Re: [PATCH] Addition of some trivial auto vacuum logging

Royce Ausburn <royce(dot)ml(at)inomial(dot)com> writes:
> The attached patch adds extra detail the the existing autovacuum log message that is emitted when the log_autovacuum_min_duration threshold is met, exposing the unremovable dead tuple count similar to what you get from VACUUM VERBOSE.

> Sample log output (my addition in bold):

> LOG: automatic vacuum of table "test.public.test": index scans: 0
> pages: 0 removed, 5 remain
> tuples: 0 removed, 1000 remain, 999 dead but not removable
> system usage: CPU 0.00s/0.00u sec elapsed 0.00 sec

This proposal seems rather ill-designed. In the first place, these
numbers are quite unrelated to vacuum duration, and in the second place,
most people who might need the info don't have that setting turned on
anyway.

I wonder whether it wouldn't be more helpful to have a pg_stat_all_tables
column that reports the number of unremovable tuples as of the last
vacuum. I've been known to object to more per-table stats counters
in the past on the basis of space required, but perhaps this one would
be worth its keep.

regards, tom lane