Horton

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

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Jacob Champion <jacob.champion@enterprisedb.com>
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: 2025-03-13T16:56:09Z
Lists: pgsql-hackers 
Hi,

On 2025-03-13 09:23:10 -0700, Jacob Champion wrote:
> On Wed, Mar 12, 2025 at 3:16 PM Jacob Champion
> <jacob.champion@enterprisedb.com> wrote:
> > I missed PAM_CONV, sorry. I'm worried about the sendAuthRequest()
> > being done there; it doesn't seem safe to potentially ereport(ERROR)
> > and longjmp through a PAM call stack?

That indeed doesn't seem safe.

I am wondering if PAM is so fundamentally incompatible with handling
interrupts / a non-blocking interface that we have little choice but to
eventually remove it...


> PAM aside... Michael, what's your level of enthusiasm for the rest of this
> patch? I was confidently, embarrassingly wrong about how CheckPAMAuth
> worked, and it makes me think I need to put this down and take a completely
> new crack at it in 19.

FWIW, I continue to think that it's better to invest in making more auth
methods non-blocking, rather than adding wait events for code that could maybe
sometimes wait on different things internally.

Greetings,

Andres Freund

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