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rocksdb/db/db_statistics_test.cc
Kevin Mingtarja 44fd914128 Fix double counting of BYTES_WRITTEN ticker (#12111) 
Summary:
Fixes https://github.com/facebook/rocksdb/issues/12061.

We were double counting the `BYTES_WRITTEN` ticker when doing writes with transactions. During transactions, after writing, a client can call `Prepare()`, which writes the values to WAL but not to the Memtable. After that, they can call `Commit()`, which writes a commit marker to the WAL and the values to Memtable.

The cause of this bug is previously during writes, we didn't take into account `writer->ShouldWriteToMemtable()` before adding to `total_byte_size`, so it is still added to during the `Prepare()` phase even though we're not writing to the Memtable, which was why we saw the value to be double of what's written to WAL.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12111

Test Plan: Added a test in `db/db_statistics_test.cc` that tests writes with and without transactions, by comparing the values of `BYTES_WRITTEN` and `WAL_FILE_BYTES` after doing writes.

Reviewed By: jaykorean

Differential Revision: D51954327

Pulled By: jowlyzhang

fbshipit-source-id: 57a0986a14e5b94eb5188715d819212529110d2c
2023-12-08 17:12:11 -08:00

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include <string>
#include "db/db_test_util.h"
#include "db/write_batch_internal.h"
#include "monitoring/thread_status_util.h"
#include "port/stack_trace.h"
#include "rocksdb/statistics.h"
#include "rocksdb/utilities/transaction_db.h"
#include "util/random.h"
namespace ROCKSDB_NAMESPACE {
class DBStatisticsTest : public DBTestBase {
public:
DBStatisticsTest()
: DBTestBase("db_statistics_test", /*env_do_fsync=*/true) {}
};
TEST_F(DBStatisticsTest, CompressionStatsTest) {
for (CompressionType type : GetSupportedCompressions()) {
if (type == kNoCompression) {
continue;
}
if (type == kBZip2Compression) {
// Weird behavior in this test
continue;
}
SCOPED_TRACE("Compression type: " + std::to_string(type));
Options options = CurrentOptions();
options.compression = type;
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
options.statistics->set_stats_level(StatsLevel::kExceptTimeForMutex);
BlockBasedTableOptions bbto;
bbto.enable_index_compression = false;
options.table_factory.reset(NewBlockBasedTableFactory(bbto));
DestroyAndReopen(options);
auto PopStat = [&](Tickers t) -> uint64_t {
return options.statistics->getAndResetTickerCount(t);
};
int kNumKeysWritten = 100;
double compress_to = 0.5;
// About three KVs per block
int len = static_cast<int>(BlockBasedTableOptions().block_size / 3);
int uncomp_est = kNumKeysWritten * (len + 20);
Random rnd(301);
std::string buf;
// Check that compressions occur and are counted when compression is turned
// on
for (int i = 0; i < kNumKeysWritten; ++i) {
ASSERT_OK(
Put(Key(i), test::CompressibleString(&rnd, compress_to, len, &buf)));
}
ASSERT_OK(Flush());
EXPECT_EQ(34, PopStat(NUMBER_BLOCK_COMPRESSED));
EXPECT_NEAR2(uncomp_est, PopStat(BYTES_COMPRESSED_FROM), uncomp_est / 10);
EXPECT_NEAR2(uncomp_est * compress_to, PopStat(BYTES_COMPRESSED_TO),
uncomp_est / 10);
EXPECT_EQ(0, PopStat(NUMBER_BLOCK_DECOMPRESSED));
EXPECT_EQ(0, PopStat(BYTES_DECOMPRESSED_FROM));
EXPECT_EQ(0, PopStat(BYTES_DECOMPRESSED_TO));
// And decompressions
for (int i = 0; i < kNumKeysWritten; ++i) {
auto r = Get(Key(i));
}
