Forum OpenACS Development: Optimum Connection Pool Size

Posted by Philip Ravenscroft on
What is the optimum number of connections for the main, subquery and log pools?  Someone told me that 2 per processor was a good place to start for the main and subquery pools with one per processor for the log pool.  We have an 8 processor Solaris box so this would give us 16/16/8, but we also have limited Oracle to two processors on the box.  Does this mean we should be starting with 4/4/2?


Philip Ravenscroft

Posted by Andrew Piskorski on
No real idea, I've never seen it discussed.

However, as long as you never run out of database handles, I doubt there's that much performance impact of how many you have. There's overhead (particularly on the Oracle side) for each handle, so probably the fewer the better, without running out, but I don't know how much overhead there is per handle.

Note that with the db api in OpenACS 4.x, the 2nd and 3rd pools (traditionally called "subquery" and "log", although they no longer have those meanings), will be used only for the unusual queries which need multiple handles. Therefore, I suspect that the vast majority of your handles should be in the first "main" pool, not the second or third pools.