[Vitess11] [VReplication] VReplication doesn't copy timestamp column with default current_timestamp

[tokikanno]

Overview of the Issue

VReplication doesn't copy timestamp column with default current_timestamp

Reproduction Steps

• Create a table which has a timestamp column with DEFAULT CURRENT_TIMESTAMP setting

create table toki_test3 (
	id varchar(3) NOT NULL,
	created TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
	PRIMARY KEY(`id`)
);

• Insert several rows into it

insert into src.toki_test3 values ('AAA', NULL);
insert into src.toki_test3 values ('BBB', NULL);

select * from src.toki_test3;
+-----+---------------------+
| id  | created             |
+-----+---------------------+
| AAA | 2021-09-02 11:41:53 |
| BBB | 2021-09-02 11:41:54 |
+-----+---------------------+

• Start MoveTables workflow on created table

vtctlclient MoveTables -source src -tables toki_test3 Create dest.test

• Verify copied table

select * from dest.toki_test3;
+-----+---------------------+
| id  | created             |
+-----+---------------------+
| AAA | 2021-09-02 11:45:13 |
| BBB | 2021-09-02 11:45:13 |
+-----+---------------------+

The created value is not the same as origin table, seems VReplication didn't copy the values of created column from origin table.

Binary version

Vitess V11 release

Related slack threads

• https://vitess.slack.com/archives/CMKTCUYNQ/p1630500506059800
• https://vitess.slack.com/archives/CMKTCUYNQ/p1630554910072800

Possible reason

This issue may caused by PR #8129

The copied table schema has an extra info DEFAULT_GENERATED (the origin table didn’t)

desc toki_test3;
+---------+------------+------+-----+-------------------+-------------------+
| Field   | Type       | Null | Key | Default           | Extra             |
+---------+------------+------+-----+-------------------+-------------------+
| id      | varchar(3) | NO   | PRI | NULL              |                   |
| created | timestamp  | NO   |     | CURRENT_TIMESTAMP | DEFAULT_GENERATED |
+---------+------------+------+-----+-------------------+-------------------+

Via these codes (merged from #8129 )

vitess/go/vt/vttablet/tabletmanager/vreplication/vreplicator.go

Line 296 in 6b52e98

if strings.Contains(extra, "generated") || strings.Contains(extra, "virtual") {

vitess/go/vt/vttablet/tabletmanager/vreplication/table_plan_builder.go

Line 340 in 332223c

if colInfo.IsGenerated {

The created timestamp column seems will be ignored during replication because Vitess think it is a generated column

[mattlord]

This was resolved via #8763 and #8796.

Thank you so much for the great issue and PR, @tokikanno !