Konstantin Osipov wrote:
> Currently one SQL statement runs from start to end in the same
> physical thread.
unless you query ndbcluster or federated tables, in this case
part of the work is handed of to external processes and in the
case of cluster several data nodes may process the low level
storage engine API requests in parallel, each working on its
active partition(s) of the data ...
But for the actual mysqld process it is true that all work it
does on a certain query itself is performed by the same single
thread.
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Hartmut Holzgraefe, MySQL Regional Support Manager, EMEA
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