EXPECT_EQ(34, PopStat(NUMBER_BLOCK_DECOMPRESSED));
EXPECT_NEAR2(uncomp_est, PopStat(BYTES_DECOMPRESSED_TO), uncomp_est / 10);
EXPECT_NEAR2(uncomp_est * compress_to, PopStat(BYTES_DECOMPRESSED_FROM),
uncomp_est / 10);
EXPECT_EQ(0, PopStat(BYTES_COMPRESSION_BYPASSED));
EXPECT_EQ(0, PopStat(BYTES_COMPRESSION_REJECTED));
EXPECT_EQ(0, PopStat(NUMBER_BLOCK_COMPRESSION_BYPASSED));
EXPECT_EQ(0, PopStat(NUMBER_BLOCK_COMPRESSION_REJECTED));
// Check when compression is rejected.
DestroyAndReopen(options);
for (int i = 0; i < kNumKeysWritten; ++i) {
ASSERT_OK(Put(Key(i), rnd.RandomBinaryString(len)));
}
ASSERT_OK(Flush());
for (int i = 0; i < kNumKeysWritten; ++i) {
auto r = Get(Key(i));
}
EXPECT_EQ(34, PopStat(NUMBER_BLOCK_COMPRESSION_REJECTED));
EXPECT_NEAR2(uncomp_est, PopStat(BYTES_COMPRESSION_REJECTED),
uncomp_est / 10);
EXPECT_EQ(0, PopStat(NUMBER_BLOCK_COMPRESSED));
EXPECT_EQ(0, PopStat(NUMBER_BLOCK_COMPRESSION_BYPASSED));
EXPECT_EQ(0, PopStat(NUMBER_BLOCK_DECOMPRESSED));
EXPECT_EQ(0, PopStat(BYTES_COMPRESSED_FROM));
EXPECT_EQ(0, PopStat(BYTES_COMPRESSED_TO));
EXPECT_EQ(0, PopStat(BYTES_COMPRESSION_BYPASSED));
EXPECT_EQ(0, PopStat(BYTES_DECOMPRESSED_FROM));
EXPECT_EQ(0, PopStat(BYTES_DECOMPRESSED_TO));
// Check when compression is disabled.
options.compression = kNoCompression;
DestroyAndReopen(options);
for (int i = 0; i < kNumKeysWritten; ++i) {
ASSERT_OK(Put(Key(i), rnd.RandomBinaryString(len)));
}
ASSERT_OK(Flush());
for (int i = 0; i < kNumKeysWritten; ++i) {
auto r = Get(Key(i));
}
EXPECT_EQ(34, PopStat(NUMBER_BLOCK_COMPRESSION_BYPASSED));
EXPECT_NEAR2(uncomp_est, PopStat(BYTES_COMPRESSION_BYPASSED),
uncomp_est / 10);
EXPECT_EQ(0, PopStat(NUMBER_BLOCK_COMPRESSED));
EXPECT_EQ(0, PopStat(NUMBER_BLOCK_COMPRESSION_REJECTED));
EXPECT_EQ(0, PopStat(NUMBER_BLOCK_DECOMPRESSED));
EXPECT_EQ(0, PopStat(BYTES_COMPRESSED_FROM));
EXPECT_EQ(0, PopStat(BYTES_COMPRESSED_TO));
EXPECT_EQ(0, PopStat(BYTES_COMPRESSION_REJECTED));
EXPECT_EQ(0, PopStat(BYTES_DECOMPRESSED_FROM));
EXPECT_EQ(0, PopStat(BYTES_DECOMPRESSED_TO));
}
}
TEST_F(DBStatisticsTest, MutexWaitStatsDisabledByDefault) {
Options options = CurrentOptions();
options.create_if_missing = true;
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
CreateAndReopenWithCF({"pikachu"}, options);
const uint64_t kMutexWaitDelay = 100;
ThreadStatusUtil::TEST_SetStateDelay(ThreadStatus::STATE_MUTEX_WAIT,
kMutexWaitDelay);
ASSERT_OK(Put("hello", "rocksdb"));
ASSERT_EQ(TestGetTickerCount(options, DB_MUTEX_WAIT_MICROS), 0);
ThreadStatusUtil::TEST_SetStateDelay(ThreadStatus::STATE_MUTEX_WAIT, 0);
}
TEST_F(DBStatisticsTest, MutexWaitStats) {
Options options = CurrentOptions();
options.create_if_missing = true;
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
options.statistics->set_stats_level(StatsLevel::kAll);
CreateAndReopenWithCF({"pikachu"}, options);
const uint64_t kMutexWaitDelay = 100;
ThreadStatusUtil::TEST_SetStateDelay(ThreadStatus::STATE_MUTEX_WAIT,
kMutexWaitDelay);
ASSERT_OK(Put("hello", "rocksdb"));
ASSERT_GE(TestGetTickerCount(options, DB_MUTEX_WAIT_MICROS), kMutexWaitDelay);
ThreadStatusUtil::TEST_SetStateDelay(ThreadStatus::STATE_MUTEX_WAIT, 0);
}
TEST_F(DBStatisticsTest, ResetStats) {
Options options = CurrentOptions();
options.create_if_missing = true;
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
DestroyAndReopen(options);
for (int i = 0; i < 2; ++i) {
