Re: HELP!!!! INDEXES and SQL Loader

Indexes can get fragmented in two ways: on one hand, if the storage characteristics are ill defined, they may split into several different extensions, sometimes far apart from each other physically; on the other hand, if many keys are deleted and inserted frequently, the B-tree formed by the index blocks might become somewhat odd, having blocks which are nearly full and other blocks with a lot of freespace remaining (in other words, a tree that is taller than it should be). Either effect is bad, and leads to a poorer performance.

You can minimize the first effect by allocating a separate tablespace for the indexes and setting a STORAGE parameter suitable for each of them. The second effect, common in volatile tables, are much more difficult to avoid and, as a rule, obliges the DBA to periodically rebuild the indexes, in order to keep good performance levels.

All the same, you mentioned "problems with views...". As views are queries, they might present poor performance if the SQL has a bad or inadequate execution plan. Check them out to see if the plans are good if the above mentioned cases don't suit yours.

Best regards Received on Tue Sep 19 1995 - 00:00:00 CEST