diff options
| author | Fujii Masao | 2021-06-30 11:57:07 +0000 |
|---|---|---|
| committer | Fujii Masao | 2021-06-30 11:57:07 +0000 |
| commit | 3465c8a8692fb628bc2710fbeedb9aeb534b0400 (patch) | |
| tree | 8dd124ec49c3453169de39a34076963acabbf6e9 | |
| parent | 61d599ede7424d88bbd4006b968bae366b6b9f5d (diff) | |
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
| -rw-r--r-- | doc/src/sgml/monitoring.sgml | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index dcbb10fb6ff..07a042254f9 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 <structfield>tup_returned</structfield> <type>bigint</type> </para> <para> - 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 </para></entry> </row> @@ -3721,7 +3721,7 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i <structfield>tup_fetched</structfield> <type>bigint</type> </para> <para> - Number of rows fetched by queries in this database + Number of live rows fetched by index scans in this database </para></entry> </row> |