200080ed72
Summary: Previously, reusing a transaction (by passing it as an argument to BeginTransaction) would not clear the transaction's snapshot. This is not a clear, well-definited behavior. Test Plan: improved test Reviewers: sdong, IslamAbdelRahman, horuff, jkedgar Reviewed By: jkedgar Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D55053
144 lines
4.1 KiB
C++
144 lines
4.1 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#pragma once
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#ifndef ROCKSDB_LITE
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#include <atomic>
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#include <stack>
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#include <string>
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#include <unordered_map>
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#include <vector>
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#include "db/write_callback.h"
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#include "rocksdb/db.h"
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#include "rocksdb/slice.h"
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#include "rocksdb/snapshot.h"
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#include "rocksdb/status.h"
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#include "rocksdb/types.h"
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#include "rocksdb/utilities/transaction.h"
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#include "rocksdb/utilities/transaction_db.h"
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#include "rocksdb/utilities/write_batch_with_index.h"
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#include "utilities/transactions/transaction_base.h"
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#include "utilities/transactions/transaction_util.h"
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namespace rocksdb {
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using TransactionID = uint64_t;
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class TransactionDBImpl;
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class TransactionImpl : public TransactionBaseImpl {
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public:
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TransactionImpl(TransactionDB* db, const WriteOptions& write_options,
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const TransactionOptions& txn_options);
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virtual ~TransactionImpl();
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void Reinitialize(TransactionDB* txn_db, const WriteOptions& write_options,
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const TransactionOptions& txn_options);
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Status Commit() override;
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Status CommitBatch(WriteBatch* batch);
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void Rollback() override;
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Status RollbackToSavePoint() override;
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// Generate a new unique transaction identifier
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static TransactionID GenTxnID();
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TransactionID GetTxnID() const { return txn_id_; }
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// Returns the time (in microseconds according to Env->GetMicros())
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// that this transaction will be expired. Returns 0 if this transaction does
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// not expire.
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uint64_t GetExpirationTime() const { return expiration_time_; }
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// returns true if this transaction has an expiration_time and has expired.
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bool IsExpired() const;
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// Returns the number of microseconds a transaction can wait on acquiring a
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// lock or -1 if there is no timeout.
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int64_t GetLockTimeout() const { return lock_timeout_; }
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void SetLockTimeout(int64_t timeout) override {
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lock_timeout_ = timeout * 1000;
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}
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// Returns true if locks were stolen successfully, false otherwise.
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bool TryStealingLocks();
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protected:
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Status TryLock(ColumnFamilyHandle* column_family, const Slice& key,
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bool read_only, bool untracked = false) override;
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private:
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enum ExecutionStatus { STARTED, COMMITTING, LOCKS_STOLEN };
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TransactionDBImpl* txn_db_impl_;
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// Used to create unique ids for transactions.
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static std::atomic<TransactionID> txn_id_counter_;
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// Unique ID for this transaction
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TransactionID txn_id_;
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// If non-zero, this transaction should not be committed after this time (in
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// microseconds according to Env->NowMicros())
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uint64_t expiration_time_;
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// Timeout in microseconds when locking a key or -1 if there is no timeout.
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int64_t lock_timeout_;
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// Execution status of the transaction.
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std::atomic<ExecutionStatus> exec_status_;
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void Clear() override;
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void Initialize(const TransactionOptions& txn_options);
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Status ValidateSnapshot(ColumnFamilyHandle* column_family, const Slice& key,
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SequenceNumber prev_seqno, SequenceNumber* new_seqno);
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Status LockBatch(WriteBatch* batch, TransactionKeyMap* keys_to_unlock);
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Status DoCommit(WriteBatch* batch);
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void RollbackLastN(size_t num);
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void UnlockGetForUpdate(ColumnFamilyHandle* column_family,
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const Slice& key) override;
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// No copying allowed
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TransactionImpl(const TransactionImpl&);
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void operator=(const TransactionImpl&);
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};
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// Used at commit time to check whether transaction is committing before its
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// expiration time.
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class TransactionCallback : public WriteCallback {
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public:
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explicit TransactionCallback(TransactionImpl* txn) : txn_(txn) {}
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Status Callback(DB* db) override {
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if (txn_->IsExpired()) {
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return Status::Expired();
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} else {
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return Status::OK();
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}
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}
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bool AllowWriteBatching() override { return true; }
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private:
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TransactionImpl* txn_;
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};
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} // namespace rocksdb
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#endif // ROCKSDB_LITE
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