rocksdb/table/table_reader_bench.cc
sdong 9d0b8f19d9 plain table reader: avoid re-read the same position for index and data in non-mmap mode
Summary: In non-mmap mode, plain table reader can issue two pread() for index checking and reading the actual data, although it's for the same location. By reusing the key decoder, we reuse the buffer used for the two to avoid it.

Test Plan: Run unit tests. Run table_reader_bench and see from strace the repeat read cases to disappear.

Reviewers: anthony, yhchiang, rven, kradhakrishnan, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D50949
2015-11-18 16:49:08 -08:00

336 lines
12 KiB
C++

// Copyright (c) 2013, 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 GFLAGS
#include <cstdio>
int main() {
fprintf(stderr, "Please install gflags to run rocksdb tools\n");
return 1;
}
#else
#include <gflags/gflags.h>
#include "rocksdb/db.h"
#include "rocksdb/slice_transform.h"
#include "rocksdb/table.h"
#include "db/db_impl.h"
#include "db/dbformat.h"
#include "table/block_based_table_factory.h"
#include "table/internal_iterator.h"
#include "table/plain_table_factory.h"
#include "table/table_builder.h"
#include "table/get_context.h"
#include "util/file_reader_writer.h"
#include "util/histogram.h"
#include "util/testharness.h"
#include "util/testutil.h"
using GFLAGS::ParseCommandLineFlags;
using GFLAGS::SetUsageMessage;
namespace rocksdb {
namespace {
// Make a key that i determines the first 4 characters and j determines the
// last 4 characters.
static std::string MakeKey(int i, int j, bool through_db) {
char buf[100];
snprintf(buf, sizeof(buf), "%04d__key___%04d", i, j);
if (through_db) {
return std::string(buf);
}
// If we directly query table, which operates on internal keys
// instead of user keys, we need to add 8 bytes of internal
// information (row type etc) to user key to make an internal
// key.
InternalKey key(std::string(buf), 0, ValueType::kTypeValue);
return key.Encode().ToString();
}
uint64_t Now(Env* env, bool measured_by_nanosecond) {
return measured_by_nanosecond ? env->NowNanos() : env->NowMicros();
}
} // namespace
// A very simple benchmark that.
// Create a table with roughly numKey1 * numKey2 keys,
// where there are numKey1 prefixes of the key, each has numKey2 number of
// distinguished key, differing in the suffix part.
// If if_query_empty_keys = false, query the existing keys numKey1 * numKey2
// times randomly.
// If if_query_empty_keys = true, query numKey1 * numKey2 random empty keys.
// Print out the total time.
// If through_db=true, a full DB will be created and queries will be against
// it. Otherwise, operations will be directly through table level.
//
// If for_terator=true, instead of just query one key each time, it queries
// a range sharing the same prefix.
namespace {
void TableReaderBenchmark(Options& opts, EnvOptions& env_options,
ReadOptions& read_options, int num_keys1,
int num_keys2, int num_iter, int prefix_len,
bool if_query_empty_keys, bool for_iterator,
bool through_db, bool measured_by_nanosecond) {
rocksdb::InternalKeyComparator ikc(opts.comparator);
std::string file_name = test::TmpDir()
+ "/rocksdb_table_reader_benchmark";
std::string dbname = test::TmpDir() + "/rocksdb_table_reader_bench_db";
WriteOptions wo;
Env* env = Env::Default();
TableBuilder* tb = nullptr;
DB* db = nullptr;
Status s;
const ImmutableCFOptions ioptions(opts);
unique_ptr<WritableFileWriter> file_writer;
if (!through_db) {
unique_ptr<WritableFile> file;
env->NewWritableFile(file_name, &file, env_options);
std::vector<std::unique_ptr<IntTblPropCollectorFactory> >
