> For instance, if there are assumptions that all data blocks are
> written before this fact is recorded in a log file, then
> "write data blocks" "fsynch" "write log" "fsynch" doesn't break
> that assumption,
>
Are we really doing a sync after the pg_log write ? While the sync
after datablock write seems necessary to guarantee consistency,
the sync after log write is actually not necessary to guarantee consistency.
Would it be a first step, to special case the writing to pg_log, as
to not sync (extra switch to backend) ? This would avoid the syncs
for read only transactions, since they don't cause data block writes.
Andreas