Overview of IMS Problem Analyzer

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Overview of IMS Problem Analyzer

  1. 1. Understanding Key Indicators in the IMS Performance Analyzer Report Gary Wicks wicks@ca.ibm.com June 2009
  2. 2. s powered es in by e bus IM IMS Worldwide Technical Support S - Starting the IMS PA Tool Reference the IMS Performance Analyzer for z/OS User’s Guide V4 R1: SC18-9778-02 From the ISPF option 6 command shell this is what I issued to invoke IMS PA V3.3 on an z/OS system at the IMS laboratory: – ex 'IMSTOOL.PA33.IPI.SIPIEXEC(IPIOREXX)' 'IMSTOOL.PA33.IPI E‘ I used two SLDS from systems IMP1 and IMP2: – IMSDUMP.PM35056.D090526.T154126.P1LOG26 – IMSDUMP.PM35056.D090526.T154127.P2LOG26 I created a ‘TEST’ Parallel Sysplex 2 way group and invoked PA for this group. Both SLDS were input into PA by the JCL creation phase. 2
  3. 3. s powered es in by e bus IM IMS Worldwide Technical Support S - First: The log records analyzed are summarized Record type Count % of total Record type Count % of total 01 (01) 481,552 2.92% 56 (38) 66 0.00% 02 (02) 1,547 0.01% 64 (40) 13,833 0.08% 03 (03) 680,118 4.13% 65 (41) 4,760 0.03% 07 (07) 391,248 2.38% 66 (42) 8 0.00% 08 (08) 391,238 2.38% 67 (43) 1000,309 6.07% 69 (45) 192 0.00% 16 (10) 12 0.00% 71 (47) 95 0.00% 17 (11) 10 0.00% 72 (48) 300,105 1.82% 18 (12) 9 0.00% 76 (4C) 69 0.00% 22 (16) 1,319 0.01% 80 (50) 4618,767 28.05% 24 (18) 25,494 0.15% 85 (55) 10 0.00% 32 (20) 4 0.00% 86 (56) 3392,251 20.60% 39 (27) 11,080 0.07% 87 (57) 1 0.00% 48 (30) 18,810 0.11% 99 (63) 1,282 0.01% 49 (31) 1097,861 6.67% 103 (67) 26,018 0.16% 50 (32) 17 0.00% 109 (6D) 1,781 0.01% 51 (33) 1106,858 6.72% 153 (99) 127 0.00% 53 (35) 844,346 5.13% 249 (F9) 337,481 2.05% 54 (36) 231,502 1.41% 250 (FA) 612,895 3.72% 55 (37) 875,717 5.32% TOTAL 16468,792 100.00% 3
  4. 4. s powered es in by e bus IM IMS Worldwide Technical Support S - Miscellaneous Statistics Where to get the data: Internal Resource Usage – Miscellaneous Statistics What to look at: Highest PST used and compare to the PST value in the DFSPBxxx member Total number of transactions per second. Good to compare throughout the week and monthly cycle. If the Number or Maximum number of RECANY buffers used is regularly high (equal to the RECA parameter in DFSPBxxx member of IMS.PROCLIB), then this may indicate a shortage. 4
  5. 5. s powered es in by e bus IM IMS Worldwide Technical Support S - Miscellaneous Statistics Miscellaneous Statistics Interval : 11.26 (HHHH.MM.SS) Count /Transact /Second ________ _________ _________ Highest PST used 159 Highest CCB ID used 1 Maximum # of CCBs in use 2 Number of Conversations started 7 .01 Number of Conversational Transactions 86 .13 Number of Wait-For-Input Transactions 0 .00 Number of NonRecoverable Transactions 17,549 25.59 Number of Response-Mode Transactions 254,362 370.93 Total number of Transactions 254,362 370.93 Average Minimum Maximum Number of RECANY Buffers used 0 0 0 Maximum number of RECANY Buffers used 44 44 44 Number of Statistics Intervals 2 IMS Release Level 9.1.0 5
  6. 6. s powered es in by e bus IM IMS Worldwide Technical Support S - Message Queue Pool Statistics Where to get the data: Internal Resource Usage – Message Queue Pool Statistics What to look at: ‘Writes done for space’ should be zero. If not zero increase the number of message queue buffers The NUMBER OF WRITE REQUESTS(TOTAL) should be approximately = NUMBER OF WRITES DONE BY PURGE (the purge here is done by system checkpoint, not application syncpoint) If not =, increase the number of message queue buffers. 6
