Subject RE: [ib-support] When do FB/IB 'flush' to disk?
Author Dmitry Yemanov
Hi,

> > I need 'forced writes = ON' without the performance penaty
> <g>, or failing
> > that, so way of signaling FB to flush its file(s) either
> manually, or
> > automatically (like the sweep thread)
>
> How would flushing differ from forced writes? I'm not sure I
> get the idea.

With forced writes there's no disk I/O caching at all. It seems to be almost
the same as flushing after each file write operation (actually, such an
additional manual flushing should be even worse from the perfomance POV). I
believe Phil meant that the engine should allow its buffers to be flushed
via an external request (by client app, for example). Don't like very much
this proposal, but do like the Phil's second one. In fact, flushing file
buffers in the idle time (yes, it's one more low-priority thread) makes
sense for me. It's still lazy writes, but much more reliable than the
current behaviour on Windoze platforms.


Cheers,
Dmitry