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Http://docs.oracle.com/database/121/REFRN/refrn30109.htm

V$LATCH_CHILDREN

V$LATCH_CHILDREN displays statistics about child latches. This view includes all columns of V$LATCH plus the CHILD# column. Note that child latches have the same parent if their LATCH# columns match each other.

ColumnDatatypeDescriptionADDRRAW (4 | 8) Address of the latch objectLATCH#NUMBERLatch number of the parent latchCHILD#NUMBERChild latch number (unique only to each parent latch) LEVEL#NUMBERLatch levelNAMEVARCHAR2 (64) Latch nameHASHNUMBERLatch hashGETSNUMBERNumber of times the latch was requested in willing-to-wait modeMISSESNUMBERNumber of times the latch was requested in willing-to-wait mode and the requester had to waitSLEEPSNUMBERNumber of times a willing-to-wait latch request resulted in a session sleeping while waiting for the latchIMMEDIATE_GETSNUMBERNumber of times a latch was requested in no-wait modeIMMEDIATE_MISSESNUMBERNumber of times a no-wait latch request did not succeed (that is Missed) WAITERS_WOKENNUMBERThis 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_LATCHNUMBERThis 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_GETSNUMBERWilling-to-wait latch requests which missed the first try but succeeded while spinningSLEEP [1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11] NUMBERThese 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_TIMENUMBERElapsed time spent waiting for the latch (in microseconds) CON_IDNUMBERThe 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

ADDR: the physical address of the latch object.

The parent latch number of the LATCH#: child latch.

CHILD#: child latch number, for each parent latch, the child latch is unique.

LEVEL#:latch level.

NAME:latch name.

HASH:latch hash value.

GETS: the number of requests for latch in Willing-to-waits mode.

MISSES: the number of times latch is requested when waiting occurs in Willing-to-waits mode.

SLEEPS: the number of times latch was requested when latch wait caused session to hibernate.

The number of latch requests in IMMEDIATE_GETS:no-wait mode.

IMMEDIATE_MISSES: the number of times the request for no-wait latch failed.

WAITERS_WOKEN: this column has been deprecated by the current version and is retained for forward compatibility.

WAITS_HOLDING_LATCH: this column has been deprecated by the current version and is retained for forward compatibility.

SPIN_GETS: when spinning, the number of successful requests for Willing-to-wait latch

The time in microseconds that WAIT_TIME:latch waits for elapsed time.

CON_ID: indicates the dependency of the data, 0 indicates that those rows belong to the data of CDB, and 1 indicates that it only belongs to the container ID to which root,n indicates application.

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