Horton

Re: On partitioning

Andres Freund <andres@2ndquadrant.com>

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From: Andres Freund <andres@2ndquadrant.com>
To: Hannu Krosing <hannu@2ndQuadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Alvaro Herrera <alvherre@2ndquadrant.com>, Greg Stark <stark@mit.edu>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2014-09-01T15:52:25Z
Lists: pgsql-hackers 
On 2014-08-29 20:12:16 +0200, Hannu Krosing wrote:
> It would need to replace plain tid (pagenr, tupnr) with triple of (partid,
> pagenr, tupnr).
> 
> Cross-partition indexes are especially needed if we want to allow putting
> UNIQUE constraints on non-partition-key columns.

I actually don't think this is necessary. I'm pretty sure that you can
build an efficient and correct version of unique constraints with
several underlying indexes in different partitions each. The way
exclusion constraints are implemented imo is a good guide.

I personally think that implementing cross partition indexes has a low
enough cost/benefit ratio that I doubt it's wise to tackle it anytime
soon.

Greetings,

Andres Freund

-- 
 Andres Freund	                   http://www.2ndQuadrant.com/
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