Re: proposal: Set effective_cache_size to greater of .conf value, shared_buffers

On 09/05/2013 03:30 PM, Merlin Moncure wrote:

>> Standard advice we've given in the past is 25% shared buffers, 75%
>> effective_cache_size.  Which would make EFS *3X* shared_buffers, not 4X.
>>  Maybe we're changing the conventional calculation, but I thought I'd
>> point that out.
> 
> This was debated upthread.

Actually, no, it wasn't.  Tom threw out a suggestion that we use 4X for
historical reasons.  That's all, there was no discussion.

So, my point stands: our historical advice has been to set EFS to 75% of
RAM.  Maybe we're changing that advice, but if so, let's change it.
Otherwise 3X makes more sense.

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