// pick arbitrary ticker and histogram. On first iteration they're zero
// because db is unused. On second iteration they're zero due to Reset().
ASSERT_EQ(0, TestGetTickerCount(options, NUMBER_KEYS_WRITTEN));
HistogramData histogram_data;
options.statistics->histogramData(DB_WRITE, &histogram_data);
ASSERT_EQ(0.0, histogram_data.max);
if (i == 0) {
// The Put() makes some of the ticker/histogram stats nonzero until we
// Reset().
ASSERT_OK(Put("hello", "rocksdb"));
ASSERT_EQ(1, TestGetTickerCount(options, NUMBER_KEYS_WRITTEN));
options.statistics->histogramData(DB_WRITE, &histogram_data);
ASSERT_GT(histogram_data.max, 0.0);
ASSERT_OK(options.statistics->Reset());
}
}
}
TEST_F(DBStatisticsTest, ExcludeTickers) {
Options options = CurrentOptions();
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
DestroyAndReopen(options);
options.statistics->set_stats_level(StatsLevel::kExceptTickers);
ASSERT_OK(Put("foo", "value"));
ASSERT_EQ(0, options.statistics->getTickerCount(BYTES_WRITTEN));
options.statistics->set_stats_level(StatsLevel::kExceptHistogramOrTimers);
Reopen(options);
ASSERT_EQ("value", Get("foo"));
ASSERT_GT(options.statistics->getTickerCount(BYTES_READ), 0);
}
TEST_F(DBStatisticsTest, VerifyChecksumReadStat) {
Options options = CurrentOptions();
options.file_checksum_gen_factory = GetFileChecksumGenCrc32cFactory();
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
Reopen(options);
// Expected to be populated regardless of `PerfLevel` in user thread
SetPerfLevel(kDisable);
{
// Scenario 0: only WAL data. Not verified so require ticker to be zero.
ASSERT_OK(Put("foo", "value"));
ASSERT_OK(db_->VerifyFileChecksums(ReadOptions()));
ASSERT_OK(db_->VerifyChecksum());
ASSERT_EQ(0,
options.statistics->getTickerCount(VERIFY_CHECKSUM_READ_BYTES));
}
// Create one SST.
ASSERT_OK(Flush());
std::unordered_map<std::string, uint64_t> table_files;
uint64_t table_files_size = 0;
ASSERT_OK(GetAllDataFiles(kTableFile, &table_files, &table_files_size));
{
// Scenario 1: Table verified in `VerifyFileChecksums()`. This should read
// the whole file so we require the ticker stat exactly matches the file
// size.
ASSERT_OK(options.statistics->Reset());
ASSERT_OK(db_->VerifyFileChecksums(ReadOptions()));
ASSERT_EQ(table_files_size,
options.statistics->getTickerCount(VERIFY_CHECKSUM_READ_BYTES));
}
{
// Scenario 2: Table verified in `VerifyChecksum()`. This opens a
// `TableReader` to verify each block. It can involve duplicate reads of the
// same data so we set a lower-bound only.
ASSERT_OK(options.statistics->Reset());
ASSERT_OK(db_->VerifyChecksum());
ASSERT_GE(options.statistics->getTickerCount(VERIFY_CHECKSUM_READ_BYTES),
table_files_size);
}
}
TEST_F(DBStatisticsTest, BlockChecksumStats) {
Options options = CurrentOptions();
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
Reopen(options);
// Scenario 0: only WAL data. Not verified so require ticker to be zero.
ASSERT_OK(Put("foo", "value"));
ASSERT_OK(db_->VerifyChecksum());
ASSERT_EQ(0,
options.statistics->getTickerCount(BLOCK_CHECKSUM_COMPUTE_COUNT));
ASSERT_EQ(0,
options.statistics->getTickerCount(BLOCK_CHECKSUM_MISMATCH_COUNT));
// Scenario 1: Flushed table verified in `VerifyChecksum()`. This opens a
// `TableReader` to verify each of the four blocks (meta-index, table
// properties, index, and data block).
ASSERT_OK(Flush());
ASSERT_OK(options.statistics->Reset());
ASSERT_OK(db_->VerifyChecksum());
ASSERT_EQ(4,
