-DISPLAY GROUPBUFFERPOOL command (Db2)

The DSNB750I message displays output from the -DISPLAY GROUPBUFFERPOOL command.

For more information, see Group buffer pool monitoring with the DISPLAY GROUPBUFFERPOOL command.

For each qualifying group buffer pool, one of the following two messages is displayed:

DSNB750I

DSNB750I DISPLAY FOR GROUP BUFFER POOL gbpname FOLLOWS

Message DSNB750I is displayed if Db2 was able to access information for the group buffer pool in the z/OS coupling facility resource management (CFRM) administrative policy.

gbpname

The name of the group buffer pool.

DSNB751I

DSNB751I MVS CFRM POLICY INFORMATION NOT AVAILABLE FOR GROUP BUFFER POOL gbpname MVS IXCQUERY RETURN CODE = retcode MVS IXCQUERY REASON CODE = reason A PARTIAL DISPLAY FOLLOWS

Message DSNB751I is displayed if Db2 could not retrieve the z/OS CFRM administrative policy information for the group buffer pool. Either the z/OS query request (IXCQUERY) did not successfully complete, or the backing structure for the group buffer pool is not defined in the z/OS CFRM administrative policy. Therefore, the information that is displayed for the group buffer pool is incomplete. For example, if the IXCQUERY request did not complete successfully, a connection list is not displayed, even if the CONNLIST option was specified on the DISPLAY GROUPBUFFERPOOL command.

gbpname

The name of the group buffer pool.

retcode

The return code from IXCQUERY.

reason

The reason code from IXCQUERY.

To determine the reason, see IXCQUERY Return and Reason Codes .

The remaining output for each group buffer pool consists of one or more of the following sections.

• DSNB755I and DSNB756I: Group buffer pool status
• DSNB757I: CFRM policy status
• DSNB758I and DSNB759I: Allocation details for the group buffer pool
• DSNB798I: Last checkpoint
• DSNB799I: Secondary group buffer pool attributes
• DSNB766I, DSNB767I, and DSNB769I: Connection list
• DSNB771I: Incremental member detail statistics
• DSNB772I: Cumulative member detail statistics
• DSNB773I and DSNB774I: Synchronous read statistics
• DSNB775I and DSNB789I: Prefetch read statistics
• DSNB776I: Synchronous write statistics
• DSNB777I: Asynchronous write statistics
• DSNB778I and DSNB796I: Castout statistics
• DSNB797I: Other interactions
• DSNB764I and DSNB793I: Secondary group buffer pool statistics
• DSNB782I: Incremental group statistics
• DSNB783I: Cumulative group statistics
• DSNB784I and DSNB785I: Group read statistics
• DSNB786I: Group write statistics
• DSNB787I: Group reclaims and castouts
• DSNB788I: Cross-invalidation statistics
• DSNB762I: Secondary group buffer pool details
• DSNB815I and DSNB816I: P-lock status
• DSNB818I: Asynchronous cross-invalidation writes

If Db2 cannot display certain information, one or more of the following messages are included in the output:

• DSNB752I: Group detail statistics are not available because a rebuild is in progress
• DSNB763I: The group buffer pool is not defined with GBPCACHE(NO)
• DSNB765I: No connection list
• DSNB768I: No group buffer pools are defined with GBPCACHE(NO)
• DSNB770I: Member detail statistics are not available
• DSNB780I: Group detail statistics are not available because the member is not connected
• DSNB781I: Group detail statistics are not available because the MVS IXLCACHE request failed
• DSNB791I: The member is not connected
• DSNB792I: No members are connected
• DSNB794I: The member is not connected to any group buffer pool
• DSNB795I: No members are connected to any group buffer pool

The DISPLAY GROUPBUFFERPOOL output ends with one of the following messages:

• DSNB790I: End of output
• DSNB499I: Display terminated because of insufficient space

Message DSNB750I or DSNB751I is followed by a description of the status of the group buffer pool.

DSNB755I - DB2 GROUP BUFFER POOL STATUS               CONNECTED = status1 
             CURRENT DIRECTORY TO DATA RATIO = ratio1
             PENDING DIRECTORY TO DATA RATIO = ratio2
             CURRENT GBPCACHE ATTRIBUTE = gcache1
             PENDING GBPCACHE ATTRIBUTE = gcache2
DSNB756I - CLASS CASTOUT THRESHOLD = class-threshold1,class-threshold2
           GROUP BUFFER POOL CASTOUT THRESHOLD = gbp-threshold % 
           GROUP BUFFER POOL CHECKPOINT INTERVAL = interval MINUTES 
           RECOVERY STATUS = status1 
           AUTOMATIC RECOVERY = auto-recovery

status1

An indication of whether the Db2subsystem on which the DISPLAY GROUPBUFFERPOOL command was issued is connected to the group buffer pool.

