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[RocbsDB] Add an option to enable set based memtable for perf_context_test

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Summary:
as title.
Some result:

-- Sequential insertion of 1M key/value with stock skip list (all in on memtable)
time ./perf_context_test  --total_keys=1000000  --use_set_based_memetable=0
Inserting 1000000 key/value pairs
...
Put uesr key comparison:
Count: 1000000  Average: 8.0179  StdDev: 176.34
Min: 0.0000  Median: 2.5555  Max: 88933.0000
Percentiles: P50: 2.56 P75: 2.83 P99: 58.21 P99.9: 133.62 P99.99: 987.50
Get uesr key comparison:
Count: 1000000  Average: 43.4465  StdDev: 379.03
Min: 2.0000  Median: 36.0195  Max: 88939.0000
Percentiles: P50: 36.02 P75: 43.66 P99: 112.98 P99.9: 824.84 P99.99: 7615.38
real	0m21.345s
user	0m14.723s
sys	0m5.677s

-- Sequential insertion of 1M key/value with set based memtable (all in on memtable)
time ./perf_context_test  --total_keys=1000000  --use_set_based_memetable=1
Inserting 1000000 key/value pairs
...
Put uesr key comparison:
Count: 1000000  Average: 61.5022  StdDev: 6.49
Min: 0.0000  Median: 62.4295  Max: 71.0000
Percentiles: P50: 62.43 P75: 66.61 P99: 71.00 P99.9: 71.00 P99.99: 71.00
Get uesr key comparison:
Count: 1000000  Average: 29.3810  StdDev: 3.20
Min: 1.0000  Median: 29.1801  Max: 34.0000
Percentiles: P50: 29.18 P75: 32.06 P99: 34.00 P99.9: 34.00 P99.99: 34.00
real	0m28.875s
user	0m21.699s
sys	0m5.749s

Worst case comparison for a Put is 88933 (skiplist) vs 71 (set based memetable)

Of course, there's other in-efficiency in set based memtable implementation, which lead to the overall worst performance. However, P99 behavior advantage is very very obvious.

Test Plan: ./perf_context_test and viewstate shadow testing

Reviewers: dhruba

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13095
This commit is contained in:
Haobo Xu 2013-09-25 14:35:01 -07:00
parent f1a60e5c3e
commit e0aa19a94e
1 changed files with 42 additions and 19 deletions
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61
db/perf_context_test.cc
View File

@ -9,6 +9,7 @@
#include "util/testharness.h"
bool FLAGS_random_key = false;
bool FLAGS_use_set_based_memetable = false;
int FLAGS_total_keys = 100;
int FLAGS_write_buffer_size = 1000000000;
int FLAGS_max_write_buffer_number = 8;
@ -27,6 +28,13 @@ std::shared_ptr<DB> OpenDb() {
options.max_write_buffer_number = FLAGS_max_write_buffer_number;
options.min_write_buffer_number_to_merge =
FLAGS_min_write_buffer_number_to_merge;
if (FLAGS_use_set_based_memetable) {
auto prefix_extractor = leveldb::NewFixedPrefixTransform(0);
options.memtable_factory =
std::make_shared<leveldb::PrefixHashRepFactory>(prefix_extractor);
}
Status s = DB::Open(options, kDbName, &db);
ASSERT_OK(s);
return std::shared_ptr<DB>(db);
@ -80,36 +88,35 @@ void ProfileKeyComparison() {
WriteOptions write_options;
ReadOptions read_options;
uint64_t total_user_key_comparison_get = 0;
uint64_t total_user_key_comparison_put = 0;
uint64_t max_user_key_comparison_get = 0;
HistogramImpl hist_put;
HistogramImpl hist_get;
std::cout << "Inserting " << FLAGS_total_keys << " key/value pairs\n...\n";
std::vector<int> keys;
for (int i = 0; i < FLAGS_total_keys; ++i) {
keys.push_back(i);
}
if (FLAGS_random_key) {
std::random_shuffle(keys.begin(), keys.end());
}
for (const int i : keys) {
std::string key = "k" + std::to_string(i);
std::string value = "v" + std::to_string(i);
perf_context.Reset();
db->Put(write_options, key, value);
total_user_key_comparison_put += perf_context.user_key_comparison_count;
hist_put.Add(perf_context.user_key_comparison_count);
perf_context.Reset();
db->Get(read_options, key, &value);
total_user_key_comparison_get += perf_context.user_key_comparison_count;
max_user_key_comparison_get =
std::max(max_user_key_comparison_get,
perf_context.user_key_comparison_count);
hist_get.Add(perf_context.user_key_comparison_count);
}
std::cout << "total user key comparison get: "
<< total_user_key_comparison_get << "\n"
<< "total user key comparison put: "
<< total_user_key_comparison_put << "\n"
<< "max user key comparison get: "
<< max_user_key_comparison_get << "\n"
<< "avg user key comparison get:"
<< total_user_key_comparison_get/FLAGS_total_keys << "\n";
std::cout << "Put uesr key comparison: \n" << hist_put.ToString()
<< "Get uesr key comparison: \n" << hist_get.ToString();
}
@ -160,7 +167,9 @@ TEST(PerfContextTest, SeekKeyComparison) {
db->Put(write_options, key, value);
}
HistogramImpl histogram;
HistogramImpl hist_seek;
HistogramImpl hist_next;
for (int i = 0; i < FLAGS_total_keys; ++i) {
std::string key = "k" + std::to_string(i);
std::string value = "v" + std::to_string(i);
@ -170,9 +179,18 @@ TEST(PerfContextTest, SeekKeyComparison) {
iter->Seek(key);
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(iter->value().ToString(), value);
histogram.Add(perf_context.user_key_comparison_count);
hist_seek.Add(perf_context.user_key_comparison_count);
}
std::cout << histogram.ToString();
std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
for (iter->SeekToFirst(); iter->Valid();) {
perf_context.Reset();
iter->Next();
hist_next.Add(perf_context.user_key_comparison_count);
}
std::cout << "Seek:\n" << hist_seek.ToString()
<< "Next:\n" << hist_next.ToString();
}
}
@ -196,6 +214,11 @@ int main(int argc, char** argv) {
FLAGS_random_key = n;
}
if (sscanf(argv[i], "--use_set_based_memetable=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
FLAGS_use_set_based_memetable = n;
}
}
std::cout << kDbName << "\n";