Subject Re: [firebird-support] My FDB corrupted after power failure...
Author Helen Borrie
At 05:59 AM 3/08/2004 +0000, you wrote:
>I am using my FB1.5 on win98, during my transactions someone
>accidentally unplugged my pc power. Afer restart the pc, my fdb
>cannot connected.
>I thought SQL DB can protect problem like these to happened. Or is
>this a known bug in FB1.5? I had experienced in power failure when I
>was using ASA but my db was not corrupted. Can someone explain to me
>why FB will have this problem? I thought FB should be intelligent
>enough to rollback all incomplete transactions in order to keep data

It does. Uncommitted data from dead transactions will be cleaned out
eventually and, in the meantime, they have no effect on committed data. The
db itself can't get corrupted by a power outage. However, if you're
running with Forced Writes turned off, or using the BDE, you would lose
uncommitted data.

However, turning off the power during disk writes isn't a good recipe for
keeping disks healthy. That's why operating systems perform disk surface
scans after abnormal shutdowns. No db engine in the world can protect the
disk's physical surface or its heads from damage when people (or Acts of
God) do this kind of thing. If the heads were left on the disk surface at
crash time, it's possible for physical disk damage to occur. If the
resting heads damage the part of the disk where your database file is,
you'll have a corrupt database.

Provide more information, including what you have tried in order to connect
to the database and what messages you are getting when you fail to connect.