YES

The Db2 subsystem is actively connected to the group buffer pool.

NO

The Db2 subsystem is not actively connected to the group buffer pool.

ratio1

The ratio of the number of directory entries to the number of data pages, as specified for the current allocation of the group buffer pool.

ratio2

The requested ratio of directory entries to data pages to take effect at the next reallocation of the group buffer pool.

gcache1

The value of the GBPCACHE attribute for the current allocation of the group buffer pool.

gcache2

The value of the GBPCACHE attribute to take effect at the next reallocation of the group buffer pool.

class-threshold1

The threshold at which class castouts are to be initiated. This value is expressed as a percentage of the group buffer pool size.

class-threshold2

The threshold at which class castouts are to be initiated. This value is expressed as an absolute number of buffers. class-threshold2 is used to determine the threshold only if class-threshold1 is zero and class-threshold2 is nonzero. Otherwise, class-threshold1 is used to determine the threshold.

gbp-threshold

The threshold at which castouts are to be initiated at the group buffer pool level. This value is expressed as a percentage of the group buffer pool size.

interval

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

status1

The recovery status for the group buffer pool. Possible values are:

DAP

Damage assessment is pending. Db2 is assessing damage to the group buffer pool in response to a coupling facility structure failure. The group buffer pool is temporarily stopped by Db2 and is unavailable for use until Db2 completes the damage assessment.

NORMAL

No pending recovery action exists for this group buffer pool.

auto-recovery

The value of the AUTOREC attribute for the group buffer pool. Possible values are:

YES

If the group buffer pool fails, Db2 is to automatically initiate recovery for the objects that use this group buffer pool. YES is the default.

NO

Db2 is not to initiate automatic group buffer pool recovery. If the group buffer pool fails, issue Db2 START DATABASE commands to recover the objects.

Related information

• -ALTER GROUPBUFFERPOOL command (Db2)
• -START DATABASE command (Db2)
• How Db2 writes from the group buffer pool to disk
• Group buffer pool thresholds

If Db2retrieved z/OS CFRM policy information for the group buffer pool, the DISPLAY GROUPBUFFERPOOL command output includes information about the structure that is associated with the group buffer pool.

DSNB757I - MVS CFRM POLICY STATUS FOR structure-name = status2
             MAX SIZE INDICATED IN POLICY = psize KB
             DUPLEX INDICATOR IN POLICY = dupstat
             CURRENT DUPLEXING MODE = dupmode
             ALLOCATED = status1

structure-name

The coupling facility structure name for this group buffer pool, such as DSNCAT_GBP0.

status2

The z/OS global status of the coupling facility structure. Possible values are:

NORMAL

The structure is defined in the current CFRM policy and has no current z/OS restrictions.

CHNGP

A change is pending in the structure policy.

psize

The size (in KBs) of the coupling facility structure, as indicated in the CFRM policy definition.

dupstat

The duplexing attribute for the coupling facility structure, as indicated by the DUPLEX parameter in the CFRM policy definition. Possible values are DISABLED, ENABLED, or ALLOWED.

dupmode

The current duplex mode of the group buffer pool. Possible values are:

SIMPLEX

The group buffer pool is in simplex mode.

DUPLEX

The group buffer pool is in duplex mode.

INTRAN

The group buffer pool is in a transition state, either from simplex mode to duplex mode, or from duplex mode to simplex mode. The rebuild status indicator in message DSNB758I gives information about the transition state.

status1

An indication of whether the backing coupling facility structure is allocated:

YES

The coupling facility structure is allocated in a coupling facility.

NO

The coupling facility structure is not allocated in any coupling facility.

Related information

• Coupling facility structures
• Defining coupling facility structures
• CFRM parameters for administrative data utility

If Db2 successfully queries the MVS CFRM policy and determines that the group buffer pool is allocated, the DISPLAY GROUPBUFFERPOOL command output includes allocation details.

DSNB758I -     ALLOCATED SIZE = asize KB 
               VOLATILITY STATUS = volstat 
               REBUILD STATUS = rbldstat 
               CFNAME = cfname 
               CFLEVEL - OPERATIONAL = cflevel1 
               CFLEVEL - ACTUAL = cflevel2
DSNB759I -     NUMBER OF DIRECTORY ENTRIES = dir# 
               NUMBER OF DATA PAGES = data#
               NUMBER OF CONNECTIONS = conn#

asize

The size (in KBs) of the allocated group buffer pool structure.

volstat

The volatility status of the backing group buffer pool structure for this group buffer pool. Possible values are:

VOLATILE

The backing coupling facility structure is volatile.

NON-VOLATILE

The backing coupling facility structure is non-volatile.

rbldstat

An indication of whether the group buffer pool structure is being rebuilt, and, if so, which part of the rebuild process is in progress. Possible values are:

NONE

The structure is not being rebuilt.

