diff --git a/src/Common/ErrorCodes.cpp b/src/Common/ErrorCodes.cpp
index 0f85ad5c792..55745ffc211 100644
--- a/src/Common/ErrorCodes.cpp
+++ b/src/Common/ErrorCodes.cpp
@@ -548,6 +548,8 @@
     M(578, INVALID_FORMAT_INSERT_QUERY_WITH_DATA) \
     M(579, INCORRECT_PART_TYPE) \
     M(580, CANNOT_SET_ROUNDING_MODE) \
+    M(581, INVALID_TRANSACTION) \
+    M(582, SERIALIZATION_ERROR) \
     \
     M(998, POSTGRESQL_CONNECTION_FAILURE) \
     M(999, KEEPER_EXCEPTION) \
diff --git a/src/Common/TransactionMetadata.cpp b/src/Common/TransactionMetadata.cpp
new file mode 100644
index 00000000000..430ea5cda29
--- /dev/null
+++ b/src/Common/TransactionMetadata.cpp
@@ -0,0 +1,18 @@
+#include <Common/TransactionMetadata.h>
+#include <DataTypes/DataTypesNumber.h>
+#include <DataTypes/DataTypeTuple.h>
+#include <DataTypes/DataTypeUUID.h>
+
+namespace DB
+{
+
+DataTypePtr TransactionID::getDataType()
+{
+    DataTypes types;
+    types.push_back(std::make_shared<DataTypeUInt64>());
+    types.push_back(std::make_shared<DataTypeUInt64>());
+    types.push_back(std::make_shared<DataTypeUUID>());
+    return std::make_shared<DataTypeTuple>(std::move(types));
+}
+
+}
diff --git a/src/Common/TransactionMetadata.h b/src/Common/TransactionMetadata.h
new file mode 100644
index 00000000000..34eaaf2d245
--- /dev/null
+++ b/src/Common/TransactionMetadata.h
@@ -0,0 +1,41 @@
+#pragma once
+#include <Core/Types.h>
+#include <Core/UUID.h>
+
+namespace DB
+{
+
+class IDataType;
+using DataTypePtr = std::shared_ptr<const IDataType>;
+
+/// FIXME Transactions: Sequential node numbers in ZooKeeper are Int32, but 31 bit is not enough
+using CSN = UInt64;
+using Snapshot = CSN;
+using LocalTID = UInt64;
+
+struct TransactionID
+{
+    CSN start_csn = 0;
+    LocalTID local_tid = 0;
+    UUID host_id = UUIDHelpers::Nil;   /// Depends on #17278, leave it Nil for now.
+
+    static DataTypePtr getDataType();
+};
+
+namespace Tx
+{
+
+const CSN UnknownCSN = 0;
+const CSN PrehistoricCSN = 1;
+
+const LocalTID PrehistoricLocalTID = 1;
+
+const TransactionID EmptyTID = {0, 0, UUIDHelpers::Nil};
+const TransactionID PrehistoricTID = {0, PrehistoricLocalTID, UUIDHelpers::Nil};
+
+/// So far, that changes will never become visible
+const CSN RolledBackCSN = std::numeric_limits<CSN>::max();
+
+}
+
+}
diff --git a/src/Functions/FunctionsTransactionCounters.cpp b/src/Functions/FunctionsTransactionCounters.cpp
new file mode 100644
index 00000000000..93a2961fb74
--- /dev/null
+++ b/src/Functions/FunctionsTransactionCounters.cpp
@@ -0,0 +1,58 @@
+#include <Functions/FunctionFactory.h>
+#include <Interpreters/Context.h>
+#include <Interpreters/MergeTreeTransaction.h>
+
+
+namespace DB
+{
+
+namespace
+{
+
+class FunctionTransactionID : public IFunction
+{
+public:
+    static constexpr auto name = "transactionID";
+
+    static FunctionPtr create(const Context & context)
+    {
+        return std::make_shared<FunctionTransactionID>(context.getCurrentTransaction());
+    }
+
+    explicit FunctionTransactionID(MergeTreeTransactionPtr && txn_) : txn(txn_)
+    {
+    }
+
+    String getName() const override { return name; }
+
+    size_t getNumberOfArguments() const override { return 0; }
+
+    DataTypePtr getReturnTypeImpl(const DataTypes &) const override
+    {
+        return TransactionID::getDataType();
+    }
+
+    bool isDeterministic() const override { return false; }
+
+    ColumnPtr executeImpl(const ColumnsWithTypeAndName &, const DataTypePtr & result_type, size_t input_rows_count) const override
+    {
+        Tuple res;
+        if (txn)
+            res = {txn->tid.start_csn, txn->tid.local_tid, txn->tid.host_id};
+        else
+            res = {UInt64(0), UInt64(0), UUIDHelpers::Nil};
+        return result_type->createColumnConst(input_rows_count, res);
+    }
+
+private:
+    MergeTreeTransactionPtr txn;
+};
+
+}
+
+void registerFunctionsTransactionCounters(FunctionFactory & factory)
+{
+    factory.registerFunction<FunctionTransactionID>();
+}
+
+}
diff --git a/src/Functions/registerFunctionsMiscellaneous.cpp b/src/Functions/registerFunctionsMiscellaneous.cpp
index d00d4a42db0..ab415740be3 100644
--- a/src/Functions/registerFunctionsMiscellaneous.cpp
+++ b/src/Functions/registerFunctionsMiscellaneous.cpp
@@ -73,6 +73,7 @@ void registerFunctionFile(FunctionFactory & factory);
 void registerFunctionConnectionId(FunctionFactory & factory);
 void registerFunctionPartitionId(FunctionFactory & factory);
 void registerFunctionIsIPAddressContainedIn(FunctionFactory &);
+void registerFunctionsTransactionCounters(FunctionFactory & factory);
 
