Re: [PATCH] Tracking statements entry timestamp in pg_stat_statements

On Sun, Apr 03, 2022 at 07:32:47AM +0300, Andrei Zubkov wrote:
> v11 attached

+       /* When requested reset only min/max statistics of an entry */ \
+       entry_counters = &entry->counters; \
+       for (int kind = 0; kind < PGSS_NUMKIND; kind++) \
+       { \
+           entry_counters->max_time[kind] = 0; \
+           entry_counters->min_time[kind] = 0; \
+       } \
[...]
+static TimestampTz
+entry_reset(Oid userid, Oid dbid, uint64 queryid, bool minmax_only)
 {
    HASH_SEQ_STATUS hash_seq;
    pgssEntry  *entry;
+   Counters   *entry_counters;

Do we really need an extra variable?  Why not simply using
entry->counters.xxx_time[kind]?

Also, I think it's better to make the macro more like function looking, so
SINGLE_ENTRY_RESET().

index f2e822acd3..c2af29866b 100644
--- a/contrib/pg_stat_statements/sql/oldextversions.sql
+++ b/contrib/pg_stat_statements/sql/oldextversions.sql
@@ -36,4 +36,12 @@ AlTER EXTENSION pg_stat_statements UPDATE TO '1.8';
 \d pg_stat_statements
 SELECT pg_get_functiondef('pg_stat_statements_reset'::regproc);

+ALTER EXTENSION pg_stat_statements UPDATE TO '1.9';
+\d pg_stat_statements
+\d pg_stat_statements_info
+SELECT pg_get_functiondef('pg_stat_statements_reset'::regproc);

I don't think this bring any useful coverage.

        Minimum time spent planning the statement, in milliseconds
        (if <varname>pg_stat_statements.track_planning</varname> is enabled,
-       otherwise zero)
+       otherwise zero), this field will contain zero until this statement
+       is planned fist time after reset performed by the
+       <function>pg_stat_statements_reset</function> function with the
+       <structfield>minmax_only</structfield> parameter set to <literal>true</literal>

I think this need some rewording (and s/fist/first).  Maybe:

Minimum time spent planning the statement, in milliseconds.

This field will be zero if <varname>pg_stat_statements.track_planning</varname>
is disabled, or if the counter has been reset using the the
<function>pg_stat_statements_reset</function> function with the
<structfield>minmax_only</structfield> parameter set to <literal>true</literal>
and never been planned since.

       <primary>pg_stat_statements_reset</primary>
      </indexterm>
@@ -589,6 +623,20 @@
       If all statistics in the <filename>pg_stat_statements</filename>
       view are discarded, it will also reset the statistics in the
       <structname>pg_stat_statements_info</structname> view.
+      When <structfield>minmax_only</structfield> is <literal>true</literal> only the
+      values of minimun and maximum execution and planning time will be reset (i.e.

Nitpicking: I would say planning and execution time, as the fields are in this
order in the view/function.