Re: On login trigger: take three - Mailing list pgsql-hackers

From Robert Haas
Subject Re: On login trigger: take three
Date
Msg-id CA+TgmoZH=rJg_HGbzJSQng4UeO5V6AkMfnDZk-KZ9sAQppjNAg@mail.gmail.com
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In response to Re: On login trigger: take three  (Daniel Gustafsson <daniel@yesql.se>)
Responses Re: On login trigger: take three
List pgsql-hackers
Sorry to have gone dark on this for a long time after having been
asked for my input back in March. I'm not having a great time trying
to keep up with email, and the threads getting split up makes it a lot
worse for me.

On Fri, Sep 29, 2023 at 6:15 AM Daniel Gustafsson <daniel@yesql.se> wrote:
> Running the same pgbench command on my laptop looking at the average connection
> times, and the averaging that over five runs (low/avg/high) I see ~5% increase
> over master with the patched version (compiled without assertions and debug):
>
> Patched event_triggers on:  6.858 ms/7.038 ms/7.434 ms
> Patched event_triggers off: 6.601 ms/6.958 ms/7.539 ms
> Master:                     6.676 ms/6.697 ms/6.760 ms

This seems kind of crazy to me. Why does it happen? It sounds to me
like we must be doing a lot of extra catalog access to find out
whether there are any on-login event triggers. Like maybe a sequential
scan of pg_event_trigger. Maybe we need to engineer a way to avoid
that. I don't have a brilliant idea off-hand, but I feel like there
should be something we can do. I think a lot of users would say that
logins on PostgreSQL are too slow already.

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



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