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

On Sun, Sep 29, 2019 at 9:24 PM Michael Paquier <michael(at)paquier(dot)xyz> wrote:
>
> On Sat, Sep 28, 2019 at 10:22:28PM -0300, Alvaro Herrera wrote:
> > I always thought that create index concurrently was prevented from
> > running concurrently in a table by the ShareUpdateExclusive lock that's
> > held during the operation.
>
> REINDEX CONCURRENTLY and CIC can deadlock while waiting for each other
> to finish after their validation phase, see:
> https://www.postgresql.org/message-id/20190507030756.GD1499@paquier.xyz
> https://www.postgresql.org/message-id/20190507032543.GH1499@paquier.xyz

Michael,

Thanks for the cross-link. Do you think this would be valuable to
document at the same time? Or did you just want to ensure we were also
aware of this particular downfall? If the latter, I appreciate it,
it's helpful info. If the latter, let me know, and I'll try to update
the patch.

Thanks,
James