Re: Concurrency issue in pg_rewind

> 18 сент. 2020 г., в 11:10, Michael Paquier <michael@paquier.xyz> написал(а):
>
> On Thu, Sep 17, 2020 at 10:20:16AM +0200, Oleksandr Shulgin wrote:
>> Ouch.  I think pg_rewind shouldn't try to remove any random files in pg_wal
>> that it doesn't know about.
>> What if the administrator made a backup of some WAL segments there?
>
> IMO, this would be a rather bad strategy anyway, so just don't do
> that, because that could also mean that this is on the same partition
> as pg_wal/

This is whole point of having prefetch. restore_command just links file from the same partition.
In WAL-G you strictly control number of cached WALs, so if you configured max_wal_size - you can configure
WALG_DOWNLOAD_CONCURRENCYtoo. 

Best regards, Andrey Borodin.