br: add a test for cached table (#31191)

close pingcap/tidb#31190

br/pkg/backup/client.go

@@ -378,6 +378,9 @@ func BuildBackupRangeAndSchema(
 				tableInfo.ClearPlacement()
 			}
 
+			// Treat cached table as normal table.
+			tableInfo.TableCacheStatusType = model.TableCacheStatusDisable
+
 			if tableInfo.PKIsHandle && tableInfo.ContainsAutoRandomBits() {
 				// this table has auto_random id, we need backup and rebase in restoration
 				var globalAutoRandID int64

br/tests/br_cache_table/run.sh

@@ -0,0 +1,42 @@
+#!/bin/sh
+#
+# Copyright 2020 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.
+
+set -eu
+DB="$TEST_NAME"
+
+run_sql "create schema $DB;"
+run_sql "create table $DB.cache_1 (id int);"
+run_sql "insert into $DB.cache_1 values (1);"
+run_sql "alter table $DB.cache_1 cache;"
+run_sql "insert into $DB.cache_1 values (2),(3);"
+
+echo "backup start..."
+run_br backup db --db "$DB" -s "local://$TEST_DIR/$DB" --pd $PD_ADDR
+
+run_sql "drop schema $DB;"
+
+echo "restore start..."
+run_br restore db --db $DB -s "local://$TEST_DIR/$DB" --pd $PD_ADDR
+
+set -x
+
+run_sql "select count(*) from $DB.cache_1;"
+check_contains 'count(*): 3'
+
+run_sql "select create_options from information_schema.tables where table_schema = '$DB' and table_name = 'cache_1';"
+check_not_contains 'create_options: cached=on'
+
+run_sql "drop schema $DB"