On 1/22/15 3:18 PM, Andres Freund wrote:
, but to then put it's entire contents into WAL? Blech.
Besides actually having a chance of being correct, doing so will save
having to do two checkpoints inside movedb(). I think it's pretty likely
that that actually saves overall IO, even including the WAL
writes. Especially if there's other databases in the cluster at the same
time.
If you're moving a small amount of data, maybe. If you're moving several
hundred GB or more? You're going to flood WAL and probably cause all
replication/archiving to lag.
Obviously, we need to do be reliable, but I think a lot of users would much
rather that they can't muck with tablespaces while a backup is running than an
ADAT suddenly consumes way more resources than before.
Is there some way we can add an option to control this? I'm thinking that by
default ADAT will error if a backup is running, but allow the user to over-ride
that.
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com
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