rocksdb/db/db_block_cache_test.cc

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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).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include <cstdlib>
#include "cache/lru_cache.h"
#include "db/db_test_util.h"
#include "port/stack_trace.h"
#include "util/compression.h"
namespace ROCKSDB_NAMESPACE {
class DBBlockCacheTest : public DBTestBase {
private:
size_t miss_count_ = 0;
size_t hit_count_ = 0;
size_t insert_count_ = 0;
size_t failure_count_ = 0;
size_t compression_dict_miss_count_ = 0;
size_t compression_dict_hit_count_ = 0;
size_t compression_dict_insert_count_ = 0;
size_t compressed_miss_count_ = 0;
size_t compressed_hit_count_ = 0;
size_t compressed_insert_count_ = 0;
size_t compressed_failure_count_ = 0;
public:
const size_t kNumBlocks = 10;
const size_t kValueSize = 100;
DBBlockCacheTest() : DBTestBase("/db_block_cache_test") {}
BlockBasedTableOptions GetTableOptions() {
BlockBasedTableOptions table_options;
// Set a small enough block size so that each key-value get its own block.
table_options.block_size = 1;
return table_options;
}
Options GetOptions(const BlockBasedTableOptions& table_options) {
Options options = CurrentOptions();
options.create_if_missing = true;
options.avoid_flush_during_recovery = false;
// options.compression = kNoCompression;
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
options.table_factory.reset(new BlockBasedTableFactory(table_options));
return options;
}
void InitTable(const Options& /*options*/) {
std::string value(kValueSize, 'a');
for (size_t i = 0; i < kNumBlocks; i++) {
ASSERT_OK(Put(ToString(i), value.c_str()));
}
}
void RecordCacheCounters(const Options& options) {
miss_count_ = TestGetTickerCount(options, BLOCK_CACHE_MISS);
hit_count_ = TestGetTickerCount(options, BLOCK_CACHE_HIT);
insert_count_ = TestGetTickerCount(options, BLOCK_CACHE_ADD);
failure_count_ = TestGetTickerCount(options, BLOCK_CACHE_ADD_FAILURES);
compressed_miss_count_ =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_MISS);
compressed_hit_count_ =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_HIT);
compressed_insert_count_ =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_ADD);
compressed_failure_count_ =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_ADD_FAILURES);
}
void RecordCacheCountersForCompressionDict(const Options& options) {
compression_dict_miss_count_ =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSION_DICT_MISS);
compression_dict_hit_count_ =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSION_DICT_HIT);
compression_dict_insert_count_ =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSION_DICT_ADD);
}
void CheckCacheCounters(const Options& options, size_t expected_misses,
size_t expected_hits, size_t expected_inserts,
size_t expected_failures) {
size_t new_miss_count = TestGetTickerCount(options, BLOCK_CACHE_MISS);
size_t new_hit_count = TestGetTickerCount(options, BLOCK_CACHE_HIT);
size_t new_insert_count = TestGetTickerCount(options, BLOCK_CACHE_ADD);
size_t new_failure_count =
TestGetTickerCount(options, BLOCK_CACHE_ADD_FAILURES);
ASSERT_EQ(miss_count_ + expected_misses, new_miss_count);
ASSERT_EQ(hit_count_ + expected_hits, new_hit_count);
ASSERT_EQ(insert_count_ + expected_inserts, new_insert_count);
ASSERT_EQ(failure_count_ + expected_failures, new_failure_count);
miss_count_ = new_miss_count;
hit_count_ = new_hit_count;
insert_count_ = new_insert_count;
failure_count_ = new_failure_count;
}
void CheckCacheCountersForCompressionDict(
const Options& options, size_t expected_compression_dict_misses,
size_t expected_compression_dict_hits,
size_t expected_compression_dict_inserts) {
size_t new_compression_dict_miss_count =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSION_DICT_MISS);
size_t new_compression_dict_hit_count =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSION_DICT_HIT);
size_t new_compression_dict_insert_count =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSION_DICT_ADD);
ASSERT_EQ(compression_dict_miss_count_ + expected_compression_dict_misses,
new_compression_dict_miss_count);
ASSERT_EQ(compression_dict_hit_count_ + expected_compression_dict_hits,
new_compression_dict_hit_count);
ASSERT_EQ(
compression_dict_insert_count_ + expected_compression_dict_inserts,
new_compression_dict_insert_count);
compression_dict_miss_count_ = new_compression_dict_miss_count;
compression_dict_hit_count_ = new_compression_dict_hit_count;
