rocksdb/utilities/transactions/transaction_db_impl.cc
agiardullo 200080ed72 Improve snapshot handling for Transaction reinitialization
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
2016-03-07 13:28:11 -08:00

320 lines
10 KiB
C++

// Copyright (c) 2011-present, 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.
#ifndef ROCKSDB_LITE
#include "utilities/transactions/transaction_db_impl.h"
#include <string>
#include <unordered_set>
#include <vector>
#include "db/db_impl.h"
#include "rocksdb/db.h"
#include "rocksdb/options.h"
#include "rocksdb/utilities/transaction_db.h"
#include "utilities/transactions/transaction_db_mutex_impl.h"
#include "utilities/transactions/transaction_impl.h"
namespace rocksdb {
TransactionDBImpl::TransactionDBImpl(DB* db,
const TransactionDBOptions& txn_db_options)
: TransactionDB(db),
txn_db_options_(txn_db_options),
lock_mgr_(this, txn_db_options_.num_stripes, txn_db_options.max_num_locks,
txn_db_options_.custom_mutex_factory
? txn_db_options_.custom_mutex_factory
: std::shared_ptr<TransactionDBMutexFactory>(
new TransactionDBMutexFactoryImpl())) {}
Transaction* TransactionDBImpl::BeginTransaction(
const WriteOptions& write_options, const TransactionOptions& txn_options,
Transaction* old_txn) {
if (old_txn != nullptr) {
ReinitializeTransaction(old_txn, write_options, txn_options);
return old_txn;
} else {
return new TransactionImpl(this, write_options, txn_options);
}
}
TransactionDBOptions TransactionDBImpl::ValidateTxnDBOptions(
const TransactionDBOptions& txn_db_options) {
TransactionDBOptions validated = txn_db_options;
if (txn_db_options.num_stripes == 0) {
validated.num_stripes = 1;
}
return validated;
}
Status TransactionDB::Open(const Options& options,
const TransactionDBOptions& txn_db_options,
const std::string& dbname, TransactionDB** dbptr) {
DBOptions db_options(options);
ColumnFamilyOptions cf_options(options);
std::vector<ColumnFamilyDescriptor> column_families;
column_families.push_back(
ColumnFamilyDescriptor(kDefaultColumnFamilyName, cf_options));
std::vector<ColumnFamilyHandle*> handles;
Status s = TransactionDB::Open(db_options, txn_db_options, dbname,
column_families, &handles, dbptr);
if (s.ok()) {
assert(handles.size() == 1);
// i can delete the handle since DBImpl is always holding a reference to
// default column family
delete handles[0];
}
return s;
}
Status TransactionDB::Open(
const DBOptions& db_options, const TransactionDBOptions& txn_db_options,
const std::string& dbname,
const std::vector<ColumnFamilyDescriptor>& column_families,
std::vector<ColumnFamilyHandle*>* handles, TransactionDB** dbptr) {
Status s;
DB* db;
std::vector<ColumnFamilyDescriptor> column_families_copy = column_families;
std::vector<size_t> compaction_enabled_cf_indices;
// Enable MemTable History if not already enabled
for (size_t i = 0; i < column_families_copy.size(); i++) {
ColumnFamilyOptions* options = &column_families_copy[i].options;
if (options->max_write_buffer_number_to_maintain == 0) {
// Setting to -1 will set the History size to max_write_buffer_number.
options->max_write_buffer_number_to_maintain = -1;
}
if (!options->disable_auto_compactions) {
// Disable compactions momentarily to prevent race with DB::Open
options->disable_auto_compactions = true;
compaction_enabled_cf_indices.push_back(i);
}
}
s = DB::Open(db_options, dbname, column_families_copy, handles, &db);
if (s.ok()) {
TransactionDBImpl* txn_db = new TransactionDBImpl(
db, TransactionDBImpl::ValidateTxnDBOptions(txn_db_options));
*dbptr = txn_db;
for (auto cf_ptr : *handles) {
txn_db->AddColumnFamily(cf_ptr);
}
// Re-enable compaction for the column families that initially had
// compaction enabled.
assert(column_families_copy.size() == (*handles).size());
std::vector<ColumnFamilyHandle*> compaction_enabled_cf_handles;
compaction_enabled_cf_handles.reserve(compaction_enabled_cf_indices.size());
for (auto index : compaction_enabled_cf_indices) {
compaction_enabled_cf_handles.push_back((*handles)[index]);
}
s = txn_db->EnableAutoCompaction(compaction_enabled_cf_handles);
}
return s;
}
// Let TransactionLockMgr know that this column family exists so it can
// allocate a LockMap for it.
void TransactionDBImpl::AddColumnFamily(const ColumnFamilyHandle* handle) {
lock_mgr_.AddColumnFamily(handle->GetID());
}
Status TransactionDBImpl::CreateColumnFamily(
const ColumnFamilyOptions& options, const std::string& column_family_name,
ColumnFamilyHandle** handle) {
InstrumentedMutexLock l(&column_family_mutex_);
Status s = db_->CreateColumnFamily(options, column_family_name, handle);
if (s.ok()) {
lock_mgr_.AddColumnFamily((*handle)->GetID());
}
return s;
}
// Let TransactionLockMgr know that it can deallocate the LockMap for this
// column family.
