542 Part V . Advanced Performance The previous (Tomcat web server)
542 Part V . Advanced Performance The previous snippet calls the functions for querying the various replication servers. Again, by adding a feature to gather this data from a MySQL database, you could use one function and call the server based on what type it is as stored in your database. function slavestatus ($host,$username,$password) { $dbconn = mysql_connect($host,$username,$password) or die ( Cannot connect to database server ); $result = mysql_query( SHOW SLAVE STATUS ); $timeresult = mysql_query( SELECT NOW() ); $time = mysql_result($timeresult, 0, 0); The next step is to make a connection to the database and issue statements, including one that queries for the current time from the replication server. while ($status = mysql_fetch_array($result)) { $mysqlserver = $host; $file = $status[4]; $position = $status[5]; $run = $status[6]; $errnum = $status[9]; $errmsg = $status[10]; } Taking the results from SHOW SLAVE SERVER, I parse them into variables that make some sense for the application context. The code looks like this: if ($run != Yes ) { $color =
; } else { $color =
$color Slave
$color $host
$additio nal
n ; } The contents of the $run variable are examined. If it is anything other than Yesis found, the background color of the table cell changes to red (otherwise it s green). Pointing a Web browser to the page results in the listing illustrated in Figure 18-13. The replication status from Figure 18-13 is taken directly from output of the appropriate SHOW statement. Notice that there is no Yes or No applicable for the master server. This is because the master server doesn t know anything about replication or the slaves that replicate from it. It simply goes about its business of recording updates and changes to the binary replication log.
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