Horton

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

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Jacob Champion <jacob.champion@enterprisedb.com>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Euler Taveira <euler.taveira@enterprisedb.com>
Date: 2024-07-09T00:04:01Z
Lists: pgsql-hackers 
On Mon, Jul 08, 2024 at 02:09:21PM -0700, Jacob Champion wrote:
> On Sun, Jun 30, 2024 at 10:48 AM Noah Misch <noah@leadboat.com> wrote:
> > That said, it
> > may be more fruitful to arrange for authentication timeout to cut through PAM
> > etc.
> 
> That seems mostly out of our hands -- the misbehaving modules are free
> to ignore our signals (and do). Is there another way to force the
> issue?

Two ways at least (neither of them cheap):
- Invoke PAM in a subprocess, and SIGKILL that process if needed.
- Modify the module to be interruptible.

> > Hanging connection slots hurt even if they lack an xmin.
> 
> Oh, would releasing the xmin not really move the needle, then?

It still moves the needle.

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