Re: Redesigning checkpoint_segments

On 03/02/2015 05:38 AM, Stephen Frost wrote:
> * Robert Haas (robertmhaas(at)gmail(dot)com) wrote:
>> On Mon, Mar 2, 2015 at 6:43 AM, Heikki Linnakangas <hlinnaka(at)iki(dot)fi> wrote:
>>> On 02/26/2015 01:32 AM, Josh Berkus wrote:
>>>> But ... I thought we were going to raise the default for max_wal_size to
>>>> something much higher, like 1GB? That's what was discussed on this
>>>> thread.
>>>
>>> No conclusion was reached on that. Me and some others were against raising
>>> the default, while others were for it.
>>
>> I guess that's a fair summary of the discussion, but I still think
>> it's the wrong conclusion. Right now, you can't get reasonable write
>> performance with PostgreSQL even on tiny databases (a few GB) without
>> increasing that setting by an order of magnitude. It seems an awful
>> shame to go to all the work to mitigate the downsides of setting a
>> large checkpoint_segments and then still ship a tiny default setting.
>> I've got to believe that the number of people who think 128MB of WAL
>> is tolerable but 512MB or 1GB is excessive is almost nobody. Disk
>> sizes these days are measured in TB.
>
> +1. I thought the conclusion had actually been in favor of the change,
> though there had been voices for and against.

That was the impression I had too, which was why I was surprised. The
last post on the topic was one by Robert Haas, agreeing with me on a
value of 1GB, and there were zero objections after that.

--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com