Re: Enforce "max_wal_size/ min_wal_size must be at least twice wal_segment_size" limit while setting GUCs

Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> writes:
> Thanks. Having check hooks for min_wal_size and max_wal_size that
> throw errors if they aren't at least twice the wal_segment_size has a
> "BIG" problem - ./initdb -D data --wal-segsize=1 (or a value < 16)
> fails.

In general, you can't do that (i.e. try to enforce constraints between
GUC values via check hooks).  It's been tried in the past and failed
miserably, because the hooks can't know whether the other value is
about to be changed.

            regards, tom lane