query logging

log_query.php

<?php 
/* SQL LOGGING FOR PAGES */
add_action( 'shutdown', 'sql_logger' );
function sql_logger() {
  global $wpdb;
  $log_file = fopen( ABSPATH.'/sql_log.txt', 'a' );
  fwrite( $log_file, "//////////////////////////////////////////\n\n" . date( 'F j, Y, g:i:s a' )."\n" );
  foreach ( $wpdb->queries as $q ) {
      fwrite( $log_file, $q[0] . " - ( $q[1] s )" . "\n\n" );
  }
  fclose( $log_file );
}