Subject Re: [firebird-support] db became corrupt - why?
Author Nick Upson
n 25 June 2010 15:50, Ann W. Harrison <aharrison@...> wrote:
> Nick Upson wrote:
>>> Did you do a gfix -mend?
>> yes, that allowed me to do a backup, attempt to restore, and use the
>> errors from the restore to restore RI by deleting invalid data
>>> Could the foreign key errors indicate that you lost records in the master (referenced) table?
>> yes, that is what happened. The question is how given that
>> a) there is no code that deletes from that table
>> b) several tables refer to it in their FK definition which should have
>> stopped it being deleted
> Gfix -mend isn't stopped by little things like foreign key constraints;
> it just whacks out whatever it doesn't like.  Better than losing the
> whole database, but far from perfect.  If you have a copy of the old
> database, you might try the free version of IBSurgeon to see if it finds
> anything it can fix.

good idea,

> Anyway, that argues that the bad data was on disk.  There are a number
> of problems that show up as "decompression overran buffer".  One is a
> bad line index entry - so the database starts reading at the wrong
> place on a page.
> Do you have a copy of the bad database?

I do but it's almost 1Gb