Preparation for rename

dbms/src/Access/AccessType.h

@@ -28,6 +28,7 @@ enum class AccessType
     ADD_COLUMN,
     DROP_COLUMN,
     MODIFY_COLUMN,
+    RENAME_COLUMN,
     COMMENT_COLUMN,
     CLEAR_COLUMN,
     ALTER_COLUMN,       /// allow to execute ALTER {ADD|DROP|MODIFY...} COLUMN
@@ -195,6 +196,7 @@ namespace impl
             ACCESS_TYPE_TO_KEYWORD_CASE(ADD_COLUMN);
             ACCESS_TYPE_TO_KEYWORD_CASE(DROP_COLUMN);
             ACCESS_TYPE_TO_KEYWORD_CASE(MODIFY_COLUMN);
+            ACCESS_TYPE_TO_KEYWORD_CASE(RENAME_COLUMN);
             ACCESS_TYPE_TO_KEYWORD_CASE(COMMENT_COLUMN);
             ACCESS_TYPE_TO_KEYWORD_CASE(CLEAR_COLUMN);
             ACCESS_TYPE_TO_KEYWORD_CASE(ALTER_COLUMN);

dbms/src/Interpreters/InterpreterAlterQuery.cpp

@@ -280,6 +280,11 @@ AccessRightsElements InterpreterAlterQuery::getRequiredAccessForCommand(const AS
             required_access.emplace_back(AccessType::REFRESH_VIEW, database, table);
             break;
         }
+        case ASTAlterCommand::RENAME_COLUMN:
+        {
+            required_access.emplace_back(AccessType::RENAME_COLUMN, database, table);
+            break;
+        }
         case ASTAlterCommand::NO_TYPE: break;
     }
 

dbms/src/Parsers/ASTAlterQuery.cpp

@@ -56,6 +56,11 @@ ASTPtr ASTAlterCommand::clone() const
         res->values = values->clone();
         res->children.push_back(res->values);
     }
+    if (rename_to)
+    {
+        res->rename_to = rename_to->clone();
+        res->children.push_back(res->rename_to);
+    }
 
     return res;
 }
@@ -285,6 +290,15 @@ void ASTAlterCommand::formatImpl(
     {
         settings.ostr << (settings.hilite ? hilite_keyword : "") << indent_str << "REFRESH " << (settings.hilite ? hilite_none : "");
     }
+    else if (type == ASTAlterCommand::RENAME_COLUMN)
+    {
+        settings.ostr << (settings.hilite ? hilite_keyword : "") << indent_str << "RENAME COLUMN " << (if_exists ? "IF EXISTS " : "")
+                      << (settings.hilite ? hilite_none : "");
+        column->formatImpl(settings, state, frame);
+
+        settings.ostr << (settings.hilite ? hilite_keyword : "") << " TO ";
+        rename_to->formatImpl(settings, state, frame);
+    }
     else
         throw Exception("Unexpected type of ALTER", ErrorCodes::UNEXPECTED_AST_STRUCTURE);
 }

dbms/src/Parsers/ASTAlterQuery.h

@@ -29,6 +29,7 @@ public:
         DROP_COLUMN,
         MODIFY_COLUMN,
         COMMENT_COLUMN,
+        RENAME_COLUMN,
         MODIFY_ORDER_BY,
         MODIFY_TTL,
         MATERIALIZE_TTL,
@@ -69,6 +70,7 @@ public:
 
     /** The ADD COLUMN query here optionally stores the name of the column following AFTER
      * The DROP query stores the column name for deletion here
+     * Also used for RENAME COLUMN.
      */
     ASTPtr column;
 
@@ -155,6 +157,9 @@ public:
     String to_database;
     String to_table;
 
+    /// Target column name
+    ASTPtr rename_to;
+
     String getID(char delim) const override { return "AlterCommand" + (delim + std::to_string(static_cast<int>(type))); }
 
