Re: Major upgrade of PostgreSQL and MySQL

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From: Thomas Kellerer <spam_eater(at)gmx(dot)net>
To: pgsql-general(at)postgresql(dot)org
Sent: Saturday, September 14, 2013 12:27 AM
Subject: Re: [GENERAL] Major upgrade of PostgreSQL and MySQL

Patrick Dung wrote on 13.09.2013 18:17:
>> The problem of pg_upgrade is that it needed to hold two set of databases data in the server.
>> This is not be desirable (very slow) or possible (space limitation) for database with huge data.
>>
>> For example, if the old version is already using over 50% of the mount point.
>> The new database may not have enough disk space for the upgrading.

> I think if you use the --link parameter, you don't need additional disk space (or only little).

Thanks for pointing out.

For small or medium sized database, I think file based snapshot (like ZFS) could create backup of the old database quickly.
Also it can rollback quickly.

Thanks,
Patrick