warm standby replication safe failover

[Andrew Puschak]

Thanks Tom!

The PostgreSQL 8.4 is coming from the default latest CentOS 6.3 updates
repository which makes it an easy install and upgrade later (yum install
postgresql-server). I'll try installing/upgrading my test setup using
http://yum.postgresql.org repository. I'm also going to need to find out
what migrating to a newer version will affect with the current production
data.
Andrew

I'm new here and have a question. I'm working on a replacement PostgreSQL
8.4 setup for a small company. They now have a Primary postgres server

and

2 secondaries which are replicated using Slony-I, however the consulting
company that set it up is afraid to failover and keeping Slony running is
taking lots of resources.

It sounds like you're trying to keep them on 8.4. Why not move them to
some newer release branch where you can make use of streaming
replication? Aside from the benefits of that, 8.4 will be out of
support next year, so setting up new servers with that release series
seems pretty short-sighted.
I realize that dealing with a version upgrade might not be their highest
priority right now, but they're going to have to deal with it before too
long, and doing so now would put them in position to have a far better
replication solution than what you're describing.
regards, tom lane

[Tom Lane]

I'm new here and have a question. I'm working on a replacement PostgreSQL
8.4 setup for a small company. They now have a Primary postgres server and
2 secondaries which are replicated using Slony-I, however the consulting
company that set it up is afraid to failover and keeping Slony running is
taking lots of resources.

It sounds like you're trying to keep them on 8.4. Why not move them to
some newer release branch where you can make use of streaming
replication? Aside from the benefits of that, 8.4 will be out of
support next year, so setting up new servers with that release series
seems pretty short-sighted.

I realize that dealing with a version upgrade might not be their highest
priority right now, but they're going to have to deal with it before too
long, and doing so now would put them in position to have a far better
replication solution than what you're describing.

regards, tom lane

[Andrew Puschak]

Hi again,

I setup PostgreSQL 9.2 to try replication and the 9.2 documentation
answered my question whereas the 8.4 documentation is missing the section
25.2.2. Standby Server Operation
http://www.postgresql.org/docs/9.2/static/warm-standby.html#STANDBY-SERVER-OPERATIONIt
explains my assumption that if you copy over the last pg_xlog from the
Primary, which I can do after safely shutting down postgres, recovery will
first apply the WALs from the archive directory and then attempt to recover
anything else in pg_xlog, but take priority over the WALs in the archive
directory.

As for upgrading to the newer release branch, I'm asking the CentOS
community where/how the PostgresSQL version is determined in their
repositories. It would be easier if I could continue to use the default
Base and Update repositories from CentOS to update postgres, but I don't
know when they plan to include 9.x versions.
Andrew

Post by Andrew Puschak
Thanks Tom!
The PostgreSQL 8.4 is coming from the default latest CentOS 6.3 updates
repository which makes it an easy install and upgrade later (yum install
postgresql-server). I'll try installing/upgrading my test setup using
http://yum.postgresql.org repository. I'm also going to need to find out
what migrating to a newer version will affect with the current production
data.
Andrew

Post by Andrew Puschak

I'm new here and have a question. I'm working on a replacement

PostgreSQL

8.4 setup for a small company. They now have a Primary postgres server

and

2 secondaries which are replicated using Slony-I, however the consulting
company that set it up is afraid to failover and keeping Slony running

is

taking lots of resources.

It sounds like you're trying to keep them on 8.4. Why not move them to
some newer release branch where you can make use of streaming
replication? Aside from the benefits of that, 8.4 will be out of
support next year, so setting up new servers with that release series
seems pretty short-sighted.
I realize that dealing with a version upgrade might not be their highest
priority right now, but they're going to have to deal with it before too
long, and doing so now would put them in position to have a far better
replication solution than what you're describing.
regards, tom lane

--
Andrew Puschak
(267) 614 - 2373
http://andrewpuschak.com