Andy's Blog » » MySQL has gone away解决办法

MySQL has gone away解决办法

最近写的一个采集系统在wordpress上面老是mysql has gone away
原因是mysql连接丢失

在一些耗时的地方, 使用mysql_ping来重新获得连接

下面给出我改进的wp-db.php类, 加入了

$wpdb->check_conn();

方法检查,如果连接丢失,自动重新连接

我非常讨厌在new一个类的时候还带上参数

$wpdb = new wpdb(DB_USER, DB_PASSWORD, DB_NAME, DB_HOST);

这个写法我是非常讨厌的,也顺便修了它

<?php
//  WordPress DB Class
//  ========================
//  fix by 21Andy.com at 2008-03-16
//  Andy Tse ([email protected])
//  http://www.21andy.com
//  ========================
//  ORIGINAL CODE FROM:
//  Justin Vincent ([email protected])
//    http://php.justinvincent.com
 
define('EZSQL_VERSION', 'WP1.25');
define('OBJECT', 'OBJECT', true);
define('ARRAY_A', 'ARRAY_A', false);
define('ARRAY_N', 'ARRAY_N', false);
 
if (!defined('SAVEQUERIES'))
    
define('SAVEQUERIES', false);
 
class wpdb {
 
    
var $show_errors = false;
    
var $num_queries = 0;
    
var $last_query;
    
var $col_info;
    
var $queries;
    
var $ready = false;
 
    
// Our tables
    
var $posts;
    
var $users;
    
var $categories;
    
var $post2cat;
    
var $comments;
    
var $links;
    
var $options;
    
var $optiontypes;
    
var $optionvalues;
    
var $optiongroups;
    
var $optiongroup_options;
    
var $postmeta;
    
var $usermeta;
    
var $terms;
    
var $term_taxonomy;
    
var $term_relationships;
 
    
var $charset;
    
var $collate;
 
    
/**
     * Connects to the database server and selects a database
     *
@param string $dbuser
     *
@param string $dbpassword
     *
@param string $dbname
     *
@param string $dbhost
     */

    
function wpdb() {
        
return $this->__construct();
    
}
 
    
function __construct() {
        
register_shutdown_function(array(&$this, "__destruct"));
 
        
if ( defined('WP_DEBUG') and WP_DEBUG == true )
            
$this->show_errors();
 
        
if ( defined('DB_CHARSET') )
            
$this->charset = DB_CHARSET;
 
        
if ( defined('DB_COLLATE') )
            
$this->collate = DB_COLLATE;
 
        
if ( ! defined('DB_USER') ||
            !
defined('DB_PASSWORD') ||
            !
defined('DB_NAME') ||
            !
defined('DB_HOST') )
            
exit('please config DB setting!!!');
 
        
$this->dbuser = DB_USER;
        
$this->dbpassword = DB_PASSWORD;
        
$this->dbname = DB_NAME;
        
$this->dbhost = DB_HOST;
        
$this->connect();
    
}
 
    
function connect() {
        
$this->dbh = @mysql_connect($this->dbhost, $this->dbuser, $this->dbpassword);
        
if (!$this->dbh) {
            
$this->bail("
<h1>Error establishing a database connection</h1>
<p>This either means that the username and password information in your <code>wp-config.php</code> file is incorrect or we can't contact the database server at <code>
$dbhost</code>. This could mean your host's database server is down.</p>
<ul>
    <li>Are you sure you have the correct username and password?</li>
    <li>Are you sure that you have typed the correct hostname?</li>
    <li>Are you sure that the database server is running?</li>
</ul>
<p>If you're unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href='http://wordpress.org/support/'>WordPress Support Forums</a>.</p>
");
            
return;
        
}
 
        
$this->ready = true;
 
        
if ( !empty($this->charset) && version_compare(mysql_get_server_info(), '4.1.0', '>=') )
            
$this->query("SET NAMES '$this->charset'");
 
        
$this->select($this->dbname);
    
}
 
    
function check_conn() {
        
if (!mysql_ping($this->dbh)) {
          
//here is the major trick, you have to close the connection (even though its not currently working) for it to recreate properly.
          
mysql_close($this->dbh);
          
$this->connect();
        
}
    
}
 
    
function __destruct() {
        
return true;
    
}
 
    
/**
     * Selects a database using the current class's $this->dbh
     *
@param string $db name
     */

    
function select($db) {
        
if ([email protected]mysql_select_db($db, $this->dbh)) {
            
$this->ready = false;
            
$this->bail("
<h1>Can&#8217;t select database</h1>
<p>We were able to connect to the database server (which means your username and password is okay) but not able to select the <code>
$db</code> database.</p>
<ul>
<li>Are you sure it exists?</li>
<li>Does the user <code>
".DB_USER."</code> have permission to use the <code>$db</code> database?</li>
<li>On some systems the name of your database is prefixed with your username, so it would be like username_wordpress. Could that be the problem?</li>
</ul>
<p>If you don't know how to setup a database you should <strong>contact your host</strong>. If all else fails you may find help at the <a href='http://wordpress.org/support/'>WordPress Support Forums</a>.</p>
");
            
return;
        
