Horton

Re: ALTER tbl rewrite loses CLUSTER ON index

Justin Pryzby <pryzby@telsasoft.com>

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From: Justin Pryzby <pryzby@telsasoft.com>
To: Amit Langote <amitlangote09@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Michael Paquier <michael@paquier.xyz>, Alvaro Herrera <alvherre@2ndquadrant.com>, pgsql-hackers@postgresql.org
Date: 2020-03-16T13:27:31Z
Lists: pgsql-hackers

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On Mon, Mar 16, 2020 at 04:01:42PM +0900, Amit Langote wrote:
> I came across a commit that recently went in:
> 
> commit 1cc9c2412cc9a2fbe6a381170097d315fd40ccca
> Author: Peter Eisentraut <peter@eisentraut.org>
> Date:   Fri Mar 13 11:28:11 2020 +0100
> 
>     Preserve replica identity index across ALTER TABLE rewrite
> 
> which fixes something very similar to what we are trying to with this
> patch.  The way it's done looks to me very close to what you are
> telling.  I have updated the patch to be similar to the above fix.

Yes, I noticed it too.

Should we use your get_index_isclustered more widely ?

Also, should we call it "is_index_clustered", since otherwise it sounds alot
like "+get_index_clustered" (without "is"), which sounds like it takes a table
and returns which index is clustered.  That might be just as useful for some of
these callers.

-- 
Justin

Commits

  1. Refactor cluster.c to use new routine get_index_isclustered()

  2. Preserve clustered index after rewrites with ALTER TABLE

  3. Preserve replica identity index across ALTER TABLE rewrite

  4. Remove RangeIOData->typiofunc

  5. Preserve pg_index.indisclustered across REINDEX CONCURRENTLY