 #if USE_ICU
 void registerFunctionConvertCharset(FunctionFactory &);
@@ -146,6 +147,7 @@ void registerFunctionsMiscellaneous(FunctionFactory & factory)
     registerFunctionConnectionId(factory);
     registerFunctionPartitionId(factory);
     registerFunctionIsIPAddressContainedIn(factory);
+    registerFunctionsTransactionCounters(factory);
 
 #if USE_ICU
     registerFunctionConvertCharset(factory);
diff --git a/src/Interpreters/Context.cpp b/src/Interpreters/Context.cpp
index 8eec5d099e2..5c6afb38ff4 100644
--- a/src/Interpreters/Context.cpp
+++ b/src/Interpreters/Context.cpp
@@ -2581,6 +2581,21 @@ ZooKeeperMetadataTransactionPtr Context::getZooKeeperMetadataTransaction() const
     return metadata_transaction;
 }
 
+void Context::setCurrentTransaction(MergeTreeTransactionPtr txn)
+{
+    assert(!merge_tree_transaction || !txn);
+    assert(this == session_context || this == query_context);
+    int enable_mvcc_test_helper = getConfigRef().getInt("_enable_mvcc_test_helper_dev", 0);
+    if (enable_mvcc_test_helper != 42)
+        throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Transactions are not supported");
+    merge_tree_transaction = std::move(txn);
+}
+
+MergeTreeTransactionPtr Context::getCurrentTransaction() const
+{
+    return merge_tree_transaction;
+}
+
 PartUUIDsPtr Context::getPartUUIDs()
 {
     auto lock = getLock();
diff --git a/src/Interpreters/Context.h b/src/Interpreters/Context.h
index 5c98a2ba64a..e035031f993 100644
--- a/src/Interpreters/Context.h
+++ b/src/Interpreters/Context.h
@@ -122,6 +122,8 @@ struct BackgroundTaskSchedulingSettings;
 
 class ZooKeeperMetadataTransaction;
 using ZooKeeperMetadataTransactionPtr = std::shared_ptr<ZooKeeperMetadataTransaction>;
+class MergeTreeTransaction;
+using MergeTreeTransactionPtr = std::shared_ptr<MergeTreeTransaction>;
 
 #if USE_EMBEDDED_COMPILER
 class CompiledExpressionCache;
@@ -290,6 +292,8 @@ private:
                                                     /// thousands of signatures.
                                                     /// And I hope it will be replaced with more common Transaction sometime.
 
