| From: | Torsten Förtsch <torsten(dot)foertsch(at)gmx(dot)net> |
|---|---|
| To: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
| Cc: | Gabriel Sánchez Martínez <gabrielesanchez(at)gmail(dot)com>, Postgres General <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: Partitioned table question |
| Date: | 2013-11-13 20:02:49 |
| Message-ID: | 5283DAE9.6090906@gmx.net |
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| Lists: | pgsql-general |
On 13/11/13 20:21, Jeff Janes wrote:
> The planner uses the check constraints to reason about the relation
> between each partition separately and the query, not between the
> different partitions. So while it may be possible to know that all rows
> in 2013_4 must be greater than all in 2013_3, it doesn't make use of
> that, instead taking the greatest value from each partition and putting
> it in a priority queue. So the one row from each table acts as a
> sentinel to prove that more rows from that table are not needed.
That makes perfect sense. Thank you very much.
Torsten
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