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Analyzing lock and I/O problems

Use the following procedure to analyze lock and I/O problems.

On STRAC, on the EXPAND line, navigate to the IO/LOCK option and press Enter.

This display is a summary of all lock and I/O activity by this application, shown by table space and index space. The lock data is available with any detail trace. The I/O data is available only if you requested I/O events on the trace request, which can be expensive, depending on the application characteristics.

Related topic

Viewing-data-for-a-single-thread

BMC SOFTWARE --------------  SUMMARY TRACE ENTRY    -----------PERFORMANCE MGMT
SERV ==> STRAC            INPUT   12:11:21  INTVL=> 3  LOG=> N  TGT==> JXODEEO
PARM ==> CB000001,SEQ=3,IOLOCK,SORT=DP               ROW 1 OF 87 SCROLL=> CSR  
EXPAND:  MON(WKLD), DETAIL, CURRENT                                            
        ACCOUNTING: ENV, ELAP, SQLCNTS, BPOOL, LOCKS, PRLL, PKG, RTN, ACC, DDF
        SUMMARIES:  SQL, SCANS, IO/LOCK, SORTS                                 
                                                                              
- - - - - - - - - DATABASE LOCK AND I/O SUMMARY (DETAIL TRACE ONLY) - - - - - -
                                                                              
                  ------ LOCKS -----  --------- SYNC. I/O ---------  ASYNC I/O
DATABASE  PAGESET  MAX. SUSP. TM/OUT   READ WRITE  ELAPSED AVG.ELAP  READ PAGES
-------- -------- ----- ----- ------  ----- ----- -------- -------- ----- -----
DSNDB01  DBD01        3     0      0      2     0   999 us   500 us     0     0
DSNDB01  SYSDBDXA     1     0      0      4     0 8,571 us 2,143 us     0     0
DSNDB01  SYSLGRNX     0     0      0      1     0 1,068 us 1,068 us     0     0
DSNDB06  DSNACX01     0     0      0      4     0 1,494 us   374 us     0     0
DSNDB06  DSNACX02     0     0      0      4     0 5,386 us 1,347 us     0     0
DSNDB06  DSNATX01     0     0      0      4     0 4,501 us 1,125 us     0     0
DSNDB06  DSNATX03     0     0      0      4     0 1,752 us   438 us     0     0
DSNDB06  DSNATX04     0     0      0      4     0    14 ms 3,429 us     0     0
DSNDB06  DSNATX05     0     0      0      4     0 1,404 us   351 us     0     0
DSNDB06  DSNCCX02     0     0      0      4     0 5,775 us 1,444 us     0     0
DSNDB06  DSNCLX03     0     0      0      4     0    11 ms 2,769 us     0     0
DSNDB06  DSNCNX01     0     0      0      4     0 1,604 us   401 us     0     0
DSNDB06  DSNDCX01     0     0      0      5     0    13 ms 2,652 us     0     0

For traces by AUTHID, where SYSOPR is included, you will also see counts for prefetch read requests and the number of pages read for this thread. The other counts are all for synchronous I/O within the application. In other words, the ELAPSED time shown here is part of the total thread elapsed time. Reducing the total number of synchronous I/Os has a direct effect on performance.

 

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