Re: why do optimizer parameters have to be set manually?

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От Christopher Browne
Тема Re: why do optimizer parameters have to be set manually?
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Msg-id 60n09q9bqg.fsf@dev6.int.libertyrms.info
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Ответ на why do optimizer parameters have to be set manually?  ("Marinos J. Yannikos" <mjy@geizhals.at>)
Ответы is it possible to get the optimizer to use indexes with a like clause  (Dave Cramer <pg@fastcrypt.com>)
Список pgsql-performance
mjy@geizhals.at ("Marinos J. Yannikos") writes:
> it seems to me that the optimizer parameters (like random_page_cost
> etc.) could easily be calculated and adjusted dynamically be the DB
> backend based on the planner's cost estimates and actual run times for
> different queries. Perhaps the developers could comment on that?

Yes, it seems like a Small Matter Of Programming.

http://wombat.doc.ic.ac.uk/foldoc/foldoc.cgi?SMOP

In seriousness, yes, it would seem a reasonable idea to calculate some
of these values a bit more dynamically.

I would be inclined to start with something that ran a workload, and
provided static values based on how that workload went.  That would
require NO intervention inside the DB server; it could be accomplished
simply by writing a database script.  Feel free to contribute either a
script or a backend "hack"...
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Christopher Browne
(416) 646 3304 x124 (land)

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