compression_dict_insert_count_ = new_compression_dict_insert_count;
}
void CheckCompressedCacheCounters(const Options& options,
size_t expected_misses,
size_t expected_hits,
size_t expected_inserts,
size_t expected_failures) {
size_t new_miss_count =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_MISS);
size_t new_hit_count =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_HIT);
size_t new_insert_count =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_ADD);
size_t new_failure_count =
TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_ADD_FAILURES);
ASSERT_EQ(compressed_miss_count_ + expected_misses, new_miss_count);
ASSERT_EQ(compressed_hit_count_ + expected_hits, new_hit_count);
ASSERT_EQ(compressed_insert_count_ + expected_inserts, new_insert_count);
ASSERT_EQ(compressed_failure_count_ + expected_failures, new_failure_count);
compressed_miss_count_ = new_miss_count;
compressed_hit_count_ = new_hit_count;
compressed_insert_count_ = new_insert_count;
compressed_failure_count_ = new_failure_count;
}
};
TEST_F(DBBlockCacheTest, IteratorBlockCacheUsage) {
ReadOptions read_options;
read_options.fill_cache = false;
auto table_options = GetTableOptions();
auto options = GetOptions(table_options);
InitTable(options);
std::shared_ptr<Cache> cache = NewLRUCache(0, 0, false);
table_options.block_cache = cache;
options.table_factory.reset(new BlockBasedTableFactory(table_options));
Reopen(options);
RecordCacheCounters(options);
std::vector<std::unique_ptr<Iterator>> iterators(kNumBlocks - 1);
Iterator* iter = nullptr;
ASSERT_EQ(0, cache->GetUsage());
iter = db_->NewIterator(read_options);
iter->Seek(ToString(0));
ASSERT_LT(0, cache->GetUsage());
delete iter;
iter = nullptr;
ASSERT_EQ(0, cache->GetUsage());
}
TEST_F(DBBlockCacheTest, TestWithoutCompressedBlockCache) {
ReadOptions read_options;
auto table_options = GetTableOptions();
auto options = GetOptions(table_options);
InitTable(options);
std::shared_ptr<Cache> cache = NewLRUCache(0, 0, false);
table_options.block_cache = cache;
options.table_factory.reset(new BlockBasedTableFactory(table_options));
Reopen(options);
RecordCacheCounters(options);
std::vector<std::unique_ptr<Iterator>> iterators(kNumBlocks - 1);
Iterator* iter = nullptr;
// Load blocks into cache.
for (size_t i = 0; i < kNumBlocks - 1; i++) {
iter = db_->NewIterator(read_options);
iter->Seek(ToString(i));
ASSERT_OK(iter->status());
CheckCacheCounters(options, 1, 0, 1, 0);
iterators[i].reset(iter);
}
size_t usage = cache->GetUsage();
ASSERT_LT(0, usage);
cache->SetCapacity(usage);
ASSERT_EQ(usage, cache->GetPinnedUsage());
// Test with strict capacity limit.
cache->SetStrictCapacityLimit(true);
iter = db_->NewIterator(read_options);
iter->Seek(ToString(kNumBlocks - 1));
ASSERT_TRUE(iter->status().IsIncomplete());
CheckCacheCounters(options, 1, 0, 0, 1);
delete iter;
iter = nullptr;
// Release iterators and access cache again.
for (size_t i = 0; i < kNumBlocks - 1; i++) {
iterators[i].reset();
CheckCacheCounters(options, 0, 0, 0, 0);
}
ASSERT_EQ(0, cache->GetPinnedUsage());
for (size_t i = 0; i < kNumBlocks - 1; i++) {
iter = db_->NewIterator(read_options);
iter->Seek(ToString(i));
ASSERT_OK(iter->status());
CheckCacheCounters(options, 0, 1, 0, 0);
iterators[i].reset(iter);
}
}
#ifdef SNAPPY
TEST_F(DBBlockCacheTest, TestWithCompressedBlockCache) {
ReadOptions read_options;
auto table_options = GetTableOptions();
auto options = GetOptions(table_options);
options.compression = CompressionType::kSnappyCompression;
InitTable(options);
std::shared_ptr<Cache> cache = NewLRUCache(0, 0, false);
std::shared_ptr<Cache> compressed_cache = NewLRUCache(1 << 25, 0, false);
table_options.block_cache = cache;
table_options.block_cache_compressed = compressed_cache;
options.table_factory.reset(new BlockBasedTableFactory(table_options));
Reopen(options);
RecordCacheCounters(options);
std::vector<std::unique_ptr<Iterator>> iterators(kNumBlocks - 1);
Iterator* iter = nullptr;
// Load blocks into cache.
for (size_t i = 0; i < kNumBlocks - 1; i++) {
iter = db_->NewIterator(read_options);
iter->Seek(ToString(i));
ASSERT_OK(iter->status());
CheckCacheCounters(options, 1, 0, 1, 0);
CheckCompressedCacheCounters(options, 1, 0, 1, 0);
iterators[i].reset(iter);
}
size_t usage = cache->GetUsage();
ASSERT_LT(0, usage);
ASSERT_EQ(usage, cache->GetPinnedUsage());
size_t compressed_usage = compressed_cache->GetUsage();
ASSERT_LT(0, compressed_usage);
// Compressed block cache cannot be pinned.
