[pgpool-general: 411] Re: pgpool2 status info

[Lazaro Ruben Garcia Martinez]

You are right, this value should be parametrized, and if the pg_xlog directory is in other partition, the size is very important, because: 

(wall_keep_segments * 16 MB) < size of pg_xlog partition. 

Regards. 

----- Mensaje original -----

> Hi Ruben,
> I have modified the wal_keep_segments to 5000, but i guess that this
> should be parametrized depending on how long do you plan to keep the
> slave down and how much traffic do you have towards the database.
> Thanks for the hint.

> I`m planning to have a slave node on a server the is powered off
> every night, so just before the machine will shutdown i will detach
> the node from cluster and then stop postgresql process. Then in the
> morning i will start the postgresql process and after 1 min i will
> attach the node to the cluster.

> Regarding the second question maybe we can find someone to confirm
> our suppositions :)

> Thanks,
> Adrian Videanu
> --- On Fri, 5/4/12, Lazaro Ruben Garcia Martinez <lgarciam at uci.cu>
> wrote:

> > From: Lazaro Ruben Garcia Martinez <lgarciam at uci.cu>
> 
> > Subject: Re: [pgpool-general: 408] pgpool2 status info
> 
> > To: "Videanu Adrian" <videanuadrian at yahoo.com>
> 
> > Cc: pgpool-general at pgpool.net
> 
> > Date: Friday, May 4, 2012, 3:39 PM
> 

> > Hello Videanu.
> 

> > About question one, it seems to me, that this is a replication
> > problem. In the postgresql.conf there is a parameter, called
> > wal_keep_segments, this is the information written in the
> > postgresql
> > documentation about this parameter (...)Specifies the minimum
> > number
> > of past log file segments kept in the pg_xlog directory,
> 
> > in case a standby server needs to fetch them for streaming
> > replication. Each segment is
> 
> > normally 16 megabytes. If a standby server connected to the primary
> > falls behind by more than
> 
> > wal_keep_segments segments, the primary might remove a WAL segment
> > still needed by the
> 
> > standby, in which case the replication connection will be
> > terminated.
> 
> > (...)
> 

> > I recommend you increase this parameter in a value of 4000 or 5000.
> 

> > About question 2, I have the same, but i think the answer is the
> > same
> > of you (that the postgresql is started on the slave node but it is
> > not attached to the cluster). If you need attache a node you can
> > use
> > pcp_attach_node.
> 

> > Regards.
> 

> > > Hi all,
> > 
> 
> > > i have a pgpool2 3.1.2 and 2 postgresql 9.1 nodes with streaming
> > > replication. I Also use pgpooladmin. The failover and recovery
> > > scenarious works just fine, but what i have a few questions
> > > regarding the slave recovery:
> > 
> 
> > > 1. Let`s say that i have stopped the slave for some
> > > administrative
> > > reasons. First i have detached from the cluster and then i had
> > > stopped the postgresql process on the slave node. If a start this
> > > node after one day i have this kind of messages in my logs :
> > 
> 
> > > FATAL: timeline 36 of the primary does not match recovery target
> > > timeline 34.
> > 
> 
> > > Do i have to perform a full base backup upon this node ?
> > 
> 

> > > 2. if i see this:
> > 
> 
> > > Down Running as standby server
> > 
> 
> > > is pgpooladmin what does this means ? that the postgresql is
> > > started
> > > on the slave node but it is not attached to the cluster (so no
> > > read
> > > queries will be send to this node) and if i want to attach it i
> > > have
> > > to run pcp_attach_node?
> > 
> 

> > > 3. If i press the disconnect (pgpooladmin) on the master node the
> > > slave would not become master unless i kill/stop postgresql
> > > process
> > > on the master machine. Is this the normal behavior ?
> > 
> 

> > > Thanks,
> > 
> 
> > > Adrian Videanu
> > 
> 
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> > 
> 
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> 
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> > 
> 

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> 


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