[WIP] Export merge tree partition to object storage

src/Access/Common/AccessType.h

@@ -74,6 +74,7 @@ enum class AccessType : uint8_t
                                                                        enabled implicitly by the grant ALTER_TABLE */\
     M(ALTER_SETTINGS, "ALTER SETTING, ALTER MODIFY SETTING, MODIFY SETTING, RESET SETTING", TABLE, ALTER_TABLE) /* allows to execute ALTER MODIFY SETTING */\
     M(ALTER_MOVE_PARTITION, "ALTER MOVE PART, MOVE PARTITION, MOVE PART", TABLE, ALTER_TABLE) \
+    M(ALTER_EXPORT_PARTITION, "ALTER EXPORT PART, EXPORT PARTITION, EXPORT PART", TABLE, ALTER_TABLE) \
     M(ALTER_FETCH_PARTITION, "ALTER FETCH PART, FETCH PARTITION", TABLE, ALTER_TABLE) \
     M(ALTER_FREEZE_PARTITION, "FREEZE PARTITION, UNFREEZE", TABLE, ALTER_TABLE) \
     M(ALTER_UNLOCK_SNAPSHOT, "UNLOCK SNAPSHOT", TABLE, ALTER_TABLE) \

src/CMakeLists.txt

@@ -130,6 +130,7 @@ add_headers_and_sources(dbms Storages/ObjectStorage/Azure)
 add_headers_and_sources(dbms Storages/ObjectStorage/S3)
 add_headers_and_sources(dbms Storages/ObjectStorage/HDFS)
 add_headers_and_sources(dbms Storages/ObjectStorage/Local)
+add_headers_and_sources(dbms Storages/ObjectStorage/MergeTree)
 add_headers_and_sources(dbms Storages/ObjectStorage/DataLakes)
 add_headers_and_sources(dbms Storages/ObjectStorage/DataLakes/Iceberg)
 add_headers_and_sources(dbms Storages/ObjectStorage/DataLakes/DeltaLake)

src/Common/CurrentMetrics.cpp

@@ -10,6 +10,7 @@
     M(Merge, "Number of executing background merges") \
     M(MergeParts, "Number of source parts participating in current background merges") \
     M(Move, "Number of currently executing moves") \
+    M(Export, "Number of currently executing exports") \
     M(PartMutation, "Number of mutations (ALTER DELETE/UPDATE)") \
     M(ReplicatedFetch, "Number of data parts being fetched from replica") \
     M(ReplicatedSend, "Number of data parts being sent to replicas") \

src/Core/ServerSettings.cpp

@@ -99,6 +99,7 @@ namespace DB
     DECLARE(UInt64, max_unexpected_parts_loading_thread_pool_size, 8, R"(The number of threads to load inactive set of data parts (Unexpected ones) at startup.)", 0) \
     DECLARE(UInt64, max_parts_cleaning_thread_pool_size, 128, R"(The number of threads for concurrent removal of inactive data parts.)", 0) \
     DECLARE(UInt64, max_mutations_bandwidth_for_server, 0, R"(The maximum read speed of all mutations on server in bytes per second. Zero means unlimited.)", 0) \
+    DECLARE(UInt64, max_exports_bandwidth_for_server, 0, R"(The maximum read speed of all exports on server in bytes per second. Zero means unlimited.)", 0) \
     DECLARE(UInt64, max_merges_bandwidth_for_server, 0, R"(The maximum read speed of all merges on server in bytes per second. Zero means unlimited.)", 0) \
     DECLARE(UInt64, max_replicated_fetches_network_bandwidth_for_server, 0, R"(The maximum speed of data exchange over the network in bytes per second for replicated fetches. Zero means unlimited.)", 0) \
     DECLARE(UInt64, max_replicated_sends_network_bandwidth_for_server, 0, R"(The maximum speed of data exchange over the network in bytes per second for replicated sends. Zero means unlimited.)", 0) \
@@ -1064,6 +1065,7 @@ The policy on how to perform a scheduling of CPU slots specified by `concurrent_
     See [Controlling behavior on server CPU overload](/operations/settings/server-overload) for more details.
     )", 0) \
     DECLARE(Float, distributed_cache_keep_up_free_connections_ratio, 0.1f, "Soft limit for number of active connection distributed cache will try to keep free. After the number of free connections goes below distributed_cache_keep_up_free_connections_ratio * max_connections, connections with oldest activity will be closed until the number goes above the limit.", 0) \
+    DECLARE(UInt64, export_merge_tree_partition_max_retries, 3, "Max number of retries for exporting merge tree partition. Currently not persisted across re-starts", 0) \
 
