Re: [HACKERS] Replication/backup defaults

On 1/5/17 12:01 PM, Andres Freund wrote:
> On 2017-01-05 08:38:32 -0500, Peter Eisentraut wrote:
>> I also suggest making the defaults for both 20 instead of 10.  That
>> leaves enough room that almost nobody ever has to change them, whereas
>> 10 can be a bit tight for some not-outrageous installations (8 standbys
>> plus backup?).
> 
> I'm afraid we need to add initdb integration / testing for those. I mean
> we have initdb test down to 10 connections to deal with limited
> resources...

Those initdb defaults were last touched in 2005, before the use of
System V shared memory was reduced to a minimum.  It might be worth
revisiting that.  The only way to end up with a low number of connection
slots would seem to be a very low semaphore configuration.

In the build farm, I have found 6 critters that do not end up with the
100/128MB setting: sidewinder, curculio, coypu, brolga, lorikeet,
opossum.  I wonder what limitations initdb is bumping against.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services