+    MergeTreeTransactionPtr merge_tree_transaction;     /// Current transaction context. Can be inside session or query context.
+
     /// Use copy constructor or createGlobal() instead
     Context();
 
@@ -757,6 +761,10 @@ public:
     /// Returns context of current distributed DDL query or nullptr.
     ZooKeeperMetadataTransactionPtr getZooKeeperMetadataTransaction() const;
 
+    void setCurrentTransaction(MergeTreeTransactionPtr txn);
+    MergeTreeTransactionPtr getCurrentTransaction() const;
+
+
     struct MySQLWireContext
     {
         uint8_t sequence_id = 0;
diff --git a/src/Interpreters/InterpreterFactory.cpp b/src/Interpreters/InterpreterFactory.cpp
index 15e4c52f040..5684150fed1 100644
--- a/src/Interpreters/InterpreterFactory.cpp
+++ b/src/Interpreters/InterpreterFactory.cpp
@@ -29,6 +29,7 @@
 #include <Parsers/ASTWatchQuery.h>
 #include <Parsers/ASTGrantQuery.h>
 #include <Parsers/MySQL/ASTCreateQuery.h>
+#include <Parsers/ASTTransactionControl.h>
 
 #include <Interpreters/Context.h>
 #include <Interpreters/InterpreterAlterQuery.h>
@@ -66,6 +67,7 @@
 #include <Interpreters/InterpreterUseQuery.h>
 #include <Interpreters/InterpreterWatchQuery.h>
 #include <Interpreters/InterpreterExternalDDLQuery.h>
+#include <Interpreters/InterpreterTransactionControlQuery.h>
 #include <Interpreters/OpenTelemetrySpanLog.h>
 
