Hi Greg

I have another query. I have postgres-8.1.2 on one of my cluster setups
.
I am using slony-1.1.5 for replication between servers in that cluster.
Now,  I want to upgrade those servers to latest release of
postgres-8.1.X i.e postgres-8.1.21 .
 
In case I upgrade the servers in a cluster one by one then there wont be

any issue with replication using slony-1.1.5 from postgres-8.1.2 to
postgres-8.1.21 because last digit of postgres version i.e revision is
same . Right ?? 

I had asked it earlier also but that was for slony-2.0.4 . Just wanted
to confirm if its same for slony-1.1.5 also.

Will slony 1.1.5 work with postgres-8.1.21 or I'll have to upgrade slony
as well.

Is there any compatibility matrix between slony and postgres . where can
I find that ??


Please Reply ...

Thanks...
Tamanna 

-----Original Message-----
From: Greg Sabino Mullane [mailto:greg at endpoint.com] 
Sent: Friday, July 23, 2010 8:28 PM
To: tamanna madaan
Cc: slony1-general at lists.slony.info
Subject: Re: [Slony1-general] replication through slony beween the nodes
having different versions of postgres

> postgres-8.4.0 and 8.4.2 are completely compatible. Does it also mean
that
> replication will work fine from postgres-8.4.0 to postgres-8.4.2 means
> from a lower to higher release. Does that holds true for
postgres-8.4.4 as
> well ??

Yes.

> Moreover, in the release notes of 8.4.2 (link below), its mentioned
that 
> "A dump/restore is not required for those running 8.4.X unless you are
having
> hash index" . Does that mean: if I am not using any hash index , then
I 
> can upgrade to postgres-8.4.2 from postgres-8.4.0 simply without any
need of 
> exporting my database schema and data in it before upgrading postgres
and 
> then importing it back after upgrade.

Yes, that is correct. Going from one revision to another (where the last
of the 
three version number changes) never requires a dump and a reload. Even
if you 
have hash indexes, a dump and reload is not required, just a REINDEX
after 
the upgrade has completed.

> won't it corrupt the data if I upgrade postgres db with my database
> schema/data in it ??

No: the only thing that is changing is the Postgres program itself. The 
underlying data is not changed, just the program that reads and writes 
that data is slightly changed, to fix bugs.

If I can further expound to this list some more best practices, you
should 
be subscribed to the pgsql-announce mailing list so you hear about new 
released (of Postgres, Slony, and other Postgres-related programs). You 
may also wish to run check_postgres.pl with the new_version_pg action, 
which will give you a Nagios alert when your version of Postgres becomes

out of date.

-- 
Greg Sabino Mullane greg at endpoint.com
End Point Corporation
PGP Key: 0x14964AC8