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From:Rafal Somla Date:September 23 2009 5:23am
Subject:Re: MOM-BACKUP-090901 action items closed - decision required
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Ingo,

You are right again - the metadata is written before tables are locked (in 
Backup_restore_ctx::do_backup() the write_preamble() call, while table 
locking happens in write_table_data() call).

What about CS driver and online operations. If there are concurrent 
transactions inserting data into a table changing its AUTO_INCREMENT, we 
should be careful to save/restore its value from the validity point time. 
Since creating a VP is the responsibility of a backup driver, this indicates 
that handling AUTO_INCREMENT should be left to the drivers I think.

Rafal

Ingo Strüwing wrote:
> Hi Rafal,
> 
> Rafal Somla, 22.09.2009 11:23:
> 
> ...
>> No, I did not understand your suggestion completely. Indeed, for each
>> table there is extra_data field in the metadata record for that table
>> and it could be used for storing AUTO_INCREMENT value. Then the general
>> handling of AUTO_INCREMENT could be implemented without changing current
>> image format. In that case I think it is a better alternative than my
>> suggestion.
> 
> I was so happy that I could make a point. However, I stumbled over a
> problem, which might invalidate it.
> 
> Since backup shall work "online", the auto_increment value can change
> while the backup is going on. The only safe moment to grab the value
> would be the lock phase. The meta data section is written before table
> data backup does even start.
> 
> I just wonder if the default and cs drivers lock the tables from changes
> before or after the meta data section is written. If they do it before,
> my idea could be modified to require auto_increment value backup from
> the native drivers and do it in meta data only for the default and cs
> drivers. If not, we need to go with your suggestion.
> 
> Regards
> Ingo
Thread
MOM-BACKUP-090901 action items closed - decision requiredIngo Strüwing21 Sep
  • Re: MOM-BACKUP-090901 action items closed - decision requiredRafal Somla22 Sep
    • Re: MOM-BACKUP-090901 action items closed - decision requiredIngo Strüwing22 Sep
      • Re: MOM-BACKUP-090901 action items closed - decision requiredRafal Somla22 Sep
        • Re: MOM-BACKUP-090901 action items closed - decision requiredIngo Strüwing22 Sep
          • Re: MOM-BACKUP-090901 action items closed - decision requiredRafal Somla23 Sep