From 3465c8a8692fb628bc2710fbeedb9aeb534b0400 Mon Sep 17 00:00:00 2001 From: Fujii Masao Date: Wed, 30 Jun 2021 20:57:07 +0900 Subject: [PATCH] doc: Improve descriptions of tup_returned and tup_fetched in pg_stat_database Previously the descriptions of tup_returned and tup_fetched columns in pg_stat_database view were confusing. This commit improves them so that they represent the following formulas of those columns more accurately. * pg_stat_database.tup_returned = sum(pg_stat_all_tables.seq_tup_read) + sum(pg_stat_all_indexes.idx_tup_read) * pg_stat_database.tup_fetched = sum(pg_stat_all_tables.idx_tup_fetch) In these formulas, note that the counters for some system catalogs like pg_database shared across all databases of a cluster are excluded from the calculations of sum. Author: Masahiro Ikeda Reviewed-by: Fujii Masao Discussion: https://postgr.es/m/9eeeccdb-5dd7-90f9-2807-a4b5d2b76ca3@oss.nttdata.com --- doc/src/sgml/monitoring.sgml | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index dcbb10fb6f..07a042254f 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -3712,7 +3712,7 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i tup_returned bigint - Number of rows returned by queries in this database + Number of live rows fetched by sequential scans and index entries returned by index scans in this database @@ -3721,7 +3721,7 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i tup_fetched bigint - Number of rows fetched by queries in this database + Number of live rows fetched by index scans in this database