Re: Estimating wal_keep_size

On 2021-06-16 17:36, Dean Gibson (DB Administrator) wrote:
> Is this reasonable thinking?
>
> I'd think that one would want a *wal_keep_size* to cover the pending
> updates while the standby server might be unavailable, however long
> one might anticipate that would be.
>
> In my case, I get a complete replacement (in the form of "|"-
> delimited ASCII files) of one of the SCHEMAs every Sunday.  The size
> of that ASCII data is about 2GB, so I'm thinking of doubling that to
> 4GB (256 WAL files) to protect me in the case of the standby being
> unavailable during the update.  Note that a complete loss of both
> servers is not catastrophic (I have backups);  it would just be annoying.
>

In the absence of any clear guidance, I temporarily set wal_keep_size to
16GB & waited for the Sunday update.  That update today created just
over 6GB of WAL files during the update, so I've set wal_keep_size to
8GB (512 WAL files).

Oh, and wal_keep_size is NOT an upper limit restricting further WAL
files. It's more like a minimum.