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Re: hints in Postgres?

From: Christopher Browne <cbbrowne(at)acm(dot)org>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: hints in Postgres?
Date: 2003-12-11 16:31:45
Message-ID: m3d6avxqmm.fsf@wolfe.cbbrowne.com (view raw or flat)
Thread:
Lists: pgsql-performance
Quoth mileruiz(at)hotmail(dot)com ("sandra ruiz"):
> I need to know if there is anything like hints of Oracle in
> Postgres..otherwise..I wish to find a way to force a query plan to use
> the indexes or tell the optimizer things like "optimize based in
> statistics", "I want to define the order of the a join" , "optimize
> based on a execution plan that I consider the best" ...

It is commonly considered a MISFEATURE of Oracle that it forces you to
tweak all of those sorts of 'knobs.'

The approach taken with PostgreSQL is to use problems discovered to
try to improve the quality of the query optimizer.  It is usually
clever enough to do a good job, and if it can be improved to
automatically notice that "better" plan, then that is a better thing
than imposing the burden of tuning each query on you.

Tom Lane is "Doctor Optimization," and if you look at past discussion
threads of this sort, you'll see that he tends to rather strongly
oppose the introduction of "hints."
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