shawfactor

This plugin logs all wordpress queries in the current page request as a html comment at the end of your output.
It only does so when the get variable lh_log_queries is set. That variable has three settings. 
1. queries: this logs queries only 
2. hooks: this logs hooks only 
3. both: this logs both hooks and filters
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LH Log Queries and hooks

Decisions not options for query and hook logging

asadkn

A simple plugin to assist both theme and plugin developers in MySQL Profiling. Once installed, MySQL statistics will be available at page footer. Visit http://wpsplash.com/mysql-profiler-plugin-for-wordpress/ for more information.

WP MySQL Profiler

Used to profile MySQL queries for performance; with backtrace information for each query (caller functions, lines, file names etc.)

LH Log Queries and hooks vs WP MySQL Profiler