DB2 Thread Class 3 Attributes

Use these attributes to view DB2 Thread Class 3 information.

ACE Address The agent control element (ACE) (see QWHSACE) of the thread that is reported. The value in QWHSACE is the ACE of the IFI application that requested this trace record (Field name: QW0148AC).

Archive Log Quiesce Events Events due to processing ARCHIVE LOG MODE(QUIESCE) commands (Field name: QWACALCT).

Archive Log Quiesce The waiting time caused by processing ARCHIVE LOG(QUIESCE) commands (DB2 field name: QWACALOG).

Archive Log Read Events Events due to processing ARCHIVE LOG READ commands (Field name: QWACANAR).

Archive Log Read The waiting time caused by processing ARCHIVE LOG READ commands (Field name: QWACAWAR).

Authorization ID The primary authorization ID from connection or signon (Field name: UWHCAID). For z/OS operator commands and DB2 system internal agents, the value is SYSOPR. Secondary authorization IDs might be the RACF groups associated with this primary authorization ID. The SQL ID is initially set to this primary authorization ID. The connection authorization exit and the signon authorization exit can change the primary authorization ID so that it is not the same as the original primary authorization ID (QWHCOPID). Distributed authorization ID translation can also change the primary authorization ID.

Collection Name The collection name (Field name: UW0148CI).

Connection ID The connection name (Field name: QWHCCN). It is not valid on end of memory and reflects the z/OS home address space (ASID) connection name for:
Batch:
'BATCH'
TSO:
'TSO'
QMF
'DB2CALL'
Utility
'UTILITY'
DB2 internal
DB2 subsystem ID
IMS
IMS-ID
CICS
CICS-ID
RRSAF
'RRSAF'
Distributed database access threads:
  • For threads from a DB2 requester, this field contains the connection name of the thread at the requesting location.
  • For threads using the DRDA protocol from a non-DB2 requester, this field contains the constant 'SERVER'.
Correlation ID The correlation ID value (Field name: QWHCCV).
  • For batch: JOBNAME
  • For TSO: LOGON-ID
  • For IMS/VS: PST#.PSBNAME
  • For CICS: CONNECTION_TYPE.THREAD_TYPE.THREAD_#.TRAN-ID
  • For RRSAF: CORRELATION-ID value from signon function
  • For threads from a DB2 requester: this field contains the correlation-ID name of the thread at the requesting location.
  • For threads using the DRDA protocol from a non-DB2 requester, this field contains the first 12 characters in the DDM external name (EXTNAM) parameter of the DDM EXCSAT command received as part of the SQL connect.

DASD Cache Hit Events Number of synchronous read I/O operations that did not use zHyperlink processing and resulted in disk cache hits (Field name: QWACAWCD).

DASD Cache Hit READS Wait time for synchronous read I/O operations that did not use zHyperlink processing and resulted in disk cache hits (Field name: QWACAWTD).

DB I/O Events The number of wait trace events processed for waits for database I/O under this thread (Field name: QWACARNE).

DB2 Subsystem The DB2 subsystem ID.

DB2 Version The DB2 version.

DSG Member Name The Data Sharing Group (DSG) member name.

Data Sharing Group The Data Sharing Group name.

Drain Lock Events Events due to drain lock processing during the execution of the package or DBRM (Field name: QWACARND).

Drain Lock The waiting time caused by drain lock processing (Field name: QWACAWDR).

End User ID The user ID of the end user's workstation (Field name: QWHCEUID). This can be different from the authorization ID used to connect to DB2. This field contains blanks if the client did not supply this information. If QWHCEUID_OFF is not 0, this value is truncated.

Extended Delete Define Dataset The accumulated wait time for a synchronous execution unit switch to the DB2 data space manager services, which include define data set, extend data set, delete data set, reset data set, and VSAM catalog access (DB2 field name: QWAXDSSE).

Extended Delete Define Events The number of wait trace events processed for waits for synchronous execution unit switching to the data space manager service tasks (Field name: QWAXDSNS).

Interval Start The start time of this interval.

Latch Events The number of wait trace events processed for waits for latch contention (Field name: QWACARLH).