 
 // clang-format on

src/Core/Settings.cpp

@@ -6874,6 +6874,9 @@ Possible values:
     DECLARE_WITH_ALIAS(Bool, allow_experimental_time_series_aggregate_functions, false, R"(
 Experimental timeSeries* aggregate functions for Prometheus-like timeseries resampling, rate, delta calculation.
 )", EXPERIMENTAL, allow_experimental_ts_to_grid_aggregate_function) \
+    DECLARE_WITH_ALIAS(Bool, allow_experimental_export_merge_tree_partition, false, R"(
+Experimental export merge tree partition.
+)", EXPERIMENTAL, allow_experimental_export_merge_tree_partition) \
     \
     /* ####################################################### */ \
     /* ############ END OF EXPERIMENTAL FEATURES ############# */ \

src/Core/SettingsChangesHistory.cpp

@@ -71,6 +71,7 @@ const VersionToSettingsChangesMap & getSettingsChangesHistory()
         addSettingsChanges(settings_changes_history, "25.6.5.2000",
         {
             {"output_format_parquet_enum_as_byte_array", true, true, "Enable writing Enum as byte array in Parquet by default"},
+            {"allow_experimental_export_merge_tree_partition", true, false, "Enable experimental export merge tree partition"},
         });
         addSettingsChanges(settings_changes_history, "25.6",
         {

src/Databases/DatabaseS3.cpp

@@ -19,6 +19,7 @@
 #include <Storages/IStorage.h>
 #include <Storages/NamedCollectionsHelpers.h>
 #include <TableFunctions/TableFunctionFactory.h>
+#include <Parsers/ASTInsertQuery.h>
 
 #include <boost/algorithm/string.hpp>
 #include <filesystem>

src/Disks/ObjectStorages/IObjectStorage.h

@@ -96,6 +96,7 @@ struct RelativePathWithMetadata
     virtual ~RelativePathWithMetadata() = default;
 
     virtual std::string getFileName() const { return std::filesystem::path(relative_path).filename(); }
+    virtual std::string getFileNameWithoutExtension() const { return std::filesystem::path(relative_path).stem(); }
     virtual std::string getPath() const { return relative_path; }
     virtual bool isArchive() const { return false; }
     virtual std::string getPathToArchive() const { throw Exception(ErrorCodes::LOGICAL_ERROR, "Not an archive"); }

src/Formats/FormatFactory.cpp

@@ -568,8 +568,12 @@ OutputFormatPtr FormatFactory::getOutputFormatParallelIfPossible(
     auto format_settings = _format_settings ? *_format_settings : getFormatSettings(context);
     const Settings & settings = context->getSettingsRef();
 
-    if (settings[Setting::output_format_parallel_formatting] && getCreators(name).supports_parallel_formatting
-        && !settings[Setting::output_format_json_array_of_rows])
+    const bool parallel_formatting_enabled = settings[Setting::output_format_parallel_formatting];
+    const bool supports_parallel_formatting = getCreators(name).supports_parallel_formatting;
+
+    bool are_we_doing_parallel_formatting = parallel_formatting_enabled && supports_parallel_formatting && !settings[Setting::output_format_json_array_of_rows];
+
+    if (are_we_doing_parallel_formatting)
     {
         auto formatter_creator = [output_getter, sample, format_settings] (WriteBuffer & output) -> OutputFormatPtr
         {

src/Interpreters/Context.cpp

@@ -288,6 +288,7 @@ namespace ServerSetting
     extern const ServerSettingsUInt64 max_local_write_bandwidth_for_server;
     extern const ServerSettingsUInt64 max_merges_bandwidth_for_server;
     extern const ServerSettingsUInt64 max_mutations_bandwidth_for_server;
+    extern const ServerSettingsUInt64 max_exports_bandwidth_for_server;
     extern const ServerSettingsUInt64 max_remote_read_network_bandwidth_for_server;
     extern const ServerSettingsUInt64 max_remote_write_network_bandwidth_for_server;
     extern const ServerSettingsUInt64 max_replicated_fetches_network_bandwidth_for_server;
@@ -504,6 +505,8 @@ struct ContextSharedPart : boost::noncopyable
     mutable ThrottlerPtr mutations_throttler;               /// A server-wide throttler for mutations
     mutable ThrottlerPtr merges_throttler;                  /// A server-wide throttler for merges
 
