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		Unique snapshot ID
DBID	NUMBER		Database ID for the snapshot
INSTANCE_NUMBER	NUMBER		Instance number for the snapshot
LATCH_HASH	NUMBER		Latch Hash
LATCH_NAME	VARCHAR2(64)		Latch name
CHILD#	NUMBER		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 requestor 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
SLEEP1	NUMBER		Waits that slept 1 time
SLEEP2	NUMBER		Waits that slept 2 times
SLEEP3	NUMBER		Waits that slept 3 times
SLEEP4	NUMBER		Waits that slept 4 or more times
WAIT_TIME	NUMBER		Elapsed time spent waiting for the latch (in microseconds)