On Aug 31, 2006, at 9:25 AM, Peter Eisentraut wrote:

Am Donnerstag, 31. August 2006 15:05 schrieb Merlin Moncure:
The proposal to supply hints to statements and functions has been
voted down several times due to the argument that it is better to fix
the planner.  I think supplying hints does fix the planner, and is a
balanced solution.

Planner hints are a way to address a deficient planner.  But neither a
manually hinted planner nor a perfectly good planner will help if the
planning decisions are based on outdated information.

I don't chime in very often, but I do think the refusal to incorporate hints into the planner system is fantastically stubborn and nonsensical. I whole-heartedly agree that it is _better_ to fix the planner, but many of us have production systems and can't just go check out CVS HEAD to address our day-to-day issues and we suffer from this decision.

There are many databases out there with better planners than PostgreSQL -- likely there will always be. Even those databases have query planner hints. Why? Because the authors of those database had the humility to realize that the planner they designed wasn't perfect and that people _still_ need their database to perform well despite a non-optimal query plan here and there.

A good query planner hint system would act as a catalyst to the improvement of the current query planner as users could share their complex queries and associated improved query plans through hinting.

I like Postgres a lot, I think the people that work on it are very very sharp. I do feel that the consistent refusal to allow query hinting to be introduced demonstrates an unhealthy amount of hubris that, in the end, negatively impacts users.

While Postgres is missing a ton of other needed features, I rarely see the attitude that they are _unwanted_. Instead I see the "if it is important to you, go build it" attitude which is what I would expect in an open source project.

// Theo Schlossnagle
// CTO -- http://www.omniti.com/~jesus/
// OmniTI Computer Consulting, Inc. -- http://www.omniti.com/

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