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MySQL Internals Manual

23.18.7 extra


Passes hints from the server to the storage engine.


virtual int extra (


enum ha_extra_function

operation ;


This is the extra method.

extra() is called whenever the server wishes to send a hint to the storage engine. The MyISAM engine implements the most hints. has the most exhaustive list of these hints.


  • operation

Return Values

There are no return values.


Most storage engines will simply return 0.

{ return 0; }

Default Implementation

By default your storage engine can opt to implement none of the hints.

{ return 0; }

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