APAR status
Closed as canceled.
Error description
5740XYR00 DB2ZIIP DB2 z/OS V8 zIIP exploitation "support use" information. KEYWORD: zIIP/K DB2 V8 zIIP APARs: PK30548 INCORRECT CALCULATION FOR WORKLOAD SHARING OR ABEND0C9 DSNTTTC WHEN IBM ZIIP ENABLED FOR CP OR SYSPLEX PARALLELISM This allows PK27578 to also be applied. PK30087 REBUILD INDEX OF AN NPI WITH ZIIP EXPERIENCES 10% ELAPSED TIME DEGRADATION IN THE BUILD PHASE PK30474 zIIP UPDATES TO DSNWMSGS PK27712 DB2PM ACCOUNTING REPORTS SHOW HIGH CLASS 1 IIPCP TIME FOR UTILITY JOBS WITH ZIIP PK20487 DB2 UTILITY TOLERATION OF SPECIALTY ENGINES SUCH AS ICF, IFL, ZAAP, AND ZIIP PK19921 DB2 Z/OS EXPLOITATION OF THE IBM SYSTEM Z9 INTEGRATED D/T2094 INFORMATION PROCESSOR (IBM ZIIP) STAR SCHEMA PARALLEL QUERIES PK19920 DB2 Z/OS EXPLOITATION OF THE IBM SYSTEM Z9 INTEGRATED D/T2094 INFORMATION PROCESSOR (IBM ZIIP) FOR UTILITIES. PK18454 DB2 Z/OS EXPLOITATION OF THE IBM SYSTEM Z9 INTEGRATED D/T2094 INFORMATION PROCESSOR (IBM ZIIP) FOR DRDA THREADS PK37312 Correct invalid blank QWACWLME values. PK46171 Correct QWACASC (accumulated elapsed time). PM12256 zIIP related performance improvement. Support for zIIP related instrumentation changes in IFCIDs 3,147,148,231,239 for zIIP usage reporting, monitoring and projection: PK25395, PK32787: IBM Tivoli OMEGAMON XE for DB2 Performance Expert on z/OS PK29966, PK32782: DB2 Performance Expert V210 PK29967, PK32782: DB2 Performance Monitor V810 A search on keyword zIIP/K will provide zIIP related APAR/PTF information for DB2 z/OS and other products as well. --------------------------------------------------------------- Question: What happens when zIIP processor is busy? Answer : DB2 doesn't force an enclave to only run on a zIIP. If the zIIP is busy some zIIP eligible work may flow to a CP. The zIIP eligible work that runs on a CP is shown as IIPCP in the RMF Workload Activity Report Service / Reporting classes an in the Omegamon DB2PE Accounting report CPU section. IIP field shows the zIIP CPU usage. Sample RMF Workload activity report zIIP CPU related information: SERVICE TIMES ---APPL %--- CPU 110.3 CP 3.16 SRB 0.0 AAPCP 0.00 RCT 0.0 IIPCP 1.19 IIT 0.0 HST 0.0 AAP 0.00 AAP 0.0 IIP 5.67 IIP 70.9 Refer to RMF Report Analysis publication for more details. Sample Omegamon DB2PE Accounting report zIIP CPU related information : AVERAGE APPL(CL.1) DB2 (CL.2) ------------ ---------- ---------- ELAPSED TIME 2:08.01174 2:07.92387 NONNESTED 2:08.01174 2:07.92387 STORED PROC 0.000000 0.000000 UDF 0.000000 0.000000 TRIGGER 0.000000 0.000000 CP CPU TIME 19.373768 19.365788 AGENT 6.779348 6.771411 NONNESTED 6.779348 6.771411 STORED PRC 0.000000 0.000000 UDF 0.000000 0.000000 TRIGGER 0.000000 0.000000 PAR.TASKS 12.594420 12.594377 IIPCP CPU 2.813831 N/A IIP CPU TIME 35.886951 35.886951 Refer to Omegamon DB2PE Report Reference publication for more details. --------------------------------------------------------------- Question: What are the considerations related WLM service class goals for parallel queries ? Answer : When running parallel task each task runs as a separate enclave. For local apps, they can now define WLM goals for each parallel thread or by default run under the priority of the calling app. For remote apps, they would still use the same goals classified for the main DDF thread. Each parallel task of the query accumulates service units, period switch is determined for each task, not the overall query. --------------------------------------------------------------- Question: What are the considerations for zparm settings for parallel queries ? Answer : Existing zparm PARAMDEG (which sets the maximum number of degrees) controls the degree of parallelism. Refer to DB2 installation manual for details. Parallelism implies multiple tasks, so a single task is actually a sequential query which does not qualify for parallelism. When trying to exploit CP query parallelism, you cannot set the degree to 1 because DB2 does