Re: use CREATE DATABASE STRATEGY = FILE_COPY in pg_upgrade

Em ter., 4 de jun. de 2024 às 16:39, Nathan Bossart <
nathandbossart@gmail.com> escreveu:

> I noticed that the "Restoring database schemas in the new cluster" part of
> pg_upgrade can take a while if you have many databases, so I experimented
> with a couple different settings to see if there are any easy ways to speed
> it up.  The FILE_COPY strategy for CREATE DATABASE helped quite
> significantly on my laptop.  For ~3k empty databases, this step went from
> ~100 seconds to ~30 seconds with the attached patch.  I see commit ad43a41
> made a similar change for initdb, so there might even be an argument for
> back-patching this to v15 (where STRATEGY was introduced).  One thing I
> still need to verify is that this doesn't harm anything when there are lots
> of objects in the databases, i.e., more WAL generated during many
> concurrent CREATE-DATABASE-induced checkpoints.
>
> Thoughts?
>
Why not use it too, if not binary_upgrade?

else
{
appendPQExpBuffer(creaQry, "CREATE DATABASE %s WITH TEMPLATE = template0
STRATEGY = FILE_COPY",
 qdatname);
}

It seems to me that it also improves in any use.

best regards,
Ranier Vilela