Horton

Re: ALTER tbl rewrite loses CLUSTER ON index (consider moving indisclustered to pg_class)

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, Amit Langote <amitlangote09@gmail.com>, pgsql-hackers@postgresql.org
Date: 2020-02-28T23:26:04Z
Lists: pgsql-hackers 
Justin Pryzby <pryzby@telsasoft.com> writes:
> I think the attached is 80% complete (I didn't touch pg_dump).
> One objection to this change would be that all relations (including indices)
> end up with relclustered fields, and pg_index already has a number of bools, so
> it's not like this one bool is wasting a byte.
> I think relisclustered was a's clever way of avoiding that overhead (c0ad5953).
> So I would be -0.5 on moving it to pg_class..
> But I think 0001 and 0002 are worthy.  Maybe the test in 0002 should live
> somewhere else.

0001 has been superseded by events (faade5d4c), so the cfbot is choking
on that one's failure to apply, and not testing any further.  Please
repost without 0001 so that we can get this testing again.

			regards, tom lane

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