+    mutable ThrottlerPtr exports_throttler;                /// A server-wide throttler for exports
+
     MultiVersion<Macros> macros;                            /// Substitutions extracted from config.
     std::unique_ptr<DDLWorker> ddl_worker TSA_GUARDED_BY(mutex); /// Process ddl commands from zk.
     LoadTaskPtr ddl_worker_startup_task;                         /// To postpone `ddl_worker->startup()` after all tables startup
@@ -992,6 +995,9 @@ struct ContextSharedPart : boost::noncopyable
 
         if (auto bandwidth = server_settings[ServerSetting::max_merges_bandwidth_for_server])
             merges_throttler = std::make_shared<Throttler>(bandwidth);
+
+        if (auto bandwidth = server_settings[ServerSetting::max_exports_bandwidth_for_server])
+            exports_throttler = std::make_shared<Throttler>(bandwidth);
     }
 };
 
@@ -4041,6 +4047,11 @@ ThrottlerPtr Context::getMergesThrottler() const
     return shared->merges_throttler;
 }
 
+ThrottlerPtr Context::getExportsThrottler() const
+{
+    return shared->exports_throttler;
+}
+
 void Context::reloadRemoteThrottlerConfig(size_t read_bandwidth, size_t write_bandwidth) const
 {
     if (read_bandwidth)

src/Interpreters/Context.h

@@ -1635,6 +1635,7 @@ class Context: public ContextData, public std::enable_shared_from_this<Context>
 
     ThrottlerPtr getMutationsThrottler() const;
     ThrottlerPtr getMergesThrottler() const;
+    ThrottlerPtr getExportsThrottler() const;
 
     void reloadRemoteThrottlerConfig(size_t read_bandwidth, size_t write_bandwidth) const;
     void reloadLocalThrottlerConfig(size_t read_bandwidth, size_t write_bandwidth) const;

src/Interpreters/InterpreterAlterQuery.cpp

@@ -502,6 +502,12 @@ AccessRightsElements InterpreterAlterQuery::getRequiredAccessForCommand(const AS
             required_access.emplace_back(AccessType::ALTER_DELETE | AccessType::INSERT, database, table);
             break;
         }
+        case ASTAlterCommand::EXPORT_PARTITION:
+        {
+            required_access.emplace_back(AccessType::ALTER_EXPORT_PARTITION, database, table);
+            required_access.emplace_back(AccessType::INSERT, command.to_database, command.to_table);
+            break;
+        }
         case ASTAlterCommand::FETCH_PARTITION:
         {
             required_access.emplace_back(AccessType::ALTER_FETCH_PARTITION, database, table);

src/Interpreters/PartLog.cpp

@@ -69,6 +69,7 @@ ColumnsDescription PartLogElement::getColumnsDescription()
             {"MovePart",      static_cast<Int8>(MOVE_PART)},
             {"MergePartsStart", static_cast<Int8>(MERGE_PARTS_START)},
             {"MutatePartStart", static_cast<Int8>(MUTATE_PART_START)},
+            {"ExportPart",      static_cast<Int8>(EXPORT_PART)},
         }
     );
 
@@ -109,7 +110,8 @@ ColumnsDescription PartLogElement::getColumnsDescription()
             "RemovePart — Removing or detaching a data part using [DETACH PARTITION](/sql-reference/statements/alter/partition#detach-partitionpart)."
             "MutatePartStart — Mutating of a data part has started, "
             "MutatePart — Mutating of a data part has finished, "
-            "MovePart — Moving the data part from the one disk to another one."},
+            "MovePart — Moving the data part from the one disk to another one."
+            "ExportPart — Exporting the data part from a merge tree table to one (e.g, object storage)."},
         {"merge_reason", std::move(merge_reason_datatype),
             "The reason for the event with type MERGE_PARTS. Can have one of the following values: "
             "NotAMerge — The current event has the type other than MERGE_PARTS, "

src/Interpreters/PartLog.h

@@ -30,6 +30,7 @@ struct PartLogElement
         MOVE_PART = 6,
         MERGE_PARTS_START = 7,
         MUTATE_PART_START = 8,
+        EXPORT_PART = 9,
     };
 