QUIESCE

The structure is being rebuilt and is currently in the rebuild quiesce phase.

CONNECT

The structure is being rebuilt and is currently in the rebuild connect phase.

CLEANUP

The rebuild process is complete, and the connected Db2 members are making final preparations to use the new group buffer pool structure.

If rbldstat is CLEANUP and the duplexing status in message DSNB757I is INTRAN, the group buffer pool is in the final stages of making the transition from duplex mode back to simplex mode. The Db2 group is switching to the secondary group buffer pool.

STOPPING

The rebuild process is stopped, and the connected Db2 members are making preparations to fall back to the original group buffer pool structure. If rbldstat is STOPPING and the duplexing status in message DSNB757I is INTRAN, the group buffer pool is making the transition from duplex mode back to simplex mode and reverting to the primary group buffer pool.

DUPLEXED

The group buffer pool is in steady-state duplexing mode.

SWITCHING

The group buffer pool is in the initial phase of making the transition from duplex mode back to simplex mode and switching to the secondary group buffer pool.

cfname

The name of the coupling facility in which the group buffer pool is allocated. If the group buffer pool is duplexed, cfname is the name of the coupling facility that is associated with the primary group buffer pool.

cflevel1

The minimum architectural level that Db2 requested for the coupling facility in which the group buffer pool is allocated. This value might be less than the actual coupling facility level, indicated by cflevel2. This happens if a higher coupling facility level than cflevel1 is needed to perform coupling facility structure operations. If the group buffer pool is duplexed, cflevel1 is the coupling facility level that is associated with the primary group buffer pool.

cflevel2

The coupling facility level for the coupling facility in which this group buffer pool is allocated. If the group buffer pool is duplexed, cflevel2 is the coupling facility level that is associated with the primary group buffer pool.

dir#

The number of directory entries that are allocated for the coupling facility structure.

data#

The number of data pages that are allocated for the coupling facility structure.

conn#

The number of Db2 subsystems that are connected to the coupling facility structure. This number includes both active connections and failed-persistent connections. If the DISPLAY GROUPBUFFERPOOL command includes the CONNLIST option, the details of the connection status are listed in message DSNB767I.

Related information

• Coupling facility structures
• Planning for coupling facility availability for data sharing
• Rebuild events
• How Db2 recovers from coupling facility failures

If Db2 determines, by successfully querying the MVS CFRM policy, that the group buffer pool is allocated, the DISPLAY GROUPBUFFERPOOL command output includes checkpoint information

DSNB798I - LAST GROUP BUFFER POOL CHECKPOINT
                                          timestamp
             GBP CHECKPOINT RECOVERY LRSN              = lrsn
             STRUCTURE OWNER                           = member-name

timestamp

The date and time of the last group buffer pool checkpoint.

lrsn

The log record sequence number (LRSN) that was recorded by the last group buffer pool checkpoint.

member-name

The name of the member that is the structure owner for the group buffer pool.

A value of UNKNOWN means that Db2 is not able to determine which member is the structure owner for the group buffer pool. This condition occurs only in error situations. See the message that is associated with that error.

The structure owner has the following responsibilities:

• Issue group buffer pool checkpoints.
• Detect the group buffer pool castout threshold (the GBPOOLT value) and initiate castout if this threshold is reached. (The structure owner initiates castout by notifying the page set or partition castout owners.)
• Coordinate the damage assessment process if the group buffer pool fails.
• Coordinate the rebuild process for the group buffer pool.

If the group buffer pool is duplexed and Db2 successfully queried the MVS CFRM administrative policy, the DISPLAY GROUPBUFFERPOOL command output includes the attributes of the secondary group buffer pool. This message is not displayed if the group buffer pool is in a transition state between simplexing and duplexing.

DSNB799I - SECONDARY GBP ATTRIBUTES
             ALLOCATED SIZE                            = ssize KB
             VOLATILITY STATUS                         = svolstat
             CFNAME                                    = cfname
             CFLEVEL - OPERATIONAL                     = cflevel1
             CFLEVEL - ACTUAL                          = cflevel2
             NUMBER OF DIRECTORY ENTRIES               = sdir#
             NUMBER OF DATA PAGES                      =  sdata#

ssize

The allocated size (in KBs) of the coupling facility structure for the secondary group buffer pool.

svolstat

The volatility status of the secondary group buffer pool. Possible values are:

VOLATILE

The structure is volatile.

NON-VOLATILE

The structure is non-volatile.

cfname

The name of the coupling facility in which the group buffer pool is allocated. If the group buffer pool is duplexed, this value is the coupling facility name that is associated with the primary group buffer pool.

cflevel1

The coupling facility level from a Db2 functionality perspective for the coupling facility in which the secondary group buffer pool is allocated.

cflevel2

The coupling facility level for the coupling facility in which the secondary group buffer pool is allocated.

sdir#

The number of directory entries that are allocated for the secondary group buffer pool.

sdata#

The number of data pages that are allocated for the secondary group buffer pool.

