Re: GSoC proposal - "make an unlogged table logged"

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
therelation itself?
 

Yes. But as I said, that's unavoidable for anything but
wal_level=minimal. If somebody wants to put in the additional nontrivial
work to make it work faster with wal_level=minimal, they can do so. But
the other case is more general and needs to be done anyway.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
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