"jatwood" <[EMAIL PROTECTED]> wrote on 28/04/2005 22:35:45:
> I am new to MySQL. Please excuse my ignorance if this question has been
> previously discussed. I was not able to
>
> find an answer to my question by searching the archives.
>
>
>
> I have MySQL installed on a dedicated AMD-64 computer with the MS XP Pro
> operating system.
>
> MS-SQLServer is installed on a 32-bit machine with a slower clock speed.
I
> am running the free binary
>
> distribution of MySQL for testing purposes and have been generally
impressed
> with
>
> MySQL's comparative performance in all but one area.
>
>
>
> I am finding that both inner and outer merges take substantially longer
with
> MySQL than with the SQLServer using the same basic code.
>
> In one application a left outer merge between a file with 600,000
records
> and a file with 4,500,000 records took about 10-15 minutes with
>
> SQLServer and 11 hours with MySQL. I am repeatedly having similar
> experiences with both inner and outer merges.
>
>
>
> Is there any way I can try to improve MySQL's performance with respect
to
> merges? Needless to say, unless I can improve MySQL's
>
> performance, I will not be converting to MySQL at this time.
You need to post the results of EXPLAIN <your select statement> together
with the structures of your tables, including indexes.
This sort of performance dropoff is usually due to inappropriate indexes,
and can be solved by adding or changing indexes.
Alec
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