ASSERT_EQ(0, compressed_cache->GetPinnedUsage());
// Set strict capacity limit flag. Now block will only load into compressed
// block cache.
cache->SetCapacity(usage);
cache->SetStrictCapacityLimit(true);
ASSERT_EQ(usage, cache->GetPinnedUsage());
iter = db_->NewIterator(read_options);
iter->Seek(ToString(kNumBlocks - 1));
ASSERT_TRUE(iter->status().IsIncomplete());
CheckCacheCounters(options, 1, 0, 0, 1);
CheckCompressedCacheCounters(options, 1, 0, 1, 0);
delete iter;
iter = nullptr;
// Clear strict capacity limit flag. This time we shall hit compressed block
// cache.
cache->SetStrictCapacityLimit(false);
iter = db_->NewIterator(read_options);
iter->Seek(ToString(kNumBlocks - 1));
ASSERT_OK(iter->status());
CheckCacheCounters(options, 1, 0, 1, 0);
CheckCompressedCacheCounters(options, 0, 1, 0, 0);
delete iter;
iter = nullptr;
}
#endif // SNAPPY
#ifndef ROCKSDB_LITE
// Make sure that when options.block_cache is set, after a new table is
// created its index/filter blocks are added to block cache.
TEST_F(DBBlockCacheTest, IndexAndFilterBlocksOfNewTableAddedToCache) {
Options options = CurrentOptions();
options.create_if_missing = true;
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
BlockBasedTableOptions table_options;
table_options.cache_index_and_filter_blocks = true;
table_options.filter_policy.reset(NewBloomFilterPolicy(20));
options.table_factory.reset(new BlockBasedTableFactory(table_options));
CreateAndReopenWithCF({"pikachu"}, options);
ASSERT_OK(Put(1, "key", "val"));
// Create a new table.
ASSERT_OK(Flush(1));
// index/filter blocks added to block cache right after table creation.
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_MISS));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_MISS));
ASSERT_EQ(2, /* only index/filter were added */
TestGetTickerCount(options, BLOCK_CACHE_ADD));
ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_DATA_MISS));
uint64_t int_num;
ASSERT_TRUE(
dbfull()->GetIntProperty("rocksdb.estimate-table-readers-mem", &int_num));
ASSERT_EQ(int_num, 0U);
// Make sure filter block is in cache.
std::string value;
ReadOptions ropt;
db_->KeyMayExist(ReadOptions(), handles_[1], "key", &value);
// Miss count should remain the same.
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_MISS));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_HIT));
db_->KeyMayExist(ReadOptions(), handles_[1], "key", &value);
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_MISS));
ASSERT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_FILTER_HIT));
// Make sure index block is in cache.
auto index_block_hit = TestGetTickerCount(options, BLOCK_CACHE_INDEX_HIT);
value = Get(1, "key");
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_MISS));
ASSERT_EQ(index_block_hit + 1,
TestGetTickerCount(options, BLOCK_CACHE_INDEX_HIT));
value = Get(1, "key");
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_MISS));
ASSERT_EQ(index_block_hit + 2,
TestGetTickerCount(options, BLOCK_CACHE_INDEX_HIT));
}
// With fill_cache = false, fills up the cache, then iterates over the entire
// db, verify dummy entries inserted in `BlockBasedTable::NewDataBlockIterator`
// does not cause heap-use-after-free errors in COMPILE_WITH_ASAN=1 runs
TEST_F(DBBlockCacheTest, FillCacheAndIterateDB) {
ReadOptions read_options;
read_options.fill_cache = false;
auto table_options = GetTableOptions();
auto options = GetOptions(table_options);
InitTable(options);
std::shared_ptr<Cache> cache = NewLRUCache(10, 0, true);
table_options.block_cache = cache;
options.table_factory.reset(new BlockBasedTableFactory(table_options));
Reopen(options);
ASSERT_OK(Put("key1", "val1"));
ASSERT_OK(Put("key2", "val2"));
ASSERT_OK(Flush());
ASSERT_OK(Put("key3", "val3"));
ASSERT_OK(Put("key4", "val4"));
ASSERT_OK(Flush());
ASSERT_OK(Put("key5", "val5"));
ASSERT_OK(Put("key6", "val6"));
ASSERT_OK(Flush());
Iterator* iter = nullptr;
iter = db_->NewIterator(read_options);
iter->Seek(ToString(0));
while (iter->Valid()) {
iter->Next();
}
delete iter;
iter = nullptr;
}
Add statistics field to show total size of index and filter blocks in block cache Summary: With `table_options.cache_index_and_filter_blocks = true`, index and filter blocks are stored in block cache. Then people are curious how much of the block cache total size is used by indexes and bloom filters. It will be nice we have a way to report that. It can help people tune performance and plan for optimized hardware setting. We add several enum values for db Statistics. BLOCK_CACHE_INDEX/FILTER_BYTES_INSERT - BLOCK_CACHE_INDEX/FILTER_BYTES_ERASE = current INDEX/FILTER total block size in bytes. Test Plan: write a test case called `DBBlockCacheTest.IndexAndFilterBlocksStats`. The result is: ``` [gzh@dev9927.prn1 ~/local/rocksdb] make db_block_cache_test -j64 && ./db_block_cache_test --gtest_filter=DBBlockCacheTest.IndexAndFilterBlocksStats Makefile:101: Warning: Compiling in debug mode. Don't use the resulting binary in production GEN util/build_version.cc make: `db_block_cache_test' is up to date. Note: Google Test filter = DBBlockCacheTest.IndexAndFilterBlocksStats [==========] Running 1 test from 1 test case. [----------] Global test environment set-up. [----------] 1 test from DBBlockCacheTest [ RUN ] DBBlockCacheTest.IndexAndFilterBlocksStats [ OK ] DBBlockCacheTest.IndexAndFilterBlocksStats (689 ms) [----------] 1 test from DBBlockCacheTest (689 ms total) [----------] Global test environment tear-down [==========] 1 test from 1 test case ran. (689 ms total) [ PASSED ] 1 test. ``` Reviewers: IslamAbdelRahman, andrewkr, sdong Reviewed By: sdong Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D58677
2016-06-03 19:47:47 +02:00
TEST_F(DBBlockCacheTest, IndexAndFilterBlocksStats) {
Options options = CurrentOptions();
options.create_if_missing = true;
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
Add statistics field to show total size of index and filter blocks in block cache Summary: With `table_options.cache_index_and_filter_blocks = true`, index and filter blocks are stored in block cache. Then people are curious how much of the block cache total size is used by indexes and bloom filters. It will be nice we have a way to report that. It can help people tune performance and plan for optimized hardware setting. We add several enum values for db Statistics. BLOCK_CACHE_INDEX/FILTER_BYTES_INSERT - BLOCK_CACHE_INDEX/FILTER_BYTES_ERASE = current INDEX/FILTER total block size in bytes. Test Plan: write a test case called `DBBlockCacheTest.IndexAndFilterBlocksStats`. The result is: ``` [gzh@dev9927.prn1 ~/local/rocksdb] make db_block_cache_test -j64 && ./db_block_cache_test --gtest_filter=DBBlockCacheTest.IndexAndFilterBlocksStats Makefile:101: Warning: Compiling in debug mode. Don't use the resulting binary in production GEN util/build_version.cc make: `db_block_cache_test' is up to date. Note: Google Test filter = DBBlockCacheTest.IndexAndFilterBlocksStats [==========] Running 1 test from 1 test case. [----------] Global test environment set-up. [----------] 1 test from DBBlockCacheTest [ RUN ] DBBlockCacheTest.IndexAndFilterBlocksStats [ OK ] DBBlockCacheTest.IndexAndFilterBlocksStats (689 ms) [----------] 1 test from DBBlockCacheTest (689 ms total) [----------] Global test environment tear-down [==========] 1 test from 1 test case ran. (689 ms total) [ PASSED ] 1 test. ``` Reviewers: IslamAbdelRahman, andrewkr, sdong Reviewed By: sdong Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D58677
2016-06-03 19:47:47 +02:00
BlockBasedTableOptions table_options;
table_options.cache_index_and_filter_blocks = true;
LRUCacheOptions co;
// 500 bytes are enough to hold the first two blocks
co.capacity = 500;
co.num_shard_bits = 0;
co.strict_capacity_limit = false;
co.metadata_charge_policy = kDontChargeCacheMetadata;
std::shared_ptr<Cache> cache = NewLRUCache(co);
Add statistics field to show total size of index and filter blocks in block cache Summary: With `table_options.cache_index_and_filter_blocks = true`, index and filter blocks are stored in block cache. Then people are curious how much of the block cache total size is used by indexes and bloom filters. It will be nice we have a way to report that. It can help people tune performance and plan for optimized hardware setting. We add several enum values for db Statistics. BLOCK_CACHE_INDEX/FILTER_BYTES_INSERT - BLOCK_CACHE_INDEX/FILTER_BYTES_ERASE = current INDEX/FILTER total block size in bytes. Test Plan: write a test case called `DBBlockCacheTest.IndexAndFilterBlocksStats`. The result is: ``` [gzh@dev9927.prn1 ~/local/rocksdb] make db_block_cache_test -j64 && ./db_block_cache_test --gtest_filter=DBBlockCacheTest.IndexAndFilterBlocksStats Makefile:101: Warning: Compiling in debug mode. Don't use the resulting binary in production GEN util/build_version.cc make: `db_block_cache_test' is up to date. Note: Google Test filter = DBBlockCacheTest.IndexAndFilterBlocksStats [==========] Running 1 test from 1 test case. [----------] Global test environment set-up. [----------] 1 test from DBBlockCacheTest [ RUN ] DBBlockCacheTest.IndexAndFilterBlocksStats [ OK ] DBBlockCacheTest.IndexAndFilterBlocksStats (689 ms) [----------] 1 test from DBBlockCacheTest (689 ms total) [----------] Global test environment tear-down [==========] 1 test from 1 test case ran. (689 ms total) [ PASSED ] 1 test. ``` Reviewers: IslamAbdelRahman, andrewkr, sdong Reviewed By: sdong Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D58677
