Index: wp-includes/wp-db.php
===================================================================
--- wp-includes/wp-db.php	(revision 6385)
+++ wp-includes/wp-db.php	(working copy)
@@ -15,7 +15,7 @@
 
 class wpdb {
 
-	var $show_errors = true;
+	var $show_errors = false;
 	var $num_queries = 0;
 	var $last_query;
 	var $col_info;
Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 6385)
+++ wp-includes/functions.php	(working copy)
@@ -249,7 +249,8 @@
 	$wpdb->hide_errors();
 	if ( !$options = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options WHERE autoload = 'yes'" ) )
 		$options = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options" );
-	$wpdb->show_errors();
+	if ( defined('WP_DEBUG') and WP_DEBUG == true )
+		$wpdb->show_errors();
 
 	foreach ( $options as $option ) {
 		// "When trying to design a foolproof system,
@@ -272,7 +273,8 @@
 		$wpdb->hide_errors();
 		if ( !$alloptions_db = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options WHERE autoload = 'yes'" ) )
 			$alloptions_db = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options" );
-		$wpdb->show_errors();
+		if ( defined('WP_DEBUG') and WP_DEBUG == true )
+			$wpdb->show_errors();
 		$alloptions = array();
 		foreach ( (array) $alloptions_db as $o )
 			$alloptions[$o->option_name] = $o->option_value;
@@ -915,7 +917,8 @@
 
 	$wpdb->hide_errors();
 	$installed = $wpdb->get_var( "SELECT option_value FROM $wpdb->options WHERE option_name = 'siteurl'" );
-	$wpdb->show_errors();
+	if ( defined('WP_DEBUG') and WP_DEBUG == true )
+		$wpdb->show_errors();
 
 	$installed = !empty( $installed ) ? true : false;
 	wp_cache_set('is_blog_installed', $installed);
Index: wp-includes/user.php
===================================================================
--- wp-includes/user.php	(revision 6385)
+++ wp-includes/user.php	(working copy)
@@ -238,7 +238,8 @@
 
 	$wpdb->hide_errors();
 	$metavalues = $wpdb->get_results($wpdb->prepare("SELECT meta_key, meta_value FROM $wpdb->usermeta WHERE user_id = %d", $user->ID));
-	$wpdb->show_errors();
+	if ( defined('WP_DEBUG') and WP_DEBUG == true )
+		$wpdb->show_errors();
 
 	if ( $metavalues ) {
 		foreach ( $metavalues as $meta ) {