options.statistics->getTickerCount(BLOCK_CHECKSUM_COMPUTE_COUNT));
ASSERT_EQ(0,
options.statistics->getTickerCount(BLOCK_CHECKSUM_MISMATCH_COUNT));
// Scenario 2: Corrupted table verified in `VerifyChecksum()`. The corruption
// is in the fourth and final verified block, i.e., the data block.
std::unordered_map<std::string, uint64_t> table_files;
ASSERT_OK(GetAllDataFiles(kTableFile, &table_files));
ASSERT_EQ(1, table_files.size());
std::string table_name = table_files.begin()->first;
// Assumes the data block starts at offset zero.
ASSERT_OK(test::CorruptFile(options.env, table_name, 0 /* offset */,
3 /* bytes_to_corrupt */));
ASSERT_OK(options.statistics->Reset());
ASSERT_NOK(db_->VerifyChecksum());
ASSERT_EQ(4,
options.statistics->getTickerCount(BLOCK_CHECKSUM_COMPUTE_COUNT));
ASSERT_EQ(1,
options.statistics->getTickerCount(BLOCK_CHECKSUM_MISMATCH_COUNT));
}
TEST_F(DBStatisticsTest, BytesWrittenStats) {
Options options = CurrentOptions();
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
options.statistics->set_stats_level(StatsLevel::kExceptHistogramOrTimers);
Reopen(options);
EXPECT_EQ(0, options.statistics->getAndResetTickerCount(WAL_FILE_BYTES));
EXPECT_EQ(0, options.statistics->getAndResetTickerCount(BYTES_WRITTEN));
const int kNumKeysWritten = 100;
// Scenario 0: Not using transactions.
// This will write to WAL and memtable directly.
ASSERT_OK(options.statistics->Reset());
for (int i = 0; i < kNumKeysWritten; ++i) {
ASSERT_OK(Put(Key(i), "val"));
}
EXPECT_EQ(options.statistics->getAndResetTickerCount(WAL_FILE_BYTES),
options.statistics->getAndResetTickerCount(BYTES_WRITTEN));
// Scenario 1: Using transactions.
// This should not double count BYTES_WRITTEN (issue #12061).
for (bool enable_pipelined_write : {false, true}) {
ASSERT_OK(options.statistics->Reset());
// Destroy the DB to recreate as a TransactionDB.
Destroy(options, true);
// Create a TransactionDB.
TransactionDB* txn_db = nullptr;
TransactionDBOptions txn_db_opts;
txn_db_opts.write_policy = TxnDBWritePolicy::WRITE_COMMITTED;
options.enable_pipelined_write = enable_pipelined_write;
ASSERT_OK(TransactionDB::Open(options, txn_db_opts, dbname_, &txn_db));
ASSERT_NE(txn_db, nullptr);
db_ = txn_db->GetBaseDB();
WriteOptions wopts;
TransactionOptions txn_opts;
Transaction* txn = txn_db->BeginTransaction(wopts, txn_opts, nullptr);
ASSERT_NE(txn, nullptr);
ASSERT_OK(txn->SetName("txn1"));
for (int i = 0; i < kNumKeysWritten; ++i) {
ASSERT_OK(txn->Put(Key(i), "val"));
}
// Prepare() writes to WAL, but not to memtable. (WriteCommitted)
ASSERT_OK(txn->Prepare());
EXPECT_NE(0, options.statistics->getTickerCount(WAL_FILE_BYTES));
// BYTES_WRITTEN would have been non-zero previously (issue #12061).
EXPECT_EQ(0, options.statistics->getTickerCount(BYTES_WRITTEN));
// Commit() writes to memtable and also a commit marker to WAL.
ASSERT_OK(txn->Commit());
delete txn;
// The WAL has an extra header of size `kHeader` written to it,
// as we are writing twice to it (first during Prepare, second during
// Commit).
EXPECT_EQ(options.statistics->getAndResetTickerCount(WAL_FILE_BYTES),
options.statistics->getAndResetTickerCount(BYTES_WRITTEN) +
WriteBatchInternal::kHeader);
// Cleanup
db_ = nullptr;
delete txn_db;
}
}
} // namespace ROCKSDB_NAMESPACE
int main(int argc, char** argv) {
ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
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