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

Old - Query 5 New - Query 5 CPU
(sec.)
SELECT DBNAME, NAME
FROM
SYSIBM.SYSTABLESPAC
E TS WHERE NTABLES
(SELECT COUNT(*)
FROM
SYSIBM.SYSTABLES TB
WHERE TYPE IN ('T',
'X','M')
AND TB.DBNAME =
TS.DBNAME AND
TB.TSNAME = TS.NAME
AND TS.NAME
'SYSDEFLT');
Old - Query 18
(DB2 V8 NF Mode)
SELECT TBCREATOR,
TBNAME, NAME FROM
SYSIBM.SYSCOLUMNS
CL WHERE FLDPROC =
'Y' AND NOT EXISTS
(SELECT *
FROM
SYSIBM.SYSFIELDS FL !
WHERE FL.TBCREATOR
= CL.TBCREATOR
AND FL.TBNAME =
CL.TBNAME AND
FL.NAME = CL.NAME
AND FL.COLNO =
CL.COLNO);
Table 9-6 shows the old and new text of Query 31.
Table 9-6 Catalog consistency - Query 31
Table 9-7 shows the old and new text of Query 33.
360 DB2 UDB for z/OS Version 8 Performance Topics
SELECT DBNAME,
NAME
FROM
SYSIBM.SYSTABLESPA
CE TS WHERE
NTABLES¨ =
(SELECT COUNT(*)
FROM
SYSIBM.SYSTABLES
TB WHERE TYPE IN
('T', 'X')
AND TB.DBNAME =
TS.DBNAME AND
TB.TSNAME =
TS.NAME
AND TB.DBID =
TS.DBID
AND TS.NAME =
'SYSDEFLT');
New - Query 18
(DB2 V8 NF Mode)
SELECT
CL.TBCREATOR,
CL.TBNAME, CL.NAME
FROM
SYSIBM.SYSCOLUMN
S CL LEFT OUTER JOIN
SYSIBM.SYSFIELDS FL
ON FL.TBCREATOR =
CL.TBCREATOR
AND FL.TBNAME =
CL.TBNAME AND
FL.NAME = CL.NAME
AND FL.COLNO =
CL.COLNO
WHERE CL.FLDPROC
= 'Y'
AND FL.TBCREATOR IS
NULL;
Elapse
d time
(sec.)
CPU
(sec.)
Elapse
d time
(sec.)
1926 2104 7.7506 10.366
CPU
(sec.)
Old - Query 31 New - Query 31
SELECT NAME
FROM SYSIBM.SYSPLAN PL
WHERE PLENTRIES = 0
AND NOT EXISTS
(SELECT * FROM SYSIBM.SYSDBRM
WHERE PLNAME = PL.NAME);
Elapse
d time
(sec.)
CPU
(sec.)
Elapse
d time
(sec.)
0.3745 0.4046 0.37382 0.3924
SELECT NAME
FROM SYSIBM.SYSPLAN
WHERE PLENTRIES = 0
AND NAME NOT IN
(SELECT PLNAME FROM
SYSIBM.SYSDBRM);