Status TransactionDBImpl::DropColumnFamily(ColumnFamilyHandle* column_family) {
InstrumentedMutexLock l(&column_family_mutex_);
Status s = db_->DropColumnFamily(column_family);
if (s.ok()) {
lock_mgr_.RemoveColumnFamily(column_family->GetID());
}
return s;
}
Status TransactionDBImpl::TryLock(TransactionImpl* txn, uint32_t cfh_id,
const std::string& key) {
return lock_mgr_.TryLock(txn, cfh_id, key, GetEnv());
}
void TransactionDBImpl::UnLock(TransactionImpl* txn,
const TransactionKeyMap* keys) {
lock_mgr_.UnLock(txn, keys, GetEnv());
}
void TransactionDBImpl::UnLock(TransactionImpl* txn, uint32_t cfh_id,
const std::string& key) {
lock_mgr_.UnLock(txn, cfh_id, key, GetEnv());
}
// Used when wrapping DB write operations in a transaction
Transaction* TransactionDBImpl::BeginInternalTransaction(
const WriteOptions& options) {
TransactionOptions txn_options;
Transaction* txn = BeginTransaction(options, txn_options, nullptr);
assert(dynamic_cast<TransactionImpl*>(txn) != nullptr);
auto txn_impl = reinterpret_cast<TransactionImpl*>(txn);
// Use default timeout for non-transactional writes
txn_impl->SetLockTimeout(txn_db_options_.default_lock_timeout);
return txn;
}
// All user Put, Merge, Delete, and Write requests must be intercepted to make
// sure that they lock all keys that they are writing to avoid causing conflicts
// with any concurent transactions. The easiest way to do this is to wrap all
// write operations in a transaction.
//
// Put(), Merge(), and Delete() only lock a single key per call. Write() will
// sort its keys before locking them. This guarantees that TransactionDB write
// methods cannot deadlock with eachother (but still could deadlock with a
// Transaction).
Status TransactionDBImpl::Put(const WriteOptions& options,
ColumnFamilyHandle* column_family,
const Slice& key, const Slice& val) {
Status s;
Transaction* txn = BeginInternalTransaction(options);
txn->DisableIndexing();
// Since the client didn't create a transaction, they don't care about
// conflict checking for this write. So we just need to do PutUntracked().
s = txn->PutUntracked(column_family, key, val);
if (s.ok()) {
s = txn->Commit();
}
delete txn;
return s;
}
Status TransactionDBImpl::Delete(const WriteOptions& wopts,
ColumnFamilyHandle* column_family,
const Slice& key) {
Status s;
Transaction* txn = BeginInternalTransaction(wopts);
txn->DisableIndexing();
// Since the client didn't create a transaction, they don't care about
// conflict checking for this write. So we just need to do
// DeleteUntracked().
s = txn->DeleteUntracked(column_family, key);
if (s.ok()) {
s = txn->Commit();
}
delete txn;
return s;
}
Status TransactionDBImpl::Merge(const WriteOptions& options,
ColumnFamilyHandle* column_family,
const Slice& key, const Slice& value) {
Status s;
Transaction* txn = BeginInternalTransaction(options);
txn->DisableIndexing();
// Since the client didn't create a transaction, they don't care about
// conflict checking for this write. So we just need to do
// MergeUntracked().
s = txn->MergeUntracked(column_family, key, value);
if (s.ok()) {
s = txn->Commit();
}
delete txn;
return s;
}
Status TransactionDBImpl::Write(const WriteOptions& opts, WriteBatch* updates) {
// Need to lock all keys in this batch to prevent write conflicts with
// concurrent transactions.
Transaction* txn = BeginInternalTransaction(opts);
txn->DisableIndexing();
assert(dynamic_cast<TransactionImpl*>(txn) != nullptr);
auto txn_impl = reinterpret_cast<TransactionImpl*>(txn);
// Since commitBatch sorts the keys before locking, concurrent Write()
// operations will not cause a deadlock.
// In order to avoid a deadlock with a concurrent Transaction, Transactions
// should use a lock timeout.
Status s = txn_impl->CommitBatch(updates);
delete txn;
return s;
}
void TransactionDBImpl::InsertExpirableTransaction(TransactionID tx_id,
TransactionImpl* tx) {
assert(tx->GetExpirationTime() > 0);
std::lock_guard<std::mutex> lock(map_mutex_);
expirable_transactions_map_.insert({tx_id, tx});
}
void TransactionDBImpl::RemoveExpirableTransaction(TransactionID tx_id) {
std::lock_guard<std::mutex> lock(map_mutex_);
expirable_transactions_map_.erase(tx_id);
}
bool TransactionDBImpl::TryStealingExpiredTransactionLocks(
TransactionID tx_id) {
std::lock_guard<std::mutex> lock(map_mutex_);
auto tx_it = expirable_transactions_map_.find(tx_id);
if (tx_it == expirable_transactions_map_.end()) {
return true;
}
TransactionImpl& tx = *(tx_it->second);
return tx.TryStealingLocks();
}
void TransactionDBImpl::ReinitializeTransaction(
Transaction* txn, const WriteOptions& write_options,
const TransactionOptions& txn_options) {
assert(dynamic_cast<TransactionImpl*>(txn) != nullptr);
auto txn_impl = reinterpret_cast<TransactionImpl*>(txn);
txn_impl->Reinitialize(this, write_options, txn_options);
}
} // namespace rocksdb
#endif // ROCKSDB_LITE