DB2 UDB for z/OS Version 8 Performance Topics - IBM Redbooks

DSNTIAUL with multi-row fetch
The results of the performance measurement between DB2 V8 DSNTIAUL and HPU are
summarized in Table 10-7 for the case where DSNTIAUL is using multi-row fetch.
Table 10-7 HPU V2.2 vs. DB2 V8 DSNTIAUL (multi-row)
Test case HPU V2.2 DB2 V8 DSNTIAUL % Difference
With Unload using multi-row fetch there is a general improvement in CPU time, almost half
than the single row case, and the elapsed time goes down accordingly.
DSNTIAUL is still the largest consumer of CPU time and also typically has longer elapsed
time when compared to HPU, although Case 7 and 10 show DSNTIAUL being the best
performer. In general HPU outperforms DSNTIAUL multi-row by using about 1/3 - 1/4 of the
CPU time.
You see better performance with DSNTIAUL than with HPU, in cases 7 and 10, by an even
larger margin than in the previous case.
HPU vs. UNLOAD with format delimited
If the UNLOAD utility prepares the output in delimited output format, you can assume that
there is more work it has to perform to add both the additional column delimited character and
character string delimiter into the output data set as opposed to the external format. In spite of
the extra CPU expended for this processing, the usability this feature provides is well worth it;
the process is much easier since you can load the data without manually reformatting the
input file for the LOAD utility.
Refer to 6.3, “LOAD and UNLOAD delimited input and output” on page 270 for the results of
this performance analysis.
376 DB2 UDB for z/OS Version 8 Performance Topics
CPU Elapsed CPU Elapsed CPU Elapsed
Case 1 11.89 62 109.27 159 819 156.45
Case 2 9.44 61 N/A N/A N/A N/A
Case 3 13.57 59 109.97 160 710.39 171.18
Case 4 9.67 46 57.21 74 491.62 60.86
Case 5 18.00 58 110.00 159 511.11 174.13
Case 6 13.93 46 57.54 74 313.06 60.86
Case 7 12.87 45 7.05 44 -45.22 -2.22
Case 8 17.80 59 110.81 160 522.52 171.18
Case 9 12.51 45 - - - -
Case 10 2.39 22 1.44 21 -39.74 -93.45
Parallel 15.33 24 N/A N/A N/A N/A