Michael_D. 1100004WAH Visits (989)
Customers running with DB2 10 NFM have noticed that table spaces associated with the DB2 directory data base or catalog (DSNDB01 and SPT01) experience significant space growth resulting from BIND/REBIND operations, DDL, utility activity (Reorg). The only way customer could sustain the issue was by frequently scheduling reorgs on the DB2 directory and catalog in DB2 10 NFM.
Updated list of APARs for excessive SPT01/DBD01 growth – Base and LOB tablespaces - including related Utility APARs in this area!
DB2 10 NFM Cat/Dir SPT01/DBD01 excessive growth
APAR PM66874 to resolve: LOB integrity abend during REORG of DBD01.
DB2 10 NFM Cat/Dir SPT01/DBD01 excessive growth related
APAR PM68842 to resolve: REORG abend. Broken aux index.
agburke 060001QPDN Visits (664)
Many of you, including our own L2 performance team have spent many years creating spreadsheets to combine the stats and accounting data to reveal things like average CPU seconds or elapsed time per occurrence or COMMIT based on the CONNTYPE. This can be used to get a profile of the typical transactions, then look for outlyers based on top 10 reports. Now there is a new IFCID that can aggregate such information, and it can be started by using the STATS CLASS 9 trace.
· PM62797 – IFCID 369 addition to aggregate stats and accounting information in Stats class 9
· PM72949 for OMPE V5.1.1
You will want to check with your vendors to determine when/if your other accounting and stats reports can take advantage of this new functionality.
agburke 060001QPDN Visits (907)
A DB2 9 for z/OS customer in NFM ran into an issue where DB2 began to run short on 31-bit virtual storage and DSNVMON messages appeared in the log:
DSNV508I -DB2 DSNVMON - DB2 DBM1 BELOW-THE-BAR 351
At the same time the CICS regions processing slowed down significantly, and these threads remained in DB2 longer than normal.
The situation manifested itself in the following way.
While Strobing DB2 (v9 NFM) with CICS Strobe 'hung',
and failed with:
STR3111E STRBFIFA.PrIf2000 Fif* Attach failed
STR3247E STRBFIFR: -STA TRA(PERF) command failed(timeout), shutdown in
progress. The Strobe log contains abend U0522 at 95DBF4BE
Strobe support Recommendations:
1) Set Strobe Parm to DB2IFIFLAG=0010 to enable Auto filtering of DB2
2) Apply PTF V60621A from Strobe maintenance file (42007). This PTF
addresses abend U0522 ABEND @ STRBGBES - STA TRACE(P) T
This PTF has also resolved similar CICS errors at some of our other accounts as well.
Both cases that were repported to us were resolved by it. They reported
that all their CICS' regions 'went down' during a Strobe measurement
because DB2 was not responding but recovered after Strobe ended. The
U0522 abend occurred as well. One of the cases also reported CICS
storage shortages during the measurement. PTF V60621A was the
resolution in each case.
After applying PTF V60621A and updating the DB2IFIFLAG to 0010 Strobe
must be recycled.
agburke 060001QPDN Visits (1627)
We have had several questions lately around z/OS 1.12 and the performance benefits seen by DB2.
A customer of mine first saw a performance degradation with z/OS 1.12 and DB2 9 with a DGTT that had many indexes defined on it. Basically any query that created and dropped many temporary objects could see a CPU increase.
PM17542 was created to avoid this overhead. Unfortunately it was marked P.E., or PTF in error and several z/OS and DB2 APARs were to follow.
Today we are back with a positive story as described in PM46045 which also summarizes the APARs that should be applied to see a performance benefit in DB2.
Michael_D. 1100004WAH Visits (2409)
PM24723: IFCID 225 REAL STORAGE STATISTICS ENHANCEMENTS IFCID225
DB2 APAR PM24723 is very important and supports REAL STOARAGE monitoring issue via a new extension to IFCID 225
See z/OS APAR z/OS APAR OA37821 and corresponding DB2 APAR PM49816 for this issue
OA37821: NEW FUNCTION IARV64 REQUEST=COUNTPAGES SUPPORT FOR UNSERIALIZED PROCESSING.
Useful commands monitoring the use of 1MB size real storage page frames on z10 and z196 :
DISPLAY BUFFERPOOL(BP1) SERVICE=4
Display provides output via DSNB999I messages of how many 1MB size page frames are being used
This z/OS command shows the total LFAREA, allocation and splits it across 4KB and 1MB size frames, via IAR019I message