db_block_buffers

Hello,

I have a database that has a DB block hit ratio of only 15%. My db_block_buffers is set to 10,000 and my db_block_size is 4096 which gives me a 40M DB buffer cache (quick math skills, huh?) At any given time we have about 80 -100 users on this database.

For a test, I increased my db_block_buffers from 5,000 to 10,000 last night and checked the result today (hence, this message). When the db_block_buffers was at 5,000, my DB block hit ratio was at 10% and, as was said above, its now only at 15% after doubling my db_block_buffers.

After running BSTAT and ESTAT for one hour during peak time, the report shows no latch contention, 98% of the sorts are done in memory, the library cache and dictionary cache are both 99%. I'm guessing that it is the application that is causing this.

It is a "canned" application so we don't have access to the code. It is a document management package called PC DOCS (if anyone is familiar with it.) It seems that, of the queries run by the users, there are a few tables they constantly query against. I'm wondering if I should pin these tables into memory.

Fortunately the users don't complain about the database being slow, but I'm at a loss as to why my ratio is so bad. Any thoughts?

Thank you in advance,

Ron Received on Fri Oct 22 1999 - 18:48:13 CDT