From 39712d1184f184ee348e701ca794fdf8d6a51510 Mon Sep 17 00:00:00 2001 From: Neil Conway Date: Tue, 15 May 2007 15:52:40 +0000 Subject: [PATCH] Make a few marginal improvements to the documentation for the AV launcher daemon. --- doc/src/sgml/maintenance.sgml | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml index d71f796851..de8df507ea 100644 --- a/doc/src/sgml/maintenance.sgml +++ b/doc/src/sgml/maintenance.sgml @@ -1,4 +1,4 @@ - + Routine Database Maintenance Tasks @@ -485,7 +485,9 @@ HINT: Stop the postmaster and use a standalone backend to VACUUM in "mydb". multi-process architecture: there is a daemon process, called the autovacuum launcher, which is in charge of starting an autovacuum worker process on each database every - seconds. + seconds. On each run, the worker + process checks each table within that database, and VACUUM or + ANALYZE commands are issued as needed. @@ -493,7 +495,7 @@ HINT: Stop the postmaster and use a standalone backend to VACUUM in "mydb". processes that may be running at any time, so if the VACUUM and ANALYZE work to do takes too long to run, the deadline may be failed to meet for other databases. Also, if a particular database - takes long to process, more than one worker may be processing it + takes a long time to process, more than one worker may be processing it simultaneously. The workers are smart enough to avoid repeating work that other workers have done, so this is normally not a problem. Note that the number of running workers does not count towards the - On each run, the worker process checks each table within that database, and - VACUUM or ANALYZE commands are - issued as needed. - - - Tables whose relfrozenxid value is more than autovacuum_freeze_max_age transactions old are always vacuumed. Otherwise, @@ -591,19 +587,19 @@ analyze threshold = analyze base threshold + analyze scale factor * number of tu The contents of the pg_autovacuum system - catalog are currently not saved in database dumps created by - the tools pg_dump and pg_dumpall. - If you want to preserve them across a dump/reload cycle, make sure you - dump the catalog manually. + catalog are currently not saved in database dumps created by the + tools pg_dump and pg_dumpall. If + you want to preserve them across a dump/reload cycle, make sure + you dump the catalog manually. - When multiple workers are running, the cost limit is "balanced" among all - the running workers, so that the total impact on the system is the same, - regardless of the number of workers actually running. + When multiple workers are running, the cost limit is + balanced among all the running workers, so that the + total impact on the system is the same, regardless of the number + of workers actually running. - -- 2.11.0