not choose parallelism since you need at least 2 degrees. --------------------------------------------------------------- Question: Is there a way to estimate or project the zIIP usage prior to installing zIIP hardware? Answer : Customers who have installed the z/OS and DB2 V8 zIIP support software can set the SYS1.PARMLIB(IEAOPTxx) parm PROJECTCPU=YES. With this setting the RMF Workload activity report and DB2PE Accounting report IIPCP field will show the projected zIIP eligible CPU information. In the RMF workload activity report, look at the DDF work service class. For Utilities and Parallel queries setup proper WLM reporting Classes. For using DB2PE Accounting report, run reports for CONNTYPE DRDA and Utility. For parallel queries, run report for their plan or package names. Customers who are on DB2 V7 and need to estimate the DRDA zIIP redirect benefit can follow the following procedure : Ensure that WLM policy is setup with Service Class(es) for SUBSYSTEM TYPE=DDF Run the RMF Workload activity report (SYSRPTS) for the peak periods of interest showing DB2 DDF work related Service and Reporting Classes. The APPL% CP under the DDF work Service or Reporting Class(es) for the DB2 Subsystem can be used to determine the DB2 enclave SRB CPU eligible to be redirected. Portion of the eligible work will be redirected to zIIP. If the eligible work is significant, contact IBM Tech Line/FTSS to help with the estimation for DRDA zIIP redirect. Indicate whether Stored Procedure and/or UDF (User Defined Function) are used extensively. Following is the procedure to estimate zIIP eligible CP time for Parallel Queries on DB2 V7: Gather DB2 Accounting trace Class(1,2,3) for the period of interest. Run Accounting report using a tool such as DB2PM / DB2PE excluding Connect Type Utility. If the average Class 2 PAR.TASKS field in the Grand Total section has significant value (> 50 ms) then there may be a potential for zIIP redirect. - Run Accounting Trace. - Using DB2PE performance database or another tool, filter the queries that use more 100 ms of PAR.TASKS CPU - Subtract 0.1 Sec * number of parallel groups executed for each query - Sum the result for all such parallel queries - Significant portion of the result will be eligible for zIIP redirect More V8 parallelism potential with parallel sort and parallel multi column merge join. Following is the rule of thumb for potential zIIP redirect DB2 Class 1 CPU savings for DB2 V7 Utilities for a configuration with 4 CPs, 2 zIIPs with fixed length Index keys: 5 to 20% for Rebuild Index 10 to 20% for Load or Reorg of a partition with one index only, or Load of entire table, or Reorg of entire tablespace 40% for Rebuild Index of logical partition of non partitioning index 40 to 50% for Reorg Index 30 to 60% for Load or Reorg of a partition with more than one index ------------------------------------------------------------ Considerations from a z/OS perspective: IIPHONORPRIORITY=YES is meant to route some of the zIIP-eligible work to standard CPs when the zIIP is heavily loaded. If it is set to NO, and the zIIP is heavily loaded you may reach a slowdown situation. It may appear that DB2 is the problem and hogging cpu resources. ZIIPAWMT concerns the weight the zIIP processor is given on a customer's LPAR. Review APAR OA25825/UA42949 and ensure it is applied. IPHONORPRIORITY ---------------------------------------------------------------
Local fix
Problem summary
Problem conclusion
Temporary fix
Comments
Informational APAR.
APAR Information
APAR number
II14219
Reported component name
PB LIB INFO ITE
Reported component ID
INFOPBLIB
Reported release
001
Status
CLOSED CAN
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2006-09-07
Closed date
2006-09-08
Last modified date
2017-12-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Applicable component levels
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Document Information
Modified date:
01 December 2017