fix virtual column not found when remote read happens (#9920) (#9926)

close #9561

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>
Signed-off-by: guo-shaoge <shaoge1994@163.com>

Co-authored-by: guo-shaoge <shaoge1994@163.com>

Author: ti-chi-bot

dbms/src/Common/FailPoint.cpp

@@ -87,6 +87,7 @@ namespace DB
     M(force_set_page_data_compact_batch)                     \
     M(force_set_dtfile_exist_when_acquire_id)                \
     M(force_no_local_region_for_mpp_task)                    \
+    M(force_random_remote_read)                              \
     M(force_remote_read_for_batch_cop)                       \
     M(force_pd_grpc_error)                                   \
     M(force_context_path)                                    \

dbms/src/Flash/Coprocessor/RemoteRequest.cpp

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 #include <Common/FmtUtils.h>
+#include <DataStreams/GeneratedColumnPlaceholderBlockInputStream.h>
 #include <Flash/Coprocessor/ChunkCodec.h>
 #include <Flash/Coprocessor/DAGContext.h>
 #include <Flash/Coprocessor/RemoteRequest.h>
@@ -51,7 +52,12 @@ RemoteRequest RemoteRequest::build(
             const auto & col = table_scan.getColumns()[i];
             auto col_id = col.id;
 
-            if (col_id == DB::TiDBPkColumnID)
+            if (col.hasGeneratedColumnFlag())
+            {
+                const auto & col_name = GeneratedColumnPlaceholderBlockInputStream::getColumnName(i);
+                schema.emplace_back(std::make_pair(col_name, std::move(col)));
+            }
+            else if (col_id == DB::TiDBPkColumnID)
             {
                 ColumnInfo ci;
                 ci.tp = TiDB::TypeLongLong;

dbms/src/Flash/Coprocessor/TablesRegionsInfo.cpp

@@ -25,6 +25,7 @@ namespace DB
 namespace FailPoints
 {
 extern const char force_no_local_region_for_mpp_task[];
+extern const char force_random_remote_read[];
 } // namespace FailPoints
 
 SingleTableRegions & TablesRegionsInfo::getOrCreateTableRegionInfoByTableID(Int64 table_id)
@@ -73,8 +74,9 @@ static void insertRegionInfoToTablesRegionInfo(
     const TMTContext & tmt_context)
 {
     auto & table_region_info = tables_region_infos.getOrCreateTableRegionInfoByTableID(table_id);
-    for (const auto & r : regions)
+    for (int i = 0; i < regions.size(); ++i) // NOLINT
     {
+        const auto & r = regions[i];
         RegionInfo region_info(
             r.region_id(),
             r.region_epoch().version(),
@@ -98,8 +100,15 @@ static void insertRegionInfoToTablesRegionInfo(
         /// 4. The remote read will fetch the newest region info via key ranges. So it is possible to find the region
         ///    is served by the same node (but still read from remote).
         bool duplicated_region = local_region_id_set.contains(region_info.region_id);
+        bool is_remote = duplicated_region || needRemoteRead(region_info, tmt_context);
+#ifndef NDEBUG
+        fiu_do_on(FailPoints::force_random_remote_read, {
+            if ((i % 2) != 0)
+                is_remote = true;
+        });
+#endif
 
-        if (duplicated_region || needRemoteRead(region_info, tmt_context))
+        if (is_remote)
             table_region_info.remote_regions.push_back(region_info);
         else
         {

tests/fullstack-test/mpp/remote_read_virtual_column.test

@@ -0,0 +1,41 @@
+# Copyright 2025 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.test_vir;
+mysql> create table test.test_vir (id int not null, str varchar(100), str_vir varchar(100) as (lower(str)) VIRTUAL);
+mysql> insert into test.test_vir (id, str) values(1, 'ABC'), (2, 'Def'), (3, 'xXXX');
+mysql> alter table test.test_vir set tiflash replica 1;
+mysql> set @@cte_max_recursion_depth = 10000000; insert into test.test_vir (id, str) with recursive cte1 as (select 1 c1, 'a' c2 union select c1+1 c1, substr(concat(c2, 'B'), 10) c2 from cte1 limit 10000) select * from cte1;
+
+func> wait_table test test_vir
+mysql> split table test.test_vir by (100), (500), (1000);
+TOTAL_SPLIT_REGION	SCATTER_FINISH_RATIO
+3	1
+
+=> DBGInvoke __enable_fail_point(force_random_remote_read)
+mysql> set @@tidb_isolation_read_engines='tiflash'; set @@tidb_enforce_mpp=1; select * from test.test_vir order by 1, 2, 3 limit 5;
+id	str	str_vir
+1	ABC	abc
+1	a	a
+2
+2	Def	def
+3
+=> DBGInvoke __disable_fail_point(force_random_remote_read)
+
+# Clean up.
+mysql> drop table if exists test.test_vir
+