From: Dan Nelson
Date: May 24 2003 2:49am
Subject: Re: Slow queries on 4.0.13, FreeBSD 4.8 STABLE, linuxthreads, zawodny blog
List-Archive: http://lists.mysql.com/mysql/140637
Message-Id: <20030524024927.GA46907@dan.emsphone.com>
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In the last episode (May 23), LS said:
> On my FreeBSD 4.8 machine running 4.0.13 with linuxthreads, I am seeing the
> symptoms described in Jeremy's blog here
> (http://jeremy.zawodny.com/blog/archives/000203.html):
> 
> The server is handling 800qps, and the slow query log is showing
> hundreds of cases where trivial unrelated INSERT DELAYED queries are
> being held up for 2 seconds. Is there something else I need to do to
> get these slow queries to go away?

If you have a mix of INSERT and DELETE queries on a table, MySQL will
not be able to do concurrent INSERT and SELECT queries (concurrent
access only works if MySQL is able to append the inserted records to
the end of the table).  It could be that your slow INSERT queries are
waiting on the table lock of a complicated SELECT.  Show us a couple of
the timing lines (the ones starting with "# Query_time:") from your
slow-query log.  If Lock_Time: is nonzero, that means your query is
waiting on the table lock.

-- 
	Dan Nelson
	dnelson@stripped