- replication support

Changed files:
    drupal-replication.patch -> 1.1

diff --git a/drupal-replication.patch b/drupal-replication.patch
new file mode 100644 (file)
index 0000000..c2dc262
--- /dev/null
+++ b/drupal-replication.patch
@@ -0,0 +1,231 @@
+Replication patch from
+http://cvs.drupal.org/viewcvs/drupal/contributions/sandbox/crackerjm/replication/
+
+--- /dev/null  2005-02-16 21:06:48.000000000 +0200
++++ ./README.replication       2005-08-15 16:08:52.000000000 +0300
+@@ -0,0 +1,34 @@
++
++This README.txt and patch are for Mysql Replication. This assumes that you have
++a master replication server and slave server(s) up and running already. If 
++you don't, then there is no purpose for reading this.  If you need help for
++replication, please read this link.  
++      http://dev.mysql.com/doc/mysql/en/Replication.html
++
++NOTE: This is meant for drupal 4.6.0
++
++Now, in includes/conf.php you have a line that looks simalar to this
++    $db_url = "mysql://username:password@localhost/database";
++Comment at the line so that it looks like this
++    //$db_url = "mysql://username:password@localhost/database";
++
++Add the following lines below it to look like this:
++     $db_url = array();
++     $db_url['default'] = "mysql://username:password@localhost/database";
++     $db_url['slave1'] = "mysql://username:password@host/database";
++     //$db_url['slave2'] = "mysql://username:password@host/database";
++
++The 'default' is your MASTER server, the slaves are just that.  make 
++sure that you have added the appropriate users to the servers so that
++if you are using round robin DNS or something to that effect, that 
++way you don't end up with permission denied. 
++
++patch your code with replication.patch and there ya go
++
++***********
++NEW: This revision of code supports the dead slave servers!
++  caveat though, if ALL of your slaves are dead, then you will
++  end up in a infinitely recursive loop searching for slave servers.
++  Hopefully in the next revision of this, I will try to come up with
++  a way to stop this recursion without the use of flags.
++***********
+diff -urN drupal-4.6.0/includes/database.inc drupal-test/includes/database.inc
+--- drupal-4.6.0/includes/database.inc 2005-04-08 09:24:10.000000000 -0500
++++ drupal-test/includes/database.inc  2005-05-29 09:30:18.710563836 -0500
+@@ -119,11 +119,98 @@
+       die('Unsupported database type');
+     }
+ 
+-    $db_conns[$name] = db_connect($connect_url);
+-
++    if($name == 'default') {
++      // die on failure
++      $db_conns[$name] = db_connect($connect_url, true);
++    }
++    else {
++      $db_conns[$name] = db_connect($connect_url);
++    }
++      
+   }
+   // Set the active connection.
+-  $active_db = $db_conns[$name];
++  if($name != 'default' && $db_conns[$name] === false){
++    print "Bad slave, killing $name\n";
++    db_find_slave(true); // kill bad slave
++    db_set_active(db_find_slave());
++  }
++  else {
++    $active_db = $db_conns[$name];
++  }
++}
++
++function _is_commit($query) {
++  $commits = array('insert', 'alter', 'update', 'delete', 'flush', 'lock');
++  foreach($commits as $type) {
++    if(preg_match("/^$type/i", $query)) {
++      return true;
++    }
++  }
++  return false;
++}
++
++function db_find_slave($killslave = false) {
++  global $db_url;
++  static $slave ;
++
++  if(!_replication_ready())
++    return 'default';
++  
++  if(!is_array($slave)){
++    $slave = array();
++    // initialize a local copy
++    foreach($db_url as $key=>$value) {
++      if(stristr($key, 'slave')) {
++        $slave[] = $key;
++      }
++    }  
++    /**
++     * Since this is the first iteration of the loop, we reset the array to 
++     * ensure we return the first element.