  7. 7. s powered es in by e bus IM IMS Worldwide Technical Support S - Message Queue Pool Statistics Message Queue Pool Statistics Interval : 11.26 (HHHH.MM.SS) Count /Transact /Second + ______________ _________ _________ Locate calls from QMGR 1,433,899 5.64 2,091.03 Record Release calls from QMGR 585,316 2.30 853.56 Locate and Alter calls from QMGR 2,895,136 11.38 4,221.92 Requests to Purge the Q pool 1 .00 .00 Address to DRRN translation requests 0 .00 .00 Total requests to QMGR not incl Translates 4,914,352 19.32 7,166.51 Read requests 143 .00 .21 57.89% of I/O's Write requests (Total) 104 .00 .15 Writes done by Purge 104 .00 .15 42.11% of I/O's Writes done for Space 0 .00 .00 .00% of I/O's Total I/O requests 247 .00 .36 Locate calls satisfied in Pool 4,328,892 ………… 7
  8. 8. s powered es in by e bus IM IMS Worldwide Technical Support S - Full Function Database Buffers: OSAM Where to get the data: Internal Resource Usage – Enhanced OSAM Buffer Pool Statistics. Create a spread sheet from the data in the report. What to look at: The buffer life must be greater than the operator think time period and the time between each BMP checkpoint When a buffer subpool is recording zero references per second, the subpool should be examined to see if any database are still using it. If not return the storage back for other subpools to use. If it is possible to fix the buffers and control blocks, do so. 8
  9. 9. s powered es in by e bus IM IMS Worldwide Technical Support S - Full Function Database Buffers: OSAM Buffer Size Buffer Ref / Sec Number of Time # already in pool # of read IO Requests Life Buffers 2048 160.5 135 5000 686 71300 21367 4096 18.9 3635 5000 686 2311853 181,855 6144 14.1 22697 17000 686 14743509 826,876 6144 P 11.2 397 850 686 220395 52,186 8192 42.5 52050 12000 686 35512176 193,793 8192 G 3426.6 1422 5000 686 974665 1,001 8192 M 5.8 16962 1000 686 11518716 117,471 9
  10. 10. s powered es in by e bus IM IMS Worldwide Technical Support S - Full Function Database Buffers: VSAM Where to get the data: Internal Resource Usage – Enhanced VSAM Buffer Pool Statistics What to look at: The buffer life must be greater than the operator think time period and the time between each BMP checkpoint When a buffer subpool is recording zero references per second, the subpool should be examined to see if any database are still using it. If not, return the storage back for other subpools to use. If it is possible to fix the buffers and control blocks, do so. 10
  11. 11. s powered es in by e bus IM IMS Worldwide Technical Support S - Full Function Database Buffers: VSAM Buffer Size Buffer Ref / Sec Number Time # already in pool # of reads from DASDI Life of Buffers CI size 512 1D 438.1 364 21000 686 217006 32,884 CI size 1024 1 D 243.0 338 5000 686 217530 14,113 CI size 2048 1 D 62.0 807 8000 686 465372 88,525 CI size 4096 1 D 78.2 6341 12000 686 4244595 105,295 CI size 8192 1 D 83.2 8210 7000 686 5574250 57,751 CI size 12228 1 D NA 0 1000 686 0 0 CI size 32768 1 D 824.5 15 500 686 9979 416 CI size 2048 1 I 114.5 661 2500 686 438,401 14,976 CI size 4096 1 I 171.5 3403 5000 686 2,314,707 20,004 CI size 8192 I 1 I 1151.8 422 2500 686 288,054 1489 CI size 12288 1 I 3790.1 981 1000 686 672,720 181 CI size 32768 1 I 112.8 4 50 686 2604 304 CI size 8192 2 D 474.7 233 2000 686 156634 2890 11
