Online DDL: new message_timestamp column in schema_migrations table (#16633)

Signed-off-by: Shlomi Noach <2607934+shlomi-noach@users.noreply.github.com>

Author: shlomi-noach

go/test/endtoend/onlineddl/scheduler/onlineddl_scheduler_test.go

@@ -1320,6 +1320,7 @@ func testScheduler(t *testing.T) {
 		for _, row := range rs.Named().Rows {
 			message := row["message"].ToString()
 			require.Contains(t, message, "errno 1146")
+			require.False(t, row["message_timestamp"].IsNull())
 		}
 	})
 
@@ -1463,6 +1464,7 @@ func testScheduler(t *testing.T) {
 				for _, row := range rs.Named().Rows {
 					message := row["message"].ToString()
 					require.Contains(t, message, vuuids[2]) // Indicating this migration failed due to vuuids[2] failure
+					require.False(t, row["message_timestamp"].IsNull())
 				}
 			}
 		})

go/vt/sidecardb/schema/onlineddl/schema_migrations.sql

@@ -42,6 +42,7 @@ CREATE TABLE IF NOT EXISTS schema_migrations
     `migration_context`               varchar(1024)    NOT NULL DEFAULT '',
     `ddl_action`                      varchar(16)      NOT NULL DEFAULT '',
     `message`                         text             NOT NULL,
+    `message_timestamp`               timestamp(6)     NULL     DEFAULT NULL,
     `eta_seconds`                     bigint           NOT NULL DEFAULT '-1',
     `rows_copied`                     bigint unsigned  NOT NULL DEFAULT '0',
     `table_rows`                      bigint           NOT NULL DEFAULT '0',

go/vt/vttablet/onlineddl/schema.go

@@ -209,7 +209,9 @@ const (
 			migration_uuid=%a
 	`
 	sqlUpdateMessage = `UPDATE _vt.schema_migrations
-			SET message=%a
+			SET
+				message=%a,
+				message_timestamp=NOW(6)
 		WHERE
 			migration_uuid=%a
 	`