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Date: Thu, 12 Jan 2012 10:12:47 -0800
From: Manoj Govindassamy <manoj@nimblestorage.com>
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To: <pgsql-general@postgresql.org>
Subject: Re: PG synchronous replication and unresponsive slave
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any help on this is much appreciated.

thanks,
Manoj


On 01/11/2012 01:50 PM, Manoj Govindassamy wrote:
> Hi,
>
> I have a PG 9.1.2 Master <--> Slave with synchronous replication 
> setup. They are all working fine as expected. I do have a case where I 
> want to flip Master to non replication mode whenever its slave is not 
> responding. I have set replication_timeout to 5s and whenever salve is 
> not responding for for more than 5s, i see the master detecting it. 
> But, the transactions on the master is stuck till the slave comes 
> back. To get over it, I reloaded the config on master with 
> synchronous_commit = local. Further transactions on the master are 
> going thru fine with this local commits turned on.
>
> Here are my questions:
>
> 1. Transaction which was stuck right when slave going away never went 
> thru even after I reloaded master's config with local commit on. I do 
> see all new transactions on master are going thru fine, except the one 
> which was stuck initially. How to get this stuck transaction complete 
> or return with error.
>
> 2. Whenever there is a problem with slave, I have to manually reload 
> master's config with local commit turned on to get master go forward. 
> Is there any automated way to reload this config with local commit on 
> on slave's unresponsiveness ? tcp connection timeouts, replication 
> timeouts all detect the failures, but i want to run some corrective 
> action on these failure detection.
>