Re: Optimizing prepared statements

"Jeroen T. Vermeulen" <jtv@xs4all.nl> writes:

> For now, I'll summarize some results I got from randomized input data.  I
> used very simple traces, with 11 prepared statements, each taking a
> different number of parameters (0 through 10, inclusive).  All calls were
> uniformly randomized.  I used LRU replacement of cached plans, with up to
> 4 retained plans per statement.  Confidence counters ran from 0 to 3
> inclusive, with the confidence threshold lying between 1 and 2.

I'm confused, what exactly are you trying to predict? Whether each parameter
will be some cached value? Or whether the cached plan was correct?

> So once again, does anyone know of any realistic logs that I can use for
> more useful simulations?

You might look at the DBT test suite, iirc the TPCC spec it implements
intentionally mixes random queries with predictable queries.

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com