IBM WEBSPHERE 6.1.X - Manual (Page 45)

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W E B S P H E R E P O R T A L V 6 . 1 T U N I N G G U I D E
DB2 Tuning (Authoring Environment)
M U L T I P L A T F O R M ( L U W )
On top of the DB2 tunings for the base portal scenario, during our testing we found that the
following tunings to the JCR database below significantly decreased load on the CPU and
disk i/o of the DB2 server in our environment.
In our authoring scenario we found that it was necessary to initially size the IBMDEFAULTP
and ICMLSMAINBP32 bufferpools. This was because DB2 was unable to autosize them
fast enough during our user ramp ups and it was therefore causing inconsistent results
during the early stages of the scenario. We also noticed a large amount of database file
handles being opened and closed during our runs stressing the disk i/o prompting us to
increase the maximum number of file handles that can be opened for the JCR database.
Finally, three indexes were added to eliminate some troublesome queries that were table
scanning.
db2 connect to jcrdb
db2 alter bufferpool IBMDEFAULTBP IMMEDIATE size 26000
db2 alter bufferpool ICMLSMAINBP32 IMMEDIATE size 24000
db2set DB2_ASYNC_IO_MAXFILOP=512
db2 update db cfg for jcrdb using MAXFILOP 512
db2 create index taw_ut01590_idx6 on jcr.icmut01590001
(attr0000001334, itemid, versionid )
db2 reorgchk update statistics on table jcr.icmut01590001
db2 create index taw_entry_idx2 on jcr.ev_entry (parentid)
db2 reorgchk update statistics on table jcr.ev_entry
db2 create index taw_ICMSTJCRWSX_2 on jcr.icmstjcrws (basewsid,
wstype)
db2 reorgchk update statistics on table jcr.icmstjcrws
db2stop force
db2start