ddl: do not unset involving schema on EntryTooLarge error (#51963)

ddl/db_test.go

@@ -1621,3 +1621,20 @@ func TestMDLTruncateTable(t *testing.T) {
 	require.True(t, timetk2.After(timeMain))
 	require.True(t, timetk3.After(timeMain))
 }
+
+func TestDDLJobErrEntrySizeTooLarge(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+
+	tk.MustExec("use test")
+	tk.MustExec("create table t (a int);")
+
+	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/ddl/mockErrEntrySizeTooLarge", `1*return(true)`))
+	t.Cleanup(func() {
+		require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/ddl/mockErrEntrySizeTooLarge"))
+	})
+
+	tk.MustGetErrCode("rename table t to t1;", errno.ErrEntryTooLarge)
+	tk.MustExec("create table t1 (a int);")
+	tk.MustExec("alter table t add column b int;") // Should not block.
+}

ddl/ddl_worker.go

@@ -423,7 +423,6 @@ func (w *worker) handleUpdateJobError(t *meta.Meta, job *model.Job, err error) e
 		}
 		// Reduce this txn entry size.
 		job.BinlogInfo.Clean()
-		job.InvolvingSchemaInfo = nil
 		job.Error = toTError(err)
 		job.ErrorCount++
 		job.SchemaState = model.StateNone