add kill transaction query

src/Access/Common/AccessType.h

@@ -102,6 +102,7 @@ enum class AccessType
     \
     M(KILL_QUERY, "", GLOBAL, ALL) /* allows to kill a query started by another user
                                       (anyone can kill his own queries) */\
+    M(KILL_TRANSACTION, "", GLOBAL, ALL) \
     \
     M(MOVE_PARTITION_BETWEEN_SHARDS, "", GLOBAL, ALL) /* required to be able to move a part/partition to a table
                                                          identified by its ZooKeeper path */\

src/Interpreters/InterpreterKillQueryQuery.cpp

@@ -7,6 +7,7 @@
 #include <Interpreters/executeQuery.h>
 #include <Interpreters/CancellationCode.h>
 #include <Interpreters/InterpreterAlterQuery.h>
+#include <Interpreters/TransactionLog.h>
 #include <Parsers/ASTAlterQuery.h>
 #include <Parsers/ParserAlterQuery.h>
 #include <Parsers/parseQuery.h>
@@ -358,6 +359,49 @@ BlockIO InterpreterKillQueryQuery::execute()
 
         break;
     }
+    case ASTKillQueryQuery::Type::Transaction:
+    {
+        getContext()->checkAccess(AccessType::KILL_TRANSACTION);
+
+        Block transactions_block = getSelectResult("tid, tid_hash, elapsed, is_readonly, state", "system.transactions");
+
+        if (!transactions_block)
+            return res_io;
+
+        const ColumnUInt64 & tid_hash_col = typeid_cast<const ColumnUInt64 &>(*transactions_block.getByName("tid_hash").column);
+
+        auto header = transactions_block.cloneEmpty();
+        header.insert(0, {ColumnString::create(), std::make_shared<DataTypeString>(), "kill_status"});
+        MutableColumns res_columns = header.cloneEmptyColumns();
+
+        for (size_t i = 0; i < transactions_block.rows(); ++i)
+        {
+            UInt64 tid_hash = tid_hash_col.getUInt(i);
+
+            CancellationCode code = CancellationCode::Unknown;
+            if (!query.test)
+            {
+                auto txn = TransactionLog::instance().tryGetRunningTransaction(tid_hash);
+                if (txn)
+                {
+                    txn->onException();
+                    if (txn->getState() == MergeTreeTransaction::ROLLED_BACK)
+                        code = CancellationCode::CancelSent;
+                    else
+                        code = CancellationCode::CancelCannotBeSent;
+                }
+                else
+                {
+                    code = CancellationCode::NotFound;
+                }
+            }
+
+            insertResultRow(i, code, transactions_block, header, res_columns);
+        }
+
+        res_io.pipeline = QueryPipeline(Pipe(std::make_shared<SourceFromSingleChunk>(header.cloneWithColumns(std::move(res_columns)))));
+        break;
+    }
     }
 
     return res_io;

src/Interpreters/MergeTreeTransaction.cpp

@@ -30,6 +30,15 @@ MergeTreeTransaction::State MergeTreeTransaction::getState() const
     return COMMITTED;
 }
 
+void MergeTreeTransaction::checkIsNotCancelled() const
+{
+    CSN c = csn.load();
+    if (c == Tx::RolledBackCSN)
+        throw Exception(ErrorCodes::INVALID_TRANSACTION, "Transaction was cancelled");
+    else if (c != Tx::UnknownCSN)
+        throw Exception(ErrorCodes::LOGICAL_ERROR, "Unexpected CSN state: {}", c);
+}
+
 void MergeTreeTransaction::addNewPart(const StoragePtr & storage, const DataPartPtr & new_part, MergeTreeTransaction * txn)
 {
     TransactionID tid = txn ? txn->tid : Tx::PrehistoricTID;
@@ -79,58 +88,61 @@ void MergeTreeTransaction::addNewPartAndRemoveCovered(const StoragePtr & storage
 
 void MergeTreeTransaction::addNewPart(const StoragePtr & storage, const DataPartPtr & new_part)
 {
-    CSN c = csn.load();
-    if (c == Tx::RolledBackCSN)
-        throw Exception(ErrorCodes::INVALID_TRANSACTION, "Transaction was cancelled");
-    else if (c != Tx::UnknownCSN)
-        throw Exception(ErrorCodes::LOGICAL_ERROR, "Unexpected CSN state: {}", c);
-
+    std::lock_guard lock{mutex};
+    checkIsNotCancelled();
     storages.insert(storage);
     creating_parts.push_back(new_part);
 }
 
