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	Wed, 13 Jan 2021 18:49:25 -0500
From: Tom Lane <tgl@sss.pgh.pa.us>
To: James Coleman <jtc331@gmail.com>
cc: Alvaro Herrera <alvherre@alvh.no-ip.org>,
        Michael Paquier <michael@paquier.xyz>,
        David Johnston <david.g.johnston@gmail.com>,
        PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>,
        Andres Freund <andres@anarazel.de>
Subject: Re: [DOC] Document concurrent index builds waiting on each other
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Comments: In-reply-to James Coleman <jtc331@gmail.com>
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James Coleman <jtc331@gmail.com> writes:
> On Wed, Jan 13, 2021 at 5:00 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> [ raised eyebrow ]  Surely REINDEX and VACUUM can't run on the same
>> table at the same time.

> + Like any long-running transaction, <command>CREATE INDEX</command> on a
> + table can affect which tuples can be removed by concurrent
> + <command>VACUUM</command> on any other table.

> The "on a table" is the table on which the REINDEX/CREATE INDEX is
> occurring. The "any other table" is where VACUUM might run.

I still think it'd be just as clear without the auxiliary clauses,
say

+ Like any long-running transaction, <command>CREATE INDEX</command>
+ can affect which tuples can be removed by concurrent
+ <command>VACUUM</command> operations.

			regards, tom lane