On 19 Sep 2014, at 3:50, Robert Nix <rob...@urban4m.com> wrote: > Thanks, David. > > I have read that page many times but clearly I have forgotten this: > > • Constraint exclusion only works when the query's WHERE clause > contains constants (or externally supplied parameters). For example, a > comparison against a non-immutable function such asCURRENT_TIMESTAMP cannot > be optimized, since the planner cannot know which partition the function > value might fall into at run time. > > I had worked around this "issue" some time ago but I clearly should have > documented _why_ I worked around it in the way I did.
What may be worth a try is to join against a UNION ALL of your partitions, with each section of the UNION having an explicirt WHERE clause matching your partitioning constraints. The idea there is that such a UNION could provide the explicit constant WHERE clauses that your JOIN implicitly depends on. If that works, then the next step would be to try a VIEW using that UNION, which - assuming you automatically generate your partition tables - could be created at the same moment that you create new partitions. Alban Hertroys -- If you can't see the forest for the trees, cut the trees and you'll find there is no forest. -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
