Re: RE: [COMMITTERS] pgsql/src/backend/access/transam ( xact.c xlog.c)

> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> >> I have to agree with Alfred here: this does not sound like a feature,
> >> it sounds like a horrid hack. You're giving up *all* consistency
> >> guarantees for a performance gain that is really going to be pretty
> >> minimal in the WAL context.
>
> > It does not give up consistency. The db is still consistent, it is just
> > consistent from a few seconds ago, rather than commit time.
>
> No, it isn't consistent. Without the fsync you don't know what order
> the kernel will choose to plop down WAL log blocks in; you could end up
> with a corrupt log. (Actually, perhaps that could be worked around if
> the log blocks are suitably marked so that you can tell where the last
> sequentially valid one is. I haven't looked at the log structure in
> any detail...)

Well, WAL already has to be careful in the order it plops down the log
blocks because a single transaction can span multiple log blocks.

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