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From:Rick James Date:November 22 2011 2:14am
Subject:Re: Concurrent table access from InnoDB
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PARTITION has very few use cases where it performs better than a single 
table.  This feels like a way to make PARTITION worth having.  Oh, well, 
I keep hoping.  Meanwhile, when someone says they will use PARTITION.  I 
say "Why?".

On 11/21/11 4:52 PM, Stewart Smith wrote:
> On Mon, 21 Nov 2011 09:55:15 +0000, Mark Leith<mark.leith@stripped>  wrote:
>> This doesn't necessarily relate to the limitation of partitioned
>> tables not having a multi-threaded read of partitions under the
>> covers, as at the handler / SQL layer, MySQL is just waiting for the
>> storage engine to return rows to it at the current step of JOIN
>> execution - under the covers the storage engine could choose to access
>> the partitions of a single table concurrently if it wanted to (we just
>> don't have that in MySQL at the moment).
> NDB does this. Multiple data nodes may be sending data back to the MySQL
> server at once.
>
> This is a pretty limited form of parallelism though.
>
> Basically, concurrent query execution is hard and for the vast majority
> of queries that MySQL processes, wouldn't see any or much improvement -
> avoiding the added complexity (and performance impact for non
> parallelized queries) of locking is a pretty big benefit.
>
>

-- 
Rick James - MySQL Geek

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