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constraint_exclusion not working correctly
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* constraint_exclusion not working correctly
@ 2024-08-14 15:28  PG Doc comments form <noreply@postgresql.org>
  0 siblings, 1 reply; 2+ messages in thread

From: PG Doc comments form @ 2024-08-14 15:28 UTC (permalink / raw)
  To: pgsql-docs@lists.postgresql.org; +Cc: hmoustaid.mships@gmail.com

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/16/ddl-partitioning.html
Description:

Hello,

I have noted that, in order for constraint exclusion to work correctly when
partitioning using inheritance, we must use simple comparisons in check
constraints (e.g., =, >=, <=, BETWEEN, etc.). If conditions are combined
using AND or OR, unnecessary partitions may be scanned.

Therefore, the example in this PostgreSQL documentation will not work
properly with constraints like CHECK (logdate >= DATE '2006-02-01' AND
logdate < DATE '2006-03-01'). However, it will work with the BETWEEN
operator.

Regards


^ permalink  raw  reply  [nested|flat] 2+ messages in thread

* Re: constraint_exclusion not working correctly
@ 2024-08-16 02:26  Tom Lane <tgl@sss.pgh.pa.us>
  parent: PG Doc comments form <noreply@postgresql.org>
  0 siblings, 0 replies; 2+ messages in thread

From: Tom Lane @ 2024-08-16 02:26 UTC (permalink / raw)
  To: hmoustaid.mships@gmail.com; +Cc: pgsql-docs@lists.postgresql.org

PG Doc comments form <noreply@postgresql.org> writes:
> I have noted that, in order for constraint exclusion to work correctly when
> partitioning using inheritance, we must use simple comparisons in check
> constraints (e.g., =, >=, <=, BETWEEN, etc.). If conditions are combined
> using AND or OR, unnecessary partitions may be scanned.

> Therefore, the example in this PostgreSQL documentation will not work
> properly with constraints like CHECK (logdate >= DATE '2006-02-01' AND
> logdate < DATE '2006-03-01'). However, it will work with the BETWEEN
> operator.

The example in the documentation works perfectly well for me.

			regards, tom lane





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