Ticket #33885: 33885.diff

src/wp-admin/includes/template-functions.php

@@ -585 +585 @@
          * @param int $limit Number of custom fields to retrieve. Default 30.
          */
         $limit = apply_filters( 'postmeta_form_limit', 30 );
-        $sql = "SELECT DISTINCT meta_key
-                FROM $wpdb->postmeta
-                WHERE meta_key NOT BETWEEN '_' AND '_z'
-                HAVING meta_key NOT LIKE %s
-                ORDER BY meta_key
-                LIMIT %d";
-        $keys = $wpdb->get_col( $wpdb->prepare( $sql, $wpdb->esc_like( '_' ) . '%', $limit ) );
+
+        /**
+         * Filter the number of rows to retrieve from the database when searching
+         * for custom field names.
+         *
+         * @since 4.4.0
+         *
+         * @param int $limit Number of rows to retrieve. Default 1000.
+         */
+        $row_limit = apply_filters( 'postmeta_form_row_limit', 1000 );
+
+        $keys = array();
+        $offset = 0;
+        while( count( $keys ) < $limit ) {
+                $sql = "SELECT DISTINCT meta_key
+                        FROM $wpdb->postmeta
+                        LIMIT %d,%d";
+                $maybe_keys = $wpdb->get_col( $wpdb->prepare( $sql, $offset, $row_limit ) );
+
+                foreach ( $maybe_keys as $key ) {
+                        if ( 0 !== strpos( $key, '_' ) ) {
+                                $keys[] = $key;
+                        }
+
+                        if ( count( $keys ) >= $limit ) {
+                                break 2;
+                        }
+                }
+
+                if ( count( $maybe_keys ) < $row_limit ) {
+                        break;
+                }
+
+                $offset += $row_limit;
+        }
+
         if ( $keys ) {
                 natcasesort( $keys );
                 $meta_key_input_id = 'metakeyselect';