Re: [PATCH] Query Jumbling for CALL and SET utility statements

Hi,

On 8/31/22 10:05 PM, Jeremy Schneider wrote:
> On 8/31/22 12:06 PM, Andres Freund wrote:
>>> Regarding SET, the compelling use case was around "application_name"
>>> whose purpose is to provide a label in pg_stat_activity and on log
>>> lines, which can be used to improve observability and connect queries to
>>> their source in application code.
>> I wasn't saying that SET shouldn't be jumbled, just that it seems more
>> reasonable to track it only when track_utility is enabled, rather than doing
>> so even when that's disabled. Which I do think makes sense for executing a
>> prepared statement and calling a procedure, since they're really only utility
>> statements by accident.
>
> I get your point about CALL, maybe it does make sense to also exclude 
> this. 

That's a good point and i think we should track CALL whatever the value 
of pgss_track_utility is.

I think so because we are tracking function calls in all the cases 
(because "linked" to select aka not a utility) and i don't see any 
reasons why not to do the same for procedure calls.

Please find attached v2 as an attempt to do so.

With v2 we get things like:

postgres=# set pg_stat_statements.track_utility=on;
SET
postgres=# call MY_PROC(20);
CALL
postgres=# call MY_PROC(10);
CALL
postgres=# set enable_seqscan=false;
SET
postgres=# set enable_seqscan=true;
SET
postgres=# select queryid,query,calls from pg_stat_statements;
        queryid       |                  query                  | calls
---------------------+-----------------------------------------+-------
  4670878543381973400 | set pg_stat_statements.track_utility=$1 |     1
  -640317129591544054 | set enable_seqscan=$1 |     2
   492647827690744963 | select pg_stat_statements_reset() |     1
  6541399678435597534 | call MY_PROC($1) |     2

and

postgres=# set pg_stat_statements.track_utility=off;
SET
postgres=# call MY_PROC(10);
CALL
postgres=# call MY_PROC(20);
CALL
postgres=# set enable_seqscan=true;
SET
postgres=# set enable_seqscan=false;
SET
postgres=# select queryid,query,calls from pg_stat_statements;
        queryid       |                  query                  | calls
---------------------+-----------------------------------------+-------
  4670878543381973400 | set pg_stat_statements.track_utility=$1 |     1
   492647827690744963 | select pg_stat_statements_reset() |     1
  6541399678435597534 | call MY_PROC($1) |     2
(3 rows)

> It might also be worth a small update to the doc for track_utility 
> about how it behaves, in this regard.
>
> https://www.postgresql.org/docs/14/pgstatstatements.html#id-1.11.7.39.9
>
> Example updated sentence:
> > |pg_stat_statements.track_utility| controls whether <<most>> utility 
> commands are tracked by the module. Utility commands are all those 
> other than |SELECT|, |INSERT|, |UPDATE| and |DELETE| <<, but this 
> parameter does not disable tracking of PREPARE, EXECUTE or CALL>>. The 
> default value is |on|. Only superusers can change this setting.

Agree, wording added to v2.

Regards,

-- 
Bertrand Drouvot
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