Subject Re: [firebird-support] Firebird 3.0.1 freezes on one table for some 10-20 minutes during backup after gfix/mend
Author Mark Rotteveel
On 11-1-2018 14:24, Mark Rotteveel mark@...
[firebird-support] wrote:
> On 11-1-2018 13:21, jonatan.lauritsen@... [firebird-support] wrote:
>> I checked the system again - we use 3.0.2 indeed.
>> There is no particular reason why we use -mend. We use it routinely
>> between backup/restore operations to prevent the situation that any
>> corruption errors my intervene in our operations. My understanding is
>> that mend can not and it should not cause any troubles.
> Use of gfix -mend can lead to data loss, see
> """
> This causes the corruptions in data records to be ignored. While this
> sounds like a good thing, it is not. Subsequent database actions (such
> as taking a backup) will not include the corrupted records, **leading to
> data loss**.
> """

I think you might have confused it with gfix -v, which does

The command to carry out default database validation is:

gfix -v[alidate] database_name

This command validates the database and makes updates to it when any
orphan pages are found. An orphan page is one which was allocated for
use by a transaction that subsequently failed, for example, when the
application aborted. In this case, committed data is safe but
uncommitted data will have been rolled back. The page appears to have
been allocated for use, but is unused.

This option updates the database and fixes any corrupted structures.

Mark Rotteveel