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rocksdb/util/transaction_test_util.cc

246 lines
7.0 KiB

// 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
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include "util/transaction_test_util.h"
#include <inttypes.h>
#include <string>
Optimize for serial commits in 2PC Summary: Throughput: 46k tps in our sysbench settings (filling the details later) The idea is to have the simplest change that gives us a reasonable boost in 2PC throughput. Major design changes: 1. The WAL file internal buffer is not flushed after each write. Instead it is flushed before critical operations (WAL copy via fs) or when FlushWAL is called by MySQL. Flushing the WAL buffer is also protected via mutex_. 2. Use two sequence numbers: last seq, and last seq for write. Last seq is the last visible sequence number for reads. Last seq for write is the next sequence number that should be used to write to WAL/memtable. This allows to have a memtable write be in parallel to WAL writes. 3. BatchGroup is not used for writes. This means that we can have parallel writers which changes a major assumption in the code base. To accommodate for that i) allow only 1 WriteImpl that intends to write to memtable via mem_mutex_--which is fine since in 2PC almost all of the memtable writes come via group commit phase which is serial anyway, ii) make all the parts in the code base that assumed to be the only writer (via EnterUnbatched) to also acquire mem_mutex_, iii) stat updates are protected via a stat_mutex_. Note: the first commit has the approach figured out but is not clean. Submitting the PR anyway to get the early feedback on the approach. If we are ok with the approach I will go ahead with this updates: 0) Rebase with Yi's pipelining changes 1) Currently batching is disabled by default to make sure that it will be consistent with all unit tests. Will make this optional via a config. 2) A couple of unit tests are disabled. They need to be updated with the serial commit of 2PC taken into account. 3) Replacing BatchGroup with mem_mutex_ got a bit ugly as it requires releasing mutex_ beforehand (the same way EnterUnbatched does). This needs to be cleaned up. Closes https://github.com/facebook/rocksdb/pull/2345 Differential Revision: D5210732 Pulled By: maysamyabandeh fbshipit-source-id: 78653bd95a35cd1e831e555e0e57bdfd695355a4
8 years ago
#include <thread>
#include "rocksdb/db.h"
#include "rocksdb/utilities/optimistic_transaction_db.h"
#include "rocksdb/utilities/transaction.h"
#include "rocksdb/utilities/transaction_db.h"
#include "util/random.h"
#include "util/string_util.h"
namespace rocksdb {
RandomTransactionInserter::RandomTransactionInserter(
Random64* rand, const WriteOptions& write_options,
const ReadOptions& read_options, uint64_t num_keys, uint16_t num_sets)
: rand_(rand),
write_options_(write_options),
read_options_(read_options),
num_keys_(num_keys),
num_sets_(num_sets) {}
RandomTransactionInserter::~RandomTransactionInserter() {
if (txn_ != nullptr) {
delete txn_;
}
if (optimistic_txn_ != nullptr) {
delete optimistic_txn_;
}
}
bool RandomTransactionInserter::TransactionDBInsert(
TransactionDB* db, const TransactionOptions& txn_options) {
txn_ = db->BeginTransaction(write_options_, txn_options, txn_);
return DoInsert(nullptr, txn_, false);
}
bool RandomTransactionInserter::OptimisticTransactionDBInsert(
OptimisticTransactionDB* db,
const OptimisticTransactionOptions& txn_options) {
optimistic_txn_ =
db->BeginTransaction(write_options_, txn_options, optimistic_txn_);
return DoInsert(nullptr, optimistic_txn_, true);
}
bool RandomTransactionInserter::DBInsert(DB* db) {
return DoInsert(db, nullptr, false);
}
bool RandomTransactionInserter::DoInsert(DB* db, Transaction* txn,
bool is_optimistic) {
Status s;
WriteBatch batch;
std::string value;
// pick a random number to use to increment a key in each set
uint64_t incr = (rand_->Next() % 100) + 1;
bool unexpected_error = false;
// For each set, pick a key at random and increment it
for (uint8_t i = 0; i < num_sets_; i++) {
uint64_t int_value = 0;
char prefix_buf[5];
// prefix_buf needs to be large enough to hold a uint16 in string form
// key format: [SET#][random#]
std::string rand_key = ToString(rand_->Next() % num_keys_);
Slice base_key(rand_key);
// Pad prefix appropriately so we can iterate over each set
snprintf(prefix_buf, sizeof(prefix_buf), "%.4u", i + 1);
std::string full_key = std::string(prefix_buf) + base_key.ToString();
Slice key(full_key);
if (txn != nullptr) {
s = txn->GetForUpdate(read_options_, key, &value);
} else {
s = db->Get(read_options_, key, &value);
}
if (s.ok()) {
// Found key, parse its value
int_value = std::stoull(value);
if (int_value == 0 || int_value == ULONG_MAX) {
unexpected_error = true;
fprintf(stderr, "Get returned unexpected value: %s\n", value.c_str());
s = Status::Corruption();
}
} else if (s.IsNotFound()) {
// Have not yet written to this key, so assume its value is 0
int_value = 0;
s = Status::OK();
} else {
// Optimistic transactions should never return non-ok status here.
