Horton

Re: [PATCH] pg_stat_activity: make slow/hanging authentication more visible

Jacob Champion <jacob.champion@enterprisedb.com>

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From: Jacob Champion <jacob.champion@enterprisedb.com>
To: Andres Freund <andres@anarazel.de>
Cc: Michael Paquier <michael@paquier.xyz>, Robert Haas <robertmhaas@gmail.com>, Noah Misch <noah@leadboat.com>, Andrew Dunstan <andrew@dunslane.net>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Euler Taveira <euler.taveira@enterprisedb.com>, Daniel Gustafsson <daniel@yesql.se>
Date: 2025-03-05T00:53:14Z
Lists: pgsql-hackers 
On Tue, Mar 4, 2025 at 4:26 PM Jacob Champion
<jacob.champion@enterprisedb.com> wrote:
> But attaching to that injection point succeeded above, for us to have
> gotten to this point... Does that error message indicate that the
> point itself doesn't exist, or that nothing is currently waiting?

Looks like the latter. With the following diff I can reproduce locally:

    --- a/src/backend/utils/init/postinit.c
    +++ b/src/backend/utils/init/postinit.c
    @@ -730,6 +730,7 @@ InitPostgres(const char *in_dbname, Oid dboid,
            if (!bootstrap)
            {
                    pgstat_bestart_initial();
    +               pg_usleep(1000000);
                    INJECTION_POINT("init-pre-auth");
            }

So I've misunderstood the API. I should have added a background
version of $node->wait_for_event(), or similar.

I'll work on a fix, but it probably won't be fast since I need to
learn more about the injection points architecture. The test may need
to be disabled, or the patch backed out, depending on how painful the
flake is for everybody.

Thanks, and sorry,
--Jacob

Commits

  1. Fix race condition in TAP test 007_pre_auth

  2. Split pgstat_bestart() into three different routines

  3. backport: Extend background_psql() to be able to start asynchronously

  4. backport: Improve handling of empty query results in BackgroundPsql

  5. Improve handling of empty query results in BackgroundPsql::query()

  6. Extend Cluster.pm's background_psql() to be able to start asynchronously

  7. dblink: Replace WAIT_EVENT_EXTENSION with custom wait events