From 37b08163ea592c58b267476b41edb84e312ff5bb Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Wed, 7 Sep 2016 14:19:31 -0700
Subject: [PATCH] Make $wgRevisionCacheExpiry default to one week

* If CACHE_DB is used, it will not use the cache however.
* If persistent cache is disabled, at least maintain the
  process caching.

Change-Id: I23b455ef46f27c313bb9573f69723b1436b2d584
---
 RELEASE-NOTES-1.28           |  1 +
 includes/DefaultSettings.php |  2 +-
 includes/Revision.php        | 15 ++++++++-------
 3 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/RELEASE-NOTES-1.28 b/RELEASE-NOTES-1.28
index 9843d90019..bd05309d6c 100644
--- a/RELEASE-NOTES-1.28
+++ b/RELEASE-NOTES-1.28
@@ -32,6 +32,7 @@ production.
 * The 'editcontentmodel' permission is now granted to all logged-in users ('user').
   instead of just administrators ('sysop'). Documentation for this feature is
   available at <https://www.mediawiki.org/wiki/Help:ChangeContentModel>.
+* $wgRevisionCacheExpiry is now set to one week by default instead of being disabled.
 
 === New features in 1.28 ===
 * User::isBot() method for checking if an account is a bot role account.
diff --git a/includes/DefaultSettings.php b/includes/DefaultSettings.php
index 3bf838121e..03947f6a07 100644
--- a/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@ -2123,7 +2123,7 @@ $wgDefaultExternalStore = false;
  *
  * Set to 0 to disable, or number of seconds before cache expiry.
  */
-$wgRevisionCacheExpiry = 0;
+$wgRevisionCacheExpiry = 86400 * 7;
 
 /** @} */ # end text storage }
 
diff --git a/includes/Revision.php b/includes/Revision.php
index ef0f03df8f..af45acc290 100644
--- a/includes/Revision.php
+++ b/includes/Revision.php
@@ -1577,19 +1577,20 @@ class Revision implements IDBAccessObject {
 	 * @return string|bool The revision's text, or false on failure
 	 */
 	private function loadText() {
-		// Caching may be beneficial for massive use of external storage
 		global $wgRevisionCacheExpiry;
 
-		if ( !$wgRevisionCacheExpiry ) {
-			return $this->fetchText();
-		}
-
 		$cache = ObjectCache::getMainWANInstance();
+		if ( $cache->getQoS( $cache::ATTR_EMULATION ) <= $cache::QOS_EMULATION_SQL ) {
+			// Do not cache RDBMs blobs in...the RDBMs store
+			$ttl = $cache::TTL_UNCACHEABLE;
+		} else {
+			$ttl = $wgRevisionCacheExpiry ?: $cache::TTL_UNCACHEABLE;
+		}
 
 		// No negative caching; negative hits on text rows may be due to corrupted replica DBs
 		return $cache->getWithSetCallback(
-			$key = $cache->makeKey( 'revisiontext', 'textid', $this->getTextId() ),
-			$wgRevisionCacheExpiry,
+			$cache->makeKey( 'revisiontext', 'textid', $this->getTextId() ),
+			$ttl,
 			function () {
 				return $this->fetchText();
 			},
-- 
2.20.1