Re: Join optimization for inheritance tables - Mailing list pgsql-hackers

From Josh Berkus
Subject Re: Join optimization for inheritance tables
Date
Msg-id 4AB96D58.1080808@agliodbs.com
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In response to Re: Join optimization for inheritance tables  (Emmanuel Cecchet <manu@asterdata.com>)
Responses Re: Join optimization for inheritance tables
List pgsql-hackers
> As I understand it, partitioning will certainly lead to some significant
> changes/enhancements to the planner. Do you think it is realistic to get
> that for 8.5?

I don't think that waiting for our plans for a more robust partitioning
implementation is a reason to put off improvements to the implementation
we have.  If Simon or Pavel or someone was going all-out on getting the
new partitioning ready, that would be one thing.  But to date, nobody
has volunteered to work on it; we just know we need it.

Of course, that completely leaves aside Tom's critique of the
implementation, which sounds like it needs some work.  Trying to fit the
target table into a range partitioning mold would break with a lot of
real partitionings; for example I have several client DBs which are
partitioned active/inactive-by-date.

What about simply eliminating joins between partitioned tables by
checking which columns' constraints match exactly or are subsets?  A lot
of partitioned DBs partition everything by month, and joining two tables
which were partitioned by month would be useful by itself.

-- 
Josh Berkus
PostgreSQL Experts Inc.
www.pgexperts.com


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