Re: adding wait_start column to pg_locks

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Ian Lawrence Barwick <barwick(at)gmail(dot)com>
Cc: torikoshia <torikoshia(at)oss(dot)nttdata(dot)com>, Justin Pryzby <pryzby(at)telsasoft(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: adding wait_start column to pg_locks
Date: 2021-01-14 18:45:13
Message-ID: CA+TgmoYowQhMhT74AsxDib6e3LFPGvXVxVOUdP0-hMNY9c1wgw@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On Wed, Jan 13, 2021 at 10:40 PM Ian Lawrence Barwick <barwick(at)gmail(dot)com> wrote:
> It looks like the logical place to store the value is in the PROCLOCK
> structure; ...

That seems surprising, because there's one PROCLOCK for every
combination of a process and a lock. But, a process can't be waiting
for more than one lock at the same time, because once it starts
waiting to acquire the first one, it can't do anything else, and thus
can't begin waiting for a second one. So I would have thought that
this would be recorded in the PROC.

But I haven't looked at the patch so maybe I'm dumb.

--
Robert Haas
EDB: http://www.enterprisedb.com

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Zhihong Yu 2021-01-14 19:04:30 Re: Transactions involving multiple postgres foreign servers, take 2
Previous Message Robert Haas 2021-01-14 18:42:15 Re: vacuum_cost_page_miss default value and modern hardware