> 1. Open WAL files with O_SYNC|O_DIRECT or O_SYNC(Not sure if
Without grouping WAL writes that does not fly. Iff however such grouping
is implemented that should deliver optimal performance. I don't think flushing
WAL to the OS early (before a tx commits) is necessary, since writing 8k or 256k
to disk with one call takes nearly the same time. The WAL write would need to be
done as soon as eighter 256k fill or a txn commits.
Andreas