If the DISPLAY GROUPBUFFERPOOL command included the CONNLIST option, the output includes a list of connections for the group buffer pool. One DSNB767I message is issued for each defined connection to the group buffer pool.

DSNB766I -  THE CONNLIST REPORT FOLLOWS
DSNB767I - CONNECTION NAME = conname        , CONNECTION STATUS = status
               CONNECTOR'S RELEASE                    =     connector-release
DSNB769I - THE CONNLIST REPORT IS COMPLETE

conname

The name of the connection. Db2 subsystems use the Db2 member name as the connection name.

status

The status of the connection. Possible values are:

A

Active.

F

Failed-persistent.

D

Dually connected to both the original structure and the new structure while the group buffer pool structure is being rebuilt.

connector-release

This value is always 10100.

For more information, see Protection of retained locks: failed-persistent connections.

If the DISPLAY GROUPBUFFERPOOL command included the MDETAIL(INTERVAL) option, the output includes incremental statistics for the member.

DSNB771I - INCREMENTAL MEMBER DETAIL STATISTICS SINCE basetime

basetime

The start time of the interval for which the statistics were accumulated. This value is the time of the previous DISPLAY GROUPBUFFERPOOL MDETAIL(INTERVAL) report for this Db2 member. If such a report does not exist, this value is the time that the member first connected to the group buffer pool.

If the DISPLAY GROUPBUFFERPOOL command included the MDETAIL(*) option, the output includes cumulative statistics for the member.

DSNB772I - CUMULATIVE MEMBER DETAIL STATISTICS SINCE basetime

basetime

The start time of the interval for which the statistics were accumulated. This value is the time that this Db2 member first connected to the group buffer pool.

If the DISPLAY GROUPBUFFERPOOL command included the MDETAIL option, the output includes synchronous read statistics for the group buffer pool. The term synchronous means that the coupling facility interaction is done under the execution unit of the Db2 user.

DSNB773I - MEMBER DETAIL STATISTICS
             SYNCHRONOUS READS
               DUE TO BUFFER INVALIDATION
                 DATA RETURNED                         = r1
                 DATA NOT RETURNED                     = r2
DSNB774I -     DUE TO DATA PAGE NOT IN BUFFER POOL
                 DATA RETURNED                         = r3
                 DATA NOT RETURNED                     = r4

The following values in message DSNB773I refer to synchronous coupling facility read requests that are issued because the virtual buffer was marked invalid.

r1

The number of times that data is successfully returned from the group buffer pool in response to the request.

r2

The number of times that data is not returned from the group buffer pool in response to the request.

The values in message DSNB774I refer to synchronous coupling facility read requests that are issued because the required data was not in the buffer pool buffer.

r3

The number of times that data is successfully returned from the group buffer pool in response to the request.

r4

The number of times that data is not returned from the group buffer pool in response to the request.

If the DISPLAY GROUPBUFFERPOOL command included the MDETAIL option, the output includes prefetch read statistics.

DSNB775I -   PREFETCH READS
               DATA NOT RETURNED                       = r5 
DSNB789I -    REGISTER PAGE LIST                       = r7
               PAGES RETRIEVED                         = r8

r5

The number of pages that were retrieved from DASD, instead of the group buffer pool, in response to the register page list (RPL) request.

The RPL feedback indicated that the page was not cached in the group buffer pool. Therefore, to avoid a coupling facility read request for the page, Db2 retrieved the page directly from DASD. No coupling facility interactions are associated with this r5 value.

r7

The number of coupling facility requests to register interest in a list of pages. Db2 makes this request when sequential or list prefetch is used and the following conditions are met:

• The Db2 member is running on a particular service level of MVS 5.2 or later.
• The group buffer pool is allocated in a coupling facility with CFLEVEL=2 or higher.

r8

The number of coupling facility requests to prefetch a page in the group buffer pool as a result of feedback from the request to register a list of pages.

If the DISPLAY GROUPBUFFERPOOL command included the MDETAIL option, the output includes synchronous write statistics for the group buffer pool. The term synchronous means that the coupling facility interaction is done under the execution unit of the Db2 user.

DSNB776I -   SYNCHRONOUS WRITES
               CHANGED PAGES                           = w1
               CLEAN PAGES                             = w2

w1

The number of changed pages that were written synchronously to the coupling facility.

w2

The number of clean pages that were written synchronously to the coupling facility.

If the DISPLAY GROUPBUFFERPOOL command included the MDETAIL option, the output includes asynchronous write and cross-invalidation statistics for the group buffer pool. The term asynchronous means that the coupling facility interaction is done under the execution unit of a Db2 system, such as with a prefetch operation.