 #include <Parsers/ASTSystemQuery.h>
@@ -264,6 +266,10 @@ std::unique_ptr<IInterpreter> InterpreterFactory::get(ASTPtr & query, Context &
     {
         return std::make_unique<InterpreterExternalDDLQuery>(query, context);
     }
+    else if (query->as<ASTTransactionControl>())
+    {
+        return std::make_unique<InterpreterTransactionControlQuery>(query, context);
+    }
     else
     {
         throw Exception("Unknown type of query: " + query->getID(), ErrorCodes::UNKNOWN_TYPE_OF_QUERY);
diff --git a/src/Interpreters/InterpreterTransactionControlQuery.cpp b/src/Interpreters/InterpreterTransactionControlQuery.cpp
new file mode 100644
index 00000000000..369f5edd1da
--- /dev/null
+++ b/src/Interpreters/InterpreterTransactionControlQuery.cpp
@@ -0,0 +1,72 @@
+#include <Interpreters/InterpreterTransactionControlQuery.h>
+#include <Parsers/ASTTransactionControl.h>
+#include <Interpreters/TransactionLog.h>
+#include <Interpreters/Context.h>
+
+namespace DB
+{
+
+namespace ErrorCodes
+{
+    extern const int LOGICAL_ERROR;
+    extern const int INVALID_TRANSACTION;
+}
+
+BlockIO InterpreterTransactionControlQuery::execute()
+{
+    if (!query_context.hasSessionContext())
+        throw Exception(ErrorCodes::INVALID_TRANSACTION, "Transaction Control Language queries are allowed only inside session");
+
+    Context & session_context = query_context.getSessionContext();
+    const auto & tcl = query_ptr->as<const ASTTransactionControl &>();
+
+    switch (tcl.action)
+    {
+        case ASTTransactionControl::BEGIN:
+            return executeBegin(session_context);
+        case ASTTransactionControl::COMMIT:
+            return executeCommit(session_context);
+        case ASTTransactionControl::ROLLBACK:
+            return executeRollback(session_context);
+    }
+}
+
+BlockIO InterpreterTransactionControlQuery::executeBegin(Context & context)
+{
+    if (context.getCurrentTransaction())
+        throw Exception(ErrorCodes::INVALID_TRANSACTION, "Nested transactions are not supported");
+
+    auto txn = TransactionLog::instance().beginTransaction();
+    context.setCurrentTransaction(txn);
+    query_context.setCurrentTransaction(txn);
+    return {};
+}
+
+BlockIO InterpreterTransactionControlQuery::executeCommit(Context & context)
+{
+    auto txn = context.getCurrentTransaction();
+    if (!txn)
+        throw Exception(ErrorCodes::INVALID_TRANSACTION, "There is no current transaction");
+    if (txn->getState() != MergeTreeTransaction::RUNNING)
+        throw Exception(ErrorCodes::INVALID_TRANSACTION, "Transaction is not in RUNNING state");
+
+    TransactionLog::instance().commitTransaction(txn);
+    context.setCurrentTransaction(nullptr);
+    return {};
+}
+
+BlockIO InterpreterTransactionControlQuery::executeRollback(Context & context)
+{
+    auto txn = context.getCurrentTransaction();
+    if (!txn)
+        throw Exception(ErrorCodes::INVALID_TRANSACTION, "There is no current transaction");
+    if (txn->getState() == MergeTreeTransaction::COMMITTED)
+        throw Exception(ErrorCodes::LOGICAL_ERROR, "Transaction is in COMMITTED state");
+
+    if (txn->getState() == MergeTreeTransaction::RUNNING)
+        TransactionLog::instance().rollbackTransaction(txn);
+    context.getSessionContext().setCurrentTransaction(nullptr);
+    return {};
+}
+
+}
diff --git a/src/Interpreters/InterpreterTransactionControlQuery.h b/src/Interpreters/InterpreterTransactionControlQuery.h
new file mode 100644
index 00000000000..4c455d22a24
--- /dev/null
+++ b/src/Interpreters/InterpreterTransactionControlQuery.h
@@ -0,0 +1,31 @@
+#pragma once
+#include <Interpreters/IInterpreter.h>
+#include <Parsers/IAST_fwd.h>
+
+namespace DB
+{
+
+class InterpreterTransactionControlQuery : public IInterpreter
+{
+public:
+    InterpreterTransactionControlQuery(const ASTPtr & query_ptr_, Context & context_)
+    : query_ptr(query_ptr_)
+    , query_context(context_)
+    {
+    }
+
+    BlockIO execute() override;
+
+    bool ignoreQuota() const override { return true; }
+    bool ignoreLimits() const override { return true; }
+private:
+    BlockIO executeBegin(Context & context);
+    BlockIO executeCommit(Context & context);
+    BlockIO executeRollback(Context & context);
+
+private:
+    ASTPtr query_ptr;
+    Context & query_context;
+};
+
+}
diff --git a/src/Interpreters/MergeTreeTransaction.cpp b/src/Interpreters/MergeTreeTransaction.cpp
new file mode 100644
index 00000000000..d1af1d61ba7
--- /dev/null
+++ b/src/Interpreters/MergeTreeTransaction.cpp
@@ -0,0 +1,14 @@
+#include <Interpreters/MergeTreeTransaction.h>
+
+namespace DB
+{
+
+MergeTreeTransaction::MergeTreeTransaction(Snapshot snapshot_, LocalTID local_tid_, UUID host_id)
+    : tid({snapshot_, local_tid_, host_id})
+    , snapshot(snapshot_)
+    , state(RUNNING)
+{
+}
+
+
+}
diff --git a/src/Interpreters/MergeTreeTransaction.h b/src/Interpreters/MergeTreeTransaction.h
new file mode 100644
index 00000000000..95c4a81c756
--- /dev/null
+++ b/src/Interpreters/MergeTreeTransaction.h
@@ -0,0 +1,35 @@
+#pragma once
+#include <Common/TransactionMetadata.h>
+
+namespace DB
+{
+
+class MergeTreeTransaction
+{
+    friend class TransactionLog;
+public:
+    enum State
+    {
+        RUNNING,
+        COMMITTED,
+        ROLLED_BACK,
+    };
+
+    Snapshot getSnapshot() const { return snapshot; }
+    State getState() const { return state; }
+
+    const TransactionID tid;
+
+    MergeTreeTransaction() = delete;
+    MergeTreeTransaction(Snapshot snapshot_, LocalTID local_tid_, UUID host_id);
+
+private:
+    Snapshot snapshot;
+    State state;
+
+    CSN csn = Tx::UnknownCSN;
+};
+
+using MergeTreeTransactionPtr = std::shared_ptr<MergeTreeTransaction>;
+
+}
diff --git a/src/Interpreters/QueryLog.cpp b/src/Interpreters/QueryLog.cpp
index b6902468242..cee1d2b5412 100644
--- a/src/Interpreters/QueryLog.cpp
+++ b/src/Interpreters/QueryLog.cpp
@@ -108,7 +108,9 @@ Block QueryLogElement::createBlock()
         {std::make_shared<DataTypeArray>(std::make_shared<DataTypeString>()), "used_formats"},
         {std::make_shared<DataTypeArray>(std::make_shared<DataTypeString>()), "used_functions"},
         {std::make_shared<DataTypeArray>(std::make_shared<DataTypeString>()), "used_storages"},
-        {std::make_shared<DataTypeArray>(std::make_shared<DataTypeString>()), "used_table_functions"}
+        {std::make_shared<DataTypeArray>(std::make_shared<DataTypeString>()), "used_table_functions"},
+
+        {TransactionID::getDataType(),                                        "transaction_id"}
     };
 
