Re: strange ADO / myODBC speed problem

vanwout@xxxxxxxxx wrote:

After (foolishly?) installing several components on the server
(including Word and Access 2000, and several ASP components needed for
our web application) I now noticed our performance through the
application plunged dramatically....the same query now took more than
6 seconds with the CPU peaking!

The strange thing is that when I performed the exact same query
directly on the mySQL server, the query was very fast (less than 1
second!).

I have no experience with mySQL, so I don't know if this is relevant.
However, on SQL Server, when a performance difference is perceived
between running a procedure from a client vs. running it in Query
Analyzer, the difference is often due to a performance optimization
behavior called "parameter sniffing". While usually a good thing,
"parameter sniffing" can sometimes cause the optimizer to choose a query
plan which may be good if the query is run using the parameters that the
optimizer "guessed" you would use, but bad for the parameter values that
would actually be used in production.

Here's a couple articles discussing the issue and the steps that can be
taken to deal with it in SQL Server:
http://tinyurl.com/f9r2
http://blogs.msdn.com/queryoptteam/archive/2006/03/31/565991.aspx

Again, I have no idea if this is relevant to mysql - you will need to
post to a mysql group to verify that.




--
Microsoft MVP -- ASP/ASP.NET
Please reply to the newsgroup. The email account listed in my From
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quicker response by posting to the newsgroup.


.

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