DBA_HIST_LATCH_CHILDREN

DBA_HIST_LATCH_CHILDREN displays historical statistics about child latches. This view includes all columns of DBA_HIST_LATCH plus the CHILD# column. Note that child latches have the same parent if their LATCH# columns match each other. This view contains snapshots of V$LATCH_CHILDREN.

Column Datatype NULL Description

SNAP_ID

NUMBER

NOT NULL

Unique snapshot ID

DBID

NUMBER

NOT NULL

Database ID for the snapshot

INSTANCE_NUMBER

NUMBER

NOT NULL

Instance number for the snapshot

LATCH_HASH

NUMBER

NOT NULL

Latch hash

LATCH_NAME

VARCHAR2(64)

NOT NULL

Latch name

CHILD#

NUMBER

NOT NULL

Child latch number (unique only to each parent latch)

GETS

NUMBER

  

Number of times the latch was requested in willing-to-wait mode

MISSES

NUMBER

  

Number of times the latch was requested in willing-to-wait mode and the requester had to wait

SLEEPS

NUMBER

  

Number of times a willing-to-wait latch request resulted in a session sleeping while waiting for the latch

IMMEDIATE_GETS

NUMBER

  

Number of times a latch was requested in no-wait mode

IMMEDIATE_MISSES

NUMBER

  

Number of times a no-wait latch request did not succeed (that is, missed)

SPIN_GETS

NUMBER

  

Number of willing-to-wait latch requests which missed the first try but succeeded while spinning

SLEEP[1 | 2 | 3 | 4]

NUMBER

  

These columns have been deprecated and are present only for compatibility with previous releases of Oracle. No data is accumulated for these columns; they will always have a value of zero.

WAIT_TIME

NUMBER

  

Elapsed time spent waiting for the latch (in microseconds)

CON_DBID

NUMBER

  

The database ID of the PDB for the sampled session

CON_ID

NUMBER

  

The ID of the container that CON_DBID identifies. Possible values include:

  • 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs.

  • 1: This value is used for rows containing data that pertain to only the root

  • n: Where n is the applicable container ID for the rows containing data

See Also: