branch-2.1: [fix](nereids)fix the cascadesContext.getMemo()==null #48771 (#49095)

Cherry-picked from #48771

Co-authored-by: zhangm365 <mzhang2048@gmail.com>

fe/fe-core/src/main/java/org/apache/doris/nereids/NereidsPlanner.java

@@ -253,8 +253,12 @@ public class NereidsPlanner extends Planner {
         // print memo before choose plan.
         // if chooseNthPlan failed, we could get memo to debug
         if (cascadesContext.getConnectContext().getSessionVariable().dumpNereidsMemo) {
-            String memo = cascadesContext.getMemo().toString();
-            LOG.info("{}\n{}", ConnectContext.get().getQueryIdentifier(), memo);
+            Memo memo = cascadesContext.getMemo();
+            if (memo != null) {
+                LOG.info("{}\n{}", ConnectContext.get().getQueryIdentifier(), memo.toString());
+            } else {
+                LOG.info("{}\nMemo is null", ConnectContext.get().getQueryIdentifier());
+            }
         }
 
         int nth = cascadesContext.getConnectContext().getSessionVariable().getNthOptimizedPlan();
@@ -583,10 +587,15 @@ public class NereidsPlanner extends Planner {
                 plan = optimizedPlan.shape("");
                 break;
             case MEMO_PLAN:
-                plan = cascadesContext.getMemo().toString()
+                Memo memo = cascadesContext.getMemo();
+                if (memo == null) {
+                    plan = "Memo is null";
+                } else {
+                    plan = memo.toString()
                         + "\n\n========== OPTIMIZED PLAN ==========\n"
                         + optimizedPlan.treeString()
                         + mvSummary;
+                }
                 break;
             case ALL_PLAN:
                 plan = "========== PARSED PLAN "

regression-test/data/correctness/test_insert_table_with_dump_nereids_memo.out

@@ -0,0 +1,5 @@
+-- This file is automatically generated. You should know what you did if you want to edit this
+-- !select --
+1	hello
+2	world
+

regression-test/suites/correctness/test_insert_table_with_dump_nereids_memo.groovy

@@ -0,0 +1,58 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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.
+
+suite("test_insert_table_with_dump_nereids_memo") {
+
+    def testTable = "test_insert_table_with_dump_nereids_memo"
+    // Clean up any existing table with the same name
+    sql "DROP TABLE IF EXISTS ${testTable}"
+
+    // Create table with with test 'dump_nereids_memo' SessionVariable
+    // set dump_nereids_memo to true
+    sql "set dump_nereids_memo = true"
+
+    // Verify that the variable is set correctly
+    def result = sql "SHOW VARIABLES LIKE 'dump_nereids_memo'"
+    assertTrue(result[0][1] == "true")
+
+    sql """
+    CREATE TABLE ${testTable}
+    (
+        id int,
+        name string
+    )
+    COMMENT "test table with dump_nereids_memo"
+    DISTRIBUTED BY HASH(id) BUCKETS 1
+    PROPERTIES (
+        "replication_num" = "1"
+    )
+    """
+
+    // Insert data into the table
+    sql "INSERT INTO ${testTable} VALUES (1, 'hello'), (2, 'world')"
+
+    // Synchronize to ensure data is visible
+    sql "SYNC"
+
+    // Verify that data was inserted correctly
+    qt_select "SELECT * FROM ${testTable} ORDER BY id"
+
+    // Clean up after the test
+    sql "DROP TABLE IF EXISTS ${testTable}"
+    sql "set dump_nereids_memo = false"
+
+}