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From Miguel González Castaños <miguel_3_gonza...@yahoo.es>
Subject Re: Tomcat pausing and no java process
Date Sat, 05 May 2012 09:41:19 GMT

>> Yes, I have pinpointed several queries that took quite long and
>> specially subqueries. I forwarded this info to the developer but
>> she said it was alright. More than a second to run a query seems to
>> be a lot to me.
> That depends on what the query does. If it checks permissions to
> login, that's insane and you should get a new programmer. If it's a
> reporting query that gathers lots of data then 1 second might not be
> quite so far-fetched.

I have checked directly the slow query log to pinpoint the real queries. 
I found many subqueries, which I believe is not a good practice, am I 
right? Many queries take around 2 seconds and I found two queries that 
took 16 seconds and 64 seconds to run (with many subqueries nested).

Is there any way I can log if any query is causing any trouble in the 
Tomcat resources?

>
>> The problem is that since the database E/R is not documented, it's
>> going to take a while to improve the performance of the queries.
> Look into SchemaSpy.
Nice
>
>> The developer is quitting so I hope a new developer is more
>> cooperative and we can work out these things.
> So you're saying that you're not going to get a lot of good
> information out of him/her?
Not much.

>
>> In the meantime I will check what I can do. I have also downloaded
>> mysqltuner script and mysqlfragfinder a long time ago and follow
>> the output of these tuning scripts.
> Just rememeber to vet all the recommendations. Don't just read
> "increase your query cache size" as a recommendation and blindly apply
> that rule. Many times the query cache is less useful that you might think.

Ok, thanks for the hint.

Miguel

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