Index: branches/5.2.x/core/units/helpers/page_helper.php
===================================================================
diff -u -N -r16634 -r16667
--- branches/5.2.x/core/units/helpers/page_helper.php	(.../page_helper.php)	(revision 16634)
+++ branches/5.2.x/core/units/helpers/page_helper.php	(.../page_helper.php)	(revision 16667)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: page_helper.php 16634 2018-11-13 09:38:24Z alex $
+* @version	$Id: page_helper.php 16667 2021-01-15 15:06:47Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2011 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -17,6 +17,13 @@
 class PageHelper extends kHelper {
 
 	/**
+	 * Content block cache per page.
+	 *
+	 * @var array
+	 */
+	protected $contentBlockCache = array();
+
+	/**
 	 * Returns page info
 	 *
 	 * @param int $page_id
@@ -421,16 +428,39 @@
 	{
 		$page_id = $page->GetID();
 
+		// Load all content blocks at once during regular page visits.
 		if ( !EDITING_MODE && !$this->Application->GetVar('preview') ) {
-			$revision_clause = 'pr.RevisionNumber = ' . $page->GetDBField('LiveRevisionNumber') . ' AND pr.IsDraft = 0';
+			if ( !isset($this->contentBlockCache[$page_id]) ) {
+				$where_clause = array(
+					$content_block->TableName . '.PageId = ' . $page_id,
+					'pr.RevisionNumber = ' . $page->GetDBField('LiveRevisionNumber'),
+					'pr.IsDraft = 0',
+				);
+
+				$sql = $content_block->GetSelectSQL() . '
+						WHERE (' . implode(') AND (', $where_clause) . ')';
+				$this->contentBlockCache[$page_id] = $this->Conn->Query($sql, 'ContentNum');
+			}
+
+			if ( isset($this->contentBlockCache[$page_id][$num]) ) {
+				$content_block->LoadFromHash($this->contentBlockCache[$page_id][$num]);
+			}
+			else {
+				$content_block->Clear();
+			}
+
+			return $content_block->isLoaded();
 		}
-		else {
-			$revision_clause = $this->getRevsionWhereClause($page_id, $page->GetDBField('LiveRevisionNumber'), 'pr.');
-		}
 
+		// Load each content block individually with fallback to draft version, when editing content.
+		$where_clause = array(
+			$content_block->TableName . '.PageId = ' . $page_id,
+			$content_block->TableName . '.ContentNum = ' . $num,
+			$this->getRevsionWhereClause($page_id, $page->GetDBField('LiveRevisionNumber'), 'pr.'),
+		);
 
-		$sql = 	$content_block->GetSelectSQL() . '
-				WHERE (' . $content_block->TableName . '.PageId = ' . $page_id . ') AND (' . $content_block->TableName . '.ContentNum = ' . $num . ') AND (' . $revision_clause . ')
+		$sql = $content_block->GetSelectSQL() . '
+				WHERE (' . implode(') AND (', $where_clause) . ')
 				ORDER BY pr.IsDraft DESC, pr.RevisionNumber DESC';
 		$content_data = $this->Conn->GetRow($sql);