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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