From 044b3ff17c8e7beb8afc0f846ac4a448baa208ec Mon Sep 17 00:00:00 2001
From: marcus <marcus@36083f99-b078-4883-b0ff-0f9b5a30f544>
Date: Fri, 7 Nov 2008 16:36:37 +0000
Subject: Refs #529: Experimental memcaching for metadata

git-svn-id: https://code.elgg.org/elgg/trunk@2425 36083f99-b078-4883-b0ff-0f9b5a30f544
---
 engine/lib/metadata.php | 41 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 34 insertions(+), 7 deletions(-)

(limited to 'engine/lib/metadata.php')

diff --git a/engine/lib/metadata.php b/engine/lib/metadata.php
index 4084d6959..204b027c3 100644
--- a/engine/lib/metadata.php
+++ b/engine/lib/metadata.php
@@ -278,7 +278,13 @@
 		$id = (int)$id;
 	
 		if (!$md = get_metadata($id)) return false;
-		if (!$md->canEdit()) return false;
+		if (!$md->canEdit()) return false;
+		
+		// If memcached then we invalidate the cache for this entry
+		static $metabyname_memcache;
+		if ((!$metabyname_memcache) && (is_memcache_available()))
+			$metabyname_memcache = new ElggMemcache('metabyname_memcache');
+		if ($metabyname_memcache) $metabyname_memcache->delete("{$md->entity_guid}:{$md->name_id}");
 		
 		//$name = sanitise_string(trim($name));
 		//$value = sanitise_string(trim($value));
@@ -349,6 +355,12 @@
 
 		$id = (int)$id;
 		$metadata = get_metadata($id);
+		
+		// Tidy up if memcache is enabled.
+		static $metabyname_memcache;
+		if ((!$metabyname_memcache) && (is_memcache_available()))
+			$metabyname_memcache = new ElggMemcache('metabyname_memcache');
+		if ($metabyname_memcache) $metabyname_memcache->delete("{$metadata->entity_guid}:{$metadata->name_id}");
 		
 		if ($metadata->canEdit())
 			return delete_data("DELETE from {$CONFIG->dbprefix}metadata where id=$id");
@@ -364,19 +376,34 @@
 	function get_metadata_byname($entity_guid,  $meta_name)
 	{
 		global $CONFIG;
-	
-		$meta_name = get_metastring_id($meta_name);
-		
-		if (empty($meta_name)) return false;
+	
+		$meta_name = get_metastring_id($meta_name);
+		
+		if (empty($meta_name)) return false;
 		
 		$entity_guid = (int)$entity_guid;
 		$access = get_access_sql_suffix("e");
-		$md_access = get_access_sql_suffix("m");
+		$md_access = get_access_sql_suffix("m");
+		
+		// If memcache is available then cache this (cache only by name for now since this is the most common query)
+		static $metabyname_memcache;
+		if ((!$metabyname_memcache) && (is_memcache_available()))
+			$metabyname_memcache = new ElggMemcache('metabyname_memcache');
+		if ($metabyname_memcache) $meta = $metabyname_memcache->load("{$entity_guid}:{$meta_name}");
+		if ($meta) return $meta;	
 
 		$result = get_data("SELECT m.*, n.string as name, v.string as value from {$CONFIG->dbprefix}metadata m JOIN {$CONFIG->dbprefix}entities e ON e.guid = m.entity_guid JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id where m.entity_guid=$entity_guid and m.name_id='$meta_name' and $access and $md_access", "row_to_elggmetadata");
 		if (!$result) 
 			return false;
-		
+			
+		// Cache if memcache available
+		if ($metabyname_memcache)
+		{ 
+			if (count($result) == 1) $r = $result[0]; else $r = $result;
+			$metabyname_memcache->setDefaultExpiry(3600); // This is a bit of a hack - we shorten the expiry on object metadata so that it'll be gone in an hour. This means that deletions and more importantly updates will filter through eventually.
+			$metabyname_memcache->save("{$entity_guid}:{$meta_name}", $r);
+			
+		}
 		if (count($result) == 1)
 			return $result[0];
 			
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