++     */
++    return reset($slave);
++  }
++
++  if(empty($slave)) {
++    return 'default';
++  }
++
++  // Failed to connect, remove from the list
++  if($killslave){
++    array_shift($slave);
++  }
++
++  $url = next($slave);
++
++  if($url === false){
++    // walked past of the end of the array, start over at first element
++    $url = reset($slave);
++  }
++
++  return $url;
++}
++
++function _replication_ready() {
++  global $db_url;
++  static $ready;
++
++  if(isset($ready)) {
++    return $ready;
++  }
++  
++  if(is_array($db_url)) {
++    foreach($db_url as $key=>$value) {
++      if(stristr($key, 'slave')) {
++        // Found at least ONE element with the word slave in it
++        // break the search to save on cycles
++        $ready = true;
++        return true;
++      }
++    }
++  }
++  
++  $ready = false;
++  return false;
+ }
+ 
+ /**
+diff -urN drupal-4.6.0/includes/database.mysql.inc drupal-test/includes/database.mysql.inc
+--- drupal-4.6.0/includes/database.mysql.inc   2005-04-14 13:50:23.000000000 -0500
++++ drupal-test/includes/database.mysql.inc    2005-05-29 09:28:22.490546558 -0500
+@@ -20,7 +20,7 @@
+  * performance, however, when the overhead to connect to your database is high
+  * (e.g. your database and web server live on different machines).
+  */
+-function db_connect($url) {
++function db_connect($url, $critical = false) {
+   $url = parse_url($url);
+ 
+   // Allow for non-standard MySQL port.
+@@ -28,10 +28,16 @@
+      $url['host'] = $url['host'] .':'. $url['port'];
+   }
+ 
+-  $connection = mysql_connect($url['host'], $url['user'], $url['pass'], TRUE) or die(mysql_error());
+-  mysql_select_db(substr($url['path'], 1)) or die('unable to select database');
++  // For replication setups, we will assume that dieing is bad 
++  $connection = mysql_pconnect($url['host'], $url['user'], $url['pass'], TRUE);
++  if(!is_resource($connection) && $critical) {
++    die(mysql_error());
++  }
++  // We die on bad slaves.  These should be taken care of
++  // maybe hook this somehow or something
++  mysql_select_db(substr($url['path'], 1)) or die(mysql_error());
+ 
+-  return $connection;
++  return ($connection)?$connection:false;
+ }
+ 
+ /**
+@@ -40,14 +46,38 @@
+ function _db_query($query, $debug = 0) {
+   global $active_db;
+   global $queries;
++  global $db_url;
+ 
+   if (variable_get('dev_query', 0)) {
+     list($usec, $sec) = explode(' ', microtime());
+     $timer = (float)$usec + (float)$sec;
+   }
+ 
++  /**
++   * If the db_url isn't an array, then we can assume that this server is not
++   * ready for a replication setup.  This outer if is purely for a speed as
++   * calling PHP's builtin functions are way faster than user functions.
++   * So, if its an array and has more than one element, we shall atleast check
++   * to see if it's possibly ready for a replication enviorment.  However, 
++   * if no [slave#] elements are found, then we assume normal operations.
++   */
++  if(is_array($db_url) && sizeof($db_url) > 1 && _replication_ready() )
++  {
++    if (_is_commit($query) === true){
++      db_set_active('default');
++    }
++    else
++    {
++      // no checks as _replication_ready() verifies 
++      // that there is atleast one slave
++      db_set_active(db_find_slave());
++    }
++  }
++
++
+   $result = mysql_query($query, $active_db);
+ 
++
+   if (variable_get('dev_query', 0)) {
+     list($usec, $sec) = explode(' ', microtime());
+     $stop = (float)$usec + (float)$sec;
+@@ -67,6 +97,7 @@
+   }
+ }
+ 
++
+ /**
+  * Fetch one result row from the previous query as an object.
+  *
+@@ -239,4 +270,4 @@
+  * @} End of "ingroup database".
+  */
+ 
+-?>
+\ No newline at end of file
++?>