Thread: Indexes documentation bug

Indexes documentation bug

From
Kouber Saparev
Date:
Hello,

I believe there is an error within this sentence in section https://www.postgresql.org/docs/current/monitoring-stats.html#MONITORING-PG-STAT-USER-FUNCTIONS-VIEW

"Therefore, a bitmap scan increments the pg_stat_all_indexes.idx_tup_read count(s) for the index(es) it uses, and it increments the pg_stat_all_tables.idx_tup_fetch count for the table, but it does not affect pg_stat_all_indexes.idx_tup_fetch."

There is repeated mentioning of pg_stat_all_indexes.idx_tup_fetch while I suppose one should read  pg_stat_all_indexes.idx_scan instead the second time. I.e. bitmap scans do not increment idx_scan.

Regards,
--
Kouber Saparev

Re: Indexes documentation bug

From
Tom Lane
Date:
Kouber Saparev <kouber@gmail.com> writes:
> I believe there is an error within this sentence in section
> https://www.postgresql.org/docs/current/monitoring-stats.html#MONITORING-PG-STAT-USER-FUNCTIONS-VIEW

> "Therefore, a bitmap scan increments the
> pg_stat_all_indexes.idx_tup_read count(s)
> for the index(es) it uses, and it increments the pg_stat_all_tables.
> idx_tup_fetch count for the table, but it does not affect
> pg_stat_all_indexes.idx_tup_fetch."

> There is repeated mentioning of pg_stat_all_indexes.idx_tup_fetch while I
> suppose one should read  pg_stat_all_indexes.idx_scan instead the second
> time. I.e. bitmap scans do not increment idx_scan.

Um ... you did notice that the mentions of idx_tup_fetch apply to two
different views, pg_stat_all_tables vs pg_stat_all_indexes?

            regards, tom lane



Re: Indexes documentation bug

From
Kouber Saparev
Date:
My bad, yes indeed, the view is different.

На пн, 4.04.2022 г. в 17:01 ч. Tom Lane <tgl@sss.pgh.pa.us> написа:
Kouber Saparev <kouber@gmail.com> writes:
> I believe there is an error within this sentence in section
> https://www.postgresql.org/docs/current/monitoring-stats.html#MONITORING-PG-STAT-USER-FUNCTIONS-VIEW

> "Therefore, a bitmap scan increments the
> pg_stat_all_indexes.idx_tup_read count(s)
> for the index(es) it uses, and it increments the pg_stat_all_tables.
> idx_tup_fetch count for the table, but it does not affect
> pg_stat_all_indexes.idx_tup_fetch."

> There is repeated mentioning of pg_stat_all_indexes.idx_tup_fetch while I
> suppose one should read  pg_stat_all_indexes.idx_scan instead the second
> time. I.e. bitmap scans do not increment idx_scan.

Um ... you did notice that the mentions of idx_tup_fetch apply to two
different views, pg_stat_all_tables vs pg_stat_all_indexes?

                        regards, tom lane