DSNB777I -   ASYNCHRONOUS WRITES
               CHANGED PAGES                           = changed-pages-count
               CLEAN PAGES                             = clean-pages-count
             FAILED WRITES DUE TO LACK OF STORAGE      = failed-writes-count
             WRITE-AROUND PAGES                        = write-around-count

changed-pages-count

The number of changed pages that were written asynchronously to the coupling facility.

clean-pages-count

The number of clean pages that were written asynchronously to the coupling facility.

failed-writes-count

The number of coupling facility write requests that were not completed because the group buffer pool did not have enough storage.

write-around-count

The number of changed pages that are written to disk through group-buffer-pool write-around protocol.

If the DISPLAY GROUPBUFFERPOOL command included the MDETAIL option, the output includes group buffer pool statistics for castouts, checkpoints, and rebuild operations.

DSNB778I - CASTOUT THRESHOLDS DETECTED
             FOR CLASSES                               = t1
             FOR GROUP BUFFER POOL                     = t2
           GBP CHECKPOINTS TRIGGERED                   = k1
           PARTICIPATION IN REBUILD                    = k2
DSNB796I - CASTOUTS
             PAGES CASTOUT                             = c1
             UNLOCK CASTOUT                            = c2
             READ CASTOUT CLASS                        = c3
             READ CASTOUT STATISTICS                   = c4
             READ DIRECTORY INFO                       = c5

t1

The number of times that the class castout threshold was detected.

t2

The number of times that the group buffer pool castout threshold was detected.

k1

The number of group buffer pool checkpoints that were triggered.

k2

The number of times that this member participated in a rebuild of the group buffer pool structure.

c1

That number of pages that were cast out.

c2

The number of requests to unlock a page for castout.

c3

The number of requests to determine which pages, from a particular page set or partition, must be cast out because they are cached as changed pages. This request is issued either by the page set or partition castout owner, or, when the group buffer pool castout threshold is reached by the group buffer pool structure owner.

c4

The number of coupling facility requests to cast out statistics.

c5

The number of requests to read directory information. These requests are made during group buffer pool checkpoints.

Related informationFor more information, see:

• Group buffer pool thresholds
• Group buffer pool checkpoint
• How Db2 recovers from coupling facility failures
• How Db2 writes from the group buffer pool to disk
• How Db2 gathers checkpoint information
• Monitoring group buffer pool delete name requests

If the DISPLAY GROUPBUFFERPOOL command included the MDETAIL option, the output includes local statistics on various operations.

DSNB797I - OTHER INTERACTIONS
             REGISTER PAGE                             = o1
             UNREGISTER PAGE                           = o2
             DELETE NAME                               = o3
             READ STORAGE STATISTICS                   = o4
             EXPLICIT CROSS INVALIDATIONS              = o5
             ASYNCHRONOUS GBP REQUESTS                 = o6

o1

The number of requests to the coupling facility to register interest in a single page.

o2

The number of requests to the coupling facility to remove the registered interest in a single page.

o3

The number of requests to the coupling facility to delete the directory entries that are associated with a set of pages.

o4

The number of requests to the coupling facility to read the statistics counters that are associated with the structure. Db2 generally issues this request once per group buffer pool checkpoint and once per DISPLAY GROUPBUFFERPOOL command with the GDETAIL option.

o5

The number of explicit cross-invalidations for pages in the group buffer pool.

o6

The number of coupling facility requests to the primary group buffer pool that were converted from synchronous to asynchronous.

For more information, see Monitoring group buffer pool delete name requests

If the DISPLAY GROUPBUFFERPOOL command included the MDETAIL option and the group buffer pool is duplexed, the output includes statistics on requests and writes to the secondary group buffer pool.

DSNB764I - DUPLEXING STATISTICS FOR secondary-gbpname
             WRITES
               FAILED DUE TO LACK OF STORAGE           = s2
               ASYNC COMPLETION CHECKS                 = s3
DSNB793I -   DELETE NAME LIST                          = s5
             READ CASTOUT STATISTICS                   = s6
             DELETE NAME                               = s7
             OTHER ASYNCHRONOUS GBP REQUESTS           = s8   

secondary-gbpname

The secondary group buffer pool name. This name is the primary group buffer pool name (such as GBP0) suffixed with -SEC.

s2

The number of times that a write request from the coupling facility did not complete because the secondary group buffer pool did not have enough storage.

s3

The number of times that Db2 checked whether a changed page was written to the secondary group buffer pool, but the write operation was not yet complete. Thus, the transaction had to wait until the write to the secondary group buffer pool completed.

s5

The number of requests to delete from the secondary group buffer pool a set of pages that were recently cast out from the primary group buffer pool. If the group buffer pool was duplexed for the entire reporting interval, this number should be roughly equal to the number of UNLOCK CASTOUT requests, as reported in message DSNB796I.

s6

The number of requests to check for orphaned data entries in the secondary group buffer pool. Orphaned data entries are changed data entries in the secondary group buffer pool without a corresponding changed data entry in the primary group buffer pool.