 void MergeTreeTransaction::removeOldPart(const StoragePtr & storage, const DataPartPtr & part_to_remove, const TransactionInfoContext & context)
 {
-    CSN c = csn.load();
-    if (c == Tx::RolledBackCSN)
-        throw Exception(ErrorCodes::INVALID_TRANSACTION, "Transaction was cancelled");
-    else if (c != Tx::UnknownCSN)
-        throw Exception(ErrorCodes::LOGICAL_ERROR, "Unexpected CSN state: {}", c);
-
     {
+        std::lock_guard lock{mutex};
+        checkIsNotCancelled();
+
         LockMemoryExceptionInThread lock_memory_tracker(VariableContext::Global);
         part_to_remove->version.lockMaxTID(tid, context);
         storages.insert(storage);
         removing_parts.push_back(part_to_remove);
     }
+
     part_to_remove->appendRemovalTIDToVersionMetadata();
 }
 
 void MergeTreeTransaction::addMutation(const StoragePtr & table, const String & mutation_id)
 {
+    std::lock_guard lock{mutex};
+    checkIsNotCancelled();
     storages.insert(table);
     mutations.emplace_back(table, mutation_id);
 }
 
 bool MergeTreeTransaction::isReadOnly() const
 {
+    std::lock_guard lock{mutex};
     assert((creating_parts.empty() && removing_parts.empty() && mutations.empty()) == storages.empty());
     return storages.empty();
 }
 
 void MergeTreeTransaction::beforeCommit()
 {
-    for (const auto & table_and_mutation : mutations)
-        table_and_mutation.first->waitForMutation(table_and_mutation.second);
-
     CSN expected = Tx::UnknownCSN;
     bool can_commit = csn.compare_exchange_strong(expected, Tx::CommittingCSN);
-    if (can_commit)
-        return;
-
+    if (!can_commit)
+    {
         if (expected == Tx::RolledBackCSN)
             throw Exception(ErrorCodes::INVALID_TRANSACTION, "Transaction was cancelled");
         throw Exception(ErrorCodes::LOGICAL_ERROR, "Unexpected CSN state: {}", expected);
+    }
+
+    RunningMutationsList mutations_to_wait;
+    {
+        std::lock_guard lock{mutex};
+        mutations_to_wait = mutations;
+    }
+
+    for (const auto & table_and_mutation : mutations_to_wait)
+        table_and_mutation.first->waitForMutation(table_and_mutation.second);
 }
 
 void MergeTreeTransaction::afterCommit(CSN assigned_csn) noexcept
@@ -195,6 +207,8 @@ String MergeTreeTransaction::dumpDescription() const
         return res;
     }
 
+    std::lock_guard lock{mutex};
+
     res += fmt::format(", affects {} tables:", storages.size());
 
     using ChangesInTable = std::tuple<Strings, Strings, Strings>;

src/Interpreters/MergeTreeTransaction.h

@@ -2,6 +2,7 @@
 #include <Interpreters/TransactionVersionMetadata.h>
 #include <boost/noncopyable.hpp>
 #include <Storages/IStorage_fwd.h>
+#include <Common/Stopwatch.h>
 
 #include <list>
 #include <unordered_set>
@@ -46,10 +47,16 @@ public:
 
     String dumpDescription() const;
 
+    Float64 elapsedSeconds() const { return elapsed.elapsedSeconds(); }
+
 private:
     void beforeCommit();
     void afterCommit(CSN assigned_csn) noexcept;
     bool rollback() noexcept;
+    void checkIsNotCancelled() const;
+
+    mutable std::mutex mutex;
+    Stopwatch elapsed;
 
     Snapshot snapshot;
 
@@ -61,7 +68,8 @@ private:
 
     std::list<Snapshot>::iterator snapshot_in_use_it;
 
-    std::vector<std::pair<StoragePtr, String>> mutations;
+    using RunningMutationsList = std::vector<std::pair<StoragePtr, String>>;
+    RunningMutationsList mutations;
 };
 
 using MergeTreeTransactionPtr = std::shared_ptr<MergeTreeTransaction>;

src/Interpreters/MergeTreeTransactionHolder.cpp

@@ -6,6 +6,11 @@
 namespace DB
 {
 
+namespace ErrorCodes
+{
+    extern const int LOGICAL_ERROR;
+}
+
 MergeTreeTransactionHolder::MergeTreeTransactionHolder(const MergeTreeTransactionPtr & txn_, bool autocommit_ = false, const Context * owned_by_session_context_)
     : txn(txn_)
     , autocommit(autocommit_)

src/Interpreters/TransactionLog.cpp

@@ -372,4 +372,10 @@ Snapshot TransactionLog::getOldestSnapshot() const
     return snapshots_in_use.front();
 }
 
