Axel Schwenke wrote:
> Jerry Stuckle <jstucklex@attglobal.net> wrote:
> > Axel Schwenke wrote:
> >> Jerry Stuckle <jstucklex@attglobal.net> wrote:
> >> ...
> >> The MyISAM engine is quite simple. Data and index are held in separate
> >> files. Data is structured in records. Whenever a record is modified,
> >> it's written to disk immediately (however the operation system might
> >> cache this). MyISAM never touches records without need. So if mysqld
> >> goes down while in normal operation, only those records can be damaged
> >> that were in use by active UPDATE, DELETE or INSERT operations.
> >
> > But the caching is all too important. It's not unusual to have hundreds
> > of MB of disk cache in a busy system. That's a lot of data which can be
> > lost.
>
> Sure. But this problem was out of scope. We didn't talk about what
> happens if the whole machine goes down, only what happens if mysqld
> crashes.
>
> Having the whole system crashing is also hard for "real" database
> engines. I remember several passages in the InnoDB manual about
> certain operating systems ignoring O_DIRECT for the tx log. Also
> there may be "hidden" caches in disk controllers and in the disks.

Indeed. Some references here:
http://groups.google.com/group/comp....17a85b71816f98

>
>
> XL
> --
> Axel Schwenke, Senior Software Developer, MySQL AB
>
> Online User Manual: http://dev.mysql.com/doc/refman/5.0/en/
> MySQL User Forums: http://forums.mysql.com/