Re: Disable WAL logging to speed up data loading

On Mon, 2021-03-22 at 09:46 -0400, Stephen Frost wrote:
> * tsunakawa.takay@fujitsu.com (tsunakawa.takay@fujitsu.com) wrote:
> > From: Stephen Frost <sfrost@snowman.net>
> > > The argument here seems to stem from the idea that issueing a 'TRUNCATE'
> > > inside the transaction before starting the 'COPY' command is 'too hard'.
> > 
> > No, we can't ask using TRUNCATE because the user wants to add data to a table.
> 
> First- what are you expecting would actually happen during crash
> recovery in this specific case with your proposed new WAL level?
> 
> Second, use partitioning, or unlogged tables (with the patch discussed
> elsewhere to allow flipping them to logged without writing the entire
> thing to WAL).

Perhaps allowing to set unlogged tables to logged ones without writing WAL
is a more elegant way to do that, but I cannot see how that would be any
more crash safe than this patch.  Besides, the feature doesn't exist yet.

So I think that argument doesn't carry much weight.

Yours,
Laurenz Albe