Re: [Maria-developers] 答复: 答复: 答复: MDEV-520: consider parallel replication patch from taobao patches

Hi!

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"Kristian" == Kristian Nielsen writes:

Kristian> Stewart Smith writes:

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What about just run those txns serially rather than attempting to do in parallel?

Kristian> Maybe. Well, first we need to generalise "MyISAM" and "InnoDB" to a general Kristian> way of putting any storage engine into one or the other category. I assume Kristian> Monty or Serg can help me figure out how to do this.

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As soon as you see a MyISAM operation, have a thread that waits for all replication up to that point to be committed, and then do the MyISAM operation. (as there's no reason why other replication couldn't be applied at the same time... after all, MyISAM isn't crash safe so would never be consistent with InnoDB txns).

<cut> Kristian> MyISAM is not MVCC nor does it have COMMIT, so it seems by default we should Kristian> do what you suggest: run MyISAM transactions serially. In fact they have to Kristian> run serially with respect to InnoDB transactions also, to avoid getting the Kristian> slave into a state that might be invalid to the application. Note that MyISAM can mix SELECT and INSERT and these behave as there would be MVCC. Regards, Monty