Re: proposal: CREATE DATABASE vs. (partial) CHECKPOINT

On 2014-10-30 18:06:02 -0500, Jim Nasby wrote:
> On 10/30/14, 2:13 PM, Heikki Linnakangas wrote:
> >On 10/30/2014 08:56 PM, Andres Freund wrote:
> >>I actually think we should *always* use the new code and not
> >>add a separate wal_level=minimal branch. Maintaining this twice just
> >>isn't worth the effort. minimal is used *far* less these days.
> >
> >I wouldn't go that far. Doing the wal_level=minimal optimization should be pretty straightforward. Note that it would be implemented more like CREATE INDEX et al with wal_level=minimal, not the way CREATE DATABASE currently works. It would not involve any extra checkpoints.

It's probably not that hard. I agree. Imo it's up to the person doing
this conversion. We imo shouldn't require that person to develop both
versions, but if they're interested in doing it: fine with me.

> At my previous job, we used createdb -T copy_from_production new_dev_database, because that was far faster than re-loading the raw SQL dump all the time. It'd be a shame to have that need to write the copied data 2x. IIRC that database was around 20MB.

At that size not doing two immediate checkpoints will still be an order
of magnitude or so bigger win.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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