2016-06-03 19:47:47 +02:00
table_options.block_cache = cache;
table_options.filter_policy.reset(NewBloomFilterPolicy(20, true));
Add statistics field to show total size of index and filter blocks in block cache Summary: With `table_options.cache_index_and_filter_blocks = true`, index and filter blocks are stored in block cache. Then people are curious how much of the block cache total size is used by indexes and bloom filters. It will be nice we have a way to report that. It can help people tune performance and plan for optimized hardware setting. We add several enum values for db Statistics. BLOCK_CACHE_INDEX/FILTER_BYTES_INSERT - BLOCK_CACHE_INDEX/FILTER_BYTES_ERASE = current INDEX/FILTER total block size in bytes. Test Plan: write a test case called `DBBlockCacheTest.IndexAndFilterBlocksStats`. The result is: ``` [gzh@dev9927.prn1 ~/local/rocksdb] make db_block_cache_test -j64 && ./db_block_cache_test --gtest_filter=DBBlockCacheTest.IndexAndFilterBlocksStats Makefile:101: Warning: Compiling in debug mode. Don't use the resulting binary in production GEN util/build_version.cc make: `db_block_cache_test' is up to date. Note: Google Test filter = DBBlockCacheTest.IndexAndFilterBlocksStats [==========] Running 1 test from 1 test case. [----------] Global test environment set-up. [----------] 1 test from DBBlockCacheTest [ RUN ] DBBlockCacheTest.IndexAndFilterBlocksStats [ OK ] DBBlockCacheTest.IndexAndFilterBlocksStats (689 ms) [----------] 1 test from DBBlockCacheTest (689 ms total) [----------] Global test environment tear-down [==========] 1 test from 1 test case ran. (689 ms total) [ PASSED ] 1 test. ``` Reviewers: IslamAbdelRahman, andrewkr, sdong Reviewed By: sdong Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D58677
2016-06-03 19:47:47 +02:00
options.table_factory.reset(new BlockBasedTableFactory(table_options));
CreateAndReopenWithCF({"pikachu"}, options);
ASSERT_OK(Put(1, "longer_key", "val"));
Add statistics field to show total size of index and filter blocks in block cache Summary: With `table_options.cache_index_and_filter_blocks = true`, index and filter blocks are stored in block cache. Then people are curious how much of the block cache total size is used by indexes and bloom filters. It will be nice we have a way to report that. It can help people tune performance and plan for optimized hardware setting. We add several enum values for db Statistics. BLOCK_CACHE_INDEX/FILTER_BYTES_INSERT - BLOCK_CACHE_INDEX/FILTER_BYTES_ERASE = current INDEX/FILTER total block size in bytes. Test Plan: write a test case called `DBBlockCacheTest.IndexAndFilterBlocksStats`. The result is: ``` [gzh@dev9927.prn1 ~/local/rocksdb] make db_block_cache_test -j64 && ./db_block_cache_test --gtest_filter=DBBlockCacheTest.IndexAndFilterBlocksStats Makefile:101: Warning: Compiling in debug mode. Don't use the resulting binary in production GEN util/build_version.cc make: `db_block_cache_test' is up to date. Note: Google Test filter = DBBlockCacheTest.IndexAndFilterBlocksStats [==========] Running 1 test from 1 test case. [----------] Global test environment set-up. [----------] 1 test from DBBlockCacheTest [ RUN ] DBBlockCacheTest.IndexAndFilterBlocksStats [ OK ] DBBlockCacheTest.IndexAndFilterBlocksStats (689 ms) [----------] 1 test from DBBlockCacheTest (689 ms total) [----------] Global test environment tear-down [==========] 1 test from 1 test case ran. (689 ms total) [ PASSED ] 1 test. ``` Reviewers: IslamAbdelRahman, andrewkr, sdong Reviewed By: sdong Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D58677
2016-06-03 19:47:47 +02:00
// Create a new table
ASSERT_OK(Flush(1));
size_t index_bytes_insert =
TestGetTickerCount(options, BLOCK_CACHE_INDEX_BYTES_INSERT);
size_t filter_bytes_insert =
TestGetTickerCount(options, BLOCK_CACHE_FILTER_BYTES_INSERT);
ASSERT_GT(index_bytes_insert, 0);
ASSERT_GT(filter_bytes_insert, 0);
ASSERT_EQ(cache->GetUsage(), index_bytes_insert + filter_bytes_insert);
// set the cache capacity to the current usage
cache->SetCapacity(index_bytes_insert + filter_bytes_insert);
// The index and filter eviction statistics were broken by the refactoring
// that moved the readers out of the block cache. Disabling these until we can
// bring the stats back.