Location Name The location name (Field name: UW0148LN). The location name contains the name of the local location or remote location, depending on where the thread executes a package. The following statements execute locally, regardless of the current package name:
  • COMMIT
  • ROLLBACK
  • SET <HOST VARIABLE> = CURRENT PACKAGE SET
  • SET <HOST VARIABLE> = CURRENT SERVER
For these statements, this field contains the location where the package executes, not the location where the statement executes.

Lock Events The number of wait trace events processed for waits for local contention for locks (Field name: QWACARNL).

Log Write I/O Events The number of wait trace events that were processed for waits for log read I/O (Field name: QWACARLG).

Logical Unit of work ID The logical unit of the work ID (LUWID) as defined for the LU 6.2 interface (Field name: QW0148LU). The LUWID uniquely identifies the thread within the network, and consists of the following:
  • A fully qualified network name (QW0148LM)
  • An LUW instance number (QW0148UV) and an LUW sequence number (see fields below).
It consists of two 8-character fields: QW0148NI and QW0148LM, which together uniquely identify a client system.

MVS System ID The MVS identifier.

Open Close Dataset The accumulated wait time for a synchronous execution unit switch to the DB2 OPEN/CLOSE data set service or the HSM recall service (Field name: QWAXOCSE).

Open Close Events The number of wait trace events processed for waits for the synchronous execution unit switching to the OPEN/CLOSE service (Field name: QWAXOCNS).

Originating System The managed system name of the agent. It is an alphanumeric text string, with a maximum of 32 characters; for example, DB91:SYS1:DB2.

Other Read I/O Events The number of wait trace events processed for waits for read I/O under another thread (Field name: QWACARNR).

Other Read I/O The accumulated wait time for read I/O that is done under a thread other than this one (Field name: QWACAWTR). This value is calculated for threads by subtracting the store clock (STCK) time on entry to event wait from STCK time on exit resume from the event. This time represents the time the thread that is reported waited for the subject I/O and not the total duration of that I/O. This field is collected if accounting class 3 is on. The following I/O waits are included in this field:
  • SEQUENTIAL PREFETCH
  • SEQUENTIAL DETECTION
  • LIST PREFETCH
  • SYNCHRONOUS READ I/O performed by a thread
  • Other than the thread that is reported.

Other Service Events The number of wait trace events processed for waits for synchronous execution unit switching to other service tasks (Field name: QWAXOTNS).

Other Services The accumulated wait time for a synchronous execution unit switch to other DB2 service tasks (Field name: QWAXOTSE).

Other Write I/O Events The number of wait trace events processed for waits for write I/O under another thread. This number includes wait trace events for buffer manager force write I/O waits (Field name: QWACARNW).

Other Write I/O The accumulated wait time for write I/O that is done under a thread other than this one (Field name: QWACAWTW). This value is calculated for threads by subtracting the store clock (STCK) time on entry to event wait from STCK time on exit resume from the event. This time represents the time the thread being reported waited for the subject I/O and not the total duration of that I/O. This field is collected if accounting class 3 is on. The following I/O waits are included in this field:
  • ASYNCHRONOUS WRITE I/O
  • SYNCHRONOUS WRITE I/O performed by a thread
  • other than the thread being reported
  • BUFFER MANAGER FORCE WRITE I/O

Package ID The package ID (Field name: UW0148PN).

Plan Name The plan name (Field name: QWHCPLAN). It shows a blank for a DB2 command thread; otherwise:
  • For SPUFI with cursor stability: 'DSNESPCS'
  • For SPUFI with repeatable read: 'DSNESPRR'
  • For TSO: the application plan name
  • For IMS: the application plan name
  • For CICS: application plan name, IMS and CICS commands have a blank plan name.
  • For RRSAF create thread with the collection parameter: '?RRSAF '
  • For QMF: 'DSQPLAN'
  • For Distributed Database Access threads:
    • For threads using the DRDA protocol from a requester, this field contains the plan name that is executed at the requesting location.
    • For threads using the DRDA protocol from a non-DB2 requester or from a DB2 2.3 requester, this field contains the constant 'DISTSERV'.
  • For binding: 'DSNBIND' (system plan)
  • For utility: 'DSNUTIL ' (system plan)
  • For authorization: 'ACT' + X'0000000000' (system plan)
  • For unallocated threads and miscellaneous DB2 system service tasks: 'BCT' + X'0000000000' (system plan)
  • For startup: 'STARTCT' + X'00' (system plan)

QWACFLGS Flags (Field name: QWACFLGS).

