session: make all DDLs reentrant in upgradeToVer212 (#56605) (#56625)

close #56574

Author: ti-chi-bot

pkg/session/bootstrap.go

@@ -3220,9 +3220,9 @@ func upgradeToVer212(s sessiontypes.Session, ver int64) {
 	// add column `repeats`.
 	doReentrantDDL(s, "ALTER TABLE mysql.tidb_runaway_queries ADD COLUMN `repeats` int DEFAULT 1 AFTER `time`;", infoschema.ErrColumnExists)
 	// rename column name from `time` to `start_time`, will auto rebuild the index.
-	doReentrantDDL(s, "ALTER TABLE mysql.tidb_runaway_queries RENAME COLUMN `time` TO `start_time`")
+	doReentrantDDL(s, "ALTER TABLE mysql.tidb_runaway_queries RENAME COLUMN `time` TO `start_time`", infoschema.ErrColumnNotExists)
 	// rename column `original_sql` to `sample_sql`.
-	doReentrantDDL(s, "ALTER TABLE mysql.tidb_runaway_queries RENAME COLUMN `original_sql` TO `sample_sql`")
+	doReentrantDDL(s, "ALTER TABLE mysql.tidb_runaway_queries RENAME COLUMN `original_sql` TO `sample_sql`", infoschema.ErrColumnNotExists)
 	// modify column type of `plan_digest`.
 	doReentrantDDL(s, "ALTER TABLE mysql.tidb_runaway_queries MODIFY COLUMN `plan_digest` varchar(64) DEFAULT '';", infoschema.ErrColumnExists)
 	// 3. modify column length of `action`.

pkg/session/bootstrap_test.go

@@ -270,12 +270,6 @@ func revertVersionAndVariables(t *testing.T, se sessiontypes.Session, ver int) {
 		// for version <= version195, tidb_enable_dist_task should be disabled before upgrade
 		MustExec(t, se, "update mysql.global_variables set variable_value='off' where variable_name='tidb_enable_dist_task'")
 	}
-	if ver < version212 && ver >= version172 {
-		// for version < version212, revert column changes related to function `upgradeToVer212`.
-		// related tables created after version172.
-		MustExec(t, se, "ALTER TABLE mysql.tidb_runaway_queries RENAME COLUMN `start_time` TO `time`")
-		MustExec(t, se, "ALTER TABLE mysql.tidb_runaway_queries RENAME COLUMN `sample_sql` TO `original_sql`")
-	}
 }
 
 // TestUpgrade tests upgrading
@@ -2433,8 +2427,6 @@ func TestTiDBUpgradeToVer212(t *testing.T) {
 	err = m.FinishBootstrap(int64(ver198))
 	require.NoError(t, err)
 	revertVersionAndVariables(t, seV198, ver198)
-	// simulate a real ver198 where mysql.tidb_runaway_queries` doesn't have `start_time`/`sample_sql` columns yet.
-	MustExec(t, seV198, "select original_sql, time from mysql.tidb_runaway_queries")
 	err = txn.Commit(context.Background())
 	require.NoError(t, err)
 	unsetStoreBootstrapped(store.UUID())