// ASSERT_EQ(TestGetTickerCount(options, BLOCK_CACHE_INDEX_BYTES_EVICT), 0);
// ASSERT_EQ(TestGetTickerCount(options, BLOCK_CACHE_FILTER_BYTES_EVICT), 0);
// Note that the second key needs to be no longer than the first one.
// Otherwise the second index block may not fit in cache.
ASSERT_OK(Put(1, "key", "val"));
Add statistics field to show total size of index and filter blocks in block cache Summary: With `table_options.cache_index_and_filter_blocks = true`, index and filter blocks are stored in block cache. Then people are curious how much of the block cache total size is used by indexes and bloom filters. It will be nice we have a way to report that. It can help people tune performance and plan for optimized hardware setting. We add several enum values for db Statistics. BLOCK_CACHE_INDEX/FILTER_BYTES_INSERT - BLOCK_CACHE_INDEX/FILTER_BYTES_ERASE = current INDEX/FILTER total block size in bytes. Test Plan: write a test case called `DBBlockCacheTest.IndexAndFilterBlocksStats`. The result is: ``` [gzh@dev9927.prn1 ~/local/rocksdb] make db_block_cache_test -j64 && ./db_block_cache_test --gtest_filter=DBBlockCacheTest.IndexAndFilterBlocksStats Makefile:101: Warning: Compiling in debug mode. Don't use the resulting binary in production GEN util/build_version.cc make: `db_block_cache_test' is up to date. Note: Google Test filter = DBBlockCacheTest.IndexAndFilterBlocksStats [==========] Running 1 test from 1 test case. [----------] Global test environment set-up. [----------] 1 test from DBBlockCacheTest [ RUN ] DBBlockCacheTest.IndexAndFilterBlocksStats [ OK ] DBBlockCacheTest.IndexAndFilterBlocksStats (689 ms) [----------] 1 test from DBBlockCacheTest (689 ms total) [----------] Global test environment tear-down [==========] 1 test from 1 test case ran. (689 ms total) [ PASSED ] 1 test. ``` Reviewers: IslamAbdelRahman, andrewkr, sdong Reviewed By: sdong Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D58677
2016-06-03 19:47:47 +02:00
// Create a new table
ASSERT_OK(Flush(1));
// cache evicted old index and block entries
ASSERT_GT(TestGetTickerCount(options, BLOCK_CACHE_INDEX_BYTES_INSERT),
index_bytes_insert);
ASSERT_GT(TestGetTickerCount(options, BLOCK_CACHE_FILTER_BYTES_INSERT),
filter_bytes_insert);
// The index and filter eviction statistics were broken by the refactoring
// that moved the readers out of the block cache. Disabling these until we can
// bring the stats back.
// ASSERT_EQ(TestGetTickerCount(options, BLOCK_CACHE_INDEX_BYTES_EVICT),
// index_bytes_insert);
// ASSERT_EQ(TestGetTickerCount(options, BLOCK_CACHE_FILTER_BYTES_EVICT),
// filter_bytes_insert);
Add statistics field to show total size of index and filter blocks in block cache Summary: With `table_options.cache_index_and_filter_blocks = true`, index and filter blocks are stored in block cache. Then people are curious how much of the block cache total size is used by indexes and bloom filters. It will be nice we have a way to report that. It can help people tune performance and plan for optimized hardware setting. We add several enum values for db Statistics. BLOCK_CACHE_INDEX/FILTER_BYTES_INSERT - BLOCK_CACHE_INDEX/FILTER_BYTES_ERASE = current INDEX/FILTER total block size in bytes. Test Plan: write a test case called `DBBlockCacheTest.IndexAndFilterBlocksStats`. The result is: ``` [gzh@dev9927.prn1 ~/local/rocksdb] make db_block_cache_test -j64 && ./db_block_cache_test --gtest_filter=DBBlockCacheTest.IndexAndFilterBlocksStats Makefile:101: Warning: Compiling in debug mode. Don't use the resulting binary in production GEN util/build_version.cc make: `db_block_cache_test' is up to date. Note: Google Test filter = DBBlockCacheTest.IndexAndFilterBlocksStats [==========] Running 1 test from 1 test case. [----------] Global test environment set-up. [----------] 1 test from DBBlockCacheTest [ RUN ] DBBlockCacheTest.IndexAndFilterBlocksStats [ OK ] DBBlockCacheTest.IndexAndFilterBlocksStats (689 ms) [----------] 1 test from DBBlockCacheTest (689 ms total) [----------] Global test environment tear-down [==========] 1 test from 1 test case ran. (689 ms total) [ PASSED ] 1 test. ``` Reviewers: IslamAbdelRahman, andrewkr, sdong Reviewed By: sdong Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D58677
2016-06-03 19:47:47 +02:00
}
namespace {
// A mock cache wraps LRUCache, and record how many entries have been
// inserted for each priority.
