On 2014-06-01 00:50:58 -0500, Jim Nasby wrote:
> On 5/31/14, 9:11 AM, Andres Freund wrote:
> >On 2014-02-21 15:14:15 -0600, Jim Nasby wrote:
> >>On 2/17/14, 7:31 PM, Robert Haas wrote:
> >>>But do you really want to keep that snapshot around long enough to
> >>>copy the entire database? I bet you don't: if the database is big,
> >>>holding back xmin for long enough to copy the whole thing isn't likely
> >>>to be fun.
> >>
> >>I can confirm that this would be epic fail, at least for londiste. It takes about 3 weeks for a new copy of a ~2TB
database.There's no way that'd work with one snapshot. (Granted, copy performance in londiste is rather lackluster, but
still...)
> >
> >I'd marked this email as todo:
> >If you have such a huge database you can, with logical decoding at
> >least, use a basebackup using pg_basebackup or pg_start/stop_backup()
> >and roll forwards from that... That'll hopefull make such huge copies
> >much faster.
> Just keep in mind that one of the use cases for logical replication is upgrades.
Should still be fine. Make a physical copy; pg_upgrade; catchup via
logical rep.
Greetings,
Andres Freund
-- Andres Freund http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services