The group buffer pool structure owner periodically issues these requests to determine whether orphaned data entries in the secondary group buffer pool need to be cleaned up. Orphaned data entries are expected periodically and do not indicate a data inconsistency problem. Orphaned data entries can be introduced by certain transaction or system failures or by the unlikely circumstance that new group buffer pool write activity occurred concurrently with castout processing.

s7

The number of requests to delete orphaned data entries from the secondary group buffer pool. The group buffer pool structure owner issues these requests if it determines that orphaned data entries need to be cleaned up.

s8

The number of asynchronous coupling facility requests that were sent to the secondary group buffer pool. This number excludes the s3 value.

Related information

• Characteristics of primary and secondary structures
• How Db2 writes from the group buffer pool to disk

If the DISPLAY GROUPBUFFERPOOL command included the GDETAIL(INTERVAL) option, the output includes incremental statistics for the group buffer pool.

DSNB782I - INCREMENTAL GROUP DETAIL STATISTICS SINCE basetime

basetime

The start time of the interval for which the statistics were accumulated. This value is the time of the previous DISPLAY GROUPBUFFERPOOL GDETAIL(INTERVAL) report from this Db2 member. If such a report does not exist, this value is the time that the group buffer pool was allocated or reallocated.

If the DISPLAY GROUPBUFFERPOOL command included the GDETAIL(*) option, the output includes cumulative statistics for the group buffer pool.

DSNB783I - CUMULATIVE GROUP DETAIL STATISTICS SINCE basetime

basetime

The start time of the interval for which the statistics were accumulated. This value is the time that the group buffer pool was first allocated or reallocated.

If the DISPLAY GROUPBUFFERPOOL command included the GDETAIL option, the output includes read statistics for the group buffer pool.

DSNB784I - GROUP DETAIL STATISTICS
             READS
               DATA RETURNED                           = r1
DSNB785I -     DATA NOT RETURNED
                 DIRECTORY ENTRY EXISTED               = r2
                 DIRECTORY ENTRY CREATED               = r3
                 DIRECTORY ENTRY NOT CREATED           = r4, r5

r1

The "read hit" counter. The number of times that a page was returned for a coupling facility read request.

r2

The "read miss directory hit" counter. The number of times that a coupling facility read request specified a page for which a directory entry exists, but no data was cached for that page. Data was not returned for the coupling facility read request.

r3

The "read miss name assigned" counter. The number of times that a coupling facility read request specified a page for which a directory entry was created. Data was not returned for the coupling facility read request.

r4

The "read miss assignment suppressed" counter. The number of times that a coupling facility read request specified a page for which no directory entry exists and no directory entry was created. Data was not returned for the coupling facility read request.

r5

The "read miss cache full" counter. The number of times that both of the following events occurred:

• A coupling facility read request specified a page for which no directory entry exists.
• A directory entry was not created because the group buffer pool did not have enough storage.

Data was not returned for the coupling facility read request.

If the DISPLAY GROUPBUFFERPOOL command included the GDETAIL option, the output includes write statistics for the group buffer pool.

DSNB786I -   WRITES
               CHANGED PAGES                           = w1
               CLEAN PAGES                             = w2
               FAILED DUE TO LACK OF STORAGE           = w3
             CHANGED PAGES SNAPSHOT VALUE              = p1

w1

The "changed page write hit" counter. The number of changed pages that were successfully written.

w2

The "clean page write hit" counter. The number of clean pages that were successfully written.

w3

The "write miss cache full" counter. The number of times that a coupling facility write request was not completed because the group buffer pool did not have enough storage.

p1

The "total changed" counter. The current number of changed pages. The number is captured at a single point in time. This value is not affected by whether the DISPLAY GROUPBUFFERPOOL output is incremental or cumulative.

If the DISPLAY GROUPBUFFERPOOL command included the GDETAIL option, the output includes statistics on reclaims and castouts for the group buffer pool.

DSNB787I -   RECLAIMS
               FOR DIRECTORY ENTRIES                   = d1
               FOR DATA ENTRIES                        = d2
             CASTOUTS                                  = c1

d1

The "directory entry reclaim" counter. The number of times that a name assignment required that a directory entry be reclaimed by the coupling facility.

d2

The "data entry reclaim" counter. The number of times that a name assignment required that a data page be reclaimed by the coupling facility.

c1

The "castout" counter. The number of pages that were cast out of the group buffer pool.

Related information

• Too few directory entries
• Too few data entries

If the DISPLAY GROUPBUFFERPOOL command included the GDETAIL option, the output includes cross-invalidation (XI) statistics for the group buffer pool.