  12. 12. s powered es in by e bus IM IMS Worldwide Technical Support S - Variable IMS Pool Statistics Where to get the data: Internal Resource Usage – Variable Pool Statistics What to look at: The variable IMS pool statistics present the initial, final, and maximum number bytes utilized for each pool. If the maximum number of bytes utilized is close to the initial value AND there were instances of a number of control blocks cast out to make room for new structures, then the pool size should be increased and then monitored via the use of IMS PA. 12
  13. 13. s powered es in by e bus IM IMS Worldwide Technical Support S - Variable IMS Pool Statistics DMB Pool Statistics (DLDP) Bytes in DMB Pool 1,228,800 Bytes allocated at End of Report 1,137,984 Maximum Bytes ever used 1,137,984 PSB pool Statistics (DLMP) Bytes in PSB Pool 7,340,032 Bytes allocated at End of Report 5,467,456 Maximum Bytes ever used 5,986,384 PSB pool (DLI/SAS Local) Statistics (DPSB) Bytes in PSB Pool 45,088,768 Bytes allocated at End of Report 41,969,632 Maximum Bytes ever used 45,079,424 PSB Work Pool Statistics (PSBW) Number of Bytes in Pool 3,584,000 Number of Bytes allocated at End of Report 1,078,248 Maximum Bytes ever used 1,742,056 DMB Work Pool Statistics (DBWP) Number of Bytes in Pool 565,248 Number of Bytes allocated at End of Report 0 Maximum Bytes ever used 8,992 13
  14. 14. s powered es in by e bus IM IMS Worldwide Technical Support S - Variable IMS Pool Statistics PSB Pool Get Statistics Count /Transact /Second Requests 215 .01 1.70 CSA PSB pool Space not immediately available 0 .00 .00 PSBs cast out to make room for new PSB 0 .00 .00 Failed 0 .00 .00 DLI PSB pool Space not immediately available 15 .00 .12 PSBs cast out to make room for new PSB 218 .01 1.72 Failed 0 .00 .00 Space not immediately available in CSA and DLI 0 .00 Time getting PSB pool space with no PSB cast out 0.004 .00 .04 Time getting PSB pool space with PSB cast out 0.220 .01 1.74 14
  15. 15. s powered es in by e bus IM IMS Worldwide Technical Support S - Resource Availability Where to get the data: Search on Resource Availability What to look at: Review the number of WFI regions to determine if the environment is adequately resourced. If regions have very low occupancy values there may be opportunities for re classification of transactions or merging of started regions. 15
  16. 16. s powered es in by e bus IM IMS Worldwide Technical Support S - Resource Availability Total IMS Up Time 9.55 (hh.mm.ss) - <-----In Use----> <-----Idle------> <--Unavailable--> <Waiting for Input> Region hh.mm.ss Pct hh.mm.ss Pct hh.mm.ss Pct + _________________ __________ _____ __________ _____ __________ _____ 0 1 IMSP1R43 14 2.3 9.41 97.7 0 .0 0 2 DENP 19 3.3 9.36 96.7 0 .0 0 > 4 IMSP1R21 9.51 99.3 4 .7 0 .0 0 > 5 IMSP1R1E 8.50 89.0 1.05 11.0 0 .0 0 6 IMSP1R1H 35 6.0 9.20 94.0 0 .0 0 7 IMSP1RA5 2.29 25.0 7.26 75.0 0 .0 0 8 IMSP1RA6 2.11 22.0 7.44 78.0 0 .0 16
  17. 17. s powered es in by e bus IM IMS Worldwide Technical Support S - Latch Conflict Statistics Where to get the data: Internal Resource Usage – Latch Conflict Statistics What to look at: Latching is an internal IMS code serialization methodology that normally does not affect the throughput through IMS. But if the LOGR latch reflects a very high value per second (above 100 per second for example) then this could result in a recommendation to increase the IMS OLDS buffer allocation in the DFSVSMxx member. Also the WADS dataset may have to be increased in size if the number of OLDS buffer has to be increased dramatically. 17
