Re: Diagnosing a massive toast file

As a follow up, n_dead_tup from pg_stat_sys_tables for this TOAST table is
7447444, live tuples, 623982, and tup_del 20823469. vacuum_count is 0.

Why can't I free those rows up?

On Mon, Aug 5, 2019 at 10:00 AM Wells Oliver <wells(dot)oliver(at)gmail(dot)com> wrote:

> Appreciate it, guys. I understand it being large isn't itself a problem,
> but relative to history and the lack of real changes, it's just strange and
> I'd like to better understand what is going on...
>
> I tracked it down to a specific table, and then doing a VACUUM FULL
> ANALYZE on that table yields: 108765 dead row versions cannot be removed
> yet.
>
> Which strikes me as odd. Any reading I can do to better understand why so
> many (relative to the overall table size) dead rows cannot be removed?
>
>
> On Mon, Aug 5, 2019 at 9:49 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
>> Wells Oliver <wells(dot)oliver(at)gmail(dot)com> writes:
>> > Yeah, trying to figure out what actual table is clearly in need of a
>> vacuum
>> > b/c of the size of that toast table.
>>
>> Something like
>>
>> select relname from pg_class
>> where reltoastrelid = 'pg_toast.pg_toast_NNN'::regclass;
>>
>> (or, if you have potential duplicate relnames, select oid::regclass ...)
>>
>> The mere fact that it's big does not indicate a problem, though.
>>
>> regards, tom lane
>>
>
>
> --
> Wells Oliver
> wells(dot)oliver(at)gmail(dot)com <wellsoliver(at)gmail(dot)com>
>

--
Wells Oliver
wells(dot)oliver(at)gmail(dot)com <wellsoliver(at)gmail(dot)com>