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From:Rick James Date:October 26 2011 11:38pm
Subject:Re: Master-Master -> duplicate entry
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This is a big reason not to allow writing to both Masters.

On 10/26/11 12:20 PM, Ricardo Freitas wrote:
> Hello, my fellow developers and admins
>
>
>
> I have a question regarding a master-master replication system.
>
>
>
> I implemented one with the help of some of you guys - however I had some
> problems regarding the agent so I have a master-master and not a mmm system
> - and now I come across the awfull 1062 error - the 'Error 'Duplicate entry
> '123020901' for key 'PRIMARY'' on query.'
>
>
>
> The issue here is I sometimes insert on master 1 (let's call it like this)
> and sometimes on master 2. I thought this wouldn't be an issue as both
> database would talk to one another however I think this might be the origin
> of the problem.
>
>
>
> I already changed the system to always force the inserts query to be on
> Master 1 however I would like to know how to avoid this. I read something
> about configuring a skip-slave-error but I don't think this would be that
> much of a solution as sometimes things happens and it's important to have
> some kind of notion or warning.
>
>
>
> I read about the auto-increment-increment = 2 or even the increment offset.
>
>
>
> If I configure Master 2 to auto-increment-increment = 2 and master 1 to
> auto-increment-increment = 1, would this help?
>
>
>
> Master 1 - example
>
> Row 1
>
> Row 2
>
> Row 3
>
>
>
> Master 2 - example
>
>
>
> Row 2
>
> Row 4
>
> Row 6
>
>
>
> As far as I'm concerned, eventually sometimes collisions would occur. I
> thought that PK's weren't replicated as the database would just receive the
> insert query and viola.
>
>
>
> How can I avoid this in the future?
>
>
>
> I read about UUID as well but as I've inherit this system I have a lot of
> sites already relaying on the pk (for query purposes) so I can't just
> changed this.
>
>
>
> Thanks a lot!
>
>
>
> Ricardo
>
>
>
>
>

-- 
Rick James - MySQL Geek

Thread
Master-Master -> duplicate entryRicardo Freitas26 Oct
  • Re: Master-Master -> duplicate entrynavid@navid.it26 Oct
    • Re: Master-Master -> duplicate entryRicardo26 Oct
  • Re: Master-Master -> duplicate entryRick James27 Oct
    • Re: Master-Master -> duplicate entryRicardo27 Oct
      • Re: Master-Master -> duplicate entryMarcus Bointon27 Oct
        • Re: Master-Master -> duplicate entryJohan De Meersman27 Oct
          • Re: Master-Master -> duplicate entryRicardo27 Oct
          • Re: Master-Master -> duplicate entryRicardo27 Oct
          • Re: Master-Master -> duplicate entryMarcus Bointon27 Oct
            • RE: Master-Master -> duplicate entryRicardo Freitas27 Oct
              • Re: Master-Master -> duplicate entrynavid@navid.it27 Oct
              • Re: Master-Master -> duplicate entryMarcus Bointon27 Oct
                • RE: Master-Master -> duplicate entryRicardo Freitas27 Oct
                  • Re: Master-Master -> duplicate entryMarcus Bointon27 Oct
                    • RE: Master-Master -> duplicate entryRicardo Freitas27 Oct
                    • Re: Master-Master -> duplicate entryRicardo27 Oct
                      • Re: Master-Master -> duplicate entryMarcus Bointon27 Oct
                        • RE: Master-Master -> duplicate entryRicardo Freitas27 Oct
                          • Re: Master-Master -> duplicate entryMarcus Bointon27 Oct
                            • Re: Master-Master -> duplicate entry (UUID lecture)Rick James27 Oct
            • Re: Master-Master -> duplicate entryJohan De Meersman28 Oct
        • Re: Master-Master -> duplicate entryRicardo27 Oct
  • Re: Master-Master -> duplicate entrylist27 Oct
    • RE: Master-Master -> duplicate entryRicardo Freitas27 Oct
      • Re: Master-Master -> duplicate entryMarcus Bointon27 Oct
        • Re: Master-Master -> duplicate entryMySQL)27 Oct
    • Re: Master-Master -> duplicate entryRick James27 Oct
      • Re: Master-Master -> duplicate entryMarcus Bointon27 Oct
        • Re: Master-Master -> duplicate entryRick James27 Oct
          • Re: Master-Master -> duplicate entryJohan De Meersman28 Oct
            • Re: Master-Master -> duplicate entryRick James28 Oct
              • Re: Master-Master -> duplicate entryMats Kindahl31 Oct
      • Re: Master-Master -> duplicate entrylist27 Oct