     ASTPtr clone() const override;

dbms/src/Storages/AlterCommands.cpp

@@ -231,10 +231,20 @@ std::optional<AlterCommand> AlterCommand::parse(const ASTAlterCommand * command_
     else if (command_ast->type == ASTAlterCommand::MODIFY_QUERY)
     {
         AlterCommand command;
+        command.ast = command_ast->clone();
         command.type = AlterCommand::MODIFY_QUERY;
         command.select = command_ast->select;
         return command;
     }
+    else if (command_ast->type == ASTAlterCommand::RENAME_COLUMN)
+    {
+        AlterCommand command;
+        command.ast = command_ast->clone();
+        command.type = AlterCommand::RENAME_COLUMN;
+        command.column_name = command_ast->column->as<ASTIdentifier &>().name;
+        command.rename_to = command_ast->rename_to->as<ASTIdentifier &>().name;
+        return command;
+    }
     else
         return {};
 }
@@ -437,6 +447,10 @@ void AlterCommand::apply(StorageInMemoryMetadata & metadata) const
                 settings_from_storage.push_back(change);
         }
     }
+    else if (type == RENAME_COLUMN)
+    {
+        metadata.columns.rename(column_name, rename_to);
+    }
     else
         throw Exception("Wrong parameter type in ALTER query", ErrorCodes::LOGICAL_ERROR);
 }
@@ -519,7 +533,7 @@ bool AlterCommand::isRequireMutationStage(const StorageInMemoryMetadata & metada
     if (ignore)
         return false;
 
-    if (type == DROP_COLUMN || type == DROP_INDEX)
+    if (type == DROP_COLUMN || type == DROP_INDEX || type == RENAME_COLUMN)
         return true;
 
     if (type != MODIFY_COLUMN || data_type == nullptr)
@@ -619,6 +633,8 @@ String alterTypeToString(const AlterCommand::Type type)
         return "MODIFY SETTING";
     case AlterCommand::Type::MODIFY_QUERY:
         return "MODIFY QUERY";
+    case AlterCommand::Type::RENAME_COLUMN:
+        return "RENAME COLUMN";
     }
     __builtin_unreachable();
 }

dbms/src/Storages/AlterCommands.h

@@ -35,6 +35,7 @@ struct AlterCommand
         MODIFY_TTL,
         MODIFY_SETTING,
         MODIFY_QUERY,
+        RENAME_COLUMN,
     };
 
     Type type;
@@ -96,6 +97,9 @@ struct AlterCommand
     /// For MODIFY_QUERY
     ASTPtr select = nullptr;
 
+    /// Target column name
+    String rename_to;
+
     static std::optional<AlterCommand> parse(const ASTAlterCommand * command);
 
     void apply(StorageInMemoryMetadata & metadata) const;

dbms/src/Storages/ColumnsDescription.cpp

@@ -1,4 +1,6 @@
 #include <Storages/ColumnsDescription.h>
+
+#include <boost/algorithm/string/replace.hpp>
 #include <Parsers/ASTLiteral.h>
 #include <Parsers/ExpressionElementParsers.h>
 #include <Parsers/ExpressionListParsers.h>
@@ -195,6 +197,27 @@ void ColumnsDescription::remove(const String & column_name)
         list_it = columns.get<0>().erase(list_it);
 }
 
+void ColumnsDescription::rename(const String & column_from, const String & column_to)
+{
+    auto range = getNameRange(columns, column_from);
+
+    if (range.first == range.second)
+        throw Exception("There is no column " + column_from + " in table.", ErrorCodes::NO_SUCH_COLUMN_IN_TABLE);
+
+    std::vector<ColumnDescription> iterators;
+    for (auto list_it = range.first; list_it != range.second;)
+    {
+        iterators.push_back(*list_it);
+        list_it = columns.get<0>().erase(list_it);
+    }
+
+    for (auto & col_desc : iterators)
+    {
+        boost::replace_all(col_desc.name, column_from, column_to);
+        add(col_desc);
+    }
+}
+
 
 void ColumnsDescription::flattenNested()
 {

dbms/src/Storages/ColumnsDescription.h

@@ -57,6 +57,9 @@ public:
     /// `column_name` can be a Nested column name;
     void remove(const String & column_name);
 
+    /// TODO(alesap)
+    void rename(const String & column_from, const String & column_to);
+
     void flattenNested(); /// TODO: remove, insert already flattened Nested columns.
 
     bool operator==(const ColumnsDescription & other) const { return columns == other.columns; }

dbms/src/Storages/MergeTree/MergeTreeData.cpp

@@ -3589,4 +3589,8 @@ bool MergeTreeData::canUsePolymorphicParts(const MergeTreeSettings & settings, S
     return true;
 }
 
+MergeTreeData::AlterConversions MergeTreeData::getAlterConversionsForPart(const MergeTreeDataPartPtr /*part*/) const
+{
+    return AlterConversions{};
+}
 }

dbms/src/Storages/MergeTree/MergeTreeData.h

@@ -33,6 +33,7 @@ namespace DB
 class MergeListEntry;
 class AlterCommands;
 class MergeTreePartsMover;
+class MutationCommands;
 
 class ExpressionActions;
 using ExpressionActionsPtr = std::shared_ptr<ExpressionActions>;
@@ -124,6 +125,11 @@ public:
 
