Made triggerOpportunisticLinksUpdate() jobs make use of parser cache

* On Wikipedia, for example, these jobs are good percent of
  all refreshLinks jobs; skipping the parse step should avoid
  runner CPU overhead
* Also fixed bad TS_MW/TS_UNIX comparison
* Moved the fudge factor to a constant and raised it a bit

Bug: T98621
Change-Id: Id6d64972739df4b26847e4374f30ddcc7f93b54a

diff --git a/includes/jobqueue/jobs/RefreshLinksJob.php b/includes/jobqueue/jobs/RefreshLinksJob.php
index 1252b0b..749913a 100644 (file)
--- a/includes/jobqueue/jobs/RefreshLinksJob.php
+++ b/includes/jobqueue/jobs/RefreshLinksJob.php
@@ -37,6 +37,8 @@
 class RefreshLinksJob extends Job {
        const PARSE_THRESHOLD_SEC = 1.0;
 
+       const CLOCK_FUDGE = 10;
+
        function __construct( $title, $params = '' ) {
                parent::__construct( 'refreshLinks', $title, $params );
                // A separate type is used just for cascade-protected backlinks
@@ -140,22 +142,38 @@ class RefreshLinksJob extends Job {
 
                $parserOutput = false;
                $parserOptions = $page->makeParserOptions( 'canonical' );
-               // If page_touched changed after this root job (with a good slave lag skew factor),
-               // then it is likely that any views of the pages already resulted in re-parses which
-               // are now in cache. This can be reused to avoid expensive parsing in some cases.
+               // If page_touched changed after this root job, then it is likely that
+               // any views of the pages already resulted in re-parses which are now in
+               // cache. The cache can be reused to avoid expensive parsing in some cases.
                if ( isset( $this->params['rootJobTimestamp'] ) ) {
-                       $skewedTimestamp = wfTimestamp( TS_UNIX, $this->params['rootJobTimestamp'] ) + 5;
-                       if ( $page->getLinksTimestamp() > wfTimestamp( TS_MW, $skewedTimestamp ) ) {
+                       $opportunistic = !empty( $this->params['isOpportunistic'] );
+
+                       $skewedTimestamp = $this->params['rootJobTimestamp'];
+                       if ( $opportunistic ) {
+                               // Neither clock skew nor DB snapshot/slave lag matter much for such
+                               // updates; focus on reusing the (often recently updated) cache
+                       } else {
+                               // For transclusion updates, the template changes must be reflected
+                               $skewedTimestamp = wfTimestamp( TS_MW,
+                                       wfTimestamp( TS_UNIX, $skewedTimestamp ) + self::CLOCK_FUDGE
+                               );
+                       }
+
+                       if ( $page->getLinksTimestamp() > $skewedTimestamp ) {
                                // Something already updated the backlinks since this job was made
                                return true;
                        }
-                       if ( $page->getTouched() > wfTimestamp( TS_MW, $skewedTimestamp ) ) {
+
+                       if ( $page->getTouched() >= $skewedTimestamp || $opportunistic ) {
+                               // Something bumped page_touched since this job was made
+                               // or the cache is otherwise suspected to be up-to-date
                                $parserOutput = ParserCache::singleton()->getDirty( $page, $parserOptions );
-                               if ( $parserOutput && $parserOutput->getCacheTime() <= $skewedTimestamp ) {
+                               if ( $parserOutput && $parserOutput->getCacheTime() < $skewedTimestamp ) {
                                        $parserOutput = false; // too stale
                                }
                        }
                }
+
                // Fetch the current revision and parse it if necessary...
                if ( $parserOutput == false ) {
                        $start = microtime( true );

diff --git a/includes/page/WikiPage.php b/includes/page/WikiPage.php
index cc182a4..7b33b02 100644 (file)
--- a/includes/page/WikiPage.php
+++ b/includes/page/WikiPage.php
@@ -3411,6 +3411,9 @@ class WikiPage implements Page, IDBAccessObject {
 
                // Check if the last link refresh was before page_touched
                if ( $this->getLinksTimestamp() < $this->getTouched() ) {
+                       $params['isOpportunistic'] = true;
+                       $params['rootJobTimestamp'] = $parserOutput->getCacheTime();
+
                        JobQueueGroup::singleton()->push( EnqueueJob::newFromLocalJobs(
                                new JobSpecification( 'refreshLinks', $params,
                                        array( 'removeDuplicates' => true ), $this->mTitle )