Re: Delays between "connection received" and "connection authenticated" because of localhost entries in hba

On Tue, 2024-10-29 at 16:30 +0000, Daniel Westermann (DWE) wrote:
> we're facing a strange issue with delays between "connection received" and "connection authenticated".
>
> # select version();
>                                                               version
> -----------------------------------------------------------------------------------------------------------------------------------
>  PostgreSQL 15.6 (Ubuntu 15.6-1.pgdg22.04+1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0, 64-bit
> (1 ligne)
>
> I know, this is not the latest minor version.
>
> # \! cat /etc/os-release | head -1
> PRETTY_NAME="Ubuntu 22.04.4 LTS"
>
> What we see in the log is this (around 4 seconds delay):
>
> 2024-05-07 15:29:50.244 CEST [369909] LOG:  connection received: host=xx.xx.xx.100 port=48434
> 2024-05-07 15:29:54.518 CEST [369909] LOG:  connection authenticated: identity="xxxxxx" method=md5 (/etc/postgresql/15/main/pg_hba.conf:121)
>
> The matching line is this ( I know md5 ):
> host    all             xxxxx     xx.xx.xx.0/24            md5
>
> What we've found out so far is, that this only happens if we have a localhost(or any other hostname) line before the line matching our connection, something like this:
> host    replication     xxxxx     localhost                md5
> host    all             xxxxx     xx.xx.xx.0/24            md5

I'd "strace" such a database connection to see where the time is spent.

Yours,
Laurenz Albe