     /// Copy of MergeAlgorithm since values are written to disk.

src/Parsers/ASTAlterQuery.cpp

@@ -355,6 +355,29 @@ void ASTAlterCommand::formatImpl(WriteBuffer & ostr, const FormatSettings & sett
             ostr << quoteString(move_destination_name);
         }
     }
+    else if (type == ASTAlterCommand::EXPORT_PARTITION)
+    {
+        ostr << (settings.hilite ? hilite_keyword : "") << "EXPORT " << (part ? "PART " : "PARTITION ")
+             << (settings.hilite ? hilite_none : "");
+        partition->format(ostr, settings, state, frame);
+        ostr << " TO ";
+        switch (move_destination_type)
+        {
+            case DataDestinationType::TABLE:
+                ostr << "TABLE ";
+                if (!to_database.empty())
+                {
+                    ostr << (settings.hilite ? hilite_identifier : "") << backQuoteIfNeed(to_database)
+                         << (settings.hilite ? hilite_none : "") << ".";
+                }
+                ostr << (settings.hilite ? hilite_identifier : "") << backQuoteIfNeed(to_table)
+                     << (settings.hilite ? hilite_none : "");
+                return;
+            default:
+                break;
+        }
+
+    }
     else if (type == ASTAlterCommand::REPLACE_PARTITION)
     {
         ostr << (settings.hilite ? hilite_keyword : "") << (replace ? "REPLACE" : "ATTACH") << " PARTITION "

src/Parsers/ASTAlterQuery.h

@@ -71,6 +71,7 @@ class ASTAlterCommand : public IAST
         FREEZE_ALL,
         UNFREEZE_PARTITION,
         UNFREEZE_ALL,
+        EXPORT_PARTITION,
 
         DELETE,
         UPDATE,

src/Parsers/CommonParsers.h

@@ -331,6 +331,7 @@ namespace DB
     MR_MACROS(MONTHS, "MONTHS") \
     MR_MACROS(MOVE_PART, "MOVE PART") \
     MR_MACROS(MOVE_PARTITION, "MOVE PARTITION") \
+    MR_MACROS(EXPORT_PARTITION, "EXPORT PARTITION") \
     MR_MACROS(MOVE, "MOVE") \
     MR_MACROS(MS, "MS") \
     MR_MACROS(MUTATION, "MUTATION") \

src/Parsers/ParserAlterQuery.cpp

@@ -82,6 +82,7 @@ bool ParserAlterCommand::parseImpl(Pos & pos, ASTPtr & node, Expected & expected
     ParserKeyword s_forget_partition(Keyword::FORGET_PARTITION);
     ParserKeyword s_move_partition(Keyword::MOVE_PARTITION);
     ParserKeyword s_move_part(Keyword::MOVE_PART);
+    ParserKeyword s_export_partition(Keyword::EXPORT_PARTITION);
     ParserKeyword s_drop_detached_partition(Keyword::DROP_DETACHED_PARTITION);
     ParserKeyword s_drop_detached_part(Keyword::DROP_DETACHED_PART);
     ParserKeyword s_fetch_partition(Keyword::FETCH_PARTITION);
@@ -564,6 +565,22 @@ bool ParserAlterCommand::parseImpl(Pos & pos, ASTPtr & node, Expected & expected
                     command->move_destination_name = ast_space_name->as<ASTLiteral &>().value.safeGet<String>();
                 }
             }
+            else if (s_export_partition.ignore(pos, expected))
+            {
+                if (!parser_partition.parse(pos, command_partition, expected))
+                    return false;
+
+                command->type = ASTAlterCommand::EXPORT_PARTITION;
+
+                if (!s_to_table.ignore(pos, expected))
+                {
+                    return false;
+                }
+
+                if (!parseDatabaseAndTableName(pos, expected, command->to_database, command->to_table))
+                    return false;
+                command->move_destination_type = DataDestinationType::TABLE;
+            }
             else if (s_add_constraint.ignore(pos, expected))
             {
                 if (s_if_not_exists.ignore(pos, expected))

src/Storages/IPartitionStrategy.cpp

@@ -332,32 +332,27 @@ ColumnPtr HiveStylePartitionStrategy::computePartitionKey(const Chunk & chunk)
     return block_with_partition_by_expr.getByName(actions_with_column_name.column_name).column;
 }
 
