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From:Shawn Green (MySQL) Date:November 18 2011 10:16pm
Subject:Re: Concurrent table access from InnoDB
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On 11/18/2011 16:29, Rick James wrote:
> Is this what keeps there from being parallelism in PARTITIONed tables?
>
>...

No. Those partitions are accessed internally. Multiple threads can be 
spawned in the context of resolving a single query. Any lack of 
parallelism in resolving PARTITIONed table queries is simply a matter of 
design time and effort.

Now, in the context of accessing internal resources any query that 
requires a JOIN will need to touch at least two tables under the same 
user context.  Perhaps I misunderstood the original question?

>
> Hi,
> Is it possible for a client connection thread to access 2 tables concurrently from
> InnoDB, say using a slave thread ?  Or is access limited to one table at a time per client
> connection thread ?

Perhaps he was asking about the optimizer processing a command that 
needed to touch two or more tables?  If that's the purpose of the 
question then of course more than one table can be accessed in the 
context of a single connection. This happens very frequently.  I cannot 
say with absolute certainty if those tables are processed in parallel 
but I would be concerned if they were not.

I was reading his question more like this: Can the same connection be 
used to open multiple queries where each query is pointing to a separate 
table? In that context, each connection can only have one active command.

-- 
Shawn Green
MySQL Principal Technical Support Engineer
Oracle USA, Inc. - Hardware and Software, Engineered to Work Together.
Office: Blountville, TN
Thread
Concurrent table access from InnoDBhwatari18 Nov
  • Re: Concurrent table access from InnoDBMySQL)18 Nov
    • Re: Concurrent table access from InnoDBRick James18 Nov
      • Re: Concurrent table access from InnoDBMySQL)18 Nov
        • Re: Concurrent table access from InnoDBHiromichi Watari19 Nov
          • Re: Concurrent table access from InnoDBMark Leith21 Nov
            • Re: Concurrent table access from InnoDBStewart Smith22 Nov
              • Re: Concurrent table access from InnoDBRick James22 Nov
                • Re: Concurrent table access from InnoDBHiromichi Watari22 Nov
                  • Re: Concurrent table access from InnoDBRick James22 Nov
                    • Re: Concurrent table access from InnoDBHiromichi Watari23 Nov
RE: Concurrent table access from InnoDBSteve Hardy21 Nov