From: Andrew Green <andrew.green.df@gmail.com>
Date: Mon, 17 Oct 2016 15:00:47 +0000 (-0500)
Subject: MessageCache: some inline comments
X-Git-Tag: 1.31.0-rc.0~4729
X-Git-Url: http://git.cyclocoop.org/%22.%20generer_url_ecrire%28%22sites_tous%22%2C%22%22%29.%20%22?a=commitdiff_plain;h=279e8982222a0c58f27ce1fb4b6a0e80cf2fbaab;p=lhc%2Fweb%2Fwiklou.git

MessageCache: some inline comments

Change-Id: I42427eef73d86c1a2e99dfa22b5dae159542e243
---

diff --git a/includes/cache/MessageCache.php b/includes/cache/MessageCache.php
index 0c2f9de9b5..4e6b2fd396 100644
--- a/includes/cache/MessageCache.php
+++ b/includes/cache/MessageCache.php
@@ -496,6 +496,7 @@ class MessageCache {
 			if ( $text === false ) {
 				// Failed to fetch data; possible ES errors?
 				// Store a marker to fetch on-demand as a workaround...
+				// TODO Use a differnt marker
 				$entry = '!TOO BIG';
 				wfDebugLog(
 					'MessageCache',
@@ -510,6 +511,10 @@ class MessageCache {
 
 		$cache['VERSION'] = MSG_CACHE_VERSION;
 		ksort( $cache );
+
+		# Hash for validating local cache (APC). No need to take into account
+		# messages larger than $wgMaxMsgCacheEntrySize, since those are only
+		# stored and fetched from memcache.
 		$cache['HASH'] = md5( serialize( $cache ) );
 		$cache['EXPIRY'] = wfTimestamp( TS_MW, time() + $this->mExpiry );
 
@@ -568,7 +573,8 @@ class MessageCache {
 		}
 
 		ScopedCallback::consume( $scopedLock );
-		// Relay the purge to APC and other DCs
+		// Relay the purge. Touching this check key expires cache contents
+		// and local cache (APC) validation hash across all datacenters.
 		$this->wanCache->touchCheckKey( wfMemcKey( 'messages', $code ) );
 
 		// Also delete cached sidebar... just in case it is affected