Avoid blocking locks during API edit stash generation

Bug: T180793
Change-Id: Ibc29a20329113c3ee54fd48cfe86ca8251e8098d

diff --git a/includes/api/ApiStashEdit.php b/includes/api/ApiStashEdit.php
index 4bd6a3f..b4b9321 100644 (file)
--- a/includes/api/ApiStashEdit.php
+++ b/includes/api/ApiStashEdit.php
@@ -181,9 +181,14 @@ class ApiStashEdit extends ApiBase {
                $title = $page->getTitle();
                $key = self::getStashKey( $title, self::getContentHash( $content ), $user );
 
                $title = $page->getTitle();
                $key = self::getStashKey( $title, self::getContentHash( $content ), $user );
 

-               // Use the master DB for fast blocking locks
+               // Use the master DB to allow for fast blocking locks on the "save path" where this
+               // value might actually be used to complete a page edit. If the edit submission request
+               // happens before this edit stash requests finishes, then the submission will block until
+               // the stash request finishes parsing. For the lock acquisition below, there is not much
+               // need to duplicate parsing of the same content/user/summary bundle, so try to avoid
+               // blocking at all here.

                $dbw = wfGetDB( DB_MASTER );
                $dbw = wfGetDB( DB_MASTER );

-               if ( !$dbw->lock( $key, __METHOD__, 1 ) ) {
+               if ( !$dbw->lock( $key, __METHOD__, 0 ) ) {

                        // De-duplicate requests on the same key
                        return self::ERROR_BUSY;
                }
                        // De-duplicate requests on the same key
                        return self::ERROR_BUSY;
                }