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* pg_autovacuum misinterpreting reltuples?
@ 2004-04-30 13:45 Jeff Boes <jboes@nexcerpt.com>
0 siblings, 1 reply; 2+ messages in thread
From: Jeff Boes @ 2004-04-30 13:45 UTC (permalink / raw)
To: pgsql-hackers
We noticed that one of our high-volume insert tables was being vacuumed
every time pg_autovacuum woke up. (I"m running it with the default
threshold values, and a 900-second sleep cycle.) The table has a few
million rows in it. With "debug = 2" on, here's what the pg_autovacuum
log reports for this table:
[2004-04-30 09:32:11 AM] table name: nexcerpt."public"."links"
[2004-04-30 09:32:11 AM] relid: 1014188; relisshared: 0
[2004-04-30 09:32:11 AM] reltuples: 3; relpages: 118888
Note that "reltuples" is being reported as "3", which seems a bit low. Aha!
# select reltuples from pg_class where relname = 'links';
reltuples
-------------
3.32127e+06
(1 row)
Is it possible that pg_autovacuum sees this value as "3"? Or is it just
mis-formatting the value in the log?
--
Jeff Boes vox 269.226.9550 ext 24
Database Engineer fax 269.349.9076
Nexcerpt, Inc. http://www.nexcerpt.com
...Nexcerpt... Extend your Expertise
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: pg_autovacuum misinterpreting reltuples?
@ 2004-05-05 18:25 Matthew T. O'Connor <matthew@zeut.net>
parent: Jeff Boes <jboes@nexcerpt.com>
0 siblings, 0 replies; 2+ messages in thread
From: Matthew T. O'Connor @ 2004-05-05 18:25 UTC (permalink / raw)
To: Jeff Boes <jboes@nexcerpt.com>; +Cc: pgsql-hackers
Jeff Boes wrote:
> We noticed that one of our high-volume insert tables was being vacuumed
> every time pg_autovacuum woke up. (I"m running it with the default
> threshold values, and a 900-second sleep cycle.) The table has a few
> million rows in it. With "debug = 2" on, here's what the pg_autovacuum
> log reports for this table:
>
> [2004-04-30 09:32:11 AM] table name: nexcerpt."public"."links"
> [2004-04-30 09:32:11 AM] relid: 1014188; relisshared: 0
> [2004-04-30 09:32:11 AM] reltuples: 3; relpages: 118888
>
> Note that "reltuples" is being reported as "3", which seems a bit low. Aha!
>
> # select reltuples from pg_class where relname = 'links';
> reltuples
> -------------
> 3.32127e+06
> (1 row)
>
> Is it possible that pg_autovacuum sees this value as "3"? Or is it just
> mis-formatting the value in the log?
Yes. This is a known bug inside of pg_autovacuum, it is fixed inside of
CVS, and will be released with 7.4.3 (whenever that happens, hopefully
soon since I'm getting lots of reports for this bug). Please downlooad
pg_autovacuum from CVS and compile by hand for the time being.
Matthew O'Connor
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2004-04-30 13:45 pg_autovacuum misinterpreting reltuples? Jeff Boes <jboes@nexcerpt.com>
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