IFCID 254 - Coupling Facility Cache Structure Statistics

Record Trace - IFCID 254 - Coupling Facility Cache Structure Statistics

The field labels shown in the following sample layout of Record Trace - IFCID 254 - Coupling Facility Cache Structure Statistics are described in the following section.

GROUP BUFFER POOL NAME              GBP0      EXPLICIT XI COUNTER            0
READ HIT                               0      CHANGED PAGE WRITE HIT         0      XI DIRECTORY ENTRY RECLAIM        0
READ MISS DIRECTORY HIT                0      CLEAN PAGE WRITE HIT           0      CASTOUT                           0
READ MISS ASSIGNMENT SUPPRESSED        0      WRITE MISS CACHE FULL          0      DIRECTORY ENTRY                   0
READ MISS NAME ASSIGNED                0      DIRECTORY ENTRY RECLAIM        0      DATA ENTRY                        0
READ MISS CACHE FULL                   0      DATE ENTRY RECLAIM             0      TOTAL CHANGED                     0
SEC-GBP CHANGED PAGE WRITE HIT         0      SEC-GBP DIRECTORY ENTRY        0      SEC-GBP TOTAL CHANGED             0
SEC-GBP WRITE MISS CACHE FULL          0      SEC-GBP DATA ENTRY             0
DATA AREA RESID TIME                   0      DATA ENTRY RESID TIME          0

GROUP BUFFER POOL NAME

The name of the group buffer pool.

Field Name: QW0254GN

EXPLICIT XI COUNTER

The number of times a request was made to the group coupling facility to explicitly cross invalidate a page and a number of XI signals were sent because the page was cached in one or more Db2 buffer pools.

Field Name: QW0254CI

READ HIT

The number of coupling facility read requests in which data was returned.

Field Name: QW0254RH

CHANGED PAGE WRITE HIT

The number of coupling facility write requests for changed pages that has successfully completed.

Field Name: QW0254WH

XI DIRECTORY ENTRY RECLAIM

The number of times that a directory entry was stolen and XI signals had to be sent because the page for the directory entry was cached in one or more Db2 buffer pools.

Field Name: QW0254XR

READ MISS DIRECTORY HIT

The number of coupling facility read requests for a page in which data was not returned but the page name was already assigned in the coupling facility directory (SES did not have to assign a directory entry for the page).

Field Name: QW0254RD

CLEAN PAGE WRITE HIT

The number of facility write requests for clean pages successfully completed.

Field Name: QW0254WC

CASTOUT

The number of castout operations performed.

Field Name: QW0254CC

READ MISS ASSIGNMENT SUPPRESSED

The number of times that a coupling facility read request specified a page for which no directory entry exists and no directory entry is created. Db2 does not create a directory entry if it does not need to register the page to the coupling facility for cross invalidation (XI); that is when no other Db2 member in the group has R/W interest in the page set/partition.

Field Name: QW0254RS

WRITE MISS CACHE FULL

The number of coupling facility write requests that could not complete due to a lack of coupling facility storage resources.

Field Name: QW0254WF

DIRECTORY ENTRY

The number of allocated directory entries (not cumulative).

Field Name: QW0254DE

READ MISS NAME ASSIGNED

The number of times that a coupling facility read request specified a page for which a directory entry was created.

Field Name: QW0254RN

DIRECTORY ENTRY RECLAIM

The number of times that a page name assignment required a coupling facility directory entry to be reclaimed (stolen).

Field Name: QW0254DR

DATA ENTRY

The number of allocated data entries (not cumulative).

Field Name: QW0254TE

READ MISS CACHE FULL

The number of times that a coupling facility read request specified a page for which no directory entry exists and no directory entry is created due to the lack of storage in the group buffer pool. A non-zero value in this field indicates that the backing coupling facility cache structure size might be too small to support the current workload.

Field Name: QW0254RF

DATA ENTRY RECLAIM

The number of times that a page name assignment required a coupling facility data entry to be reclaimed (stolen).

Field Name: QW0254TR

TOTAL CHANGED

The snapshot value of the current number of changed pages.

Field Name: QW0254TC

SEC-GBP CHANGED PAGE WRITE HIT

The number of successful coupling facility write requests for changed pages.

Field Name: QW02542W

SEC-GBP WRITE MISS CACHE FULL

The number of unsuccessful coupling facility write requests because of insufficient coupling facility storage resources.

Field Name: QW02542F

SEC-GBP DIRECTORY ENTRY

The number of allocated directory entries. This is a snapshot value.

Field Name: QW02542D

SEC-GBP DATA ENTRY

The number of allocated data entries. This is a snapshot value.

The number of allocated data entries that are currently in changed state. This is a snapshot value.

Field Name: QW02542C

DATA AREA RESID TIME

Weighted average in microseconds of the elapsed time a data area resides in a group buffer pool before it is reclaimed.

Field Name: QW0254AR

DATA ENTRY RESID TIME

Weighted average in microseconds of the elapsed time a directory entry resides in a group buffer pool before it is reclaimed.

Field Name: QW0254ER