84 lines
2.5 KiB
C++
84 lines
2.5 KiB
C++
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#pragma once
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#include <atomic>
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#include <experimental/optional>
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#include <unordered_map>
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#include "communication/messaging/distributed.hpp"
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#include "communication/rpc/rpc.hpp"
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#include "durability/wal.hpp"
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#include "threading/sync/spinlock.hpp"
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#include "transactions/commit_log.hpp"
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#include "transactions/engine.hpp"
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#include "transactions/transaction.hpp"
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#include "utils/exceptions.hpp"
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namespace tx {
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/** Indicates an error in transaction handling (currently
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* only command id overflow). */
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class TransactionError : public utils::BasicException {
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public:
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using utils::BasicException::BasicException;
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};
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/** Single-node deployment transaction engine. Has complete functionality. */
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class SingleNodeEngine : public Engine {
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public:
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/**
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* @param wal - Optional. If present, the Engine will write tx
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* Begin/Commit/Abort atomically (while under lock).
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*/
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explicit SingleNodeEngine(durability::WriteAheadLog *wal = nullptr);
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/**
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* Begins a transaction and returns a pointer to
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* it's object.
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*
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* The transaction object is owned by this engine.
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* It will be released when the transaction gets
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* committted or aborted.
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*/
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Transaction *Begin();
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/**
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* Advances the command on the transaction with the
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* given id.
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*
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* @param id - Transation id. That transaction must
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* be currently active.
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*/
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void Advance(transaction_id_t id);
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/** Comits the given transaction. Deletes the transaction object, it's not
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* valid after this function executes. */
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void Commit(const Transaction &t);
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/** Aborts the given transaction. Deletes the transaction object, it's not
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* valid after this function executes. */
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void Abort(const Transaction &t);
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CommitLog::Info Info(transaction_id_t tx) const override;
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Snapshot GlobalGcSnapshot() override;
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Snapshot GlobalActiveTransactions() override;
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bool GlobalIsActive(transaction_id_t tx) const override;
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tx::transaction_id_t LocalLast() const override;
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void LocalForEachActiveTransaction(
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std::function<void(Transaction &)> f) override;
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protected:
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// Exposed for MasterEngine. Transaction for tx_id must be alive.
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Snapshot GetSnapshot(tx::transaction_id_t tx_id);
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private:
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std::atomic<transaction_id_t> counter_{0};
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CommitLog clog_;
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std::unordered_map<transaction_id_t, std::unique_ptr<Transaction>> store_;
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Snapshot active_;
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SpinLock lock_;
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// Optional. If present, the Engine will write tx Begin/Commit/Abort
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// atomically (while under lock).
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durability::WriteAheadLog *wal_{nullptr};
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};
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} // namespace tx
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