From 376014e981da83017a7759d4230a00e4b9f0f8b8 Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@users.mediawiki.org>
Date: Mon, 18 Sep 2006 18:10:20 +0000
Subject: [PATCH] * Added experimental $wgRevisionCacheExpiry to cache
 extracted revision text   in $wgMemc, to further reduce hits to external
 storage.   Set to 0 (disabled) by default.

---
 RELEASE-NOTES                |  3 +++
 includes/DefaultSettings.php |  8 ++++++++
 includes/Parser.php          |  2 +-
 includes/Revision.php        | 16 ++++++++++++++++
 4 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index b484337e96..2b722acf17 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -210,6 +210,9 @@ it from source control: http://www.mediawiki.org/wiki/Download_from_SVN
   for page titles which shouldn't be converted on display/linking
 * Lazy extraction of text chunks in Revision objects, may reduce hits to
   external storage when actual text content is not used
+* Added experimental $wgRevisionCacheExpiry to cache extracted revision text
+  in $wgMemc, to further reduce hits to external storage.
+  Set to 0 (disabled) by default.
 
 
 == Languages updated ==
diff --git a/includes/DefaultSettings.php b/includes/DefaultSettings.php
index e035dfe5f9..7375be9443 100644
--- a/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@ -2070,6 +2070,14 @@ $wgExternalServers = array();
  */
 $wgDefaultExternalStore = false;
 
+/**
+ * Revision text may be cached in $wgMemc to reduce load on external storage
+ * servers and object extraction overhead for frequently-loaded revisions.
+ *
+ * Set to 0 to disable, or number of seconds before cache expiry.
+ */
+$wgRevisionCacheExpiry = 0;
+
 /**
 * list of trusted media-types and mime types.
 * Use the MEDIATYPE_xxx constants to represent media types.
diff --git a/includes/Parser.php b/includes/Parser.php
index e099144154..539557398c 100644
--- a/includes/Parser.php
+++ b/includes/Parser.php
@@ -2716,7 +2716,7 @@ class Parser
 		if ( !$argsOnly ) {
 			$braceCallbacks[2] = array( &$this, 'braceSubstitution' );
 		}
-		if ( !$this->mOutputType != OT_MSG ) {
+		if ( $this->mOutputType != OT_MSG ) {
 			$braceCallbacks[3] = array( &$this, 'argSubstitution' );
 		}
 		if ( $braceCallbacks ) {
diff --git a/includes/Revision.php b/includes/Revision.php
index 8591dc13c1..a915a96019 100644
--- a/includes/Revision.php
+++ b/includes/Revision.php
@@ -672,6 +672,17 @@ class Revision {
 		$fname = 'Revision::loadText';
 		wfProfileIn( $fname );
 		
+		// Caching may be beneficial for massive use of external storage
+		global $wgRevisionCacheExpiry, $wgMemc, $wgDBname;
+		$key = "$wgDBname:revisiontext:textid:" . $this->getTextId();
+		if( $wgRevisionCacheExpiry ) {
+			$text = $wgMemc->get( $key );
+			if( is_string( $text ) ) {
+				wfProfileOut( $fname );
+				return $text;
+			}
+		}
+		
 		// If we kept data for lazy extraction, use it now...
 		$row = $this->mTextRow;
 		$this->mTextRow = null;
@@ -695,6 +706,11 @@ class Revision {
 		}
 
 		$text = Revision::getRevisionText( $row );
+		
+		if( $wgRevisionCacheExpiry ) {
+			$wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
+		}
+		
 		wfProfileOut( $fname );
 
 		return $text;
-- 
2.20.1