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
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