DBA_HIST_LATCH

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	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)