On Thu, Jun 7, 2012 at 5:07 PM, Jerry Sievers <gsievers19(at)comcast(dot)net> wrote:
> Lonni J Friedman <netllama(at)gmail(dot)com> writes:
>> On Thu, Jun 7, 2012 at 12:40 PM, Magnus Hagander <magnus(at)hagander(dot)net> wrote:
>>> On Thu, Jun 7, 2012 at 8:04 PM, Lonni J Friedman <netllama(at)gmail(dot)com> wrote:
>>>> On Thu, Jun 7, 2012 at 10:41 AM, Lonni J Friedman <netllama(at)gmail(dot)com> wrote:
>>>>> I have a 4 server postgresql-9.1.3 cluster (one master doing streaming
>>>>> replication to 3 hot standby servers). All of them are running
>>>> err, i included that URL but neglected to explain why. On a different
>>>> list someone suggested that I verify that there were no locks that
>>>> were blocking things, and I did so, and found no locks.
>>>> So I'm still at a loss why pg_basebackup is killing perf, and would
>>>> appreciate pointers on how to debug it or at least reduce its impact
>>>> on performance if that is possible.
>>> My guess would be that you are overloading your I/O system. You should
>>> look at values from iostat and vmstat from when the system works fine
>>> and when you run pg_basebackup, that should give you a hint in the
>>> right direction.
>> ok, thanks. i'll take a look at that. If this turns out to be the
>> issue, is there some way to get pg_basebackup to run more slowly, so
>> that it has less impact? Or could I do this with ionice on the
>> pg_basebackup process?
> You might try stopping pg_basebackup in place with SIGSTOP and check
> if problem goes away. SIGCONT and you should start having
> sluggishness again.
> If verified, then any sort of throttling mechanism should work.
I'm certain that the problem is triggered only when pg_basebackup is
running. Its very predictable, and goes away as soon as pg_basebackup
finishes running. What do you mean by a throttling mechanism?
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