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From:Dan Nelson Date:September 12 2000 9:47pm
Subject:Re: MyODBC/MySQL Speed?
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In the last episode (Sep 12), Garry Dunn said:
> So I went through the process with a few of the tables (i.e. created
> MySQL tables, exported the data from MSAccess, imported the data into
> MySQL). Everything works fine.
> The problem is that the MyODBC/MySQL combination runs SLOWER than the
> MSAccess (equivalent queries take about twice the time on the MyODBC/MySQL
> combination, compared to the MSAccess linked tables).  I'm holding

We did the exact same thing a few years ago.  Some of our troubles are
documented in the MySQL manual (the example tables under the "explain
syntax" section are ours) :) 

Make sure when you copied the tables over that you generated the same
indexes, and make sure that any fields that you use to join tables with
are identical (i.e. don't have char(10) joining to a char(15) or an
int).  Also run myisamchk -a on your tables to generate column counts
mysql can use to optimize queries.

You might also be running into subquery emulation issues.   If you have
any stored queries that use subqueries or other features that Mysql
doesn't support, the ODBC driver manager will emulate the features
(usually by generating a zillion small queries and joining them
together on the client).  Turn on "log" and "log-slow-queries" on the
mysql server, and see what kind of queries your client is generating.

	Dan Nelson
MyODBC/MySQL Speed?Garry Dunn12 Sep
  • Re: MyODBC/MySQL Speed?Dan Nelson12 Sep
    • RE: MyODBC/MySQL Speed?Garry Dunn13 Sep
      • RE: MyODBC/MySQL Speed?James Treworgy13 Sep