From: Aaron Schulz <aschulz@wikimedia.org>
Date: Mon, 8 Jun 2015 23:05:54 +0000 (-0700)
Subject: Avoid parser cache miss that often occurs post-save
X-Git-Tag: 1.31.0-rc.0~11146
X-Git-Url: https://git.heureux-cyclage.org/?p=lhc%2Fweb%2Fwiklou.git;a=commitdiff_plain;h=6b0163391b291fcf8a74dba9f84e34816a42c654

Avoid parser cache miss that often occurs post-save

* This should not happen as doEditContent() saves the parser cache,
  so only the rare casing if incompatible options should have misses
* The bug could also cause post-save misses with edit stashing
* Avoid the second page parse post-redirect by making sure cache
  timestamps match up instead of calling time() at several points
* Likewise for null edits, which used a different code path
* Removed redundant purge in onArticleCreate() as the new row sets _touched
* Removed pointless purge in onArticleDelete() as there is no row to update
  (the method no-ops in that case to avoid contention already)

Change-Id: I178fe334a3f8691ffd9452bec30561a0c5d37c6c
---

diff --git a/includes/Title.php b/includes/Title.php
index d5eff46105..7aa4113446 100644
--- a/includes/Title.php
+++ b/includes/Title.php
@@ -4380,9 +4380,10 @@ class Title {
 	/**
 	 * Updates page_touched for this page; called from LinksUpdate.php
 	 *
+	 * @param integer $purgeTime TS_MW timestamp [optional]
 	 * @return bool True if the update succeeded
 	 */
-	public function invalidateCache() {
+	public function invalidateCache( $purgeTime = null ) {
 		if ( wfReadOnly() ) {
 			return false;
 		}
@@ -4394,11 +4395,13 @@ class Title {
 		$method = __METHOD__;
 		$dbw = wfGetDB( DB_MASTER );
 		$conds = $this->pageCond();
-		$dbw->onTransactionIdle( function () use ( $dbw, $conds, $method ) {
+		$dbw->onTransactionIdle( function () use ( $dbw, $conds, $method, $purgeTime ) {
+			$dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
+
 			$dbw->update(
 				'page',
-				array( 'page_touched' => $dbw->timestamp() ),
-				$conds,
+				array( 'page_touched' => $dbTimestamp ),
+				$conds + array( 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ),
 				$method
 			);
 		} );
diff --git a/includes/page/WikiPage.php b/includes/page/WikiPage.php
index abb22a021d..5e72151e5b 100644
--- a/includes/page/WikiPage.php
+++ b/includes/page/WikiPage.php
@@ -1264,10 +1264,9 @@ class WikiPage implements Page, IDBAccessObject {
 			$conditions['page_latest'] = $lastRevision;
 		}
 
-		$now = wfTimestampNow();
 		$row = array( /* SET */
 			'page_latest'      => $revision->getId(),
-			'page_touched'     => $dbw->timestamp( $now ),
+			'page_touched'     => $dbw->timestamp( $revision->getTimestamp() ),
 			'page_is_new'      => ( $lastRevision === 0 ) ? 1 : 0,
 			'page_is_redirect' => $rt !== null ? 1 : 0,
 			'page_len'         => $len,
@@ -1865,7 +1864,7 @@ class WikiPage implements Page, IDBAccessObject {
 				$revision = null;
 				// Update page_touched, this is usually implicit in the page update
 				// Other cache updates are done in onArticleEdit()
-				$this->mTitle->invalidateCache();
+				$this->mTitle->invalidateCache( $now );
 			}
 		} else {
 			// Create new article
@@ -2168,9 +2167,11 @@ class WikiPage implements Page, IDBAccessObject {
 			$editInfo = $this->mPreparedEdit;
 		}
 
-		// Save it to the parser cache
+		// Save it to the parser cache.
+		// Make sure the cache time matches page_touched to avoid double parsing.
 		ParserCache::singleton()->save(
-			$editInfo->output, $this, $editInfo->popts, $editInfo->timestamp, $editInfo->revid
+			$editInfo->output, $this, $editInfo->popts,
+			$revision->getTimestamp(), $editInfo->revid
 		);
 
 		// Update the links tables and other secondary data
@@ -3159,7 +3160,6 @@ class WikiPage implements Page, IDBAccessObject {
 		// Update existence markers on article/talk tabs...
 		$other = $title->getOtherPage();
 
-		$other->invalidateCache();
 		$other->purgeSquid();
 
 		$title->touchLinks();
@@ -3176,7 +3176,6 @@ class WikiPage implements Page, IDBAccessObject {
 		// Update existence markers on article/talk tabs...
 		$other = $title->getOtherPage();
 
-		$other->invalidateCache();
 		$other->purgeSquid();
 
 		$title->touchLinks();
diff --git a/includes/parser/CacheTime.php b/includes/parser/CacheTime.php
index 950c0d46df..c450689708 100644
--- a/includes/parser/CacheTime.php
+++ b/includes/parser/CacheTime.php
@@ -47,7 +47,7 @@ class CacheTime {
 	/**
 	 * setCacheTime() sets the timestamp expressing when the page has been rendered.
 	 * This does not control expiry, see updateCacheExpiry() for that!
-	 * @param string $t
+	 * @param string $t TS_MW timestamp
 	 * @return string
 	 */
 	public function setCacheTime( $t ) {