Re: [DOC] Document concurrent index builds waiting on each other

On Wed, Jan 13, 2021 at 5:00 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> James Coleman <jtc331@gmail.com> writes:
> > On Wed, Jan 13, 2021 at 4:29 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> but the antecedent of "a table" is a bit unclear; people might
> >> wonder if it means the table being reindexed.
>
> > It does mean the table being reindexed; the last phrase says "any
> > table" meaning "any other table".
>
> [ 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.

James