MDEV-8297: information_schema.innodb_sys_tablestats.modified_counter doesn't change on UPDATE

Update modified-counter also if update effects non-indexed columns.

mysql-test/suite/innodb/r/innodb-stats-modified-counter.result

+set global innodb_stats_auto_recalc=off;
+CREATE TABLE t1 (i int) ENGINE=InnoDB;
+SELECT NAME, STATS_INITIALIZED, NUM_ROWS, MODIFIED_COUNTER FROM INFORMATION_SCHEMA.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+NAME	STATS_INITIALIZED	NUM_ROWS	MODIFIED_COUNTER
+test/t1	Initialized	0	0
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (2);
+SELECT NAME, STATS_INITIALIZED, NUM_ROWS, MODIFIED_COUNTER FROM INFORMATION_SCHEMA.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+NAME	STATS_INITIALIZED	NUM_ROWS	MODIFIED_COUNTER
+test/t1	Initialized	2	2
+DELETE FROM t1 WHERE i = 1;
+SELECT NAME, STATS_INITIALIZED, NUM_ROWS, MODIFIED_COUNTER FROM INFORMATION_SCHEMA.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+NAME	STATS_INITIALIZED	NUM_ROWS	MODIFIED_COUNTER
+test/t1	Initialized	1	3
+UPDATE t1 SET i = 4 WHERE i = 2;
+SELECT NAME, STATS_INITIALIZED, NUM_ROWS, MODIFIED_COUNTER FROM INFORMATION_SCHEMA.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+NAME	STATS_INITIALIZED	NUM_ROWS	MODIFIED_COUNTER
+test/t1	Initialized	1	4
+DROP TABLE t1;
+set global innodb_stats_auto_recalc=default;

mysql-test/suite/innodb/t/innodb-stats-modified-counter.opt

+--loose-innodb-sys-tablestats

mysql-test/suite/innodb/t/innodb-stats-modified-counter.test

+-- source include/have_innodb.inc
+
+#
+# MDEV-8297: information_schema.innodb_sys_tablestats.modified_counter doesn't change on UPDATE
+#
+
+set global innodb_stats_auto_recalc=off;
+
+CREATE TABLE t1 (i int) ENGINE=InnoDB;
+
+SELECT NAME, STATS_INITIALIZED, NUM_ROWS, MODIFIED_COUNTER FROM INFORMATION_SCHEMA.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (2);
+
+SELECT NAME, STATS_INITIALIZED, NUM_ROWS, MODIFIED_COUNTER FROM INFORMATION_SCHEMA.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+DELETE FROM t1 WHERE i = 1;
+
+SELECT NAME, STATS_INITIALIZED, NUM_ROWS, MODIFIED_COUNTER FROM INFORMATION_SCHEMA.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+UPDATE t1 SET i = 4 WHERE i = 2;
+
+SELECT NAME, STATS_INITIALIZED, NUM_ROWS, MODIFIED_COUNTER FROM INFORMATION_SCHEMA.INNODB_SYS_TABLESTATS WHERE NAME = 'test/t1';
+
+DROP TABLE t1;
+
+set global innodb_stats_auto_recalc=default;

storage/innobase/row/row0mysql.cc

@@ -1861,6 +1861,12 @@ row_update_for_mysql(
 	columns would not affect statistics. */
 	if (node->is_delete || !(node->cmpl_info & UPD_NODE_NO_ORD_CHANGE)) {
 		row_update_statistics_if_needed(prebuilt->table);
+	} else {
+		/* Update the table modification counter even when
+		non-indexed columns change if statistics is initialized. */
+		if (prebuilt->table->stat_initialized) {
+			prebuilt->table->stat_modified_counter++;
+		}
 	}
 
 	trx->op_info = "";

storage/xtradb/row/row0mysql.cc

@@ -1870,6 +1870,12 @@ row_update_for_mysql(
 	columns would not affect statistics. */
 	if (node->is_delete || !(node->cmpl_info & UPD_NODE_NO_ORD_CHANGE)) {
 		row_update_statistics_if_needed(prebuilt->table);
+	} else {
+		/* Update the table modification counter even when
+		non-indexed columns change if statistics is initialized. */
+		if (prebuilt->table->stat_initialized) {
+			prebuilt->table->stat_modified_counter++;
+		}
 	}
 
 	trx->op_info = "";