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From:Ron Hu Date:March 16 2009 6:37pm
Subject:RE: Is handler object shared by two concurrent users?
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Many thanks, Sergei.  Your reply clarifies the proper use of a handler
object. 

Regards,
  -Ron Hu 

> -----Original Message-----
> From: Sergei Golubchik [mailto:serg@stripped]
> Sent: Monday, March 16, 2009 9:25 AM
> To: Ron Hu
> Cc: internals@stripped
> Subject: Re: Is handler object shared by two concurrent users?
> 
> Hi, Ron!
> 
> On Mar 12, Ron Hu wrote:
> > Hi Sergei:
> >
> > Thanks for your reply.  It helps.  I have a more complex test case to
> show
> > that same handler is shared by two concurrent users to some degree.  I
> want
> > to know the scope where a handler is not shared among users.  Is it
> between
> > the pair of ::external_lock calls (imposing a lock and release a lock)?
> If
> > so, then store_lock is not within the scope.
> 
> Right, but store_lock() is more like a class method, it isn't supposed
> to modify (or even access) the object's state. All it should do is to
> store its third parameter's value into its second parameter's value
> pointer. Possibly modifying the value according to the engine's logic.
> But nothing dependent on the handler object itself.
> 
> > Also some methods such as delete_table is not within the pair of
> > ::external_lock calls.  What other methods are not within the pair of
> > ::external_lock calls?
> 
> Certain DDL and admin methods, like rename or repair. But metadata locks
> (name locks in 5.1) should protect agains concurrent renames or repairs
> (or delete_table()s).
> 
> Regards / Mit vielen Grüßen,
> Sergei
> 
> --
>    __  ___     ___ ____  __
>   /  |/  /_ __/ __/ __ \/ /   Sergei Golubchik <serg@stripped>
>  / /|_/ / // /\ \/ /_/ / /__  Principal Software Engineer/Server Architect
> /_/  /_/\_, /___/\___\_\___/  Sun Microsystems GmbH, HRB München 161028
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Thread
Is active_index thread safe?Ron Hu11 Mar
  • Re: Is active_index thread safe?Sergei Golubchik11 Mar
    • RE: Is active_index thread safe?Ron Hu11 Mar
      • Re: Is active_index thread safe?MARK CALLAGHAN11 Mar
      • Re: Is active_index thread safe?Sergei Golubchik12 Mar
        • Is handler object shared by two concurrent users?Ron Hu12 Mar
          • Re: Is handler object shared by two concurrent users?Sergei Golubchik16 Mar
            • RE: Is handler object shared by two concurrent users?Ron Hu16 Mar
    • RE: Is active_index thread safe? --ResendRon Hu11 Mar