 }
@@ -237,6 +239,8 @@ void QueryLogElement::appendToBlock(MutableColumns & columns) const
         fill_column(used_storages, column_storage_factory_objects);
         fill_column(used_table_functions, column_table_function_factory_objects);
     }
+
+    columns[i++]->insert(Tuple{tid.start_csn, tid.local_tid, tid.host_id});
 }
 
 void QueryLogElement::appendClientInfo(const ClientInfo & client_info, MutableColumns & columns, size_t & i)
diff --git a/src/Interpreters/QueryLog.h b/src/Interpreters/QueryLog.h
index 8617a8d1cbc..7532f2d14f2 100644
--- a/src/Interpreters/QueryLog.h
+++ b/src/Interpreters/QueryLog.h
@@ -2,6 +2,7 @@
 
 #include <Interpreters/SystemLog.h>
 #include <Interpreters/ClientInfo.h>
+#include <Common/TransactionMetadata.h>
 
 
 namespace ProfileEvents
@@ -80,6 +81,8 @@ struct QueryLogElement
     std::shared_ptr<ProfileEvents::Counters> profile_counters;
     std::shared_ptr<Settings> query_settings;
 
+    TransactionID tid;
+
     static std::string name() { return "QueryLog"; }
 
     static Block createBlock();
diff --git a/src/Interpreters/TransactionLog.cpp b/src/Interpreters/TransactionLog.cpp
new file mode 100644
index 00000000000..00dbb3352b4
--- /dev/null
+++ b/src/Interpreters/TransactionLog.cpp
@@ -0,0 +1,44 @@
+#include <Interpreters/TransactionLog.h>
+
+namespace DB
+{
+
+TransactionLog & TransactionLog::instance()
+{
+    static TransactionLog inst;
+    return inst;
+}
+
+TransactionLog::TransactionLog()
+{
+    csn_counter = 1;
+    local_tid_counter = 1;
+}
+
+Snapshot TransactionLog::getLatestSnapshot() const
+{
+    return csn_counter.load();
+}
+
+MergeTreeTransactionPtr TransactionLog::beginTransaction()
+{
+    Snapshot snapshot = csn_counter.load();
+    LocalTID ltid = 1 + local_tid_counter.fetch_add(1);
+    return std::make_shared<MergeTreeTransaction>(snapshot, ltid, UUIDHelpers::Nil);
+}
+
+CSN TransactionLog::commitTransaction(const MergeTreeTransactionPtr & txn)
+{
+    txn->csn = 1 + csn_counter.fetch_add(1);
+    /// TODO Transactions: reset local_tid_counter
+    txn->state = MergeTreeTransaction::COMMITTED;
+    return txn->csn;
+}
+
+void TransactionLog::rollbackTransaction(const MergeTreeTransactionPtr & txn)
+{
+    txn->csn = Tx::RolledBackCSN;
+    txn->state = MergeTreeTransaction::ROLLED_BACK;
+}
+
+}
diff --git a/src/Interpreters/TransactionLog.h b/src/Interpreters/TransactionLog.h
new file mode 100644
index 00000000000..073d2a2929d
--- /dev/null
+++ b/src/Interpreters/TransactionLog.h
@@ -0,0 +1,30 @@
+#pragma once
+#include <Interpreters/MergeTreeTransaction.h>
+#include <boost/noncopyable.hpp>
+#include <mutex>
+
+namespace DB
+{
+
+class TransactionLog final : private boost::noncopyable
+{
+public:
+    static TransactionLog & instance();
+
+    TransactionLog();
+
+    Snapshot getLatestSnapshot() const;
+
+    /// Allocated TID, returns transaction object
+    MergeTreeTransactionPtr beginTransaction();
+
+    CSN commitTransaction(const MergeTreeTransactionPtr & txn);
+
+    void rollbackTransaction(const MergeTreeTransactionPtr & txn);
+
+private:
+    std::atomic<CSN> csn_counter;
+    std::atomic<LocalTID> local_tid_counter;
+};
+
+}
diff --git a/src/Interpreters/executeQuery.cpp b/src/Interpreters/executeQuery.cpp
index a5c21405ff1..a00f8301622 100644
--- a/src/Interpreters/executeQuery.cpp
+++ b/src/Interpreters/executeQuery.cpp
@@ -50,6 +50,7 @@
 #include <Interpreters/ReplaceQueryParameterVisitor.h>
 #include <Interpreters/SelectQueryOptions.h>
 #include <Interpreters/executeQuery.h>
+#include <Interpreters/MergeTreeTransaction.h>
 #include <Common/ProfileEvents.h>
 
 #include <Common/SensitiveDataMasker.h>
@@ -266,6 +267,9 @@ static void onExceptionBeforeStart(const String & query_for_logging, Context & c
     if (elem.log_comment.size() > settings.max_query_size)
         elem.log_comment.resize(settings.max_query_size);
 
+    if (auto txn = context.getCurrentTransaction())
+        elem.tid = txn->tid;
+
     if (settings.calculate_text_stack_trace)
         setExceptionStackTrace(elem);
     logException(context, elem);
@@ -634,6 +638,9 @@ static std::tuple<ASTPtr, BlockIO> executeQueryImpl(
 
             elem.client_info = context.getClientInfo();
 
+            if (auto txn = context.getCurrentTransaction())
+                elem.tid = txn->tid;
+
             bool log_queries = settings.log_queries && !internal;
 
             /// Log into system table start of query execution, if need.
diff --git a/src/Parsers/ASTTransactionControl.cpp b/src/Parsers/ASTTransactionControl.cpp
new file mode 100644
index 00000000000..d12c9d6d6e4
--- /dev/null
+++ b/src/Parsers/ASTTransactionControl.cpp
@@ -0,0 +1,34 @@
+#include <Parsers/ASTTransactionControl.h>
+#include <IO/Operators.h>
+#include <Common/SipHash.h>
+
+namespace DB
+{
+
+namespace ErrorCodes
+{
+    extern const int LOGICAL_ERROR;
+}
+
+void ASTTransactionControl::formatImpl(const FormatSettings & format /*state*/, FormatState &, FormatStateStacked /*frame*/) const
+{
+    switch (action)
+    {
+        case BEGIN:
+            format.ostr << (format.hilite ? hilite_keyword : "") << "BEGIN TRANSACTION" << (format.hilite ? hilite_none : "");
+            break;
+        case COMMIT:
+            format.ostr << (format.hilite ? hilite_keyword : "") << "COMMIT" << (format.hilite ? hilite_none : "");
+            break;
+        case ROLLBACK:
+            format.ostr << (format.hilite ? hilite_keyword : "") << "ROLLBACK" << (format.hilite ? hilite_none : "");
+            break;
+    }
+}
+
+void ASTTransactionControl::updateTreeHashImpl(SipHash & hash_state) const
+{
+    hash_state.update(action);
+}
+
+}
diff --git a/src/Parsers/ASTTransactionControl.h b/src/Parsers/ASTTransactionControl.h
new file mode 100644
index 00000000000..c01c4172627
--- /dev/null
+++ b/src/Parsers/ASTTransactionControl.h
@@ -0,0 +1,29 @@
+#pragma once
+#include <Parsers/IAST.h>
+
+namespace DB
+{
+
+/// Common AST for TCL queries
+class ASTTransactionControl : public IAST
+{
+public:
+    enum QueryType
+    {
+        BEGIN,
+        COMMIT,
+        ROLLBACK,
+    };
+
+    QueryType action;
+
+    ASTTransactionControl(QueryType action_) : action(action_) {}
+
+    String getID(char /*delimiter*/) const override { return "ASTTransactionControl"; }
+    ASTPtr clone() const override { return std::make_shared<ASTTransactionControl>(*this); }
+
+    void formatImpl(const FormatSettings & format, FormatState & /*state*/, FormatStateStacked /*frame*/) const override;
+    void updateTreeHashImpl(SipHash & hash_state) const override;
+};
+
+}
diff --git a/src/Parsers/ParserQuery.cpp b/src/Parsers/ParserQuery.cpp
index 4550bdc8a75..f9c11f1c870 100644
--- a/src/Parsers/ParserQuery.cpp
+++ b/src/Parsers/ParserQuery.cpp
@@ -18,6 +18,7 @@
 #include <Parsers/ParserSystemQuery.h>
 #include <Parsers/ParserUseQuery.h>
 #include <Parsers/ParserExternalDDLQuery.h>
+#include <Parsers/ParserTransactionControl.h>
 
