From: John Scalia <jayknowsunix@gmail.com>
To: David F. Skoll <dfs@roaringpenguin.com>
To: pgsql-admin@postgresql.org
Subject: Re: Weird spikes in delay for async streaming replication on 9.1
Date: Thu, 26 Feb 2015 10:51:55 -0500
Message-ID: <54EF411B.80202@gmail.com> (raw)
In-Reply-To: <20150226104433.1b0df1db@hydrogen.roaringpenguin.com>
References: <20150214110050.2f032f05@ollie.roaringpenguin.com>
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<54EF3E6F.60403@gmail.com>
<20150226104433.1b0df1db@hydrogen.roaringpenguin.com>
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On 2/26/2015 10:44 AM, David F. Skoll wrote:
> On Thu, 26 Feb 2015 10:40:31 -0500
> John Scalia <jayknowsunix@gmail.com> wrote:
>
>> Apologies, David, but as I don't check this list very often, I
>> thought you should have received an answer. Have you tried watching
>> the transaction with tcpdump or wireshark?
> Yes. Haven't observed anything unusual.
>
>> To me this sounds like either a network problem or like you're
>> thinking a contention problem.
> It is not a network problem; we monitor the link between sites. And it
> happens absolutely regularly, like clockwork, when we run our nightly
> pg_dump on the master.
>
>> Also, are you running streaming replication? If so, there
>> shouldn't be ANY delay as the standby gets the commit before the
>> primary. Otherwise, how are you replicating? -- Jay
> We are running asynchronous streaming replication.
>
OK, if it's asynchronous, is your script checking that primary isn't holding up closing out and transmitting the latest WAL segment during these times? And if the Standby really
needs to be up to date, why not try synchronous replication?
--
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To: pgsql-admin@postgresql.org
Cc: jayknowsunix@gmail.com, dfs@roaringpenguin.com
Subject: Re: Weird spikes in delay for async streaming replication on 9.1
In-Reply-To: <54EF411B.80202@gmail.com>
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