rocksdb/utilities/transactions/transaction_base.h
Jay Edgar 8f143e03fb Add ClearSnapshot()
Summary:
MyRocks needs the ability to clear a snapshot for Read Committed support

Test Plan: transaction_test

Reviewers: anthony

Reviewed By: anthony

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48861
2015-10-16 11:53:30 -07:00

278 lines
9.6 KiB
C++

// Copyright (c) 2015, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
#pragma once
#ifndef ROCKSDB_LITE
#include <stack>
#include <string>
#include <vector>
#include "rocksdb/db.h"
#include "rocksdb/slice.h"
#include "rocksdb/snapshot.h"
#include "rocksdb/status.h"
#include "rocksdb/types.h"
#include "rocksdb/utilities/transaction.h"
#include "rocksdb/utilities/transaction_db.h"
#include "rocksdb/utilities/write_batch_with_index.h"
#include "utilities/transactions/transaction_util.h"
namespace rocksdb {
class TransactionBaseImpl : public Transaction {
public:
TransactionBaseImpl(DB* db, const WriteOptions& write_options);
virtual ~TransactionBaseImpl();
// Remove pending operations queued in this transaction.
virtual void Clear();
// Called before executing Put, Merge, Delete, and GetForUpdate. If TryLock
// returns non-OK, the Put/Merge/Delete/GetForUpdate will be failed.
// untracked will be true if called from PutUntracked, DeleteUntracked, or
// MergeUntracked.
virtual Status TryLock(ColumnFamilyHandle* column_family, const Slice& key,
bool untracked = false) = 0;
void SetSavePoint() override;
Status RollbackToSavePoint() override;
Status Get(const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, std::string* value) override;
Status Get(const ReadOptions& options, const Slice& key,
std::string* value) override {
return Get(options, db_->DefaultColumnFamily(), key, value);
}
Status GetForUpdate(const ReadOptions& options,
ColumnFamilyHandle* column_family, const Slice& key,
std::string* value) override;
Status GetForUpdate(const ReadOptions& options, const Slice& key,
std::string* value) override {
return GetForUpdate(options, db_->DefaultColumnFamily(), key, value);
}
std::vector<Status> MultiGet(
const ReadOptions& options,
const std::vector<ColumnFamilyHandle*>& column_family,
const std::vector<Slice>& keys,
std::vector<std::string>* values) override;
std::vector<Status> MultiGet(const ReadOptions& options,
const std::vector<Slice>& keys,
std::vector<std::string>* values) override {
return MultiGet(options, std::vector<ColumnFamilyHandle*>(
keys.size(), db_->DefaultColumnFamily()),
keys, values);
}
std::vector<Status> MultiGetForUpdate(
const ReadOptions& options,
const std::vector<ColumnFamilyHandle*>& column_family,
const std::vector<Slice>& keys,
std::vector<std::string>* values) override;
std::vector<Status> MultiGetForUpdate(
const ReadOptions& options, const std::vector<Slice>& keys,
std::vector<std::string>* values) override {
return MultiGetForUpdate(options,
std::vector<ColumnFamilyHandle*>(
keys.size(), db_->DefaultColumnFamily()),
keys, values);
}
Iterator* GetIterator(const ReadOptions& read_options) override;
Iterator* GetIterator(const ReadOptions& read_options,
ColumnFamilyHandle* column_family) override;
Status Put(ColumnFamilyHandle* column_family, const Slice& key,
const Slice& value) override;
Status Put(const Slice& key, const Slice& value) override {
return Put(nullptr, key, value);
}
Status Put(ColumnFamilyHandle* column_family, const SliceParts& key,
const SliceParts& value) override;
Status Put(const SliceParts& key, const SliceParts& value) override {
return Put(nullptr, key, value);
}
Status Merge(ColumnFamilyHandle* column_family, const Slice& key,
const Slice& value) override;
Status Merge(const Slice& key, const Slice& value) override {
return Merge(nullptr, key, value);
}
Status Delete(ColumnFamilyHandle* column_family, const Slice& key) override;
Status Delete(const Slice& key) override { return Delete(nullptr, key); }
Status Delete(ColumnFamilyHandle* column_family,
const SliceParts& key) override;
Status Delete(const SliceParts& key) override { return Delete(nullptr, key); }
Status SingleDelete(ColumnFamilyHandle* column_family,
const Slice& key) override;
Status SingleDelete(const Slice& key) override {
return SingleDelete(nullptr, key);
}
Status SingleDelete(ColumnFamilyHandle* column_family,
const SliceParts& key) override;
Status SingleDelete(const SliceParts& key) override {
return SingleDelete(nullptr, key);
}
Status PutUntracked(ColumnFamilyHandle* column_family, const Slice& key,
