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#pragma once
#include <Interpreters/TransactionVersionMetadata.h>
#include <boost/noncopyable.hpp>
#include <Storages/IStorage_fwd.h>
#include <Storages/TableLockHolder.h>
#include <Common/Stopwatch.h>
#include <base/scope_guard.h>
#include <list>
#include <unordered_set>
namespace DB
{
class IMergeTreeDataPart;
using DataPartPtr = std::shared_ptr<const IMergeTreeDataPart>;
using DataPartsVector = std::vector<DataPartPtr>;
/// This object is responsible for tracking all changes that some transaction is making in MergeTree tables.
/// It collects all changes that queries of current transaction made in data part sets of all MergeTree tables
/// to either make them visible when transaction commits or undo when transaction rolls back.
class MergeTreeTransaction : public std::enable_shared_from_this<MergeTreeTransaction>, private boost::noncopyable
{
friend class TransactionLog;
public:
enum State
{
RUNNING,
COMMITTING,
COMMITTED,
ROLLED_BACK,
};
CSN getSnapshot() const { return snapshot.load(std::memory_order_relaxed); }
void setSnapshot(CSN new_snapshot);
State getState() const;
const TransactionID tid;
MergeTreeTransaction(CSN snapshot_, LocalTID local_tid_, UUID host_id, std::list<CSN>::iterator snapshot_it_);
void addNewPart(const StoragePtr & storage, const DataPartPtr & new_part);
void removeOldPart(const StoragePtr & storage, const DataPartPtr & part_to_remove, const TransactionInfoContext & context);
void addMutation(const StoragePtr & table, const String & mutation_id);
static void addNewPart(const StoragePtr & storage, const DataPartPtr & new_part, MergeTreeTransaction * txn);
static void removeOldPart(const StoragePtr & storage, const DataPartPtr & part_to_remove, MergeTreeTransaction * txn);
static void addNewPartAndRemoveCovered(const StoragePtr & storage, const DataPartPtr & new_part, const DataPartsVector & covered_parts, MergeTreeTransaction * txn);
bool isReadOnly() const;
void onException();
String dumpDescription() const;
Float64 elapsedSeconds() const { return elapsed.elapsedSeconds(); }
/// Waits for transaction state to become not equal to the state corresponding to current_state_csn
bool waitStateChange(CSN current_state_csn) const;
CSN getCSN() const { return csn; }
private:
scope_guard beforeCommit();
void afterCommit(CSN assigned_csn) noexcept;
bool rollback() noexcept;
void afterFinalize();
void checkIsNotCancelled() const;
mutable std::mutex mutex;
Stopwatch elapsed;
/// Usually it's equal to tid.start_csn, but can be changed by SET SNAPSHOT query (for introspection purposes and time-traveling)
std::atomic<CSN> snapshot;
const std::list<CSN>::iterator snapshot_in_use_it;
bool finalized TSA_GUARDED_BY(mutex) = false;
/// Indicates if transaction was read-only before `afterFinalize`
bool is_read_only TSA_GUARDED_BY(mutex) = false;
/// Lists of changes made by transaction
std::unordered_set<StoragePtr> storages TSA_GUARDED_BY(mutex);
DataPartsVector creating_parts TSA_GUARDED_BY(mutex);
DataPartsVector removing_parts TSA_GUARDED_BY(mutex);
using RunningMutationsList = std::vector<std::pair<StoragePtr, String>>;
RunningMutationsList mutations TSA_GUARDED_BY(mutex);
std::atomic<CSN> csn;
};
using MergeTreeTransactionPtr = std::shared_ptr<MergeTreeTransaction>;
}
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