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From: Sami Imseih <samimseih@gmail.com>
Date: Mon, 24 Mar 2025 20:51:14 -0500
Message-ID: <CAA5RZ0t4XQ_SANiJ5VfuoKnAuxMaY2ggQWoGKkHo+U2H+Sh-Sw@mail.gmail.com>
Subject: Re: query_id: jumble names of temp tables for better
 pg_stat_statement UX
To: Michael Paquier <michael@paquier.xyz>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Christoph Berg <myon@debian.org>, 
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, ma lz <ma100@hotmail.com>
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> So your idea to use the relation name in eref while skipping the
> column list looks kind of promising.  Per se the attached.  Thoughts?

I feel really uneasy about this behavior becoming the default.
I can bet there are some users which run common queries across
different schemas ( e.g. multi-tenancy ) will consider this behavior a
regression
in pg_stat_statements as now all their common queries have been merged
into a single entry.

For example, I have seen users add comments to SQLs to differentiate
similar SQLs coming from different tenants. This patch makes this no longer a
somewhat decent workaround  to overcome the fact that pg_stat_statements
does not track schemas or search path.

```
select pg_stat_statements_reset();

set search_path = s1;
select /*+ user s1 */ * from foo;

set search_path = s2;
select /*+ user s2 */  * from foo;

reset search_path;
select userid, queryid, query, calls from public.pg_stat_statements;

test=# select userid, queryid, query, calls from public.pg_stat_statements;
 userid |       queryid        |               query               | calls
--------+----------------------+-----------------------------------+-------
     10 |  1788423388555345932 | select /*+ user s1 */ * from foo  |     2
     10 | -8935568138104064674 | select pg_stat_statements_reset() |     1
     10 | -8663970364987885379 | set search_path = $1              |     2
     10 | -6563543739552933350 | reset search_path                 |     1
(4 rows)
```

--
Sami Imseih
Amazon Web Services (AWS)