temp commit

lib/backend/class-wp-lock-backend-db.php

@@ -62,20 +62,21 @@ public function drop_ghosts( $lock_id ) {
 
 		$locks  = $wpdb->get_results( "SELECT * FROM {$this->get_table_name()} WHERE `lock_key` = '$lock_key'", ARRAY_A );
 		$ghosts = [];
-		foreach ( $locks as $lock ) {
-			if ( ! empty( $lock['expire'] ) && $lock['expire'] > microtime( true ) ) {
-				// This is an unexpired lock, keep it actual. No matter if it's a ghost or not.
-				continue;
-			}
 
+		// Remove unexpired locks from the list in order to keep them in DB.
+		$expired = array_filter(
+			$locks,
+			fn( $lock ) => empty( $lock['expire'] ) || $lock['expire'] <= microtime( true )
+		);
+
+		// Get active CIDs from the database to check if the given connections are still alive.
+		$active_cids = $wpdb->get_col( "SELECT id FROM information_schema.processlist WHERE id IN (" . implode( ',', array_column( $expired, 'cid' ) ) . ")" );
+
+		foreach ( $expired as $lock ) {
 			if (
 				( empty( $lock['pid'] ) && empty( $lock['cid'] ) ) ||
 				( ! empty( $lock['pid'] ) && ! file_exists( "/proc/{$lock['pid']}" ) ) ||
-				( ! empty( $lock['cid'] ) && empty(
-					$wpdb->get_var(
-						$wpdb->prepare( "SELECT id FROM information_schema.processlist WHERE id = %s", $lock['cid'] )
-					)
-					) )
+				( ! empty( $lock['cid'] ) && empty( array_filter( $active_cids, fn( $cid ) => $cid == $lock['cid'] ) ) )
 			) {
 				// This is a ghost lock, remove it.
 				$ghosts[] = $lock['id'];