  18. 18. s powered es in by e bus IM IMS Worldwide Technical Support S - Latch Conflict Statistics Latch Conflict Statistics Excl Grant Shr Grant Excl IWAIT Shr IWAIT LOGL 0 0 38344 0 /Tran .00 .00 .15 .00 /Sec .00 .00 55.91 .00 This reflects 56 waits for the internal logical buffer latch per second in IMP1 18
  19. 19. s powered es in by e bus IM IMS Worldwide Technical Support S - Logger Statistics Where to get the data: Internal Resource Usage – Logger Statistics What to look at: The buffer waits for non – checkpoint invokers should be zero. When a checkpoint occurs, all the OLDS buffers are purged to disk so it is not unusual to experience a wait for buffers at that time. The amount of data being written to the WADS can be calculated by multiplying the number of 2K segment writes initiated per second by 2048. It provides an indication of how quickly log records are being externalized. 19
  20. 20. s powered es in by e bus IM IMS Worldwide Technical Support S - Logger Statistics Count /Transact /Second + 0 Logical Logger: Records Written 5,859,067 23.03 8,544.17 Check Write requests 483,907 1.90 705.67 Waits for Writes 90,091 .35 131.38 Buffer Waits: CHKPT Invokers 53 .00 .08 Buffer Waits: Non-CHKPT Invokers 27 .00 .04 AWE submitted on Wrt 0 .00 .00 - Physical Logger: WADS EXCPVRs 275,556 1.08 401.84 2K Segment Writes initiated 1,004,876 3.95 1,465.39 OLDS Writes initiated 113,372 .45 165.33 OLDS Reads initiated 2 .00 .00 Internal Check Write requests 0 .00 .00 Accumulative WTWT Wait Time 236,968 .93 345.57 OLDS Block Size 18,432 Log Buffers 102 WADS Track Groups 102 WADS Tracks in 1 cylinder 15 Blocks in 1 WADS track 18 Bytes in 1 WADS track 36,864 20
  21. 21. s powered es in by e bus IM IMS Worldwide Technical Support S - Scheduling Statistics Where to get the data: Internal Resource Usage – Scheduling Statistics What to look at: The dependent region might run into scheduling failures if the pool size is small. Five pools are associated with scheduling: - PSB pools (PSBP and DPSB) - PSB work pool - EPCB pool (Related to Fast Path) - DMB pool - DMB work pool The reasons for a miscellaneous schedule failure are varied, but the most common is when the TRANSACT PARLIM (PARALLEL SCHEDULING THRESHOLD) limit has been reached. 21
  22. 22. s powered es in by e bus IM IMS Worldwide Technical Support S - Scheduling Statistics Scheduling Statistics Interval : 2.07 (HHHH.MM.SS) Count /Transact /Second Program Conflicts 0 .00 .00 Database Intent Conflicts 0 .00 .00 Conflicts for Miscellaneous Reasons 97 .00 .77 100.00% of all Conflicts SMBs tried for Scheduling 21,564 .55 170.21 Programs Scheduled 21,467 .55 169.44 Total Conflicts 97 .00 .77 .45% of SMBS tried Number of active BMPs 7 Number of active MPPs 77 22
  23. 23. s powered es in by e bus IM IMS Worldwide Technical Support S - Conclusion For more information refer to: IBM IMS Performance Analyzer for z/OS, Report Reference Version 4 Release 1: SC18-9779-02 IMS Performance Analyzer for z/OS User’s Guide: SC18-9778 IMS Performance and Tuning Guide: SG24-7324-00 23

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