3 files changed, 18 insertions, 3 deletions
diff --git a/phpBB/includes/acp/acp_search.php b/phpBB/includes/acp/acp_search.php
index dc6f3d1c44..66edbd44ae 100644
--- a/phpBB/includes/acp/acp_search.php
+++ b/phpBB/includes/acp/acp_search.php
@@ -63,6 +63,7 @@ class acp_search
 			'load_search'				=> 'bool',
 			'limit_search_load'			=> 'float',
 			'min_search_author_chars'	=> 'integer',
+			'max_num_search_keywords'	=> 'integer',
 			'search_store_results'		=> 'integer',
 		);
 
@@ -216,6 +217,7 @@ class acp_search
 			'SEARCH_INTERVAL'		=> (float) $config['search_interval'],
 			'SEARCH_GUEST_INTERVAL'	=> (float) $config['search_anonymous_interval'],
 			'SEARCH_STORE_RESULTS'	=> (int) $config['search_store_results'],
+			'MAX_NUM_SEARCH_KEYWORDS'	=> (int) $config['max_num_search_keywords'],
 
 			'S_SEARCH_TYPES'		=> $search_options,
 			'S_YES_SEARCH'			=> (bool) $config['load_search'],
diff --git a/phpBB/includes/search/fulltext_mysql.php b/phpBB/includes/search/fulltext_mysql.php
index 2a67b58246..e1e7951367 100644
--- a/phpBB/includes/search/fulltext_mysql.php
+++ b/phpBB/includes/search/fulltext_mysql.php
@@ -118,7 +118,7 @@ class fulltext_mysql extends search_backend
 	*/
 	function split_keywords(&$keywords, $terms)
 	{
-		global $config;
+		global $config, $user;
 
 		if ($terms == 'all')
 		{
@@ -167,6 +167,12 @@ class fulltext_mysql extends search_backend
 			$this->split_words = $matches[1];
 		}
 
+		// We limit the number of allowed keywords to minimize load on the database
+		if ($config['max_num_search_keywords'] && sizeof($this->split_words) > $config['max_num_search_keywords'])
+		{
+			trigger_error($user->lang('MAX_NUM_SEARCH_KEYWORDS_REFINE', $config['max_num_search_keywords'], sizeof($this->split_words)));
+		}
+
 		// to allow phrase search, we need to concatenate quoted words
 		$tmp_split_words = array();
 		$phrase = '';
diff --git a/phpBB/includes/search/fulltext_native.php b/phpBB/includes/search/fulltext_native.php
index 1c6a64d07c..ee36039454 100644
--- a/phpBB/includes/search/fulltext_native.php
+++ b/phpBB/includes/search/fulltext_native.php
@@ -167,6 +167,13 @@ class fulltext_native extends search_backend
 		);
 
 		$keywords = preg_replace($match, $replace, $keywords);
+		$num_keywords = sizeof(explode(' ', $keywords));
+
+		// We limit the number of allowed keywords to minimize load on the database
+		if ($config['max_num_search_keywords'] && $num_keywords > $config['max_num_search_keywords'])
+		{
+			trigger_error($user->lang('MAX_NUM_SEARCH_KEYWORDS_REFINE', $config['max_num_search_keywords'], $num_keywords));
+		}
 
 		// $keywords input format: each word separated by a space, words in a bracket are not separated
 
@@ -693,7 +700,7 @@ class fulltext_native extends search_backend
 				$sql_where[] = 'f.forum_id = p.forum_id';
 			break;
 		}
-		
+
 		if ($left_join_topics)
 		{
 			$sql_array['LEFT_JOIN'][$left_join_topics] = array(
@@ -1110,7 +1117,7 @@ class fulltext_native extends search_backend
 
 		// Get unique words from the above arrays
 		$unique_add_words = array_unique(array_merge($words['add']['post'], $words['add']['title']));
-		
+
 		// We now have unique arrays of all words to be added and removed and
 		// individual arrays of added and removed words for text and title. What
 		// we need to do now is add the new words (if they don't already exist)