Re: Redesigning checkpoint_segments

Heikki Linnakangas <hlinnakangas@vmware.com> wrote:
> On 02/02/2015 04:21 PM, Andres Freund wrote:
>> On 2015-02-02 08:36:41 -0500, Robert Haas wrote:
>>> Also, I'd like to propose that we set the default value of
>>> max_checkpoint_segments/checkpoint_wal_size to something at
>>> least an order of magnitude larger than the current default
>>> setting.
>>
>> +1
>
> I don't agree with that principle. I wouldn't mind increasing it
> a little bit, but not by an order of magnitude.

Especially without either confirming that this effect is no longer
present, or having an explanation for it:

http://www.postgresql.org/message-id/4A44E58C0200002500027FCF@gw.
wicourts.gov

Note that Greg Smith found the same effect on a machine without any
write caching, which shoots down my theory, at least on his
machine:

http://www.postgresql.org/message-id/flat/4BCCDAD5.3040101@2ndquadrant.com#4BCCDAD5.3040101@2ndquadrant.com

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company