#!/usr/bin/php
<?php

# mysql-reset-master-replication-log.php

$master_quota = 3;
exec("mysqladmin flush-logs");

$dbh = mysql_connect("localhost", "root", "passwd") or die(mysql_error($dbh));
$resp = mysql_query("SHOW MASTER STATUS;", $dbh) or die(mysql_error($dbh));
$row = mysql_fetch_assoc($resp);

if (preg_match("/^([^\.]+)\.(\d+)$/", $row["File"], $matches))
{
        $fileprefix = $matches[1];
        $filesufix = $matches[2];

        $delind = $filesufix - $master_quota;
        if ($delind > 0)
        {
                while (strlen($delsufix.$delind) < strlen($filesufix))
                        $delsufix .= "0";
                $delsufix .= $delind;
                $logfilename = "$fileprefix.$delsufix";
                echo "Delete binary logs up to $logfilename\n";
                mysql_query("PURGE MASTER LOGS TO '$logfilename';", $dbh) or die(mysql_error($dbh));
        }
        else
                echo "No binary logs to delete\n";
}
?>