Interval Statistics Attributes

Use these attributes to view interval statistics information.

Abend EOM The number of times a non-Db2 address space was deleted by z/OS while connected to Db2. (Field name: Q3STMEOM).

Abend EOT The number of times non-Db2 tasks abended while connected to Db2. (Field name: Q3STMEOT).

CF global contention The total number of suspends because of contention divided by the total number of synchronous requests that went to XES, and the lock requests that were converted from synchronous to asynchronous locks, and the locks because of child lock propagation. (Field name: SGLOBRAT). If multiple members from the same data sharing group run on the same LPAR, the global contention rate should be ignored for a member where the QTGSFCON flag is zero. The QTGSFCON flag indicates whether the false contention is reported at the subsystem (=1) or LPAR level (=0).

Commit Phase 1 The number of successful requests for commit phase 1 in a two-phase commit environment such as CICS or IMS. (Field name: Q3STPREP). It includes successfully prepared agents associated with threads that use the Recoverable Resource Manager Services Attach Facility (RRSAF). It does not include successful single-phase commits or distributed two-phase commits. Background and Tuning Information: IMS and CICS applications use the PREPARE and COMMIT sequence to commit work.

Commit Phase 2 The number of successful requests for commit phase 2. IMS,CICS, and RRSAF applications use the prepare and commit sequence to commit work. (Field name: Q3STCOMM). This value does not include successful single-phase commits or distributed two-phase commits.

Create Thread The number of threads created. This count does not include database access threads. (Field name: Q3STCTHD). A thread is required before an application can use SQL. Once established, a thread might have one or multiple authorization IDs (secondaries). A thread is needed to perform any Db2 activity. For example, a thread is needed to run a Db2 utility, to do an IFI request such as reads, or to process a Db2 Command such as -DISPLAY THREAD. However, a thread is not created if the command failed because of a syntax error.

Create Thread Wait The number of create thread requests queued. This count does not include database access threads. (Field name: Q3STCTHW). The total number of threads accessing data that can be allocated concurrently is the MAX USERS on the install panel DSNTIPE. Requests are queued when the maximum allowable value (MAX USERS) is exceeded. If no threads are queued during peak hours, the value of the maximum number of threads might be set too high.

Data Sharing Group The data sharing group name. (Field name: GROUP).

Db2 ID The Db2 subsystem ID. (Field name: DB2ID).

Db2 Version The Db2 Version. (Field name: DB2VER).

Deadlocks The number of times deadlocks were detected. This number should be low, ideally 0. (Field name: QTXADEA). Background and Tuning Information: Deadlocks occur when two or more application processes each hold locks on resources that the others need, without which they cannot proceed. Ensure that all applications accessing the same tables access them in the same order. Deadlocks can also occur through index page splits if there is high insert activity. In this case, the recommendation is to set SUBPAGES to 1 for the index. This field is incremented once for each deadlock encountered. There is no correlation between this field and the deadlock events reported in the Locking report set or the number of IFCID 172 records written. This field reports all deadlocks, regardless of how they were resolved. The locking report and record trace IFCID 172 show only those deadlocks that were resolved by Db2.

DSG Member Name The data sharing group member name. (Field name: MEMBER).

DWQT reached The number of times the deferred write threshold (DWTH) was reached. (Field name: AQBSTDWT). This threshold is a percentage of the virtual buffer pool that might be occupied by unavailable pages, including both updated pages and pages in use. Db2 checks this threshold when an update to a page is completed. If the percentage of unavailable pages in the virtual buffer pool exceeds the threshold, write operations are scheduled for enough data sets (up to 128 pages per data set) to reduce the number of unavailable buffers to 10% below the threshold.

Identify Requests The number of successful connections to Db2 by TSO, IMS, CICS, CAF, RRSAF, or a utility. (Field name: Q3STIDEN).

Indoubt The number of indoubt units of recovery (Field name: Q3STINDT). A unit of recovery is indoubt when a failure occurs after a successful prepare but before a successful commit. The failure can occur in the address space of the application, the transaction manager, Db2, or all of these. IMS and CICS applications use the prepare and commit sequence to commit work. Ideally, this value should be 0.

Indoubt Resolved The successful resolution of indoubt unit of recovery requests (4 bytes). (Field name: Q3STRIUR). The number of times requests to handle indoubt work units were successfully processed. A unit of recovery is indoubt when a failure occurs after a successful PREPARE but before a successful COMMIT. This value includes counts for resolving indoubt database access threads. For allied agent threads, this count is incremented by 2 for each indoubt thread. For database access threads, this count is incremented by 2 for each indoubt thread.

Interval End Time The current time. (Field name: SS_TB2).

Interval Start Time The time when the snapshot was taken. (Field name: SS_TB1).

Lock Change Requests The change request count. (Field name: QTXACHG).

Lock Esc Exc The count of lock escalations to shared mode. (Field name: QTXALEX). This field represents the number of times the value specified in the LOCKS PER TABLE(SPACE) installation parameter on IRLM Panel 2 (DSNTIPJ) or in the LOCKMAX CLAUSE of the CREATE TABLESPACE statement was exceeded and the table space lock was prompted from a page or row lock (IX) to a table or table space lock (X) for this thread. Escalation can cause unpredictable response times. Lock escalation should only happen when an application process updates or references (if repeatable read is used) more pages or rows than it normally does.

Lock Esc Shr The count of lock escalations to shared mode. (Field name: QTXALES). This field represents the number of times the value specified in the LOCKS PER TABLE(SPACE) installation parameter on IRLM Panel 2 (DSNTIPJ) or in the LOCKMAX CLAUSE of the CREATE TABLESPACE statement was exceeded and the table space lock was prompted from a page or row lock (IS) to a table or table space lock (S) for this thread. Escalation can cause unpredictable response times. Lock escalation should only happen when an application process updates or references (if repeatable read is used) more pages or rows than it normally does.

Lock escalations The number of all types of lock escalations. (Field name: SLCLKET).

Lock Query Requests The query request count. (Field name: QTXAQRY).

Lock Requests The lock request count. (Field name: QTXALOCK).

MVS System ID The MVS identifier. (Field name: MVSID).

Number of Active DBATs The current number of active and disconnected (pooled) DBATs. (Field name: QDSTCNAT).

Originating System ID The managed system name of the agent. Valid format is alphanumeric, with a maximum of 32 characters; example, DB91:SYS1:DB2. (Field name: ORIGINNODE).

Other IRLM Requests The other IRLM request count. (Field name: QTXAIRLM).

Read Only Commit The number of read-only commits. (Field name: Q3STRDON). There are occasions when CICS or IMS invokes Db2 when no Db2 resource was altered since the completion of the last commit process with prepare request. When this occurs, Db2 performs both phases of the two-phase commit during the first commit phase and records that the user or job is read-only in relation to its Db2 processing. This count does not include sync requests made by CICS.

Resource Timeout The number of seconds before a timeout is detected.  (Field name: QWP4TOUT). This is an integer multiple of DEADLOCK TIME on panel DSNTIPJ. Timeout means that a lock request has waited for a resource (or for claims on a resource for a particular claim class to be released) longer than this time.  For data sharing, the actual timeout period is longer than the timeout value. Install parameter RESOURCE TIMEOUT on panel DSNTIPI, or ZPARM IRLMRWT in DSN6SPRM.

Signon Requests The number of signons that identified a new user of an existing thread. (Field name: Q3STSIGN). This field applies to threads created for CICS, IMS, and RRSAF only (not TSO, CALL ATTACHMENT, or UTILITY jobs). Initial signon does no authorization check because the thread does not exist, but re-signon might do an authorization check.

Single Commit The number of synchronized commit requests. TSO, CAF, and UTILITY use the synchronized request. (Field name: Q3STSYNC). IMS and RRSAF applications use the prepare and commit sequence. CICS applications use both the synchronized commit request and the prepare and commit sequence to commit work. Single-phase commit requests occur when Db2 is the only resource manager that makes updates to a resource, or when another resource manager makes updates and Db2 has read-only access to the resource. The latter case is called a read-only commit.

Successful Claims The number of successful claim requests. (Field name: QTXACLNO).

Successful Drains The number of successful drain requests. (Field name: QTXADRNO).

Susp Latch The suspend count because of IRLM latch conflict. (Field name: QTXASLAT).

Susp Lock The number of suspends because of a lock conflict. (Field name: QTXASLOC). The number of times a lock could not be obtained and the unit of work was suspended. Suspensions are highly dependent on the application and table space locking protocols. This number should be low, ideally zero.

Term Thread The number of times threads are terminated. (Field name: Q3STTERM). This count does not agree with the create thread count because each level of a thread's access (IDENTIFY, SIGNON, AND CREATE THREAD) must be terminated.

Time Stamp The start time of this interval. (Field name: TIMESTAMP).

Timeouts The number of times a unit of work was suspended for a time exceeding the timeout value. This number should be low, ideally 0. (Field name: QTXATIM).

Total Commit The total number of commit requests. (Field name: SDCOMMIT).

Total Suspends The total number of suspends. (Field name: SLRSUSP).

Unsuccessful Claims The number of unsuccessful claim requests. (Field name: QTXACLUN).

Unsuccessful Drains The number of unsuccessful drain requests. (Field name: QTXADRUN).

Unlock Requests The unlock request count. (Field name: QTXAUNLK).