On Thu, Nov 30, 2000 at 07:02:01PM -0400, The Hermit Hacker wrote:
>
> v7.1 should improve crash recovery ...
> ... with the WAL stuff that Vadim is producing, you'll be able to
> recover up until the point that the power cable was pulled out of
> the wall.
Please do not propagate falsehoods like the above. It creates
unsatisfiable expectations, and leads people to fail to take
proper precautions and recovery procedures.
After a power outage on an active database, you may have corruption
at low levels of the system, and unless you have enormous redundancy
(and actually use it to verify everything) the corruption may go
undetected and result in (subtly) wrong answers at any future time.
The logging in 7.1 protects transactions against many sources of
database crash, but not necessarily against OS crash, and certainly
not against power failure. (You might get lucky, or you might just
think you were lucky.) This is the same as for most databases; an
embedded database that talks directly to the hardware might be able
to do better.
Nathan Myers
ncm@zembu.com