V$LATCH

V$LATCH displays aggregate latch statistics for both parent and child latches, grouped by latch name. Individual parent and child latch statistics are broken down in the views V$LATCH_PARENT and V$LATCH_CHILDREN.

Column Datatype Description

ADDR

RAW(4 | 8)

Address of the latch object

LATCH#

NUMBER

Latch number

LEVEL#

NUMBER

Latch level

NAME

VARCHAR2(64)

Latch name

HASH

NUMBER

Latch hash

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)

WAITERS_WOKEN

NUMBER

This column has been deprecated and is present only for compatibility with previous releases of Oracle. No data is accumulated for this column; it will always have a value of zero.

WAITS_HOLDING_LATCH

NUMBER

This column has been deprecated and is present only for compatibility with previous releases of Oracle. No data is accumulated for this column; it will always have a value of zero.

SPIN_GETS

NUMBER

Willing-to-wait latch requests which missed the first try but succeeded while spinning

SLEEP[1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11]

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. As a substitute for these columns you can query the appropriate rows of the V$EVENT_HISTOGRAM view where the EVENT column has a value of latch free or latch:%.

WAIT_TIME

NUMBER

Elapsed time spent waiting for the latch (in microseconds)

CON_ID

NUMBER

The ID of the container to which the data pertains. 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: