How To
Summary
Incremental update feature in IBM Db2 Analytics Accelerator for z/OS allows the propagation of changes from Db2 for z/OS to an accelerator. Those changes are replicated in near-real time and there is a low latency between the source and target. There are two options for incremental updates, IBM Integrated Synchronization or IBM InfoSphere Data Replication for z/OS (CDC)
This document provides information about:
• The counters provided by an accelerator for replication monitoring
• The interfaces that can be used for replication monitoring
Steps
https://www.ibm.com/support/knowledgecenter/SSUSPS_5.4.0/kdp54/ko2rr/rh002out.html
IFCID 002 - Accelerator Data - Accelerator Perspective V4 or later
IFCID 002 - Accelerator SQL Call Data V4 or later
https://www.ibm.com/support/knowledgecenter/SSUSPS_5.4.0/kdp54/ko2rr/rk002out.html
Counter |
Comment |
Q8STNLRS - LOG RECORDS READ: The number of log records read by the replication capture agent for this Db2 system. |
capacity planning, utilization |
Q8STNLRA - LOG RECORDS READ: The number of log records read by the replication capture agents for all Db2 systems. |
capacity planning, utilization |
Q8STNLTS - LOG RECORDS FOR ACCELERATOR TABLES: The number of log records (read by the replication capture agent for this Db2 system) that are applicable to tables in this accelerator. |
capacity planning, utilization |
Q8STNLTA - LOG RECORDS FOR ACCELERATOR TABLES: The number of log records read by the replication capture agents for all Db2 systems that are applicable to tables on this accelerator. |
capacity planning, utilization |
Q8STNBS - LOG RECORD BYTES PROCESSED: The number of log record bytes processed by the replication capture agent for this Db2 system. |
capacity planning, utilization |
Q8STNBA - LOG RECORD BYTES PROCESSED: The number of log record bytes processed by the replication capture agents for all Db2 systems. |
capacity planning, utilization |
Q8STNIS - INSERT ROWS FOR ACCELERATOR TABLES: The number of INSERT rows applicable to accelerator tables that were processed by the replication capture agent for this Db2 system. |
capacity planning, utilization |
Q8STNIA - INSERT ROWS FOR ACCELERATOR TABLES: The number of INSERT rows applicable to accelerator tables that were processed by the replication capture agents for all Db2 systems. |
capacity planning, utilization |
Q8STNUS - UPDATE ROWS FOR ACCELERATOR TABLES: The number of UPDATE rows applicable to accelerator tables that were processed by the replication capture agent for this Db2 system. |
capacity planning, utilization |
Q8STNUA - UPDATE ROWS FOR ACCELERATOR TABLES: The number of UPDATE rows applicable to accelerator tables that were processed by the replication capture agents for all Db2 systems. |
capacity planning, utilization |
Q8STNDS - DELETE ROWS FOR ACCELERATOR TABLES: The number of DELETE rows applicable to accelerator tables that were processed by the replication capture agent for this Db2 system. |
capacity planning, utilization |
Q8STNDA - DELETE ROWS FOR ACCELERATOR TABLES: The number of DELETE rows applicable to accelerator tables that were processed by the replication capture agents for all Db2 systems. |
capacity planning, utilization |
Q8STCRL - REPLICATION LATENCY: The current replication latency for this Db2 system. Latency is defined as the time difference between the time when the last log record was applied to the target and the current time. |
utilization |
Q8STCSS - The current replication state of the accelerator for this subsystem |
availability |
Q8STTLSC - The timestamp when the last status change of the replication state occurred. The timestamp is specified in UTC. |
availability |
Q8STTCCS - The total CPU cost associated to the replication apply process for this Db2 system. |
only valid for CDC, resource |
Q8STLRCP - CPU time used by the asynchronous log reader task of the Integrated Synchronization function on behalf of this accelerator |
valid for Integrated Synchronization, requires Db2 z/OS APAR PH26681 (UI71042) and V7.5.3 or higher resource |
Q8STLRZI - zIIP time used by the asynchronous log reader task of the Integrated Synchronization function on behalf of this accelerator |
valid for Integrated Synchronization, requires Db2 z/OS APAR PH26681 (UI71042) and V7.5.3 or higher resource |
Q8STLRZE - zIIP-eligible time used by the asynchronous log reader task of the Integrated Synchronization function on behalf of this accelerator |
valid for Integrated Synchronization, requires Db2 z/OS APAR PH26681 (UI71042) and V7.5.3 or higher resource |
QISTLRCP – CPU time used by all log reader tasks since the Db2 start |
valid for Integrated Synchronization, requires Db2 z/OS APAR PH18334 (UI70139) resource |
QISTLRZI - zIIP time used by all log reader tasks since the Db2 start |
valid for Integrated Synchronization, requires Db2 z/OS APAR PH18334 (UI70139) resource |
QISTLRZE - zIIP-eligible time executed on CP in all log reader tasks since Db2 start |
valid for Integrated Synchronization, requires Db2 z/OS APAR PH18334 (UI70139) resource |
HTAP Counters |
|
Q8STTDPS - total number of query requests that have been run under the Delay Protocol sent by this Db2 system to the accelerator |
capacity planning, utilization |
Q8STEDPS - total number of query requests that have been run under the Delay Protocol sent by this Db2 system to the accelerator, and that expired because the total wait time was higher than the specified WAITFORDATA value. |
capacity planning, utilization |
Q8STTDPA - total number of query requests that have been run under the Delay Protocol sent by all Db2 systems to the accelerator |
capacity planning, utilization |
Q8STEDPA - total number of query requests that have been run under the Delay Protocol sent by all Db2 systems to the accelerator, and that expired because the total wait time was higher than the specified WAITFORDATA value |
capacity planning, utilization |
Q8STVLCS - the replication velocity for this db2 system, calculated as the ratio of log reader seconds to the number of replication changes per second. A value greater than 1 means that the accelerator can currently process changes faster than they are generated in Db2 for z/OS, and is catching up. The replication latency is decreasing. A value lower than 1 means that there are currently more changes in Db2 for z/OS than the log reader can consume, thus the replication latency is increasing. |
utilization |
-DIS ACCEL DETAIL Command
This is one of the online monitoring interfaces. As opposed to IFCID2 reports, which are generated by monitoring tools, the -DISPLAY ACCEL command displays information about accelerators in real time. If you need to monitor the total CPU, replication latency, and replication velocity in real time, -DISPLAY ACCEL is the correct choice. Below is an extract of a monitoring output, which covers replication only.
The details of the command can be found here
https://www.ibm.com/support/knowledgecenter/SSEPEK_12.0.0/comref/src/tpc/db2z_cmd_displayaccel.html
DSNX830I -DBZ1 DSNX8CDA
ACCELERATOR MEMB STATUS REQUESTS ACTV QUED MAXQ
-------------------------------- ---- -------- -------- ---- ---- ----
IDAAZV7 DBZ1 STARTED 37 0 0 N/A
LOCATION=IDAAZV7 HEALTHY
DETAIL STATISTICS
LEVEL = AQT07052
STATUS = ONLINE
TOTAL CPU FOR REPLICATION FOR THIS DB2 SYSTEM = 580 MS
CURRENT REPLICATION LATENCY FOR THIS DB2 SYSTEM = 120 MS
NUMBER OF SUCCESSFUL QUERY REQUESTS WITH DELAY PROTOCOL
FOR ALL DB2 SYSTEMS = 0
NUMBER OF EXPIRED QUERY REQUESTS WITH DELAY PROTOCOL
FOR ALL DB2 SYSTEMS = 0
REPLICATION VELOCITY = 1.000374
Q8STCRL - REPLICATION LATENCY: The current replication latency for this DB2 system. Latency is defined as the time difference between the time when the last log record was applied to the target and the current time.
Q8STVLCS - the replication velocity for this db2 system, calculated as the ratio of log reader seconds to the number of replication changes per second.
This section is for Integrated Synchronization only. There are new DSNI messages that report on the availability of the log reader task. If there are outages or replication errors, you need to monitor and automatically process these messages. The status information for error analysis can be found here:
DSNI090I: It means that an asynchronous task (SRB) for reading Db2 logs has started.
DSNI091I: The replication is unable to receive data changes. A resynchronization of the data might be required. An attempt is made to restart data replication.
You can also issue a -DISPLAY STATS command with the LOGREADERTASKS option. Check the DSNT788I message output for the details of the message. If multiple Integrated Synchronisation clients are connected to the same Db2 for z/OS subsystem, you might see multiple log reader SRBs in the output. For example:
SESSIONID STATUS CURR. POSITION NUM RECS AGE
---------------- ---------- -------------------- ---------- ------
2BE6DF0A87BB0801 SUSP READ 00000000000188B2CD0D 12420 84s
2BE6E6B580FE0A02 SUSP EOS 00000000000188B4DA2D 1703 7s
******* DISPLAY OF STATS TERMINATED *********************************
DSN9022I -DB2A DSNTDSTS 'DISPLAY STATS' NORMAL COMPLETION
Document Location
Worldwide
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Document Information
Modified date:
25 June 2021
UID
ibm16405758