Re: unlogged tables

On Sat, Dec 11, 2010 at 2:53 PM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
> On Wed, Dec 8, 2010 at 6:52 AM, Marti Raudsepp <marti(at)juffo(dot)org> wrote:
>> A very useful feature for unlogged tables would be the ability to
>> switch them back to normal tables -- this way you could do bulk
>> loading into an unlogged table and then turn it into a regular table
>> using just fsync(), bypassing all the WAL-logging overhead.
>
> If archive_mode is off, then you can often find a way to bypass
> WAL-logging during bulk loading anyway.
>
> If archive_mode is on, then I don't see how this can work without
> massive changes.

Well, you'd need to work your way through the heap and all of its
indices and XLOG every page. And you've got to do that in a way
that's transaction-safe, and I don't have a design in mind for that
off the top of my head. But I think "massive changes" is probably an
overstatement. We can already handle ALTER TABLE operations that
involve a full relation rewrite, and that already does the
full-table-XLOG thing.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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