}
    
}
 
    
/**
     * Escapes content for insertion into the database, for security
     *
     *
@param string $string
     *
@return string query safe string
     */

    
function escape($string) {
        
return addslashes( $string ); // Disable rest for now, causing problems
        
if( !$this->dbh || version_compare( phpversion(), '4.3.0' ) == '-1' )
            
return mysql_escape_string( $string );
        
else
            
return mysql_real_escape_string( $string, $this->dbh );
    
}
 
    
/**
     * Escapes content by reference for insertion into the database, for security
     *
@param string $s
     */

    
function escape_by_ref(&$s) {
        
$s = $this->escape($s);
    
}
 
    
/**
     * Prepares a SQL query for safe use, using sprintf() syntax
     */

    
function prepare($args=NULL) {
        
if ( NULL === $args )
            
return;
        
$args = func_get_args();
        
$query = array_shift($args);
        
$query = str_replace("'%s'", '%s', $query); // in case someone mistakenly already singlequoted it
        
$query = str_replace('"%s"', '%s', $query); // doublequote unquoting
        
$query = str_replace('%s', "'%s'", $query); // quote the strings
        
array_walk($args, array(&$this, 'escape_by_ref'));
        
return @vsprintf($query, $args);
    
}
 
    
// ==================================================================
    
//    Print SQL/DB error.
 
    
function print_error($str = '') {
        
global $EZSQL_ERROR;
        
if (!$str) $str = mysql_error($this->dbh);
        
$EZSQL_ERROR[] =
        
array ('query' => $this->last_query, 'error_str' => $str);
 
        
$error_str = "WordPress database error $str for query $this->last_query";
        
error_log($error_str, 0);
 
        
// Is error output turned on or not..
        
if ( !$this->show_errors )
            
return false;
 
        
$str = htmlspecialchars($str, ENT_QUOTES);
        
$query = htmlspecialchars($this->last_query, ENT_QUOTES);
 
        
// If there is an error then take note of it
        
print "<div id='error'>
        <p class='wpdberror'><strong>WordPress database error:</strong> [
$str]<br />
        <code>
$query</code></p>
        </div>
";
    
}
 
    
// ==================================================================
    
//    Turn error handling on or off..
 
    
function show_errors( $show = true ) {
        
$errors = $this->show_errors;
        
$this->show_errors = $show;
        
return $errors;
    
}
 
    
function hide_errors() {
        
$show = $this->show_errors;
        
$this->show_errors = false;
        
return $show;
    
}
 
    
// ==================================================================
    
//    Kill cached query results
 
    
function flush() {
        
$this->last_result = array();
        
$this->col_info = null;
        
$this->last_query = null;
    
}
 
    
// ==================================================================
    
//    Basic Query    - see docs for more detail
 
    
function query($query) {
        
if ( ! $this->ready )
            
return false;
 
        
// filter the query, if filters are available
        
// NOTE: some queries are made before the plugins have been loaded, and thus cannot be filtered with this method
        
if ( function_exists('apply_filters') )
            
$query = apply_filters('query', $query);
 
        
// initialise return
        
$return_val = 0;
        
$this->flush();
 
        
// Log how the function was called
        
$this->func_call = "\$db->query(\"$query\")";
 
        
// Keep track of the last query for debug..
        
$this->last_query = $query;
 
        
// Perform the query via std mysql_query function..
        
if (SAVEQUERIES)
            
$this->timer_start();
 
        
$this->result = @mysql_query($query, $this->dbh);
        ++
$this->num_queries;
 
        
if (SAVEQUERIES)
            
$this->queries[] = array( $query, $this->timer_stop() );
 
        
// If there is an error then take note of it..
        
if ( mysql_error($this->dbh) ) {
            
$this->print_error();
            
return false;
        
}
 
        
if ( preg_match("/^\\s*(insert|delete|update|replace) /i",$query) ) {
            
$this->rows_affected = mysql_affected_rows($this->dbh);
            
// Take note of the insert_id
            
if ( preg_match("/^\\s*(insert|replace) /i",$query) ) {
                
$this->insert_id = mysql_insert_id($this->dbh);
            
}
            
// Return number of rows affected
            
$return_val = $this->rows_affected;
        
} else {
            
$i = 0;
            
while ($i < @mysql_num_fields($this->result)) {
                
$this->col_info[$i] = @mysql_fetch_field($this->result);
                
$i++;
            
}
            
$num_rows = 0;
            
while ( $row = @mysql_fetch_object($this->result) ) {
                
$this->last_result[$num_rows] = $row;
                
$num_rows++;
            
}
 
            @
mysql_free_result($this->result);
 
            
// Log number of rows the query returned
            
$this->num_rows = $num_rows;
 
            
// Return number of rows selected
            
$return_val = $this->num_rows;
        
}
 
        
return $return_val;
    
}
 
    
/**
     * Get one variable from the database
     *
@param string $query (can be null as well, for caching, see codex)
     *
@param int $x = 0 row num to return
     *
@param int $y = 0 col num to return
     *
@return mixed results
     */

    
function get_var($query=null, $x = 0, $y = 0) {
        
$this->func_call = "\$db->get_var(\"$query\",$x,$y)";
        
if ( $query )
            
