Re: [HACKERS] Full page writes improvement, code update

> I don't insist the name and the default of the GUC parameter.
> I'm afraid wal_fullpage_optimization = on (default) makes
> some confusion because the default behavior becomes a bit
> different on WAL itself.

Seems my wal_fullpage_optimization is not a good name if it caused
misinterpretation already :-(

> >> Amount of WAL after 60min. run of DBT-2 benchmark
> >> wal_add_optimization_info = off (default) 3.13GB
> >
> > how about wal_fullpage_optimization = on (default)

The meaning of wal_fullpage_optimization = on (default)
would be the same as your wal_add_optimization_info = off (default).
(Reversed name, reversed meaning of the boolean value)

It would be there to *turn off* the (default) WAL full_page
optimization.
For your pg_compresslog it would need to be set to off.
"add_optimization_info" sounded like added info about/for some
optimization
which it is not. We turn off an optimization with the flag for the
benefit
of an easier pg_compresslog implementation.

As already said I would decouple this setting from the part that sets
the "removeable full page" flag in WAL, and making the recovery able to
skip dummy records. This I would do unconditionally.

Andreas