDM internal rules

SELECT rule_id, name, description
FROM x$kehr;
X$KEHRP -- lookup table with 38 rows

SELECT parameter_id, name, description
FROM x$kehrp;
X$KEHR_CHILD raw/numeric - 86 rows
X$KEHSQT -
X$KEHSYSMAP -
X$KEHTIMMAP -
X$KELRSGA -
X$KELRTD -
X$KELRXMR -
X$KELTGSD -
X$KELTOSD -
X$KELTSD -
X$KEOMNMON_SESSTAT -
X$KERPIREPREQ -
X$KERPISTATS -
X$KESPLAN -
X$KESSPAMET -
X$KESWXMON -
X$KESWXMON_PLAN -
X$KESWXMON_STATNAME -
X$KETCL -
X$KETOP -
X$KETTG -
X$KEWAM -
X$KEWASH -
X$KEWECLS -
X$KEWEFXT -
X$KEWEPCS -
X$KEWESMAS -
X$KEWESMS -
X$KEWMAFMV -
X$KEWMDRMV -
X$KEWMDSM -
X$KEWMEVMV -
X$KEWMFLMV -
X$KEWMGSM -
X$KEWMIOFMV -
X$KEWMRMGMV -
X$KEWMRSM -
X$KEWMRWMV -
X$KEWMSEMV -
X$KEWMSMDV -
X$KEWMSVCMV -
X$KEWMWCRMV -
X$KEWMWPCMV -
X$KEWPDBIX -
X$KEWRATTRNEW -
X$KEWRATTRSTALE -
X$KEWRSQLCRIT -
X$KEWRSQLIDTAB -
X$KEWRSQLSUM -
X$KEWRTB -
X$KEWRTOPTENV -
X$KEWRTSEGSTAT -
X$KEWRTSQLPLAN -
X$KEWRTSQLTEXT -
X$KEWSSESV -
X$KEWSSMAP -
X$KEWSSVCV -
X$KEWSSYSV -
X$KEWXOCF -
X$KEWX_SEGMENTS -
X$KF Objects
Object Name Notes
X$KFALS 0 rows
X$KFBH raw/numeric - 0 rows
X$KFCBH raw/numeric - 0 rows
X$KFCCE -
X$KFCLLE -
X$KFCSTAT -
X$KFDAP -
X$KFDPARTNER -
X$KFDSD -
X$KFDSK -
X$KFDSK_STAT -
X$KFDSR -
X$KFDXEXT -
X$KFDAT -
X$KFDDD -
X$KFDFS -
X$KFENV -
X$KFFIL -
X$KFFOF -
X$KFFXP -
X$KFGBRB -
X$KFGBRC -
X$KFGBRS -
X$KFGBRW -
X$KFGMG -
X$KFGRP -
X$KFGRP_STAT -
X$KFGXP -
X$KFIAS_CLNT -
X$KFIAS_FILE -
X$KFIAS_PROC -
X$KFKID -
X$KFKLIB -
X$KFKLSOD -
X$KFMDGRP -
X$KFNCL -
X$KFNRCL -
X$KFNSDSKIOST -
X$KFRC -
X$KFTMTA -
X$KFVACFS -
X$KFVACFSADMIN -
X$KFVACFSCMDRULE -
X$KFVACFSENCR -
X$KFVACFSREALM -
X$KFVACFSREALMFILTER -
X$KFVACFSREALMGROUP -
X$KFVACFSREALMS -
X$KFVACFSREALMUSER -
X$KFVACFSREPL -
X$KFVACFSREPLTAG -
X$KFVACFSRULE -
X$KFVACFSRULESET -
X$KFVACFSRULESETRULE -
X$KFVACFSS -
X$KFVACFSTAG -
X$KFVACFSV -
X$KFVOL -
X$KFVOLSTAT -
X$KFZGDR -
X$KFZPBLK -
X$KFZUAGR -
X$KFZUDR -
X$KM Objects
Object Name Notes
X$KMCQS raw/numeric - 6 rows
X$KMCVC -
X$KMGSBSADV -
X$KMGSBSMEMADV -
X$KMGSCT -
X$KMGSOP -
X$KMGSTFR -
X$KMMDI -
X$KMMDP -
X$KMMHST -
X$KMMNV -
X$KMMRD -
X$KMMSAS -
X$KMMSG -
X$KMMSI 16 rows
X$KMPDH -
X$KMPCMON 4 rows
X$KMPCP -
X$KMPCSO -
X$KMPSRV -
X$KN Objects
Object Name Notes
X$KNGFL -
X$KNGFLE -
X$KNLAROW -
X$KNLASG -
X$KNSTACR -
X$KNSTANR -
X$KNSTASL -
X$KNSTCAP -
X$KNSTCAPCACHE 0 rows
X$KNSTCAPS -
X$KNSTMT -
X$KNSTMVR Kernel replication, statistics materialized view refresh. Base table of v$mvrefresh. Stores MV refresh history info, such as session SID and serial#. Un-exposed columns reftype_knstmvr, groupstate_knstmvr and total_* are useful; see the query in Note: 258021.1.
X$KNSTOGGC -
X$KNSTRPP -
X$KNSTRQU -
X$KNSTSESS -
X$KNSTTXN -
X$KNSTXSTS -
X$KP Objects
Object Name Notes
X$KPONDESTAT -
X$KPONESTAT -
X$KPONJSTAT -
X$KPOQSTA -
X$KPPLCC_INFO -
