Re: Native DB replication for PG

On Fri, Apr 30, 2010 at 11:33 PM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:
> On Fri, Apr 30, 2010 at 9:02 PM, Greg Smith <greg(at)2ndquadrant(dot)com> wrote:
>> Joshua D. Drake wrote:
>>>
>>> On Fri, 2010-04-30 at 13:42 -0700, Gauthier, Dave wrote:
>>>
>>>>>>
>>>>>> If I had to plan server deployments for the next year (and I do) I'd
>>>>>> be sticking with pg 8.3 and a proven replication engine.  Next summer
>>>>>>
>>>>>
>>>>> Surely you mean 8.4? :-)
>>>>>
>>>
>>> No, I would buy the 8.3 argument as well. Depending on your conservative
>>> level. 8.4 is fine and all but 8.3 is about as rock solid as it gets.
>>
>> Unless you don't vacuum enough on a bigger database, run out of FSM pages,
>> and the whole vacuum strategy goes to hell afterwards.  I would say that
>> running into that issue is *probable* for an 8.3 install of any significant
>> size, whereas the odds of running into a regression in 8.4 relative to 8.3
>> is pretty low.  The whole "the older version is always more reliable" mantra
>> doesn't make sense when you've got a major known issue in the older release
>> that just goes away by using the newer one, and I feel that's the case with
>> 8.4 vs. 8.3.
>
> Exactly.  I've got a LOT of effort involved in free space map sizing
> and monitoring on 8.3.  However, for me it's no longer a serious
> problem.  Free space map is 10 to 20x what it needs to be on my
> machines now and works like a charm in 8.3.  8.4 randomly crashed, and
> honestly I can't afford to test and help fix it right now.  This
> summer I can and will either with 9.0 or 8.4.  But we're talking db
> crashes that were happening once every 2 to 3 weeks for me, so testing
> it takes a lot of time for me.  And I can't do it with my productions
> servers.  I tested 8.4 what I thought was fairly hardly last year only
> to have 8.4.1 die under the same load that 8.3 handled without a
> problem, and reverted to the known working version putting testing
> 8.4.1 on hold.
>
> So to ME, the choice is a fully functional 8.3 installation that has
> NO problems with free space map because of configuration choices, or
> an 8.4 with a known (to me) issue of crashing and dying.

Note that it could well be fixed by now, and I'll first test either
9.0 beta or 8.4.latest. as slony slaves before I go any further.