rocksdb/db/prefix_test.cc

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#include <algorithm>
#include <iostream>
#include <vector>
#include <gflags/gflags.h>
#include "rocksdb/comparator.h"
#include "rocksdb/db.h"
#include "rocksdb/perf_context.h"
#include "util/histogram.h"
#include "util/stop_watch.h"
#include "util/testharness.h"
DEFINE_bool(use_prefix_hash_memtable, true, "");
DEFINE_bool(trigger_deadlock, false,
"issue delete in range scan to trigger PrefixHashMap deadlock");
DEFINE_uint64(bucket_count, 100000, "number of buckets");
DEFINE_uint64(num_locks, 10001, "number of locks");
DEFINE_bool(random_prefix, false, "randomize prefix");
DEFINE_uint64(total_prefixes, 1000, "total number of prefixes");
DEFINE_uint64(items_per_prefix, 10, "total number of values per prefix");
DEFINE_int64(write_buffer_size, 1000000000, "");
DEFINE_int64(max_write_buffer_number, 8, "");
DEFINE_int64(min_write_buffer_number_to_merge, 7, "");
// Path to the database on file system
const std::string kDbName = rocksdb::test::TmpDir() + "/prefix_test";
namespace rocksdb {
struct TestKey {
uint64_t prefix;
uint64_t sorted;
TestKey(uint64_t prefix, uint64_t sorted) : prefix(prefix), sorted(sorted) {}
};
// return a slice backed by test_key
inline Slice TestKeyToSlice(const TestKey& test_key) {
return Slice((const char*)&test_key, sizeof(test_key));
}
inline const TestKey* SliceToTestKey(const Slice& slice) {
return (const TestKey*)slice.data();
}
class TestKeyComparator : public Comparator {
public:
// Compare needs to be aware of the possibility of a and/or b is
// prefix only
virtual int Compare(const Slice& a, const Slice& b) const {
const TestKey* key_a = SliceToTestKey(a);
const TestKey* key_b = SliceToTestKey(b);
if (key_a->prefix != key_b->prefix) {
if (key_a->prefix < key_b->prefix) return -1;
if (key_a->prefix > key_b->prefix) return 1;
} else {
ASSERT_TRUE(key_a->prefix == key_b->prefix);
// note, both a and b could be prefix only
if (a.size() != b.size()) {
// one of them is prefix
ASSERT_TRUE(
(a.size() == sizeof(uint64_t) && b.size() == sizeof(TestKey)) ||
(b.size() == sizeof(uint64_t) && a.size() == sizeof(TestKey)));
if (a.size() < b.size()) return -1;
if (a.size() > b.size()) return 1;
} else {
// both a and b are prefix
if (a.size() == sizeof(uint64_t)) {
return 0;
}
// both a and b are whole key
ASSERT_TRUE(a.size() == sizeof(TestKey) && b.size() == sizeof(TestKey));
if (key_a->sorted < key_b->sorted) return -1;
if (key_a->sorted > key_b->sorted) return 1;
if (key_a->sorted == key_b->sorted) return 0;
}
}
return 0;
}
virtual const char* Name() const override {
return "TestKeyComparator";
}
virtual void FindShortestSeparator(
std::string* start,
const Slice& limit) const {
}
virtual void FindShortSuccessor(std::string* key) const {}
};
class PrefixTest {
public:
std::shared_ptr<DB> OpenDb() {
DB* db;
options.create_if_missing = true;
options.write_buffer_size = FLAGS_write_buffer_size;
options.max_write_buffer_number = FLAGS_max_write_buffer_number;
options.min_write_buffer_number_to_merge =
FLAGS_min_write_buffer_number_to_merge;
options.comparator = new TestKeyComparator();
if (FLAGS_use_prefix_hash_memtable) {
auto prefix_extractor = NewFixedPrefixTransform(8);
options.prefix_extractor = prefix_extractor;
options.memtable_factory.reset(NewHashSkipListRepFactory(
prefix_extractor, FLAGS_bucket_count));
}
Status s = DB::Open(options, kDbName, &db);
ASSERT_OK(s);
return std::shared_ptr<DB>(db);
}
~PrefixTest() {
delete options.comparator;
}
protected:
Options options;
};
TEST(PrefixTest, DynamicPrefixIterator) {
DestroyDB(kDbName, Options());
auto db = OpenDb();
WriteOptions write_options;
ReadOptions read_options;
std::vector<uint64_t> prefixes;
for (uint64_t i = 0; i < FLAGS_total_prefixes; ++i) {
prefixes.push_back(i);
}
if (FLAGS_random_prefix) {
std::random_shuffle(prefixes.begin(), prefixes.end());
}
// insert x random prefix, each with y continuous element.
