Partitioning

From: James Sewell <james(dot)sewell(at)lisasoft(dot)com>
To: "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org>
Subject: Partitioning
Date: 2015-01-19 01:58:59
Message-ID: CANkGpBvbnZFFhrRtOE4rTZPODFMgbaH-O5Xe4sK+NAFC08Rdpw@mail.gmail.com
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Hello,

I am using partitioning with around 100 sub-tables. Each sub-table is
around 11GB and partitioned on the 'id' column. I have an index on the id
column on each sub-table.

Is it possible to get a query like the following working using constraint
exclusion, or am I doomed to do index/sequential scans of every sub-table?

I want to select all rows which have an id which is in another query, so
something like:

WITH idlist as (SELECT id from othertable)
SELECT id from mastertable WHERE id = idlist.id);

I am guessing that I am not getting constraint exclusion to work as the
planner doesn't know the outcome of my subquery at plan time?

Any tricks I am overlooking?

James Sewell,
PostgreSQL Team Lead / Solutions Architect
______________________________________

Level 2, 50 Queen St, Melbourne VIC 3000

*P *(+61) 3 8370 8000 *W* www.lisasoft.com *F *(+61) 3 8370 8099

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