-ColumnRawPtrs HiveStylePartitionStrategy::getFormatChunkColumns(const Chunk & chunk)
+Chunk HiveStylePartitionStrategy::getFormatChunk(const Chunk & chunk)
 {
-    ColumnRawPtrs result;
+    Chunk result;
+
     if (partition_columns_in_data_file)
     {
         for (const auto & column : chunk.getColumns())
         {
-            result.emplace_back(column.get());
+            result.addColumn(column);
         }
 
         return result;
     }
 
-    if (chunk.getNumColumns() != sample_block.columns())
-    {
-        throw Exception(
-            ErrorCodes::LOGICAL_ERROR,
-            "Incorrect number of columns in chunk. Expected {}, found {}",
-            sample_block.columns(), chunk.getNumColumns());
-    }
+    chassert(chunk.getColumns().size() == sample_block.columns());
 
     for (size_t i = 0; i < sample_block.columns(); i++)
     {
         if (!partition_columns_name_set.contains(sample_block.getByPosition(i).name))
         {
-            result.emplace_back(chunk.getColumns()[i].get());
+            result.addColumn(chunk.getColumns()[i]);
         }
     }
 

src/Storages/IPartitionStrategy.h

@@ -29,21 +29,18 @@ struct IPartitionStrategy
 
     virtual ColumnPtr computePartitionKey(const Chunk & chunk) = 0;
 
-    virtual std::string getPathForRead(const std::string & prefix) = 0;
-    virtual std::string getPathForWrite(const std::string & prefix, const std::string & partition_key) = 0;
-
-    virtual ColumnRawPtrs getFormatChunkColumns(const Chunk & chunk)
+    ColumnPtr computePartitionKey(Block & block)
     {
-        ColumnRawPtrs result_columns;
-
-        for (const auto & column : chunk.getColumns())
-        {
-            result_columns.emplace_back(column.get());
-        }
+        actions_with_column_name.actions->execute(block);
 
-        return result_columns;
+        return block.getByName(actions_with_column_name.column_name).column;
     }
 
+    virtual std::string getPathForRead(const std::string & prefix) = 0;
+    virtual std::string getPathForWrite(const std::string & prefix, const std::string & partition_key) = 0;
+
+    virtual Chunk getFormatChunk(const Chunk & chunk) { return chunk.clone(); }
+
     virtual Block getFormatHeader() { return sample_block; }
 
     NamesAndTypesList getPartitionColumns() const;
@@ -53,6 +50,7 @@ struct IPartitionStrategy
     const KeyDescription partition_key_description;
     const Block sample_block;
     ContextPtr context;
+    PartitionExpressionActionsAndColumnName actions_with_column_name;
 };
 
 /*
@@ -91,9 +89,6 @@ struct WildcardPartitionStrategy : IPartitionStrategy
     ColumnPtr computePartitionKey(const Chunk & chunk) override;
     std::string getPathForRead(const std::string & prefix) override;
     std::string getPathForWrite(const std::string & prefix, const std::string & partition_key) override;
-
-private:
-    PartitionExpressionActionsAndColumnName actions_with_column_name;
 };
 
 /*
@@ -114,14 +109,13 @@ struct HiveStylePartitionStrategy : IPartitionStrategy
     std::string getPathForRead(const std::string & prefix) override;
     std::string getPathForWrite(const std::string & prefix, const std::string & partition_key) override;
 
-    ColumnRawPtrs getFormatChunkColumns(const Chunk & chunk) override;
+    Chunk getFormatChunk(const Chunk & chunk) override;
     Block getFormatHeader() override;
 
 private:
     const std::string file_format;
     const bool partition_columns_in_data_file;
     std::unordered_set<std::string> partition_columns_name_set;
-    PartitionExpressionActionsAndColumnName actions_with_column_name;
     Block block_without_partition_columns;
 };