// Non-optimistic transactions may return write-coflict/timeout errors.
if (is_optimistic || !(s.IsBusy() || s.IsTimedOut() || s.IsTryAgain())) {
fprintf(stderr, "Get returned an unexpected error: %s\n",
s.ToString().c_str());
unexpected_error = true;
}
break;
}
if (s.ok()) {
// Increment key
std::string sum = ToString(int_value + incr);
if (txn != nullptr) {
s = txn->Put(key, sum);
if (!s.ok()) {
// Since we did a GetForUpdate, Put should not fail.
fprintf(stderr, "Put returned an unexpected error: %s\n",
s.ToString().c_str());
unexpected_error = true;
}
} else {
batch.Put(key, sum);
}
}
}
if (s.ok()) {
if (txn != nullptr) {
Optimize for serial commits in 2PC Summary: Throughput: 46k tps in our sysbench settings (filling the details later) The idea is to have the simplest change that gives us a reasonable boost in 2PC throughput. Major design changes: 1. The WAL file internal buffer is not flushed after each write. Instead it is flushed before critical operations (WAL copy via fs) or when FlushWAL is called by MySQL. Flushing the WAL buffer is also protected via mutex_. 2. Use two sequence numbers: last seq, and last seq for write. Last seq is the last visible sequence number for reads. Last seq for write is the next sequence number that should be used to write to WAL/memtable. This allows to have a memtable write be in parallel to WAL writes. 3. BatchGroup is not used for writes. This means that we can have parallel writers which changes a major assumption in the code base. To accommodate for that i) allow only 1 WriteImpl that intends to write to memtable via mem_mutex_--which is fine since in 2PC almost all of the memtable writes come via group commit phase which is serial anyway, ii) make all the parts in the code base that assumed to be the only writer (via EnterUnbatched) to also acquire mem_mutex_, iii) stat updates are protected via a stat_mutex_. Note: the first commit has the approach figured out but is not clean. Submitting the PR anyway to get the early feedback on the approach. If we are ok with the approach I will go ahead with this updates: 0) Rebase with Yi's pipelining changes 1) Currently batching is disabled by default to make sure that it will be consistent with all unit tests. Will make this optional via a config. 2) A couple of unit tests are disabled. They need to be updated with the serial commit of 2PC taken into account. 3) Replacing BatchGroup with mem_mutex_ got a bit ugly as it requires releasing mutex_ beforehand (the same way EnterUnbatched does). This needs to be cleaned up. Closes https://github.com/facebook/rocksdb/pull/2345 Differential Revision: D5210732 Pulled By: maysamyabandeh fbshipit-source-id: 78653bd95a35cd1e831e555e0e57bdfd695355a4
8 years ago
std::hash<std::thread::id> hasher;
char name[64];
snprintf(name, 64, "txn%zu-%d", hasher(std::this_thread::get_id()),
txn_id_++);
assert(strlen(name) < 64 - 1);
txn->SetName(name);
s = txn->Prepare();
s = txn->Commit();
if (!s.ok()) {
if (is_optimistic) {
// Optimistic transactions can have write-conflict errors on commit.
// Any other error is unexpected.
if (!(s.IsBusy() || s.IsTimedOut() || s.IsTryAgain())) {
unexpected_error = true;
}
} else {
// Non-optimistic transactions should only fail due to expiration
// or write failures. For testing purproses, we do not expect any
// write failures.
if (!s.IsExpired()) {
unexpected_error = true;
}
}
if (unexpected_error) {
fprintf(stderr, "Commit returned an unexpected error: %s\n",
s.ToString().c_str());
}
}
} else {
s = db->Write(write_options_, &batch);
if (!s.ok()) {
unexpected_error = true;
fprintf(stderr, "Write returned an unexpected error: %s\n",
s.ToString().c_str());
}
}
} else {
if (txn != nullptr) {
txn->Rollback();
}
}
if (s.ok()) {
success_count_++;
} else {
failure_count_++;
}
last_status_ = s;
// return success if we didn't get any unexpected errors
return !unexpected_error;
}
Status RandomTransactionInserter::Verify(DB* db, uint16_t num_sets) {
uint64_t prev_total = 0;
// For each set of keys with the same prefix, sum all the values
for (uint32_t i = 0; i < num_sets; i++) {
char prefix_buf[6];
snprintf(prefix_buf, sizeof(prefix_buf), "%.4u", i + 1);
uint64_t total = 0;
Iterator* iter = db->NewIterator(ReadOptions());
for (iter->Seek(Slice(prefix_buf, 4)); iter->Valid(); iter->Next()) {
Slice key = iter->key();
// stop when we reach a different prefix
if (key.ToString().compare(0, 4, prefix_buf) != 0) {
break;
}
Slice value = iter->value();
uint64_t int_value = std::stoull(value.ToString());
if (int_value == 0 || int_value == ULONG_MAX) {
fprintf(stderr, "Iter returned unexpected value: %s\n",
value.ToString().c_str());
return Status::Corruption();
}
total += int_value;
}
delete iter;
if (i > 0) {
if (total != prev_total) {
fprintf(stderr,
"RandomTransactionVerify found inconsistent totals. "
"Set[%" PRIu32 "]: %" PRIu64 ", Set[%" PRIu32 "]: %" PRIu64
" \n",
i - 1, prev_total, i, total);
return Status::Corruption();
}
}
prev_total = total;
}
return Status::OK();
}
} // namespace rocksdb
#endif // ROCKSDB_LITE