Index: branches/5.2.x/core/units/helpers/search_helper.php
===================================================================
diff -u -N -r16513 -r16655
--- branches/5.2.x/core/units/helpers/search_helper.php	(.../search_helper.php)	(revision 16513)
+++ branches/5.2.x/core/units/helpers/search_helper.php	(.../search_helper.php)	(revision 16655)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: search_helper.php 16513 2017-01-20 14:10:53Z alex $
+* @version	$Id: search_helper.php 16655 2021-01-04 08:47:57Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -811,17 +811,19 @@
 		public function ensureEmptySearchTable()
 		{
 			$search_table = $this->getSearchTable();
-			$this->Conn->Query('DROP TABLE IF EXISTS ' . $search_table);
-			$sql = 'CREATE TABLE ' . $search_table . ' (
+			$sql = 'CREATE TABLE IF NOT EXISTS ' . $search_table . ' (
 					  `Relevance` decimal(8,5) DEFAULT NULL,
 					  `ItemId` int(11) NOT NULL DEFAULT 0,
 					  `ResourceId` int(11) DEFAULT NULL,
 					  `ItemType` int(1) NOT NULL DEFAULT 0,
 					  `EdPick` tinyint(4) NOT NULL DEFAULT 0,
 					  KEY `ResourceId` (`ResourceId`),
 					  KEY `Relevance` (`Relevance`)
-					)';
+					) ENGINE = MEMORY';
 			$this->Conn->Query($sql);
+
+			$sql = 'TRUNCATE TABLE ' . $search_table;
+			$this->Conn->Query($sql);
 		}
 
 		/**
Index: branches/5.2.x/core/kernel/db/cat_event_handler.php
===================================================================
diff -u -N -r16621 -r16655
--- branches/5.2.x/core/kernel/db/cat_event_handler.php	(.../cat_event_handler.php)	(revision 16621)
+++ branches/5.2.x/core/kernel/db/cat_event_handler.php	(.../cat_event_handler.php)	(revision 16655)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: cat_event_handler.php 16621 2018-04-06 14:17:13Z alex $
+* @version	$Id: cat_event_handler.php 16655 2021-01-04 08:47:57Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -1352,17 +1352,21 @@
 		}
 
 		// building final search query
+		$search_table_exists = $this->Conn->Query('SHOW TABLES LIKE "'.$search_table.'"');
+
 		if (!$this->Application->GetVar('do_not_drop_search_table')) {
-			$this->Conn->Query('DROP TABLE IF EXISTS '.$search_table); // erase old search table if clean k4 event
+			if ( $search_table_exists ) {
+				$this->Conn->Query('TRUNCATE TABLE '.$search_table);
+			}
+
 			$this->Application->SetVar('do_not_drop_search_table', true);
 		}
 
-		$search_table_exists = $this->Conn->Query('SHOW TABLES LIKE "'.$search_table.'"');
 		if ($search_table_exists) {
 			$select_intro = 'INSERT INTO '.$search_table.' (Relevance, ItemId, ResourceId, ItemType, EdPick) ';
 		}
 		else {
-			$select_intro = 'CREATE TABLE '.$search_table.' AS ';
+			$select_intro = 'CREATE TABLE '.$search_table.' ENGINE = MEMORY AS ';
 		}
 
 		$edpick_clause = $this->Application->getUnitOption($event->Prefix.'.EditorsPick', 'Fields') ? $items_table.'.EditorsPick' : '0';
@@ -1647,25 +1651,38 @@
 
 		// Building final search query.
 		$search_table = $search_helper->getSearchTable();
-		$this->Conn->Query('DROP TABLE IF EXISTS '.$search_table);
+		$search_table_exists = $this->Conn->Query('SHOW TABLES LIKE "'.$search_table.'"');
 
+		if ($search_table_exists) {
+			$this->Conn->Query('TRUNCATE TABLE '.$search_table);
+			$select_intro = 'INSERT INTO '.$search_table.' (Relevance, ItemId, ResourceId, ItemType, EdPick) ';
+		}
+		else {
+			$select_intro = 'CREATE TABLE '.$search_table.' ENGINE = MEMORY AS ';
+		}
+
 		$id_field = $this->Application->getUnitOption($event->Prefix, 'IDField');
 		$fields = $this->Application->getUnitOption($event->Prefix, 'Fields');
 		$pick_field = isset($fields['EditorsPick']) ? $items_table.'.EditorsPick' : '0';
 
-		$sql = '	CREATE TABLE '.$search_table.'
-					SELECT 	'.$relevance_clause.' AS Relevance,
-							'.$items_table.'.'.$id_field.' AS ItemId,
-							'.$items_table.'.ResourceId AS ResourceId,
-							11 AS ItemType,
-							'.$pick_field.' AS EdPick
-					FROM '.$items_table.'
-					'.implode(' ', $join_clauses).'
-					WHERE '.$where_clause.'
-					GROUP BY '.$items_table.'.'.$id_field.
-					$having_clause;
-
+		$sql = $select_intro.'SELECT 	'.$relevance_clause.' AS Relevance,
+										'.$items_table.'.'.$id_field.' AS ItemId,
+										'.$items_table.'.ResourceId AS ResourceId,
+										11 AS ItemType,
+										'.$pick_field.' AS EdPick
+								FROM '.$items_table.'
+								'.implode(' ', $join_clauses).'
+								WHERE '.$where_clause.'
+								GROUP BY '.$items_table.'.'.$id_field.
+								$having_clause;
 		$this->Conn->Query($sql);
+
+		if ( !$search_table_exists ) {
+			$sql = 'ALTER TABLE ' . $search_table . '
+					ADD INDEX (ResourceId),
+					ADD INDEX (Relevance)';
+			$this->Conn->Query($sql);
+		}
 	}
 
 	function getAdvancedSearchCondition($field_name, $record, $keywords, $verbs, &$highlight_keywords)
Index: branches/5.2.x/core/units/categories/categories_event_handler.php
===================================================================
diff -u -N -r16621 -r16655
--- branches/5.2.x/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 16621)
+++ branches/5.2.x/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 16655)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: categories_event_handler.php 16621 2018-04-06 14:17:13Z alex $
+* @version	$Id: categories_event_handler.php 16655 2021-01-04 08:47:57Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -2764,17 +2764,21 @@
 			}
 
 			// building final search query
+			$search_table_exists = $this->Conn->Query('SHOW TABLES LIKE "'.$search_table.'"');
+
 			if (!$this->Application->GetVar('do_not_drop_search_table')) {
-				$this->Conn->Query('DROP TABLE IF EXISTS '.$search_table); // erase old search table if clean k4 event
+				if ( $search_table_exists ) {
+					$this->Conn->Query('TRUNCATE TABLE '.$search_table);
+				}
+
 				$this->Application->SetVar('do_not_drop_search_table', true);
 			}
 
-			$search_table_exists = $this->Conn->Query('SHOW TABLES LIKE "'.$search_table.'"');
 			if ($search_table_exists) {
 				$select_intro = 'INSERT INTO '.$search_table.' (Relevance, ItemId, ResourceId, ItemType, EdPick) ';
 			}
 			else {
-				$select_intro = 'CREATE TABLE '.$search_table.' AS ';
+				$select_intro = 'CREATE TABLE '.$search_table.' ENGINE = MEMORY AS ';
 			}
 
 			$edpick_clause = $this->Application->getUnitOption($event->Prefix.'.EditorsPick', 'Fields') ? $items_table.'.EditorsPick' : '0';