Sync I/O Events The total number of synchronous I/O suspensions (Field name: ADIOSUSC).

SYSLGRNG Events The number of wait trace events processed for waits for synchronous execution unit switching to the SYSLGRNG recording service (Field name: QWAXSLNS).

SYSLGRNG Accumulated wait time for a synchronous execution unit switch to the DB2 SYSLGRNG recording service. This service is also sometimes used for level ID checking for down-level detection (Field name: QWAXSLSE).

Service Task Switch Events The total number of suspensions due to a synchronous execution unit switching to DB2 services from the thread being reported (Field name: ADSTSUSC).

Service Task Switch The accumulated waiting time due to a synchronous execution unit switching to DB2 services from the thread being reported (Field name: ADSTSUST). It includes:
  • Open/close data set
  • SYSLGRNG or SYSLGRNX update
  • Commit phase 2 for read-only threads originating from TSO or batch
  • Dataspace manager services
  • Define data set
  • Extend data set
  • Delete data set
  • Log I/Os for commit and abort processing
Special Considerations:
  1. A probable cause for high values in this field is data set preformatting.
  2. There are no service waits associated with commit phase 2 under read-only threads originating from CICS or IMS. There is a service wait for any thread doing commit phase 2 after an update.
  3. There is no overlap between the elapsed time reported in this field and the other class 3 elapsed times.

Thread Type The connecting system type code (in hexadecimal). This field can have a null value. For example, this field contains a null value for some utilities (Field name: QWHCATYP).

Transaction Name The transaction or application name that the end user is running (Field name: QWHCEUTX). This identifies the application that is currently running, not the product that is used to run the application. This field contains blanks if the client did not supply this information.

Update Commit Events The number of wait trace events processed for waits for synchronous execution unit switching for COMMIT or ABORT (Field name: QWACARNS).

Update Commit The accumulated wait time because of a synchronous execution unit switch for DB2 COMMIT, ABORT, or DEALLOCATION processing (Field name: QWACAWTE). For RRSAF threads, this value includes explicit COMMIT time for SRRCMIT calls. See QWACAWLG for implicit RRS COMMIT time.

Wait Time DB I/O The accumulated I/O elapsed wait time for database I/O done under this thread (Field name: QWACAWTI). This field is for synchronous I/O only. It includes synchronous read and write I/O. This value is calculated for threads by subtracting the store clock (STCK) time on entry to event wait from STCK time on exit resume from the event. Its value indicates the elapsed time the allied agent waited for its I/O in DB2. When db2 makes an I/O request for an allied agent and makes the agent wait, the store clock value is saved. When the I/O completes, the ending time is used to calculate the total elapsed I/O time. The result is added to the previously saved elapsed synchronous I/O wait time in DB2.

Wait Time Latches The accumulated wait time due to latch contention (Field name: QWACAWLH).

Wait Time Locks The accumulated wait time due to local contention for locks (Field name: QWACAWTL). Local contention does not involve intersystem communication. Local contention is resolved entirely within a single subsystem. Global contention, which involves intersystem communication, is reported in field QWACAWTJ.

Wait Time Log Write The accumulated wait time for log write I/O (Field name: QWACAWLG). For RRSAF threads, this value includes implicit commit time for RRS at EOT if uncommitted work exists. SEE QWACAWTE for explicit RRS commit time.

Wait Time Sync I/O The I/O elapsed time accumulated due to synchronous I/O suspensions. DB2 calculates this value by subtracting the store clock time when an agent begins waiting for a synchronous I/O from the time the agent is resumed (Field name: ADIOSUST).

Workstation Name The end user's workstation name. This field contains blanks if the client did not supply this information (Field name: QWHCEUWN).