Set remote requst's DagRequest flags field (pingcap#8606)

close pingcap#8607

dbms/src/Flash/Coprocessor/RemoteRequest.cpp

@@ -86,6 +86,8 @@ RemoteRequest RemoteRequest::build(
     /// do not collect execution summaries because in this case because the execution summaries
     /// will be collected by CoprocessorBlockInputStream
     dag_req.set_collect_execution_summaries(false);
+    dag_req.set_flags(dag_context.getFlags());
+    dag_req.set_sql_mode(dag_context.getSQLMode());
     const auto & original_dag_req = *dag_context.dag_request;
     if (original_dag_req.has_time_zone_name() && !original_dag_req.time_zone_name().empty())
         dag_req.set_time_zone_name(original_dag_req.time_zone_name());

tests/fullstack-test/issues/issue_8607.test

@@ -0,0 +1,45 @@
+# Copyright 2023 PingCAP, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Preparation.
+=> DBGInvoke __init_fail_point()
+
+mysql> drop table if exists test.t
+mysql> create table test.t (a int);
+
+mysql> insert into test.t values (123456789);
+
+mysql> alter table test.t set tiflash replica 1;
+func> wait_table test t
+
+mysql> set tidb_isolation_read_engines='tiflash'; set tidb_enforce_mpp=1; select * from test.t where cast(a as char(5)) = '12345';
++-----------+
+| a         |
++-----------+
+| 123456789 |
++-----------+
+
+=> DBGInvoke __enable_fail_point(force_remote_read_for_batch_cop)
+
+mysql> set tidb_isolation_read_engines='tiflash'; set tidb_enforce_mpp=1; select * from test.t where cast(a as char(5)) = '12345';
++-----------+
+| a         |
++-----------+
+| 123456789 |
++-----------+
+
+=> DBGInvoke __disable_fail_point(force_remote_read_for_batch_cop)
+
+# Clean up.
+mysql> drop table if exists test.t;