Simple PHP MySQL slow query (i.e. most likely stuck waiting for a lock) monitor.

lockmonitor.php

#!/usr/bin/env php
<?php

$mysqli = new mysqli('localhost', 'user', 'pass');
if ($mysqli->connect_errno) {
    echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}

$out = false;
$output = array();
$ignorecommands = array('Sleep', 'Binlog Dump', 'Connect');
foreach($mysqli->query('SHOW FULL PROCESSLIST') as $row) {
    if (in_array($row['Command'], $ignorecommands) or $row['Info'] == 'SHOW FULL PROCESSLIST') {
        continue;
    }
    //Spot anything older than 5 mins
    if ($row['Time'] > 300) {
       $out = true;
    }
    $output[] = $row;
}

if ($out and count($output) > 0) {
    echo json_encode($output)."\n";
}
if (count($output) > 0) {
    file_put_contents('lockcheck.log', json_encode($output)."\n", FILE_APPEND | LOCK_EX);
}