SpecialWatchlist: Always apply a LIMIT

In non-extended mode, the query that SpecialWatchlist ran
was unlimited, which is a very bad idea, since some users
have tens of thousands of pages on their watchlist.
There are broader performance issues with large watchlists,
but this doesn't help.

With this patch the wllimit preference is used to limit
the number of results both in expanded and in non-expanded mode.

Bug: T171027
Change-Id: Ifcefe6f77fa4adeca2e50714813004018819aee8

diff --git a/includes/specials/SpecialWatchlist.php b/includes/specials/SpecialWatchlist.php
index 549362f..9e01d2d 100644 (file)
--- a/includes/specials/SpecialWatchlist.php
+++ b/includes/specials/SpecialWatchlist.php
@@ -277,7 +277,6 @@ class SpecialWatchlist extends ChangesListSpecialPage {
 
                # Toggle watchlist content (all recent edits or just the latest)
                if ( $opts['extended'] ) {
-                       $limitWatchlist = $user->getIntOption( 'wllimit' );
                        $usePage = false;
                } else {
                        # Top log Ids for a page are not stored
@@ -292,14 +291,16 @@ class SpecialWatchlist extends ChangesListSpecialPage {
                                        LIST_OR
                                );
                        }
-                       $limitWatchlist = 0;
                        $usePage = true;
                }
 
                $tables = array_merge( [ 'recentchanges', 'watchlist' ], $tables );
                $fields = array_merge( RecentChange::selectFields(), $fields );
 
-               $query_options = array_merge( [ 'ORDER BY' => 'rc_timestamp DESC' ], $query_options );
+               $query_options = array_merge( [
+                       'ORDER BY' => 'rc_timestamp DESC',
+                       'LIMIT' => $user->getIntOption( 'wllimit' )
+               ], $query_options );
                $join_conds = array_merge(
                        [
                                'watchlist' => [
@@ -317,9 +318,6 @@ class SpecialWatchlist extends ChangesListSpecialPage {
                if ( $this->getConfig()->get( 'ShowUpdatedMarker' ) ) {
                        $fields[] = 'wl_notificationtimestamp';
                }
-               if ( $limitWatchlist ) {
-                       $query_options['LIMIT'] = $limitWatchlist;
-               }
 
                $rollbacker = $user->isAllowed( 'rollback' );
                if ( $usePage || $rollbacker ) {

diff --git a/languages/i18n/en.json b/languages/i18n/en.json
index aa1254c..a14e926 100644 (file)
--- a/languages/i18n/en.json
+++ b/languages/i18n/en.json
@@ -1021,7 +1021,7 @@
        "prefs-editwatchlist-clear": "Clear your watchlist",
        "prefs-watchlist-days": "Days to show in watchlist:",
        "prefs-watchlist-days-max": "Maximum $1 {{PLURAL:$1|day|days}}",
-       "prefs-watchlist-edits": "Maximum number of changes to show in expanded watchlist:",
+       "prefs-watchlist-edits": "Maximum number of changes to show in watchlist:",
        "prefs-watchlist-edits-max": "Maximum number: 1000",
        "prefs-watchlist-token": "Watchlist token:",
        "prefs-misc": "Misc",