Group Buffer Pool Parameters

This topic shows detailed information about System Parameters - Group Buffer Pool Parameters.

This block shows the merged group buffer pool data from all the members of a Db2 data sharing group. To produce this report, statistics class 5 must be active.

Each time an ALTER GROUPBUFFERPOOL command is issued for a member, an IFCID 230 record is produced showing information about the group buffer pools connected to that particular member of a data sharing group. If the IFCID 230 record indicates that the status of the group buffer pools has changed since the last IFCID 230 record was produced (regardless of which member produced it), or if this is the first IFCID 230 encountered, the new status of the group buffer pools is printed.

The status of the group buffer pools changes if the IFCID 230 record indicates one of the following:

A member uses a new group buffer pool.
A member does not use a group buffer pool that it used previously.
At least one of the group buffer pool attributes has changed.

All the group buffer pools connected to the member, whether or not they have changed, are printed.

System Parameters - Group Buffer Pool Parameters

The field labels shown in the following sample layout of System Parameters - Group Buffer Pool Parameters are described in the following section.


Mode Simplex:

GROUP BUFFER POOL PARAMETERS                                                                     
 -------------------------------------------------------------------------------------------------
 TIMESTAMP             05/10/22 18:47:00.48          CURRENT DIRECTORY TO DATA RATIO             5
 MEMBER                                CEB1          CLASS CASTOUT THRESHOLD (%)                 5
 GBP ID                                GBP0          CLASS CASTOUT THRESHOLD (PAGES)             0
 ALLOCATED GBP SIZE (4K)              16128          GBP CASTOUT THRESHOLD (%)                  30
 ACTUAL DIRECTORY                     51252          GBP CHECKPOINT INTERVAL (MIN)               1
 ACTUAL DATA ENTRY                    10248          GBP CACHE SETTING                         YES
 PENDING DIRECTORY TO DATA RATIO          5          AUTO REC                                  YES
 MODE                               SIMPLEX          DATA AREA RESIDENCY TIME                    0
                                                     DIRECTORY ENTRY RESIDENCY TIME              0
                                                     
Mode Duplex:

 GROUP BUFFER POOL PARAMETERS                                                                     
 -------------------------------------------------------------------------------------------------
 TIMESTAMP             05/10/22 18:47:00.48          CURRENT DIRECTORY TO DATA RATIO             5
 MEMBER                                CEB1          CLASS CASTOUT THRESHOLD (%)                 5
 GBP ID                                GBP0          CLASS CASTOUT THRESHOLD (PAGES)             0
 ALLOCATED GBP SIZE (4K)              16128          GBP CASTOUT THRESHOLD (%)                  30
 ACTUAL DIRECTORY                     51252          GBP CHECKPOINT INTERVAL (MIN)               1
 ACTUAL DATA ENTRY                    10248          GBP CACHE SETTING                         YES
 PENDING DIRECTORY TO DATA RATIO          5          AUTO REC                                  YES
 MODE                                DUPLEX          DATA AREA RESIDENCY TIME                    0
 SEC-GBP ALLOC                        16128          DIRECTORY ENTRY RESIDENCY TIME              0
 SEC-GBP ALLOC DIRECTORY ENTRY        51252                                                       
 SEC-GBP DATA ENTRY                   10248

CURRENT DIRECTORY TO DATA RATIO

The current directory entry to data entry ratio.

For ALTER GROUPBUFFERPOOL commands, this field reports the value specified in the RATIO keyword.

Field Name: QBGBGR1

CLASS CASTOUT THRESHOLD (%)

The threshold at which the class castout is to be initiated. It is expressed as a percentage of the size of the group buffer pool.

For ALTER GROUPBUFFERPOOL commands, it reports the value specified in the CLASST keyword.

Field Name: QBGBGCT

GBP ID

Group buffer pool name.

Field Name: QBGBGN

CLASS CASTOUT THRESHOLD (PAGES)

The class castout threshold based on the number of pages.

Field Name: QBGBGCTN

ALLOCATED GBP SIZE (4K)

The allocated size of the group buffer pool in 4 KB blocks.

Field Name: QBGBGSZ

GBP CASTOUT THRESHOLD (%)

The threshold at which the castout is to be initiated for the group buffer pool. It is expressed as a percentage of the size of the group buffer pool.

For ALTER GROUPBUFFERPOOL commands, it reports the value specified in the GBPOOLT keyword.

Field Name: QBGBGGT

ACTUAL DIRECTORY

The actual number of allocated directory entries.

Field Name: QBGBGDR

GBP CHECKPOINT INTERVAL (MIN)

The time interval, in minutes, between successive group buffer pool checkpoints.

For ALTER GROUPBUFFERPOOL commands, it reports the value specified in the GBPCHKPT keyword.

Field Name: QBGBGCK

ACTUAL DATA ENTRY

The actual number of allocated data entries.

Field Name: QBGBGDT

GBP CACHE SETTING

GBP cache attribute. Possible values are:

YES: GBP is used for both data caching and cross-invalidation.
NO: GBP is used for cross-invalidation only.

Field Name: QBGBGCS

PENDING DIRECTORY TO DATA RATIO

The pending directory entry to data entry ratio.

Field Name: QBGBGR2

AUTO REC

Indicates whether automatic recovery takes place in the event of a structure failure or a loss of connectivity. When automatic recovery is active, all members of the group are recovered to the group buffer pool.

Field Name: QBGBGAS

MODE

Simplex or duplex mode indicator.

Field Name: QBGBDUP

SEC-GBP ALLOC

The allocated size of the secondary GBP when the GBP is DUPLEX.

This field is not shown when MODE is SIMPLEX.

Field Name: QBGBGSZ2

SEC-GBP ALLOC DIRECTORY ENTRY

Number of allocated directory entries in the secondary GBP when MODE is DUPLEX.

Field Name: QBGBGDR2

SEC-GBP ALLOC DATA ENTRY

The allocated data entries in the secondary GBP when MODE is DUPLEX.

Field Name: QBGBGDT2

DATA AREA RESIDENCY TIME

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

Field Name: QBGBART

DIRECTORY ENTRY RESIDENCY TIME

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

Field Name: QBGBERT