DBA_HIST_LATCH

DBA_HIST_LATCH displays historical aggregate latch statistics for both parent and child latches, grouped by latch name. This view contains snapshots of V$LATCH.

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
`LEVEL#`	`NUMBER`		Latch level
`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 multitenant container database (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