Re: Performance issues

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On 3/13/15 7:12 PM, Tomas Vondra wrote:
(4) I suspect many of the relations referenced in the views are not
     actually needed in the query, i.e. the join is performed but
     then it's just discarded because those columns are not used.
     Try to simplify the views as much has possible - remove all the
     tables that are not really necessary to run the query. If two
     queries need different tables, maybe defining two views is
     a better approach.

A better alternative with multi-purpose views is to use an outer join instead of an inner join. With an outer join if you ultimately don't refer to any of the columns in a particular table Postgres will remove the table from the query completely.
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com


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