$this->query($query);
 
        
// Extract var out of cached results based x,y vals
        
if ( $this->last_result[$y] ) {
            
$values = array_values(get_object_vars($this->last_result[$y]));
        
}
 
        
// If there is a value return it else return null
        
return (isset($values[$x]) && $values[$x]!=='') ? $values[$x] : null;
    
}
 
    
/**
     * Get one row from the database
     *
@param string $query
     *
@param string $output ARRAY_A | ARRAY_N | OBJECT
     *
@param int $y row num to return
     *
@return mixed results
     */

    
function get_row($query = null, $output = OBJECT, $y = 0) {
        
$this->func_call = "\$db->get_row(\"$query\",$output,$y)";
        
if ( $query )
            
$this->query($query);
        
else
            
return null;
 
        
if ( !isset($this->last_result[$y]) )
            
return null;
 
        
if ( $output == OBJECT ) {
            
return $this->last_result[$y] ? $this->last_result[$y] : null;
        
} elseif ( $output == ARRAY_A ) {
            
return $this->last_result[$y] ? get_object_vars($this->last_result[$y]) : null;
        
} elseif ( $output == ARRAY_N ) {
            
return $this->last_result[$y] ? array_values(get_object_vars($this->last_result[$y])) : null;
        
} else {
            
$this->print_error(" \$db->get_row(string query, output type, int offset) -- Output type must be one of: OBJECT, ARRAY_A, ARRAY_N");
        
}
    
}
 
    
/**
     * Gets one column from the database
     *
@param string $query (can be null as well, for caching, see codex)
     *
@param int $x col num to return
     *
@return array results
     */

    
function get_col($query = null , $x = 0) {
        
if ( $query )
            
$this->query($query);
 
        
$new_array = array();
        
// Extract the column values
        
for ( $i=0; $i < count($this->last_result); $i++ ) {
            
$new_array[$i] = $this->get_var(null, $x, $i);
        
}
        
return $new_array;
    
}
 
    
/**
     * Return an entire result set from the database
     *
@param string $query (can also be null to pull from the cache)
     *
@param string $output ARRAY_A | ARRAY_N | OBJECT
     *
@return mixed results
     */

    
function get_results($query = null, $output = OBJECT) {
        
$this->func_call = "\$db->get_results(\"$query\", $output)";
 
        
if ( $query )
            
$this->query($query);
        
else
            
return null;
 
        
// Send back array of objects. Each row is an object
        
if ( $output == OBJECT ) {
            
return $this->last_result;
        
} elseif ( $output == ARRAY_A || $output == ARRAY_N ) {
            
if ( $this->last_result ) {
                
$i = 0;
                
foreach( $this->last_result as $row ) {
                    
$new_array[$i] = (array) $row;
                    
if ( $output == ARRAY_N ) {
                        
$new_array[$i] = array_values($new_array[$i]);
                    
}
                    
$i++;
                
}
                
return $new_array;
            
} else {
                
return null;
            
}
        
}
    
}
 
    
/**
     * Grabs column metadata from the last query
     *
@param string $info_type one of name, table, def, max_length, not_null, primary_key, multiple_key, unique_key, numeric, blob, type, unsigned, zerofill
     *
@param int $col_offset 0: col name. 1: which table the col's in. 2: col's max length. 3: if the col is numeric. 4: col's type
     *
@return mixed results
     */

    
function get_col_info($info_type = 'name', $col_offset = -1) {
        
if ( $this->col_info ) {
            
if ( $col_offset == -1 ) {
                
$i = 0;
                
foreach($this->col_info as $col ) {
                    
$new_array[$i] = $col->{$info_type};
                    
$i++;
                
}
                
return $new_array;
            
} else {
                
return $this->col_info[$col_offset]->{$info_type};
            
}
        
}
    
}
 
    
/**
     * Starts the timer, for debugging purposes
     */

    
function timer_start() {
        
$mtime = microtime();
        
$mtime = explode(' ', $mtime);
        
$this->time_start = $mtime[1] + $mtime[0];
        
return true;
    
}
 
    
/**
     * Stops the debugging timer
     *
@return int total time spent on the query, in milliseconds
     */

    
function timer_stop() {
        
$mtime = microtime();
        
$mtime = explode(' ', $mtime);
        
$time_end = $mtime[1] + $mtime[0];
        
$time_total = $time_end - $this->time_start;
        
return $time_total;
    
}
 
    
/**
     * Wraps fatal errors in a nice header and footer and dies.
     *
@param string $message
     */

    
function bail($message) { // Just wraps errors in a nice header and footer
        
if ( !$this->show_errors ) {
            
if ( class_exists('WP_Error') )
                
$this->error = new WP_Error('500', $message);
            
else
                
$this->error = $message;
            
return false;
        
}
        
wp_die($message);
    
}
}
 
if ( ! isset($wpdb) )
    
$wpdb = new wpdb;
?>

Incoming search terms:

Tags: wordpress, wpdb, bug, mysql_ping, wp-db.php, 修正

本文地址: http://www.21andy.com/new/20080316/1055.html