some changes

src/DataTypes/NestedUtils.cpp

@@ -4,6 +4,7 @@
 #include <Common/typeid_cast.h>
 #include <Common/assert_cast.h>
 #include <Common/StringUtils/StringUtils.h>
+#include "Columns/IColumn.h"
 
 #include <DataTypes/DataTypeArray.h>
 #include <DataTypes/DataTypeTuple.h>
@@ -119,7 +120,11 @@ Block flatten(const Block & block)
             {
                 const DataTypes & element_types = type_tuple->getElements();
                 const Strings & names = type_tuple->getElementNames();
-                const ColumnTuple * column_tuple = typeid_cast<const ColumnTuple *>(elem.column.get());
+                const ColumnTuple * column_tuple;
+                if(isColumnConst(*elem.column))
+                    column_tuple = typeid_cast<const ColumnTuple *>(&assert_cast<const ColumnConst &>(*elem.column).getDataColumn());
+                else
+                    column_tuple = typeid_cast<const ColumnTuple *>(elem.column.get());
                 size_t tuple_size = column_tuple->tupleSize();
                 for (size_t i = 0; i < tuple_size; ++i)
                 {
@@ -306,7 +311,7 @@ std::optional<ColumnWithTypeAndName> NestedColumnExtractHelper::extractColumn(
     {
         if (nested_table->has(new_column_name_prefix, case_insentive))
         {
-            ColumnWithTypeAndName column = nested_table->getByName(new_column_name_prefix, case_insentive);
+            ColumnWithTypeAndName column = *nested_table->findByName(new_column_name_prefix, case_insentive);
             if (case_insentive)
                 column.name = original_column_name;
             return {column};

src/DataTypes/NestedUtils.h

@@ -18,8 +18,9 @@ namespace Nested
     /// Returns the prefix of the name to the first '.'. Or the name is unchanged if there is no dot.
     std::string extractTableName(const std::string & nested_name);
 
-    /// Replace Array(Tuple(...)) columns to a multiple of Array columns in a form of `column_name.element_name`.
+    /// Flat a column of nested type into columns
-    /// only for named tuples that actually represent Nested structures.
+    /// 1) For named tuples，t Tuple(x .., y ..., ...), replace it with t.x ..., t.y ... , ...
+    /// 2) For an Array with named Tuple element column, a Array(Tuple(x ..., y ..., ...)), replace it with multiple Array Columns, a.x ..., a.y ..., ...
     Block flatten(const Block & block);
 
     /// Collect Array columns in a form of `column_name.element_name` to single Array(Tuple(...)) column.
@@ -35,6 +36,9 @@ namespace Nested
     std::unordered_set<String> getAllTableNames(const Block & block, bool to_lower_case = false);
 }
 
+/// Use this class to extract element columns from columns of nested type in a block, e.g. named Tuple. 
+/// It can extract a column from a multiple nested type column, e.g. named Tuple in named Tuple
+/// Keeps some intermediate datas to avoid rebuild them multi-times.
 class NestedColumnExtractHelper
 {
 public:

src/Storages/Hive/StorageHive.cpp

@@ -565,8 +565,8 @@ HiveFiles StorageHive::collectHiveFilesFromPartition(
     const ContextPtr & context_,
     PruneLevel prune_level) const
 {
-    //LOG_DEBUG(
+    LOG_DEBUG(
-    //    log, "Collect hive files from partition {}, prune_level:{}", boost::join(partition.values, ","), pruneLevelToString(prune_level));
+        log, "Collect hive files from partition {}, prune_level:{}", boost::join(partition.values, ","), pruneLevelToString(prune_level));
 
     /// Skip partition "__HIVE_DEFAULT_PARTITION__"
     bool has_default_partition = false;
@@ -794,7 +794,7 @@ Pipe StorageHive::read(
             auto subset_column = nested_columns_extractor.extractColumn(column);
             if (subset_column)
             {
-                sample_block.insert(*subset_column);
+                sample_block.insert(std::move(*subset_column));
                 continue;
             }
         }