On 04/11/2019 06:20 PM, Tom Lane wrote:
> rihad <rihad(at)mail(dot)ru> writes:
>> Thanks! Our autovacuum_work_mem = 1GB, so this probably means any space
>> would be available for reuse only at the end of the vacuum?
> It's six bytes per dead tuple, last I checked ... you do the math.
>
>> Are there
>> any downsides in decreasing it to, say, 64MB? I see only pluses )
> Well, usually people prefer to minimize the number of passes over
> the indexes.
>
> regards, tom lane
> .
>
Yup, it's just that n_dead_tuples grows by several hundred thousand (the
table sees much much more updates than inserts) and disk usage grows
constantly between several hour long vacuum runs. Running vacuum full
isn't an option.