IBM 6.1.X manual Execute

R E C O M M E N D E D O R A C L E D A T A B A S E M A I N T E N A N C E

Optimizer statistics are a collection of data about the database and the objects in the database, these statistics are used by the query optimizer to choose the best execution plan for each SQL statement. Because the objects in a database can be constantly changing, statistics must be regularly updated so that they accurately describe these database objects, particularly after periods of heavy data modifications (inserts, updates, and deletes) such as a population phase. We have used the following commands in our environment to recompute these statistics:

execute

dbms_stats.gather_database_stats(dbms_stats.auto_sample_size, method_opt=>'FOR ALL INDEXED COLUMNS SIZE AUTO',cascade=>TRUE);

O T H E R D A T A B A S E C O N S I D E R A T I O N S

WebSphere Portal maintains some information about users in its database tables, which grow when a user first logs in. We were interested in the steady-state performance of WebSphere Portal, not the performance of a user’s first login to the site. Therefore our performance evaluates after all users logged in at least one time.

One of the most important database tuning factors is bufferpool sizing. It is important to evaluate the database's physical versus logical reads and size the bufferpools to achieve as much as a 95% logical read rate if possible.

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W E BS P HE R E P O R T AL V 6 . 1 T U N I N G G U I D E