Re: Re: autovacuum vacuum creates bad statistics for planner when it log index scans: 0 - Mailing list pgsql-performance

From Tom Lane
Subject Re: Re: autovacuum vacuum creates bad statistics for planner when it log index scans: 0
Date
Msg-id 32562.1402020121@sss.pgh.pa.us
Whole thread Raw
In response to Re: autovacuum vacuum creates bad statistics for planner when it log index scans: 0  (tim_wilson <tim.wilson@telogis.com>)
List pgsql-performance
tim_wilson <tim.wilson@telogis.com> writes:
> Thanks for you response Tom:
> but what does index_scans:0 mean? vs index scans: 1?

I believe the former means that VACUUM found no removable tuples, so it
had no need to make any passes over the table's indexes.

(Ordinarily you wouldn't see the number of scans as more than 1, unless
VACUUM removed quite a lot of dead tuples, more than it could remember
within maintenance_work_mem; in which case it would make multiple passes
over the indexes to remove index entries.)

            regards, tom lane


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