+TransactionLog::TransactionsList TransactionLog::getTransactionsList() const
+{
+    std::lock_guard lock{running_list_mutex};
+    return running_list;
+}
+
 }

src/Interpreters/TransactionLog.h

@@ -75,6 +75,9 @@ public:
 
     MergeTreeTransactionPtr tryGetRunningTransaction(const TIDHash & tid);
 
+    using TransactionsList = std::unordered_map<TIDHash, MergeTreeTransactionPtr>;
+    TransactionsList getTransactionsList() const;
+
 private:
     void loadLogFromZooKeeper();
     void runUpdatingThread();
@@ -100,7 +103,7 @@ private:
     std::unordered_map<TIDHash, CSN> tid_to_csn;
 
     mutable std::mutex running_list_mutex;
-    std::unordered_map<TIDHash, MergeTreeTransactionPtr> running_list;
+    TransactionsList running_list;
     std::list<Snapshot> snapshots_in_use;
 
     String zookeeper_path;

src/Parsers/ASTKillQueryQuery.cpp

@@ -24,6 +24,9 @@ void ASTKillQueryQuery::formatQueryImpl(const FormatSettings & settings, FormatS
         case Type::PartMoveToShard:
             settings.ostr << "PART_MOVE_TO_SHARD";
             break;
+        case Type::Transaction:
+            settings.ostr << "TRANSACTION";
+            break;
     }
 
     formatOnCluster(settings);

src/Parsers/ASTKillQueryQuery.h

@@ -14,6 +14,7 @@ public:
         Query,      /// KILL QUERY
         Mutation,   /// KILL MUTATION
         PartMoveToShard, /// KILL PART_MOVE_TO_SHARD
+        Transaction,     /// KILL TRANSACTION
     };
 
     Type type = Type::Query;

src/Parsers/ParserKillQueryQuery.cpp

@@ -18,6 +18,7 @@ bool ParserKillQueryQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & expect
     ParserKeyword p_query{"QUERY"};
     ParserKeyword p_mutation{"MUTATION"};
     ParserKeyword p_part_move_to_shard{"PART_MOVE_TO_SHARD"};
+    ParserKeyword p_transaction{"TRANSACTION"};
     ParserKeyword p_on{"ON"};
     ParserKeyword p_test{"TEST"};
     ParserKeyword p_sync{"SYNC"};
@@ -34,6 +35,8 @@ bool ParserKillQueryQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & expect
         query->type = ASTKillQueryQuery::Type::Mutation;
     else if (p_part_move_to_shard.ignore(pos, expected))
         query->type = ASTKillQueryQuery::Type::PartMoveToShard;
+    else if (p_transaction.ignore(pos, expected))
+        query->type = ASTKillQueryQuery::Type::Transaction;
     else
         return false;
 

src/Storages/System/StorageSystemTransactions.cpp

@@ -0,0 +1,49 @@
+#include <Storages/System/StorageSystemTransactions.h>
+#include <Interpreters/TransactionLog.h>
+#include <Interpreters/MergeTreeTransaction.h>
+#include <DataTypes/DataTypesNumber.h>
+#include <DataTypes/DataTypeEnum.h>
+#include <Interpreters/Context.h>
+
+
+namespace DB
+{
+
+static DataTypePtr getStateEnumType()
+{
+    return std::make_shared<DataTypeEnum8>(
+    DataTypeEnum8::Values
+        {
+            {"RUNNING",           static_cast<Int8>(MergeTreeTransaction::State::RUNNING)},
+            {"COMMITTED",         static_cast<Int8>(MergeTreeTransaction::State::COMMITTED)},
+            {"ROLLED_BACK",       static_cast<Int8>(MergeTreeTransaction::State::ROLLED_BACK)},
+        });
+}
+
+NamesAndTypesList StorageSystemTransactions::getNamesAndTypes()
+{
+    return {
+        {"tid", getTransactionIDDataType()},
+        {"tid_hash", std::make_shared<DataTypeUInt64>()},
+        {"elapsed", std::make_shared<DataTypeFloat64>()},
+        {"is_readonly", std::make_shared<DataTypeUInt8>()},
+        {"state", getStateEnumType()},
+    };
+}
+
+void StorageSystemTransactions::fillData(MutableColumns & res_columns, ContextPtr, const SelectQueryInfo &) const
+{
+    auto list = TransactionLog::instance().getTransactionsList();
+    for (const auto & elem : list)
+    {
+        auto txn = elem.second;
+        size_t i = 0;
+        res_columns[i++]->insert(Tuple{txn->tid.start_csn, txn->tid.local_tid, txn->tid.host_id});
+        res_columns[i++]->insert(txn->tid.getHash());
+        res_columns[i++]->insert(txn->elapsedSeconds());
+        res_columns[i++]->insert(txn->isReadOnly());
+        res_columns[i++]->insert(txn->getState());
+    }
+}
+
+}