int_tbl_prop_collector_factories;
file_writer.reset(new WritableFileWriter(std::move(file), env_options));
tb = opts.table_factory->NewTableBuilder(
TableBuilderOptions(ioptions, ikc, &int_tbl_prop_collector_factories,
CompressionType::kNoCompression,
CompressionOptions(), false),
0, file_writer.get());
} else {
s = DB::Open(opts, dbname, &db);
ASSERT_OK(s);
ASSERT_TRUE(db != nullptr);
}
// Populate slightly more than 1M keys
for (int i = 0; i < num_keys1; i++) {
for (int j = 0; j < num_keys2; j++) {
std::string key = MakeKey(i * 2, j, through_db);
if (!through_db) {
tb->Add(key, key);
} else {
db->Put(wo, key, key);
}
}
}
if (!through_db) {
tb->Finish();
file_writer->Close();
} else {
db->Flush(FlushOptions());
}
unique_ptr<TableReader> table_reader;
if (!through_db) {
unique_ptr<RandomAccessFile> raf;
s = env->NewRandomAccessFile(file_name, &raf, env_options);
if (!s.ok()) {
fprintf(stderr, "Create File Error: %s\n", s.ToString().c_str());
exit(1);
}
uint64_t file_size;
env->GetFileSize(file_name, &file_size);
unique_ptr<RandomAccessFileReader> file_reader(
new RandomAccessFileReader(std::move(raf)));
s = opts.table_factory->NewTableReader(
TableReaderOptions(ioptions, env_options, ikc), std::move(file_reader),
file_size, &table_reader);
if (!s.ok()) {
fprintf(stderr, "Open Table Error: %s\n", s.ToString().c_str());
exit(1);
}
}
Random rnd(301);
std::string result;
HistogramImpl hist;
for (int it = 0; it < num_iter; it++) {
for (int i = 0; i < num_keys1; i++) {
for (int j = 0; j < num_keys2; j++) {
int r1 = rnd.Uniform(num_keys1) * 2;
int r2 = rnd.Uniform(num_keys2);
if (if_query_empty_keys) {
r1++;
r2 = num_keys2 * 2 - r2;
}
if (!for_iterator) {
// Query one existing key;
std::string key = MakeKey(r1, r2, through_db);
uint64_t start_time = Now(env, measured_by_nanosecond);
if (!through_db) {
std::string value;
MergeContext merge_context;
GetContext get_context(ioptions.comparator, ioptions.merge_operator,
ioptions.info_log, ioptions.statistics,
GetContext::kNotFound, Slice(key), &value,
nullptr, &merge_context, env);
s = table_reader->Get(read_options, key, &get_context);
} else {
s = db->Get(read_options, key, &result);
}
hist.Add(Now(env, measured_by_nanosecond) - start_time);
} else {
int r2_len;
if (if_query_empty_keys) {
r2_len = 0;
} else {
r2_len = rnd.Uniform(num_keys2) + 1;
if (r2_len + r2 > num_keys2) {
r2_len = num_keys2 - r2;
}
}
std::string start_key = MakeKey(r1, r2, through_db);
std::string end_key = MakeKey(r1, r2 + r2_len, through_db);
uint64_t total_time = 0;
uint64_t start_time = Now(env, measured_by_nanosecond);
Iterator* iter = nullptr;
InternalIterator* iiter = nullptr;
if (!through_db) {
iiter = table_reader->NewIterator(read_options);
} else {
iter = db->NewIterator(read_options);
}
int count = 0;
for (through_db ? iter->Seek(start_key) : iiter->Seek(start_key);
through_db ? iter->Valid() : iiter->Valid();
through_db ? iter->Next() : iiter->Next()) {
if (if_query_empty_keys) {
break;
}
// verify key;
total_time += Now(env, measured_by_nanosecond) - start_time;
assert(Slice(MakeKey(r1, r2 + count, through_db)) == iter->key());
start_time = Now(env, measured_by_nanosecond);
if (++count >= r2_len) {
break;
}
}
if (count != r2_len) {
fprintf(
stderr, "Iterator cannot iterate expected number of entries. "
"Expected %d but got %d\n", r2_len, count);
assert(false);
}
delete iter;
total_time += Now(env, measured_by_nanosecond) - start_time;
hist.Add(total_time);
}
}
}
}
fprintf(
stderr,
"==================================================="
"====================================================\n"
