public inbox for [email protected]  

help / color / mirror / Atom feed

From: Achilleas Mantzios - cloud <[email protected]>
To: Tom Lane <[email protected]>
Cc: Tomas Vondra <[email protected]>
Cc: [email protected]
Cc: P.Groidis <[email protected]>
Subject: Re: tds_fdw : Severe performance degradation from postgresql 10.23 to 16.4
Date: Wed, 13 Nov 2024 09:14:18 +0200
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>


On 11/12/24 21:37, Tom Lane wrote:
> Achilleas Mantzios <[email protected]> writes:
>> Our sysadm created the system debian Debian GNU/Linux 12 (bookworm)with
>> postgres as user 1000. Now at some point we realized that whenever we
>> run a pgsql cluster with another user (I found that after spending two
>> good days testing), the above query runs in about 1 second. With user
>> postgres 1000 in 30 seconds. As you saw the perf output are completely
>> different.
> Don't recall details offhand, but in some situations where the calling
> SQL user doesn't have permissions to read particular columns, the
> planner will not consult statistics for those columns.  That can lead
> to a different, less optimal plan being used.  Maybe something like
> that is happening here?

Thank you Tom,

In all runs of this query the user is postgres (superuser). Besides, 
this is just a simple query run on a FOREIGN TABLE living in a MS SQL 
Server.

>
> 			regards, tom lane

view thread (13+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected], [email protected]
  Subject: Re: tds_fdw : Severe performance degradation from postgresql 10.23 to 16.4
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox