Re: HOT pgbench results

Tom Lane wrote:
> Heikki Linnakangas <heikki@enterprisedb.com> writes:
>>         unpatched    HOT    
>> autovacuums    116        43
>> autoanalyzes    139        60
> 
>> HOT greatly reduces the number of vacuums needed. That's good, that's
>> where the gains in throughput in longer I/O bound runs comes from.
> 
> But surely failing to auto-analyze after a HOT update is a bad thing.

Hmm, I suppose. I don't think we've spend any time thinking about how to
factor in HOT updates into the autovacuum and autoanalyze formulas yet.

I'd argue that HOT updates are not as significant as cold ones from
statistics point of view, though, because they don't change indexed
columns. HOT-updated fields are not likely used as primary search quals.

--  Heikki Linnakangas EnterpriseDB   http://www.enterprisedb.com