Apple

On Mar 7, 2014, at 10:20 AM, Robin Smith <email@hidden> wrote:

I'm not sure about fetch plans, all i know at the moment is if i remove the LIMIT query i get millisecond performance on my query but if i include a LIMIT clause i get a full table scan.

You can log the query WO generates and run that through EXPLAIN? Try it with and without the limit.

On 7 March 2014 17:15, Jesse Tayler <email@hidden> wrote:

did you check to make sure your database is using the index fetch plan you expect?

I recall with MySQL sometimes indexes would fail but there would be no indication until I actually reviewed the fetch internals…

something chuck would know off the top of his head I’m sure…

On Mar 7, 2014, at 12:02 PM, Robin Smith <email@hidden> wrote:

Hi All

We have been experiencing some performace issues with our DB queries that we have narrowed down to the "limitClause" applied to sql queries. It seems that out of the box MySQL uses no indexes when supplied with a LIMIT clause.

Taking this into consideration we were wondering if anything like batch fetch iterator rely on the limit clause being applied to queries or if we could safely remove (or add switch to) this part of _MySqlPlugin.

Thanks

Robin

--
Robin Smith
Engineering Team Leader BEng (Hons) MBCS

http://www.clicktravel.com

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Robin Smith
Engineering Team Leader BEng (Hons) MBCS

http://www.clicktravel.com

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References:
	>MySqlPlugin (From: Robin Smith <email@hidden>)
	>Re: MySqlPlugin (From: Jesse Tayler <email@hidden>)
	>Re: MySqlPlugin (From: Robin Smith <email@hidden>)