Re: Upgrading using streaming replication

On Fri, Mar 11, 2011 at 13:02, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> Damien Churchill wrote:
>> Hi there,
>>
>> I have done quite a bit of searching but have been unable to find any
>> way to do this. I am quite keen to use PostgreSQL 9.0's streaming
>> replication to create a master/slave write/read setup. However I am
>> unsure of an upgrade procedure whilst using streaming replication that
>> doesn't yield any downtime (including being able to write). From what
>> I have read the WAL won't be compatible between 9.0 and 9.1 so it
>> won't be possible to take the slave off-line and upgrade it, promote
>> it to master and then upgrade the old master.
>>
>> So I was wondering if anyone knows of a method that allows you to do
>> this. Sorry if this is an often asked question and I just haven't been
>> able to find the answer.
>
> Good question.  I think you have to disconnect the slave, use pg_upgrade
> to upgrade the master, and make a new slave.  It is something we had not
> considered.  I don't think you can run pg_upgrade on the slave and have
> it work.

No, you can't. Because it gets a new systemid and things like that.

If you use rsync to push from the master to the slave, the
re-provisioning of the slave will be fairly quick, but again it's well
above zero.

--
 Magnus Hagander
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