Re: complicated queries in pl/pgsql - Mailing list pgsql-performance

From Tomasz Myrta
Subject Re: complicated queries in pl/pgsql
Date
Msg-id 3E25B29C.9040408@klaster.net
Whole thread Raw
In response to complicated queries in pl/pgsql  (Tomasz Myrta <jasiek@klaster.net>)
Responses Re: complicated queries in pl/pgsql  (Josh Berkus <josh@agliodbs.com>)
List pgsql-performance
Josh Berkus wrote:

 >  Tomasz,
 >
 >
 > >What happens to view planning - is it performed
 > >during view creation, or rather each time view is quered?
 >
 >
 > Each time the view is executed.   The only savings in running a view
over a
 > regular query is that the view will have taken care of some reference
 > expansion and JOIN explication during the CREATE process, but not
planning.
 > Also, views can actually be slower if the view is complex enough that
any
 > query-time parameters cannot be "pushed down" into the view.

Thanks a lot.
I'm asking, because I use some queries which are easy to change into
views. Most of their execution time takes planning, they use 5-10
explicit table joins with not too many rows in these tables and returns
few values.

Now I know, that queries inside pl/pgsql functions are better in these
situations:
- complex queries whith deep parameters
- execution several times during conection lifetime.

Can anyone add something?

Tomasz Myrta


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