 
 namespace DB
@@ -40,6 +41,7 @@ bool ParserQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
     ParserGrantQuery grant_p;
     ParserSetRoleQuery set_role_p;
     ParserExternalDDLQuery external_ddl_p;
+    ParserTransactionControl transaction_control_p;
 
     bool res = query_with_output_p.parse(pos, node, expected)
         || insert_p.parse(pos, node, expected)
@@ -54,7 +56,8 @@ bool ParserQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
         || create_settings_profile_p.parse(pos, node, expected)
         || drop_access_entity_p.parse(pos, node, expected)
         || grant_p.parse(pos, node, expected)
-        || external_ddl_p.parse(pos, node, expected);
+        || external_ddl_p.parse(pos, node, expected)
+        || transaction_control_p.parse(pos, node, expected);
 
     return res;
 }
diff --git a/src/Parsers/ParserTransactionControl.cpp b/src/Parsers/ParserTransactionControl.cpp
new file mode 100644
index 00000000000..a5591a0447e
--- /dev/null
+++ b/src/Parsers/ParserTransactionControl.cpp
@@ -0,0 +1,25 @@
+#include <Parsers/ParserTransactionControl.h>
+#include <Parsers/ASTTransactionControl.h>
+#include <Parsers/CommonParsers.h>
+
+namespace DB
+{
+
+bool ParserTransactionControl::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
+{
+    ASTTransactionControl::QueryType action;
+
+    if (ParserKeyword("BEGIN TRANSACTION").ignore(pos, expected))
+        action = ASTTransactionControl::BEGIN;
+    else if (ParserKeyword("COMMIT").ignore(pos, expected))
+        action = ASTTransactionControl::COMMIT;
+    else if (ParserKeyword("ROLLBACK").ignore(pos, expected))
+        action = ASTTransactionControl::ROLLBACK;
+    else
+        return false;
+
+    node = std::make_shared<ASTTransactionControl>(action);
+    return true;
+}
+
+}
diff --git a/src/Parsers/ParserTransactionControl.h b/src/Parsers/ParserTransactionControl.h
new file mode 100644
index 00000000000..157c088624c
--- /dev/null
+++ b/src/Parsers/ParserTransactionControl.h
@@ -0,0 +1,14 @@
+#pragma once
+#include <Parsers/IParserBase.h>
+
+namespace DB
+{
+
+class ParserTransactionControl : public IParserBase
+{
+public:
+    const char * getName() const override { return "TCL query"; }
+    bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected) override;
+};
+
+}
diff --git a/src/Storages/MergeTree/IMergeTreeDataPart.h b/src/Storages/MergeTree/IMergeTreeDataPart.h
index 03f6564788a..c990bdcc65b 100644
--- a/src/Storages/MergeTree/IMergeTreeDataPart.h
+++ b/src/Storages/MergeTree/IMergeTreeDataPart.h
@@ -16,6 +16,7 @@
 #include <Storages/MergeTree/MergeTreeDataPartTTLInfo.h>
 #include <Storages/MergeTree/MergeTreeIOSettings.h>
 #include <Storages/MergeTree/KeyCondition.h>
+#include <Common/TransactionMetadata.h>
 
 #include <Poco/Path.h>
 
@@ -301,6 +302,19 @@ public:
 
     CompressionCodecPtr default_codec;
 