class MockCache : public LRUCache {
public:
static uint32_t high_pri_insert_count;
static uint32_t low_pri_insert_count;
MockCache()
: LRUCache((size_t)1 << 25 /*capacity*/, 0 /*num_shard_bits*/,
false /*strict_capacity_limit*/, 0.0 /*high_pri_pool_ratio*/) {
}
Status Insert(const Slice& key, void* value, size_t charge,
void (*deleter)(const Slice& key, void* value), Handle** handle,
Priority priority) override {
if (priority == Priority::LOW) {
low_pri_insert_count++;
} else {
high_pri_insert_count++;
}
return LRUCache::Insert(key, value, charge, deleter, handle, priority);
}
};
uint32_t MockCache::high_pri_insert_count = 0;
uint32_t MockCache::low_pri_insert_count = 0;
} // anonymous namespace
TEST_F(DBBlockCacheTest, IndexAndFilterBlocksCachePriority) {
for (auto priority : {Cache::Priority::LOW, Cache::Priority::HIGH}) {
Options options = CurrentOptions();
options.create_if_missing = true;
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
BlockBasedTableOptions table_options;
table_options.cache_index_and_filter_blocks = true;
table_options.block_cache.reset(new MockCache());
table_options.filter_policy.reset(NewBloomFilterPolicy(20));
table_options.cache_index_and_filter_blocks_with_high_priority =
priority == Cache::Priority::HIGH ? true : false;
options.table_factory.reset(new BlockBasedTableFactory(table_options));
DestroyAndReopen(options);
MockCache::high_pri_insert_count = 0;
MockCache::low_pri_insert_count = 0;
// Create a new table.
ASSERT_OK(Put("foo", "value"));
ASSERT_OK(Put("bar", "value"));
ASSERT_OK(Flush());
ASSERT_EQ(1, NumTableFilesAtLevel(0));
// index/filter blocks added to block cache right after table creation.
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_MISS));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_MISS));
ASSERT_EQ(2, /* only index/filter were added */
TestGetTickerCount(options, BLOCK_CACHE_ADD));
ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_DATA_MISS));
if (priority == Cache::Priority::LOW) {
ASSERT_EQ(0u, MockCache::high_pri_insert_count);
ASSERT_EQ(2u, MockCache::low_pri_insert_count);
} else {
ASSERT_EQ(2u, MockCache::high_pri_insert_count);
ASSERT_EQ(0u, MockCache::low_pri_insert_count);
}
// Access data block.
ASSERT_EQ("value", Get("foo"));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_MISS));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_MISS));
ASSERT_EQ(3, /*adding data block*/
TestGetTickerCount(options, BLOCK_CACHE_ADD));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_DATA_MISS));
// Data block should be inserted with low priority.
if (priority == Cache::Priority::LOW) {
ASSERT_EQ(0u, MockCache::high_pri_insert_count);
ASSERT_EQ(3u, MockCache::low_pri_insert_count);
} else {
ASSERT_EQ(2u, MockCache::high_pri_insert_count);
ASSERT_EQ(1u, MockCache::low_pri_insert_count);
}
}
}
Stats for redundant insertions into block cache (#6681) Summary: Since read threads do not coordinate on loading data into block cache, two threads between Lookup and Insert can end up loading and inserting the same data. This is particularly concerning with cache_index_and_filter_blocks since those are hot and more likely to be race targets if ejected from (or not pre-populated in) the cache. Particularly with moves toward disaggregated / network storage, the cost of redundant retrieval might be high, and we should at least have some hard statistics from which we can estimate impact. Example with full filter thrashing "cliff": $ ./db_bench --benchmarks=fillrandom --num=15000000 --cache_index_and_filter_blocks -bloom_bits=10 ... $ ./db_bench --db=/tmp/rocksdbtest-172704/dbbench --use_existing_db --benchmarks=readrandom,stats --num=200000 --cache_index_and_filter_blocks --cache_size=$((130 * 1024 * 1024)) --bloom_bits=10 --threads=16 -statistics 2>&1 | egrep '^rocksdb.block.cache.(.*add|.*redundant)' | grep -v compress | sort rocksdb.block.cache.add COUNT : 14181 rocksdb.block.cache.add.failures COUNT : 0 rocksdb.block.cache.add.redundant COUNT : 476 rocksdb.block.cache.data.add COUNT : 12749 rocksdb.block.cache.data.add.redundant COUNT : 18 rocksdb.block.cache.filter.add COUNT : 1003 rocksdb.block.cache.filter.add.redundant COUNT : 217 rocksdb.block.cache.index.add COUNT : 429 rocksdb.block.cache.index.add.redundant COUNT : 241 $ ./db_bench --db=/tmp/rocksdbtest-172704/dbbench --use_existing_db --benchmarks=readrandom,stats --num=200000 --cache_index_and_filter_blocks --cache_size=$((120 * 1024 * 1024)) --bloom_bits=10 --threads=16 -statistics 2>&1 | egrep '^rocksdb.block.cache.