Re: [HACKERS] MERGE SQL Statement for PG11 - Mailing list pgsql-hackers

Hi,

On 02/07/2018 10:24 AM, Pavan Deolasee wrote:
>

       if (startWAL < GetXactWALBytes())
           ereport(ERROR,
                   (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                    errmsg("cannot write to database ...")));

I think this actually fails to enforce the rule, because some writes may
not produce WAL (think of unlogged tables). I also suspect it may be
incorrect "in the opposite direction" because a query may not do any
changes and yet it may produce WAL (e.g. due to wal_hint_bits=true).

So we may need to think of a different way to enforce this ...