src/Storages/System/StorageSystemTransactions.h

@@ -0,0 +1,27 @@
+#pragma once
+#include <base/shared_ptr_helper.h>
+#include <Storages/System/IStorageSystemOneBlock.h>
+
+
+namespace DB
+{
+
+class Context;
+
+class StorageSystemTransactions final : public shared_ptr_helper<StorageSystemTransactions>, public IStorageSystemOneBlock<StorageSystemTransactions>
+{
+    friend struct shared_ptr_helper<StorageSystemTransactions>;
+public:
+    String getName() const override { return "SystemTransactions"; }
+
+    static NamesAndTypesList getNamesAndTypes();
+
+    static NamesAndAliases getNamesAndAliases() { return {}; }
+
+protected:
+    using IStorageSystemOneBlock::IStorageSystemOneBlock;
+
+    void fillData(MutableColumns & res_columns, ContextPtr context, const SelectQueryInfo & query_info) const override;
+};
+
+}

src/Storages/System/attachSystemTables.cpp

@@ -68,6 +68,7 @@
 #include <Storages/System/StorageSystemUserDirectories.h>
 #include <Storages/System/StorageSystemPrivileges.h>
 #include <Storages/System/StorageSystemAsynchronousInserts.h>
+#include <Storages/System/StorageSystemTransactions.h>
 
 #ifdef OS_LINUX
 #include <Storages/System/StorageSystemStackTrace.h>
@@ -162,6 +163,9 @@ void attachSystemTablesServer(ContextPtr context, IDatabase & system_database, b
 
     if (has_zookeeper)
         attach<StorageSystemZooKeeper>(context, system_database, "zookeeper");
+
+    if (context->getConfigRef().getInt("_enable_experimental_mvcc_prototype_test_helper_dev", 0) == 42)
+        attach<StorageSystemTransactions>(context, system_database, "transactions");
 }
 
 void attachSystemTablesAsync(ContextPtr context, IDatabase & system_database, AsynchronousMetrics & async_metrics)

tests/queries/0_stateless/01168_mutations_isolation.reference

@@ -31,7 +31,8 @@ tx11	9	21	all_1_14_1_17
 tx11	9	41	all_1_14_1_17
 tx11	9	61	all_1_14_1_17
 tx11	9	81	all_1_14_1_17
-tx13	10	22	all_1_14_1_18
-tx13	10	42	all_1_14_1_18
-tx13	10	62	all_1_14_1_18
-tx13	10	82	all_1_14_1_18
+1	1	RUNNING
+tx14	10	22	all_1_14_1_18
+tx14	10	42	all_1_14_1_18
+tx14	10	62	all_1_14_1_18
+tx14	10	82	all_1_14_1_18

tests/queries/0_stateless/01168_mutations_isolation.sh

@@ -81,6 +81,13 @@ tx_wait 11
 tx_wait 12
 
 tx 13                                           "begin transaction"
-tx 13 "select 10, n, _part from mt order by n"
+tid_to_kill=$(tx 13 "select transactionID()" | grep -Po "\(.*")
+$CLICKHOUSE_CLIENT -q "select count(), any(is_readonly), any(state) from system.transactions where tid=$tid_to_kill"
+tx_async 13                                      "alter table mt update n = 0 where 1" >/dev/null
+$CLICKHOUSE_CLIENT -q "kill transaction where tid=$tid_to_kill format Null"
+tx_sync 13                                            "rollback"
+
+tx 14 "begin transaction"
+tx 14 "select 10, n, _part from mt order by n"
 
 $CLICKHOUSE_CLIENT --database_atomic_wait_for_drop_and_detach_synchronously=0 -q "drop table mt"