5.2 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:

• "DBA_HIST_LATCH"

• "V$LATCH"