Re: why is max standby delay only 35 minutes?

On Fri, Mar 4, 2011 at 18:19, Robert Treat <rob(at)xzilla(dot)net> wrote:
> On Fri, Mar 4, 2011 at 2:03 AM, Magnus Hagander <magnus(at)hagander(dot)net> wrote:
>> On Fri, Mar 4, 2011 at 04:00, Robert Treat <rob(at)xzilla(dot)net> wrote:
>>> I have a server where I wanted to do some reporting on a standby, and
>>> wanted to set the max standby delay to 1 hour. upon doing that, i get
>>> this in the logs:
>>>
>>> 2011-03-03 21:20:08 EST () [2656]: [2-1] user=,db=LOG:  received
>>> SIGHUP, reloading configuration files
>>> 2011-03-03 21:20:08 EST () [2656]: [3-1] user=,db=LOG:  3600000 is
>>> outside the valid range for parameter "max_standby_archive_delay" (-1
>>> .. 2147483)
>>>
>>> The error is clear enough, but is there some reason that the parameter
>>> is coded this way? istm people are much more likely to want to be able
>>> to set the precision in hours than in microseconds.
>>>
>>> OTOH, maybe it's a bug? The default resolution is in milliseconds, and
>>> you can't set it to anything less than that (afaict). I asked on irc
>>> and the consensus seemed to be that the internal representation is
>>> off, are we missing something?
>>
>> See this thread here:
>> http://archives.postgresql.org/pgsql-hackers/2010-12/msg01517.php
>>
>> Summary: should be fixed, but it needs to be verified that it works
>> across all possible codepaths. It's not an issue with just
>> max_standby_delay.
>>
>
> Thanks for the pointer!  I guess the next question is if anyone is
> working on that, and/or what would need to be done to know we've done
> a satisfactory job of verifying nothing breaks across all codepaths
> were someone to take on the job?

I have it sitting on my list somewhere, but I haven't actually started
doing anything...

A good start is to just change the code (likely quite easy) and then
test all the different ways that you can set and reset and read the
values of a guc (set/show/pg_settings/anythingelseyoucanthinkof), that
it's passed properly across exec_backend etc - and testing tihs on
multiple platforms I guess, in particular both 32 and 64-bit...

At least that's my understanding of what needs to be done :-)

--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/