const Slice& value) override;
Status PutUntracked(const Slice& key, const Slice& value) override {
return PutUntracked(nullptr, key, value);
}
Status PutUntracked(ColumnFamilyHandle* column_family, const SliceParts& key,
const SliceParts& value) override;
Status PutUntracked(const SliceParts& key, const SliceParts& value) override {
return PutUntracked(nullptr, key, value);
}
Status MergeUntracked(ColumnFamilyHandle* column_family, const Slice& key,
const Slice& value) override;
Status MergeUntracked(const Slice& key, const Slice& value) override {
return MergeUntracked(nullptr, key, value);
}
Status DeleteUntracked(ColumnFamilyHandle* column_family,
const Slice& key) override;
Status DeleteUntracked(const Slice& key) override {
return DeleteUntracked(nullptr, key);
}
Status DeleteUntracked(ColumnFamilyHandle* column_family,
const SliceParts& key) override;
Status DeleteUntracked(const SliceParts& key) override {
return DeleteUntracked(nullptr, key);
}
void PutLogData(const Slice& blob) override;
WriteBatchWithIndex* GetWriteBatch() override;
virtual void SetLockTimeout(int64_t timeout) override { /* Do nothing */
}
const Snapshot* GetSnapshot() const override {
return snapshot_ ? snapshot_->snapshot() : nullptr;
}
void SetSnapshot() override;
void SetSnapshotOnNextOperation() override;
void ClearSnapshot() override {
snapshot_.reset();
snapshot_needed_ = false;
}
void DisableIndexing() override { indexing_enabled_ = false; }
void EnableIndexing() override { indexing_enabled_ = true; }
uint64_t GetElapsedTime() const override;
uint64_t GetNumPuts() const override;
uint64_t GetNumDeletes() const override;
uint64_t GetNumMerges() const override;
uint64_t GetNumKeys() const override;
// Get list of keys in this transaction that must not have any conflicts
// with writes in other transactions.
const TransactionKeyMap& GetTrackedKeys() const { return tracked_keys_; }
protected:
// Add a key to the list of tracked keys.
// seqno is the earliest seqno this key was involved with this transaction.
void TrackKey(uint32_t cfh_id, const std::string& key, SequenceNumber seqno);
const TransactionKeyMap* GetTrackedKeysSinceSavePoint();
// Sets a snapshot if SetSnapshotOnNextOperation() has been called.
void SetSnapshotIfNeeded();
DB* const db_;
const WriteOptions write_options_;
const Comparator* cmp_;
// Records writes pending in this transaction
std::unique_ptr<WriteBatchWithIndex> write_batch_;
// Stores that time the txn was constructed, in microseconds.
const uint64_t start_time_;
// Stores the current snapshot that was was set by SetSnapshot or null if
// no snapshot is currently set.
std::shared_ptr<ManagedSnapshot> snapshot_;
// Count of various operations pending in this transaction
uint64_t num_puts_ = 0;
uint64_t num_deletes_ = 0;
uint64_t num_merges_ = 0;
struct SavePoint {
std::shared_ptr<ManagedSnapshot> snapshot_;
bool snapshot_needed_;
uint64_t num_puts_;
uint64_t num_deletes_;
uint64_t num_merges_;
// Record all keys tracked since the last savepoint
TransactionKeyMap new_keys_;
SavePoint(std::shared_ptr<ManagedSnapshot> snapshot, bool snapshot_needed,
uint64_t num_puts, uint64_t num_deletes, uint64_t num_merges)
: snapshot_(snapshot),
snapshot_needed_(snapshot_needed),
num_puts_(num_puts),
num_deletes_(num_deletes),
num_merges_(num_merges) {}
};
private:
// Stack of the Snapshot saved at each save point. Saved snapshots may be
// nullptr if there was no snapshot at the time SetSavePoint() was called.
std::unique_ptr<std::stack<TransactionBaseImpl::SavePoint>> save_points_;
// Map from column_family_id to map of keys that are involved in this
// transaction.
// Pessimistic Transactions will do conflict checking before adding a key
// by calling TrackKey().
// Optimistic Transactions will wait till commit time to do conflict checking.
TransactionKeyMap tracked_keys_;
// If true, future Put/Merge/Deletes will be indexed in the
// WriteBatchWithIndex.
// If false, future Put/Merge/Deletes will be inserted directly into the
// underlying WriteBatch and not indexed in the WriteBatchWithIndex.
bool indexing_enabled_ = true;
// SetSnapshotOnNextOperation() has been called and the snapshot has not yet
// been reset.
bool snapshot_needed_ = false;
Status TryLock(ColumnFamilyHandle* column_family, const SliceParts& key,
bool untracked = false);
WriteBatchBase* GetBatchForWrite();
};
} // namespace rocksdb
#endif // ROCKSDB_LITE