diff --git a/includes/logging/LogPager.php b/includes/logging/LogPager.php
index 781df06f491..0b78a360330 100644
--- a/includes/logging/LogPager.php
+++ b/includes/logging/LogPager.php
@@ -361,6 +361,11 @@ class LogPager extends ReverseChronologicalPager {
 		if ( !$this->mTagFilter && !array_key_exists( 'ls_field', $this->mConds ) ) {
 			$options[] = 'STRAIGHT_JOIN';
 		}
+		if ( $this->performer !== '' ) {
+			// T223151: MariaDB's optimizer, at least 10.1, likes to choose a wildly bad plan for
+			// some reason for this code path. Tell it not to use the wrong index it wants to pick.
+			$options['IGNORE INDEX'] = [ 'logging' => [ 'times' ] ];
+		}
 
 		$info = [
 			'tables' => $tables,