DSNB788I -   CROSS INVALIDATIONS
               DUE TO DIRECTORY RECLAIMS               = x1
               DUE TO WRITES                           = x2
               EXPLICIT                                = x3

x1

The "XI for directory reclaim" counter. The number of times that a directory entry with registered Db2 interest was reclaimed. Therefore, cross-invalidation occurred.

x2

The "XI for write" counter. The number of times that a coupling facility write request caused cross-invalidation to occur for one or more registered Db2 members.

x3

The "XI for explicit invalidation" counter. The number of times that cross-invalidation occurred for one or more registered Db2 members, because it was explicitly requested by the coupling facility.

Related information

• Group buffer pool size is too small
• How Db2 writes to the group buffer pool
• Too few directory entries

If the DISPLAY GROUPBUFFERPOOL command included the GDETAIL option, and the group buffer pool is duplexed, the output includes the following information about the secondary group buffer pool:

• Statistics on writes to the secondary group buffer pool
• The total number of changed pages for the secondary group buffer pool.

DSNB762I - DUPLEXING STATISTICS FOR secondary-gbpname 
              WRITES 
                CHANGED PAGES = changed-pages
                FAILED DUE TO LACK OF STORAGE = writes-full 
                CHANGED PAGES SNAPSHOT VALUE       = changed-pages-snapshot 

secondary-gbpname

The secondary group buffer pool name. This name is the primary group buffer pool name (such as GBP0) suffixed with -SEC.

changed-pages

The number of times that a coupling facility write request for a changed page completed successfully.

If the group buffer pool was duplexed for the entire reporting interval, this number should be roughly equal to the "changed page write hit" counter in message DSNB786I. However, these counts might not be the same because of timing windows in gathering these values or if previous transaction failures occurred.

writes-full

The number of times that a write request from the coupling facility was not completed because of a lack of storage in the secondary group buffer pool.

changed-pages-snapshot

The total changed counter and snapshot value of the current number of changed pages in the secondary group buffer pool. This value is not affected by whether the DISPLAY GROUPBUFFERPOOL output is incremental or cumulative.

If the group buffer pool is duplexed, this number should be roughly equal to the "total changed"counter in message DSNB786I. However, these counts might not be the same because of timing windows in gathering these values or if previous transaction failures occurred.

Related information

• Duplexed structures for Db2 data sharing
• How updates are made in a data sharing environment

The DISPLAY GROUPBUFFERPOOL command output includes the physical lock (P-lock) status for the group buffer pool. This P-lock information can be useful when you are monitoring and tuning database performance, especially in a data sharing environment.

DSNB815I - PAGE P-LOCK LOCK/UNLOCK,
             REQUESTS FOR SPACE MAP                           = nn
             REQUESTS FOR DATA PAGES                          = nn
             REQUESTS FOR INDEX LEAF                          = nn 
             UNLOCK REQUESTS                                  = nn
DSNB816I - PAGE P-LOCK SUSPENSIONS/NEGOTIATIONS, 
             SUSPENSIONS FOR SPACE MAP                        = nn 
             P-LOCK SUSPENSIONS FOR DATA                      = nn 
             P-LOCK SUSPENSIONS FOR INDEX LEAF                = nn 
             NEGOTIATIONS FOR SPACE MAP                       = nn 
             P-LOCK NEGOTIATIONS FOR DATA PAGES               = nn 
             NEGITIATIONS FOR INDEX LEAF PAGES                = nn

If the DISPLAY GROUPBUFFERPOOL command included the MDETAIL option, the output includes asynchronous cross-invalidation statistics for the group buffer pool. The term asynchronous means that the cross-invalidation operations occur asynchronously with the completion of coupling facility write requests.

DSNB818I ASYNCHRONOUS CROSS-INVALIDATION
                      WRITES WITH ASYNCH XI          = asynch-xi-write-count
                      SYNCH-UP CALLS                 = synch-up-call-count
                      SUSPENSIONS FOR SYNCH-UP       = suspension-count

asynch-xi-write-count

The number of coupling facility write requests for which cross-invalidation operations occurred asynchronously with the completion of write requests.

synch-up-call-count

The number of calls to the coupling facility asynchronous cross-invalidation service that were made to determine when asynchronous cross-invalidation operations completed.

suspension-count

The number of suspensions of the coupling facility asynchronous cross-invalidation service that occurred during waits for asynchronous cross-invalidation operations to complete.

DSNB752I - GROUP DETAIL STATISTICS ARE NOT AVAILABLE FOR THE GROUP BUFFER POOL 
BECAUSE A REBUILD IS IN PROGRESS

The DISPLAY GROUPBUFFERPOOL command included the GDETAIL option. However, Db2cannot retrieve group statistics because the group buffer pool is being rebuilt.

DSNB763I - gbpname IS NOT DEFINED WITH GBPCACHE NO

The DISPLAY GROUPBUFFERPOOL command included the TYPE(NOCACHE) option and either one name or a list of names in the selection list. However, the indicated group buffer pool is not defined with the GBPCACHE(NO) attribute, and therefore does not meet the qualification to be included in the output.

gbpname

The group buffer pool name.

