Re: Support reset of Shared objects statistics in "pg_stat_reset" function

On Fri, 6 Aug 2021 at 13:56, Sadhuprasad Patro <b(dot)sadhu(at)gmail(dot)com> wrote:
>
> Hi,
>
> The call to “pg_stat_reset“ does reset all the statistics data for
> tables belonging to the current database but does not take care of
> shared tables e.g pg_attribute. Similarly to reset the statistics at
> table level, the call to “pg_stat_reset_single_table_counters“ does
> not take care of shared tables.
>
> When we reset all the statistics using the call “pg_stat_reset”, the
> postgres process internally makes calls to “
> pgstat_recv_resetcounter“, which resets the statistics of all the
> tables of the current database. But not resetting the statistics of
> shared objects using database ID as 'InvalidOid'.
>
> The same fix is made in the internal function
> “pgstat_recv_resetsinglecounter“ to reset the statistics for the
> shared table for the call "pg_stat_reset_single_table_counters".
>

Hi Sadhu,
I was looking into the patch. I will look more in the coming days. I
have below comments.

1. Please can you share the test case to reproduce the issue and
please add the test case in patch.

2. diff --git a/src/backend/postmaster/pgstat.c
b/src/backend/postmaster/pgstat.c
index 56755cb92b..f272931276 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -5092,7 +5092,6 @@ pgstat_recv_resetcounter(PgStat_MsgResetcounter
*msg, int len)
* Lookup the database in the hashtable. Nothing to do if not there.
*/
dbentry = pgstat_get_db_entry(msg->m_databaseid, false);
-
if (!dbentry)
return;

I think, by mistake, you removed one line in the patch.

--
Thanks and Regards
Mahendra Singh Thalor
EnterpriseDB: http://www.enterprisedb.com