On 12/08/16 15:15, Peter Eisentraut wrote:
> On 8/11/16 11:59 AM, Jeff Janes wrote:
>> Insertions and HOT-updates clear vm bits but don't increment the
>> counters that those existing parameters are compared to.
>>
>> Also, the relationship between number of updated/deleted rows and the
>> number of hint-bits cleared can be hard to predict due to possible
>> clustering of the updates into the same blocks. So it would be hard
>> to know what to set the values to.
>
> Well, the current threshold formulas aren't an exact science either.
> They just trigger autovacuum often enough relative to table size and
> activity. Just fudging in the insert and HOT update counters times some
> factor might be enough, and it would get this functionality out to all
> users without more effort.
I have a patch I wrote a while ago that does this. I haven't submitted
it yet because the documentation is lacking. I will post it over the
weekend (I had planned to do it before the commitfest anyway).
--
Vik Fearing +33 6 46 75 15 36
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