     STRONG_TYPEDEF(String, PartitionID)
 
+    struct AlterConversions
+    {
+        std::unordered_map<String, String> rename_map;
+    };
+
     struct LessDataPart
     {
         using is_transparent = void;
@@ -647,6 +653,8 @@ public:
     /// Reserves 0 bytes
     ReservationPtr makeEmptyReservationOnLargestDisk() { return getStoragePolicy()->makeEmptyReservationOnLargestDisk(); }
 
+    AlterConversions getAlterConversionsForPart(const MergeTreeDataPartPtr part) const;
+
     MergeTreeDataFormatVersion format_version;
 
     Context & global_context;
@@ -908,6 +916,7 @@ protected:
     /// mechanisms for parts locking
     virtual bool partIsAssignedToBackgroundOperation(const DataPartPtr & part) const = 0;
 
+    virtual MutationCommands getFirtsAlterMutationCommandsForPart(const DataPartPtr & part) const = 0;
     /// Moves part to specified space, used in ALTER ... MOVE ... queries
     bool movePartsToSpace(const DataPartsVector & parts, SpacePtr space);
 

dbms/src/Storages/MergeTree/ReplicatedMergeTreeQueue.cpp

@@ -1309,6 +1309,21 @@ ReplicatedMergeTreeMergePredicate ReplicatedMergeTreeQueue::getMergePredicate(zk
 }
 
 
+MutationCommands ReplicatedMergeTreeQueue::getFirstAlterMutationCommandsForPart(const MergeTreeData::DataPartPtr & part) const
+{
+    std::lock_guard lock(state_mutex);
+    auto in_partition = mutations_by_partition.find(part->info.partition_id);
+    if (in_partition == mutations_by_partition.end())
+        return MutationCommands{};
+
+    Int64 part_version = part->info.getDataVersion();
+    for (auto [mutation_version, mutation_status] : in_partition->second)
+        if (mutation_version > part_version && mutation_status->entry->alter_version != -1)
+            return mutation_status->entry->commands;
+
+    return MutationCommands{};
+}
+
 MutationCommands ReplicatedMergeTreeQueue::getMutationCommands(
     const MergeTreeData::DataPartPtr & part, Int64 desired_mutation_version) const
 {

dbms/src/Storages/MergeTree/ReplicatedMergeTreeQueue.h

@@ -331,6 +331,9 @@ public:
 
     MutationCommands getMutationCommands(const MergeTreeData::DataPartPtr & part, Int64 desired_mutation_version) const;
 
+    /// TODO(alesap)
+    MutationCommands getFirstAlterMutationCommandsForPart(const MergeTreeData::DataPartPtr & part) const;
+
     /// Mark finished mutations as done. If the function needs to be called again at some later time
     /// (because some mutations are probably done but we are not sure yet), returns true.
     bool tryFinalizeMutations(zkutil::ZooKeeperPtr zookeeper);

dbms/src/Storages/StorageMergeTree.h

@@ -164,6 +164,8 @@ protected:
         const MergingParams & merging_params_,
         std::unique_ptr<MergeTreeSettings> settings_,
         bool has_force_restore_data_flag);
+
+    MutationCommands getFirtsAlterMutationCommandsForPart(const DataPartPtr & /* part */) const override { return {}; }
 };
 
 }

dbms/src/Storages/StorageReplicatedMergeTree.cpp

@@ -5297,4 +5297,9 @@ StorageReplicatedMergeTree::getMetadataFromSharedZookeeper(const String & metada
 
 }
 
+MutationCommands StorageReplicatedMergeTree::getFirtsAlterMutationCommandsForPart(const DataPartPtr & part) const
+{
+    return queue.getFirstAlterMutationCommandsForPart(part);
+}
+
 }

dbms/src/Storages/StorageReplicatedMergeTree.h

@@ -527,6 +527,9 @@ private:
 
     StorageInMemoryMetadata getMetadataFromSharedZookeeper(const String & metadata_str, const String & columns_str) const;
 
+
+    MutationCommands getFirtsAlterMutationCommandsForPart(const DataPartPtr & part) const override;
+
 protected:
     /** If not 'attach', either creates a new table in ZK, or adds a replica to an existing table.
       */
@@ -542,6 +545,7 @@ protected:
         const MergingParams & merging_params_,
         std::unique_ptr<MergeTreeSettings> settings_,
         bool has_force_restore_data_flag);
+
 };