X$KPPLCC_STATS -
X$KPPLCONN_INFO -
X$KPPLCP_STATS -
X$KR Objects
Object Name Notes
X$KRASGA raw/numeric - 1 row
X$KRBAFF -
X$KRBMCA -
X$KRBMROT -
X$KRBMRST -
X$KRBMSFT -
X$KRBPDATA -
X$KRBPDIR -
X$KRBPHEAD -
X$KRBZA -
X$KRCBIT Bitmap Block
X$KRCCDE -
X$KRCCDR -
X$KRCCDS -
X$KRCEXT Allocate Bitmap Extent Map
X$KRCFBH Bitmap Extent Header
X$KRCFDE Datafile Descriptor
X$KRCFH Block Change Tracking File Header
X$KRCGFE -
X$KRCSTAT -
X$KRDEVTHIST -
X$KRDMMIRA -
X$KRDRSBROV -
X$KRFBLOG -
X$KRFGSTAT -
X$KRFSTHRD -
X$KRSSMS -
X$KRSTALG -
X$KRSTAPPSTATS -
X$KRSTDEST -
X$KRSTDGC -
X$KRVSLV -
X$KRVSLVPG -
X$KRVSLVS -
X$KRVSLVST -
X$KRVSLVTHRD -
X$KRSTPVRS -
X$KRVXDKA -
X$KRVXDTA -
X$KRVXISPCHK -
X$KRVXISPLCR -
X$KRVXOP -
X$KRVXSV -
X$KRVXTHRD -
X$KRVXTX -
X$KRVXWARNV -
X$KW Objects
Object Name Notes
X$KWDDEF -
X$KWQBPMT -
X$KWQDLSTAT -
X$KWQITCX -
X$KWQMNC -
X$KWQMNJIT -
X$KWQMNSCTX -
X$KWQMNTASK -
X$KWQMNTASKSTAT -
X$KWQPD -
X$KWQPS -
X$KWQSI -
X$KWRSNV -
X$KWSBGAQPCSTAT -
X$KWSBGQMNSTAT -
X$KWSBJCSQJIT -
X$KWSBSMSLVSTAT -
X$KWSCPJOBSTAT -
Miscellaneous Objects
Object Name Notes
X$KAUVRSTAT -
X$BMAPNONDURSUB -
X$KBRPSTAT -
X$BUFFER -
X$BUFFERED_PUBLISHERS -
X$BUFFER2 -
X$CDBVW$ 0 rows
X$COMVW$ -
X$CON -
X$CONTEXT -
X$CON_KEWSSYSV -
X$CON_KSLEI -
X$CON_KSLSCS -
X$CON_KSUSGSTA -
X$DGLPARAM -
X$DGLXDAT -
X$DRA_FAILURE -
X$DRA_FAILURE_CHECK -
X$DRA_FAILURE_CHECK_MAP -
X$DRA_FAILURE_PARAM -
X$DRA_FAILURE_PARENT_MAP -
X$DRA_FAILURE_REPAIR -
X$DRA_FAILURE_REPAIR_MAP -
X$DRA_REPAIR -
X$DRA_REPAIR_PARAM -
X$DRM_HISTORY -
X$DRM_HISTORY_STATS -
X$DURABLE_SHARDED_SUBS -
X$GIMSA -
X$GLOBALCONTEXT -
X$HEATMAPSEGMENT -
X$HOFP -
X$IEE -
X$IEE_CONDITION -
X$IEE_ORPIECE -
X$JOXFC -
X$JOXFD -
X$JOXFM -
X$JOXFR -
X$JOXFS -
X$JOXFT -
X$JSKJOBQ -
X$JSKMIMMD -
X$JSKMIMRT -
X$JSKSLV -
X$KLCIE -
X$KLPT -
X$KOCST -
X$KUPVA -
X$KUPVJ -
X$KYWMCLTAB -
X$KYWMNF -
X$KYWMPCMN -
X$KYWMPCTAB -
X$KYWMWRCTAB -
X$MSGBM -
X$MODACT_LENGTH -
X$NONDURSUB -
X$NONDURSUB_LWM -
X$NSV -
X$OBJECT_POLICY_STATISTICS -
X$OCT -
X$OFSMOUNT -
X$OFS_RW_LATENCY_STATS -
X$OFS_STATS -
X$OPARG -
X$OPDESC -
X$OPERATORS SELECT name, operands, in_type, out_type
FROM x$operators
ORDER BY 1;
X$OPTIM_CALIB_STATS -
X$OPTION 15 of the 64 rows tie back to DBA_FEATURE_USAGE_STATISTICS
X$OPVERSION -
X$ORAFN -
X$POLICY_HISTORY -
X$PRMSLTYX -
X$PROPS -
X$QERFXTST -
X$QESBLSTAT -
X$QESMMAHIST -
X$QESMMAPADV -
X$QESMMIWH -
X$QESMMIWT -
X$QESMMSGA -
X$QESRCDEP -
X$QESRCDR -
X$QESRCMEM -
X$QESRCMSG -
X$QESRCOBJ -
X$QESRCRD -
X$QESRCRR -
X$QESRCSTA -
X$QESRSTAT -
X$QESRSTATALL -
X$QKSBGSES -
X$QKSBGSYS -
X$QKSCESES -
X$QKSCESYS -
X$QKSCR -
X$QKSCR_RSN -
X$QKSXA_REASON -
X$QKSFM -
X$QKSFMDEP -
X$QKSFMPRT -
X$QKSHT -
X$QKSMMWDS -
X$QUIESCE -
X$RFMP -
X$RFAFO -
X$RFAHIST -
X$RFMTE -
X$RO_USER_ACCOUNT -
X$RULE_SET col name format a12

