Re: View vs. direct Table access

Darren Ferguson wrote:
> I am not to sure about Postgres. I just quoted the SQL standard on views.
>
> Although judging from the ones i use and there relative slow speed i do
> not think Postgres caches them in any way
>
> Please Correct me if i am wrong

The SQL standard describes the visible behaviour, not the
implementation. PostgreSQL doesn't cache them any different
from regular table scans (in the buffer cache). Nor does
PostgreSQL materialize the entire view when you do a
qualified SELECT on it.

The performance of the view should be exactly the same as the
SELECT statement you defined for it with the additional
qualifications you're using when selecting from the view. I
think you should use EXPLAIN a little to figure out what
exactly happens when you select from the view and then try to
optimize the view definition and the indexes on the base
tables a little.

Jan

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