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

Table 9-7 Catalog consistency - Query 33
Old - Query 33 New - Query 33
SELECT NAME
FROM SYSIBM.SYSPLAN PL
WHERE PLENTRIES = 0
AND NOT EXISTS
(SELECT * FROM SYSIBM.SYSSTMT
WHERE PLNAME = PL.NAME);
As shown in Figure 9-8, the performance of the two queries has improved noticeably.
Query
31
Old DSNTESQ
CPU
38 min
53 sec
E.T
10 hr
32 min
36 sec
Figure 9-8 Catalog consistency queries - Measurement results
The old consistency Query 35 and Query 36 have merged into a new query, as shown in
Table 9-8.
Table 9-8 Catalog consistency - Queries 35 and 36 from SDSNSAMP.
SELECT NAME
FROM SYSIBM.SYSPLAN
WHERE PLENTRIES = 0
AND NAME NOT IN
(SELECT PLNAME FROM SYSIBM.SYSSTMT);
Old Query 35 Old Query 36 New Query 35 and 36
SELECT PLNAME, NAME
FROM SYSIBM.SYSDBRM DR
WHERE NOT EXISTS
(SELECT *
FROM SYSIBM.SYSSTMT ST
WHERE ST.PLNAME =
DR.PLNAME
AND ST.NAME = DR.NAME);
V8 Compatibility Mode
New DSNTESQ
CPU
1.2
sec
E.T
17 sec
CPU
25 min
35 sec
SELECT DISTINCT PLNAME,
NAME
FROM SYSIBM.SYSSTMT ST
WHERE NOT EXISTS
(SELECT *
FROM SYSIBM.SYSDBRM DR
WHERE DR.PLNAME =
ST.PLNAME
AND DR.NAME =
ST.NAME);
V8 New Function Mode
Old DSNTESQ
10 hr
2 min
39 sec
CPU
14 sec
SELECT DBRM.PLNAME,
DBRM.NAME,
STMT.PL NAME, STMT.NAME
FROM SYSIBM.SYSDBRM
DBRM FULL OUTER JOIN
SYSIBM.SYSSTMT STMT
ON DBRM.PLNAME =
STMT.PLNAME
AND DBRM.NAME =
STMT.NAME
WHERE (STMT.NAME IS
NULL OR DBRM.NAME IS
NULL)
GROUP BY DBRM.PLNAME,
DBRM.NAME,
STMT.PLNAME, STMT.NAME;
The performance of these queries has improved quite a lot as shown in Figure 9-9.
23 sec
33 49 min 9 hr 3.5 17.5 42 min 10 hr 18 sec 25 sec
2 sec 58 min sec sec 12 sec 3 min
55 sec
37 sec
E.T
New DSNTESQ
E.T
Chapter 9. Installation and migration 361