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From:Konstantin Osipov Date:September 25 2009 3:24pm
Subject:Re: is MySQL query execution single threaded?
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* Zardosht Kasheff <zardosht@stripped> [09/09/25 19:01]:
> I want to maintain some statistics while a statement is executing
> (number of rows inserted, updated, deleted, or read). If query
> execution is single threaded (e.g. two handlers will not be reading
> rows from different indexes in parallel for an index merge), then
> maintaining these statistics becomes easy. I do not have to worry
> about concurrency issues.
> 
> With that said, is query execution single-threaded? Or are threads
> spawned for parallel execution?

Currently one SQL statement runs from start to end in the same 
physical thread.

We have been looking into opportunities with multi-threaded ALTER
TABLE. 

In other words, today execution is single-threaded, but there are
middle-term plans for that to change.

-- 
Thread
is MySQL query execution single threaded?Zardosht Kasheff25 Sep
  • Re: is MySQL query execution single threaded?Konstantin Osipov25 Sep
    • Re: is MySQL query execution single threaded?Hartmut Holzgraefe28 Sep
      • RE: is MySQL query execution single threaded?Rick James2 Oct
      • RE: is MySQL query execution single threaded?Rick James7 Dec