The display is terminated for this group buffer pool. If the command has other group buffer pool names to process, command processing continues.

This message is issued once for each group buffer pool that does not match the criterion to be defined with GBPCACHE(NO).

DSNB765I - NO CONNLIST REPORT IS GENERATED. THERE ARE NO CONNECTIONS TO THIS GROUP BUFFER POOL. 

The DISPLAY GROUPBUFFERPOOL command included the CONNLIST option. However, no connections currently exist to report for the group buffer pool.

DSNB768I - THERE ARE NO GROUP BUFFER POOLS DEFINED WITH GBPCACHE NO

The DISPLAY GROUPBUFFERPOOL command included the TYPE(NOCACHE) option and an asterisk (*) as the selection list. However, no group buffer pools are defined with the GBPCACHE(NO) attribute.

Command processing is terminated.

DSNB770I - MEMBER DETAIL STATISTICS ARE NOT AVAILABLE FOR THE GROUP BUFFER POOL.
             THIS DB2 HAS NEVER BEEN CONNECTED TO THE GROUP BUFFER POOL.

The DISPLAY GROUPBUFFERPOOL command included the MDETAIL option. However, member statistics are not available for the requested group buffer pool because this member has not connected to the group buffer pool since it was started.

DSNB780I - GROUP DETAIL STATISTICS ARE NOT AVAILABLE FOR THE GROUP BUFFER POOL.
             THIS DB2 IS NOT CURRENTLY CONNECTED TO THE GROUP BUFFER POOL.

The DISPLAY GROUPBUFFERPOOL command included the GDETAIL option. However, Db2 could not retrieve group statistics because this Db2 member is not currently connected to the group buffer pool.

DSNB781I - GROUP DETAIL STATISTICS ARE NOT AVAILABLE FOR THE GROUP BUFFER POOL.
             MVS IXLCACHE RETURN CODE = retcode MVS IXLCACHE REASON CODE = reason

The DISPLAY GROUPBUFFERPOOL command included the GDETAIL option. However, Db2 could not retrieve group statistics because the statistics request (through the z/OS MVS IXLCACHE macro) did not successfully complete.

retcode

The return code from MVS for the statistics request.

reason

The reason code from MVS for the statistics request.

For more information, see:

• IXLCACHE — Cache Services
• Return and Reason Codes for IXLCACHE REQUEST=READ_STGSTATS

DSNB791I - THIS DB2 IS NOT CONNECTED TO gbpname

The DISPLAY GROUPBUFFERPOOL command included the TYPE(MCONN) option and either one name or a list of names in the selection list. However, the Db2 member on which the DISPLAY GROUPBUFFERPOOL command was issued is not currently connected to the specified group buffer pool.

gbpname

The group buffer pool name.

The display is terminated for this group buffer pool. If the command includes other group buffer pool names to process, command processing continues.

DSNB792I - NO DB2 IN THE GROUP IS CONNECTED TO gbpname

The DISPLAY GROUPBUFFERPOOL command included the TYPE(GCONN) option and either one name or a list of names in the selection list. However, no Db2 member in the group is connected to the specified group buffer pool.

gbpname

The group buffer pool name.

The display is terminated for this group buffer pool. If the command includes other group buffer pool names to process, command processing continues.

DSNB794I - THIS DB2 IS NOT CONNECTED TO ANY GROUP BUFFER POOL

The DISPLAY GROUPBUFFERPOOL command included the TYPE(MCONN) option and an asterisk (*) as the selection list. However, the Db2 member on which the DISPLAY GROUPBUFFERPOOL command was issued is not connected to any group buffer pools.

Command processing is terminated.

DSNB795I - NO DB2 IN THE GROUP IS CONNECTED TO ANY GROUP BUFFER POOL

The DISPLAY GROUPBUFFERPOOL command included the TYPE(GCONN) option and an asterisk (*) as the selection list. However, no group buffer pools are connected to any Db2 members in the data sharing group.

Command processing is terminated.

The following message indicates the end of the output from the DISPLAY GROUPBUFFERPOOL command.

DSNB790I - DISPLAY FOR GROUP BUFFER POOL gbpname IS COMPLETE

gbpname

The group buffer pool name.

If the DISPLAY GROUPBUFFERPOOL output is too long, the output ends with message DSNB499I. This message indicates that the command was unable to obtain storage for more messages. This situation occurs only for a long display request, such as a detail display for many group buffer pools.

DSNB499I - DISPLAY TERMINATED DUE TO INSUFFICIENT MESSAGE SPACE

The output is truncated.

To see all of the output, reissue the DISPLAY GROUPBUFFERPOOL command, and specify a smaller number of group buffer pools.