fix bug select from virtual table report -4201

src/sql/engine/px/ob_granule_pump.cpp

@@ -1075,9 +1075,19 @@ int ObAffinitizeGranuleSplitter::split_tasks_affinity(ObExecContext &ctx,
           LOG_WARN("fail to build tablet idx map", K(ret));
         }
       }
-      if (OB_FAIL(ret)) {
+      if (OB_SUCC(ret)) {
+        // see issue
+        // for virtual table, we can directly mock a tablet id
+        // function build_tablet_idx_map will mock a idx map whose key
+        // varies from 1 to table_schema->get_all_part_num(), and the value = key + 1
+        // so we can directly set tablet_idx = tablet_loc.tablet_id_.id() + 1, the result is same
+        if (is_virtual_table(table_schema->get_table_id())) {
+          tablet_idx = tablet_loc.tablet_id_.id() + 1;
         } else if (OB_FAIL(idx_map.get_refactored(tablet_loc.tablet_id_.id(), tablet_idx))) {
           LOG_WARN("fail to get tablet idx", K(ret));
+        }
+      }
+      if (OB_FAIL(ret)) {
       } else if (OB_FAIL(ObPxAffinityByRandom::get_tablet_info(tablet_loc.tablet_id_.id(),
                                                                partitions_info_,
                                                                partition_row_info))) {

src/sql/engine/px/ob_px_util.cpp

@@ -1450,6 +1450,12 @@ int ObPXServerAddrUtil::build_tablet_idx_map(
   } else if (OB_FAIL(idx_map.create(table_schema->get_all_part_num(), "TabletOrderIdx"))) {
     LOG_WARN("fail create index map", K(ret), "cnt", table_schema->get_all_part_num());
   } else if (is_virtual_table(table_schema->get_table_id())) {
+    // In observer 4.2, the table schema of a distributed virtual table will show all_part_num as 1,
+    // whereas in lower versions it would display as 65536.
+    // For a distrubuted virtual table, we may encounter a situation where part_id is 1 in sqc1,
+    // part_id is 2 in sqc2 and so on, but the idx_map only contains one item with key=1.
+    // Hence, if we seek with part_id=2, the idx_map will return -4201 (OB_HASH_NOT_EXIST)
+    // will return -4201(OB_HASH_NOT_EXIST). In such cases, we can directly obtain the value that equals part_id + 1.
     for (int i = 0; OB_SUCC(ret) && i < table_schema->get_all_part_num(); ++i) {
       if (OB_FAIL(idx_map.set_refactored(i + 1, tablet_idx++))) {
         LOG_WARN("fail set value to hashmap", K(ret));