On Wed, Jul 26, 2023 at 9:54 PM Matthias van de Meent
<boekewurm+postgres@gmail.com> wrote:
>
> Then you ignore the max_wal_size GUC as PostgreSQL so often already
> does. At least, it doesn't do what I expect it to do at face value -
> limit the size of the WAL directory to the given size.
That would require stopping any new writes at wal size == max_wal_size
until the checkpoint is completed.
I don't think anybody would want that.
> But more reasonably, you'd keep track of the count of modified pages
> that are yet to be fully WAL-logged, and keep that into account as a
> debt that you have to the current WAL insert pointer when considering
> checkpoint distances and max_wal_size.
I think Peter Geoghegan has worked on somewhat similar approach to
account for "accumulated work needed until some desired outcome"
though I think it was on the VACUUM side of things.