+    struct VersionMetadata
+    {
+        TransactionID mintid = Tx::EmptyTID;
+        TransactionID maxtid = Tx::EmptyTID;
+
+        bool maybe_visible = false;
+
+        CSN mincsn = Tx::UnknownCSN;
+        CSN maxcsn = Tx::UnknownCSN;
+    };
+
+    mutable VersionMetadata versions;
+
     /// For data in RAM ('index')
     UInt64 getIndexSizeInBytes() const;
     UInt64 getIndexSizeInAllocatedBytes() const;
diff --git a/src/Storages/MergeTree/MergeTreeData.cpp b/src/Storages/MergeTree/MergeTreeData.cpp
index d61de13b604..7610239662e 100644
--- a/src/Storages/MergeTree/MergeTreeData.cpp
+++ b/src/Storages/MergeTree/MergeTreeData.cpp
@@ -993,6 +993,8 @@ void MergeTreeData::loadDataParts(bool skip_sanity_checks)
         {
             (*it)->remove_time.store((*it)->modification_time, std::memory_order_relaxed);
             modifyPartState(it, DataPartState::Outdated);
+            (*it)->versions.maxtid = Tx::PrehistoricTID;
+            (*it)->versions.maxcsn = Tx::PrehistoricCSN;
             removePartContributionToDataVolume(*it);
         };
 
@@ -1000,6 +1002,14 @@ void MergeTreeData::loadDataParts(bool skip_sanity_checks)
 
         while (curr_jt != data_parts_by_state_and_info.end() && (*curr_jt)->getState() == DataPartState::Committed)
         {
+            /// We do not have version metadata and transactions history for old parts,
+            /// so let's consider that such parts were created by some ancient transaction
+            /// and were committed with some prehistoric CSN.
+            /// TODO Transactions: distinguish "prehistoric" parts from uncommitted parts in case of hard restart
+            (*curr_jt)->versions.mintid = Tx::PrehistoricTID;
+            (*curr_jt)->versions.mincsn = Tx::PrehistoricCSN;
+            (*curr_jt)->versions.maybe_visible = true;
+
             /// Don't consider data parts belonging to different partitions.
             if ((*curr_jt)->info.partition_id != (*prev_jt)->info.partition_id)
             {
@@ -1030,7 +1040,6 @@ void MergeTreeData::loadDataParts(bool skip_sanity_checks)
 
     calculateColumnSizesImpl();
 
-
     LOG_DEBUG(log, "Loaded data parts ({} items)", data_parts_indexes.size());
 }
 
diff --git a/src/Storages/System/StorageSystemParts.cpp b/src/Storages/System/StorageSystemParts.cpp
index 6a643dbe1b9..f100ecdfa9b 100644
--- a/src/Storages/System/StorageSystemParts.cpp
+++ b/src/Storages/System/StorageSystemParts.cpp
@@ -12,6 +12,7 @@
 #include <Databases/IDatabase.h>
 #include <Parsers/queryToString.h>
 #include <Common/hex.h>
+#include <Common/TransactionMetadata.h>
 
 namespace DB
 {
@@ -75,7 +76,12 @@ StorageSystemParts::StorageSystemParts(const StorageID & table_id_)
 
         {"rows_where_ttl_info.expression",              std::make_shared<DataTypeArray>(std::make_shared<DataTypeString>())},
         {"rows_where_ttl_info.min",                     std::make_shared<DataTypeArray>(std::make_shared<DataTypeDateTime>())},
-        {"rows_where_ttl_info.max",                     std::make_shared<DataTypeArray>(std::make_shared<DataTypeDateTime>())}
+        {"rows_where_ttl_info.max",                     std::make_shared<DataTypeArray>(std::make_shared<DataTypeDateTime>())},
+
+        {"mintid",                                      TransactionID::getDataType()},
+        {"maxtid",                                      TransactionID::getDataType()},
+        {"mincsn",                                      std::make_shared<DataTypeUInt64>()},
+        {"maxcsn",                                      std::make_shared<DataTypeUInt64>()},
     }
     )
 {
@@ -257,6 +263,20 @@ void StorageSystemParts::processNextStorage(
         /// Do not use part->getState*, it can be changed from different thread
         if (has_state_column)
             columns[res_index++]->insert(IMergeTreeDataPart::stateToString(part_state));
+
+        auto get_tid_as_field = [](const TransactionID & tid) -> Field
+        {
+            return Tuple{tid.start_csn, tid.local_tid, tid.host_id};
+        };
+
+        if (columns_mask[src_index++])
+            columns[res_index++]->insert(get_tid_as_field(part->versions.mintid));
+        if (columns_mask[src_index++])
+            columns[res_index++]->insert(get_tid_as_field(part->versions.maxtid));
+        if (columns_mask[src_index++])
+            columns[res_index++]->insert(part->versions.mincsn);
+        if (columns_mask[src_index++])
+            columns[res_index++]->insert(part->versions.maxcsn);
     }
 }