for (auto prefix : prefixes) {
for (uint64_t sorted = 0; sorted < FLAGS_items_per_prefix; sorted++) {
TestKey test_key(prefix, sorted);
Slice key = TestKeyToSlice(test_key);
std::string value = "v" + std::to_string(sorted);
ASSERT_OK(db->Put(write_options, key, value));
}
}
// test seek existing keys
HistogramImpl hist_seek_time;
HistogramImpl hist_seek_comparison;
if (FLAGS_use_prefix_hash_memtable) {
read_options.prefix_seek = true;
}
std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
for (auto prefix : prefixes) {
TestKey test_key(prefix, FLAGS_items_per_prefix / 2);
Slice key = TestKeyToSlice(test_key);
std::string value = "v" + std::to_string(0);
perf_context.Reset();
StopWatchNano timer(Env::Default(), true);
uint64_t total_keys = 0;
for (iter->Seek(key); iter->Valid(); iter->Next()) {
if (FLAGS_trigger_deadlock) {
std::cout << "Behold the deadlock!\n";
db->Delete(write_options, iter->key());
}
auto test_key = SliceToTestKey(iter->key());
if (test_key->prefix != prefix) break;
total_keys++;
}
hist_seek_time.Add(timer.ElapsedNanos());
hist_seek_comparison.Add(perf_context.user_key_comparison_count);
ASSERT_EQ(total_keys, FLAGS_items_per_prefix - FLAGS_items_per_prefix/2);
}
std::cout << "Seek key comparison: \n"
<< hist_seek_comparison.ToString()
<< "Seek time: \n"
<< hist_seek_time.ToString();
// test non-existing keys
HistogramImpl hist_no_seek_time;
HistogramImpl hist_no_seek_comparison;
for (auto prefix = FLAGS_total_prefixes;
prefix < FLAGS_total_prefixes + 100;
prefix++) {
TestKey test_key(prefix, 0);
Slice key = TestKeyToSlice(test_key);
perf_context.Reset();
StopWatchNano timer(Env::Default(), true);
iter->Seek(key);
hist_no_seek_time.Add(timer.ElapsedNanos());
hist_no_seek_comparison.Add(perf_context.user_key_comparison_count);
ASSERT_TRUE(!iter->Valid());
}
std::cout << "non-existing Seek key comparison: \n"
<< hist_no_seek_comparison.ToString()
<< "non-existing Seek time: \n"
<< hist_no_seek_time.ToString();
}
TEST(PrefixTest, PrefixHash) {
DestroyDB(kDbName, Options());
auto db = OpenDb();
WriteOptions write_options;
ReadOptions read_options;
std::vector<uint64_t> prefixes;
for (uint64_t i = 0; i < FLAGS_total_prefixes; ++i) {
prefixes.push_back(i);
}
if (FLAGS_random_prefix) {
std::random_shuffle(prefixes.begin(), prefixes.end());
}
// insert x random prefix, each with y continuous element.
HistogramImpl hist_put_time;
HistogramImpl hist_put_comparison;
for (auto prefix : prefixes) {
for (uint64_t sorted = 0; sorted < FLAGS_items_per_prefix; sorted++) {
TestKey test_key(prefix, sorted);
Slice key = TestKeyToSlice(test_key);
std::string value = "v" + std::to_string(sorted);
perf_context.Reset();
StopWatchNano timer(Env::Default(), true);
ASSERT_OK(db->Put(write_options, key, value));
hist_put_time.Add(timer.ElapsedNanos());
hist_put_comparison.Add(perf_context.user_key_comparison_count);
}
}
std::cout << "Put key comparison: \n" << hist_put_comparison.ToString()
<< "Put time: \n" << hist_put_time.ToString();
// test seek existing keys
HistogramImpl hist_seek_time;
HistogramImpl hist_seek_comparison;
for (auto prefix : prefixes) {
TestKey test_key(prefix, 0);
Slice key = TestKeyToSlice(test_key);
std::string value = "v" + std::to_string(0);
Slice key_prefix;
if (FLAGS_use_prefix_hash_memtable) {
key_prefix = options.prefix_extractor->Transform(key);
read_options.prefix = &key_prefix;
}
std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
perf_context.Reset();
StopWatchNano timer(Env::Default(), true);
uint64_t total_keys = 0;
for (iter->Seek(key); iter->Valid(); iter->Next()) {
if (FLAGS_trigger_deadlock) {
std::cout << "Behold the deadlock!\n";
db->Delete(write_options, iter->key());
}
auto test_key = SliceToTestKey(iter->key());
if (test_key->prefix != prefix) break;
total_keys++;
}
hist_seek_time.Add(timer.ElapsedNanos());
hist_seek_comparison.Add(perf_context.user_key_comparison_count);
ASSERT_EQ(total_keys, FLAGS_items_per_prefix);
}
std::cout << "Seek key comparison: \n"
<< hist_seek_comparison.ToString()
<< "Seek time: \n"
<< hist_seek_time.ToString();
// test non-existing keys
HistogramImpl hist_no_seek_time;
HistogramImpl hist_no_seek_comparison;
for (auto prefix = FLAGS_total_prefixes;
prefix < FLAGS_total_prefixes + 100;
prefix++) {
TestKey test_key(prefix, 0);
Slice key = TestKeyToSlice(test_key);
if (FLAGS_use_prefix_hash_memtable) {
Slice key_prefix = options.prefix_extractor->Transform(key);
read_options.prefix = &key_prefix;
}
std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
perf_context.Reset();
StopWatchNano timer(Env::Default(), true);
iter->Seek(key);
hist_no_seek_time.Add(timer.ElapsedNanos());
hist_no_seek_comparison.Add(perf_context.user_key_comparison_count);
ASSERT_TRUE(!iter->Valid());
}
std::cout << "non-existing Seek key comparison: \n"
<< hist_no_seek_comparison.ToString()
<< "non-existing Seek time: \n"
<< hist_no_seek_time.ToString();
}
}
int main(int argc, char** argv) {
google::ParseCommandLineFlags(&argc, &argv, true);
std::cout << kDbName << "\n";
rocksdb::test::RunAllTests();
return 0;
}