"InMemoryTableSimpleBenchmark: %20s num_key1: %5d "
"num_key2: %5d %10s\n"
"==================================================="
"===================================================="
"\nHistogram (unit: %s): \n%s",
opts.table_factory->Name(), num_keys1, num_keys2,
for_iterator ? "iterator" : (if_query_empty_keys ? "empty" : "non_empty"),
measured_by_nanosecond ? "nanosecond" : "microsecond",
hist.ToString().c_str());
if (!through_db) {
env->DeleteFile(file_name);
} else {
delete db;
db = nullptr;
DestroyDB(dbname, opts);
}
}
} // namespace
} // namespace rocksdb
DEFINE_bool(query_empty, false, "query non-existing keys instead of existing "
"ones.");
DEFINE_int32(num_keys1, 4096, "number of distinguish prefix of keys");
DEFINE_int32(num_keys2, 512, "number of distinguish keys for each prefix");
DEFINE_int32(iter, 3, "query non-existing keys instead of existing ones");
DEFINE_int32(prefix_len, 16, "Prefix length used for iterators and indexes");
DEFINE_bool(iterator, false, "For test iterator");
DEFINE_bool(through_db, false, "If enable, a DB instance will be created and "
"the query will be against DB. Otherwise, will be directly against "
"a table reader.");
DEFINE_bool(mmap_read, true, "Whether use mmap read");
DEFINE_string(table_factory, "block_based",
"Table factory to use: `block_based` (default), `plain_table` or "
"`cuckoo_hash`.");
DEFINE_string(time_unit, "microsecond",
"The time unit used for measuring performance. User can specify "
"`microsecond` (default) or `nanosecond`");
int main(int argc, char** argv) {
SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) +
" [OPTIONS]...");
ParseCommandLineFlags(&argc, &argv, true);
std::shared_ptr<rocksdb::TableFactory> tf;
rocksdb::Options options;
if (FLAGS_prefix_len < 16) {
options.prefix_extractor.reset(rocksdb::NewFixedPrefixTransform(
FLAGS_prefix_len));
}
rocksdb::ReadOptions ro;
rocksdb::EnvOptions env_options;
options.create_if_missing = true;
options.compression = rocksdb::CompressionType::kNoCompression;
if (FLAGS_table_factory == "cuckoo_hash") {
#ifndef ROCKSDB_LITE
options.allow_mmap_reads = FLAGS_mmap_read;
env_options.use_mmap_reads = FLAGS_mmap_read;
rocksdb::CuckooTableOptions table_options;
table_options.hash_table_ratio = 0.75;
tf.reset(rocksdb::NewCuckooTableFactory(table_options));
#else
fprintf(stderr, "Plain table is not supported in lite mode\n");
exit(1);
#endif // ROCKSDB_LITE
} else if (FLAGS_table_factory == "plain_table") {
#ifndef ROCKSDB_LITE
options.allow_mmap_reads = FLAGS_mmap_read;
env_options.use_mmap_reads = FLAGS_mmap_read;
rocksdb::PlainTableOptions plain_table_options;
plain_table_options.user_key_len = 16;
plain_table_options.bloom_bits_per_key = (FLAGS_prefix_len == 16) ? 0 : 8;
plain_table_options.hash_table_ratio = 0.75;
tf.reset(new rocksdb::PlainTableFactory(plain_table_options));
options.prefix_extractor.reset(rocksdb::NewFixedPrefixTransform(
FLAGS_prefix_len));
#else
fprintf(stderr, "Cuckoo table is not supported in lite mode\n");
exit(1);
#endif // ROCKSDB_LITE
} else if (FLAGS_table_factory == "block_based") {
tf.reset(new rocksdb::BlockBasedTableFactory());
} else {
fprintf(stderr, "Invalid table type %s\n", FLAGS_table_factory.c_str());
}
if (tf) {
// if user provides invalid options, just fall back to microsecond.
bool measured_by_nanosecond = FLAGS_time_unit == "nanosecond";
options.table_factory = tf;
rocksdb::TableReaderBenchmark(options, env_options, ro, FLAGS_num_keys1,
FLAGS_num_keys2, FLAGS_iter, FLAGS_prefix_len,
FLAGS_query_empty, FLAGS_iterator,
FLAGS_through_db, measured_by_nanosecond);
} else {
return 1;
}
return 0;
}
#endif // GFLAGS