From: Martijn Tonies
Date: April 12 2007 12:44pm
Subject: Re: when rebuilding keys?
List-Archive: http://lists.mysql.com/mysql/206096
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> >> >> before load data.
> >> >
> >> > You want to rebuild the indices after loading data,
> >> > correct?
> >
> > Then what exactly is the question?
> >
> >
> > Please write your answer BELOW, not above.
>
> sorry ,my english is poor.
>
> There is  a  observable event.
> My table's engine is myisam.
> Rows above 1000000 in my table.
> I did "alter table ......disable keys" before loading data.
> I did "alter table ......enable keys" after loading data.
> The operation of enable keys is so fast!
>
> I am not sure than if the keys have been rebuild.I think the course of
> rebuilding should need very long time.

According to the documentation:

 ALTER TABLE ... ENABLE KEYS then should be used to re-create missing
indexes. MySQL does this with a special algorithm that is much faster than
inserting keys one by one, so disabling keys before performing bulk insert
operations should give a considerable speedup.


Martijn Tonies
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