Re: Datatypes and performance

Richard Huxton wrote:
> > If the answer is "yes", then I understand the use of FSYNC.
> >
> > If the answer is "no", then i don't see the point in using FSYNC at all.
> 
> The answer is "yes" providing:
> 1. Your hardware didn't suffer a failure during the outage.
> 2. Your disks don't like to the operating-system.
> 
> The second point is important - some disks have write-cache enabled and report 
> "done" when data is written to the cache not the platter. Google for 
> discussion.

The problem here is whether write-cache is enabled _and_ the disk drive
doesn't use some trick of using the disk drive rotational energy to
ensure that the write cache gets flushed to disk on a power failure, or
perhaps uses some short-term battery to make sure the data gets flushed.

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