On 04/01/2014 08:58 PM, Andres Freund wrote:
On 2014-04-01 12:56:04 -0500, Jim Nasby wrote:
On 3/4/14, 8:50 AM, Andres Freund wrote:
Can't that be solved by just creating the permanent relation in a new
relfilenode? That's equivalent to a rewrite, yes, but we need to do that
for anything but wal_level=minimal anyway.


Maybe I'm missing something, but doesn't this actually involve writing the data 
twice? Once into WAL and again into the relation itself?

Yes. But as I said, that's unavoidable for anything but
wal_level=minimal.

Ideally, you would *only* write the data to WAL, when you do ALTER TABLE ... SET LOGGED. There's no fundamental reason you need to rewrite the heap, too. I understand that it might be difficult to do, because of the way the system catalogs work, but it's worthy goal.

- Heikki


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