SELECT name, cpu_time, elapsed_time, last_loading_time,
first_load_time, last_load_time, sharable_mem, reloads
FROM x$rule_set;
X$RXS_SESSION_ROLES -
X$SKGXPIA 0 rows
X$TARGETRBA raw/numeric: 1 row
X$TRACE 8,870 rows
X$TRACE_EVENTS 1000 rows
X$UGANCO 0 rows
X$VINST 0 rows
X$XML_AUDIT_TRAIL 0 rows
X$XSAWSO raw/numeric: 16 rows
X$XPLTON -- explain plan lookup table

SELECT xplton_name
FROM x$xplton
ORDER BY 1;
X$XPLTOO -- explain plan lookup table

SELECT xpltoo_name
FROM x$xpltoo
ORDER BY 1;
X$XSAGGR 0 rows
X$XSAGOP -
X$XSOBJECT -
X$XSOQMEHI -
X$XSOQOJHI -
X$XSOQOPHI -
X$XSOQOPLU -
X$XSOQSEHI -
X$XSSINFO 0 rows
X$XS_SESSIONS -
X$XS_SESSION_NS_ATTRIBUTES -
X$XS_SESSION_ROLES 0 rows
X$ZASAXTAB -
 
X$ Demos
Find sessions originating across db links

Courtesy of Mark Bobak
Finding open database links database wide

Mark Bobak's query (originally in Metalink forum thread 524821.994, where he further attributed authorship) uses this table to find sessions coming from or going to a remote database; in short, x$k2gte.k2gtdses matches v$session.saddr, .k2gtdxcb matches v $transaction.addr. It's more robust than this query, and better than checking for DX locks for outgoing sessions (since a DX lock only shows up in v$lock for the current distributed transaction session).
SELECT /*+ ORDERED */ SUBSTR(s.ksusemnm,1,10)||'-'|| SUBSTR(s.ksusepid,1,10) ORIGIN, SUBSTR(g.k2gtitid_ora,1,35) GTXID,
SUBSTR(s.indx,1,4) ||'.'|| SUBSTR(s.ksuseser,1,5) LSESSION,
s2.username,
SUBSTR(DECODE(BITAND(s.ksuseidl,11),
       1,'ACTIVE', 0,
       DECODE(BITAND(s.ksuseflg,4096) , 0,'INACTIVE','CACHED'),
       2,'SNIPED',
       3,'SNIPED',
       'KILLED' ),1,1) S,
SUBSTR(w.event,1,10) "WAITING"
FROM x$k2gte g, x$ktcxb t, x$ksuse s, gv$session_wait w, gv$session s2
WHERE g.K2GTDXCB =t.ktcxbxba
AND g.K2GTDSES=t.ktcxbses
AND s.addr=g.k2gtdses
AND w.sid=s.indx
AND s2.sid = w.sid;
Largest number of blocks per write SELECT kviival write_batch_size
FROM x$kvii
WHERE kviitag = 'kcbswc';
GETS and WAITS for different queue types col ksqstexpl format a52
col ksqstrsn format a27

SELECT *
FROM x$ksqst
WHERE ksqstsgt > 0;

Related Topics
Data Dictionary
GV$ and V$ Dynamic Performance Views
Kernel Subsystems

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