(.*add|.*redundant)' | grep -v compress | sort rocksdb.block.cache.add COUNT : 1182223 rocksdb.block.cache.add.failures COUNT : 0 rocksdb.block.cache.add.redundant COUNT : 302728 rocksdb.block.cache.data.add COUNT : 31425 rocksdb.block.cache.data.add.redundant COUNT : 12 rocksdb.block.cache.filter.add COUNT : 795455 rocksdb.block.cache.filter.add.redundant COUNT : 130238 rocksdb.block.cache.index.add COUNT : 355343 rocksdb.block.cache.index.add.redundant COUNT : 172478 Pull Request resolved: https://github.com/facebook/rocksdb/pull/6681 Test Plan: Some manual testing (above) and unit test covering key metrics is included Reviewed By: ltamasi Differential Revision: D21134113 Pulled By: pdillinger fbshipit-source-id: c11497b5f00f4ffdfe919823904e52d0a1a91d87
2020-04-27 22:18:18 +02:00
namespace {
// An LRUCache wrapper that can falsely report "not found" on Lookup.
// This allows us to manipulate BlockBasedTableReader into thinking
// another thread inserted the data in between Lookup and Insert,
// while mostly preserving the LRUCache interface/behavior.
class LookupLiarCache : public CacheWrapper {
int nth_lookup_not_found_ = 0;
public:
explicit LookupLiarCache(std::shared_ptr<Cache> target)
: CacheWrapper(std::move(target)) {}
Handle* Lookup(const Slice& key, Statistics* stats) override {
if (nth_lookup_not_found_ == 1) {
nth_lookup_not_found_ = 0;
return nullptr;
}
if (nth_lookup_not_found_ > 1) {
--nth_lookup_not_found_;
}
return CacheWrapper::Lookup(key, stats);
}
// 1 == next lookup, 2 == after next, etc.
void SetNthLookupNotFound(int n) { nth_lookup_not_found_ = n; }
};
} // anonymous namespace
TEST_F(DBBlockCacheTest, AddRedundantStats) {
const size_t capacity = size_t{1} << 25;
const int num_shard_bits = 0; // 1 shard
int iterations_tested = 0;
for (std::shared_ptr<Cache> base_cache :
{NewLRUCache(capacity, num_shard_bits),
NewClockCache(capacity, num_shard_bits)}) {
if (!base_cache) {
// Skip clock cache when not supported
continue;
}
++iterations_tested;
Options options = CurrentOptions();
options.create_if_missing = true;
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
std::shared_ptr<LookupLiarCache> cache =
std::make_shared<LookupLiarCache>(base_cache);
BlockBasedTableOptions table_options;
table_options.cache_index_and_filter_blocks = true;
table_options.block_cache = cache;
table_options.filter_policy.reset(NewBloomFilterPolicy(50));
options.table_factory.reset(new BlockBasedTableFactory(table_options));
DestroyAndReopen(options);
// Create a new table.
ASSERT_OK(Put("foo", "value"));
ASSERT_OK(Put("bar", "value"));
ASSERT_OK(Flush());
ASSERT_EQ(1, NumTableFilesAtLevel(0));
// Normal access filter+index+data.
ASSERT_EQ("value", Get("foo"));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD));
// --------
ASSERT_EQ(3, TestGetTickerCount(options, BLOCK_CACHE_ADD));
ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD_REDUNDANT));
ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD_REDUNDANT));
ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD_REDUNDANT));
// --------
ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_ADD_REDUNDANT));
// Againt access filter+index+data, but force redundant load+insert on index
cache->SetNthLookupNotFound(2);
ASSERT_EQ("value", Get("bar"));
ASSERT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD));
// --------
ASSERT_EQ(4, TestGetTickerCount(options, BLOCK_CACHE_ADD));
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD_REDUNDANT));
ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD_REDUNDANT));
ASSERT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD_REDUNDANT));
// --------
ASSERT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_ADD_REDUNDANT));
// Access just filter (with high probability), and force redundant
// load+insert
cache->SetNthLookupNotFound(1);
ASSERT_EQ("NOT_FOUND", Get("this key was not added"));
EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD));
EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD));
EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD));
// --------
EXPECT_EQ(5, TestGetTickerCount(options, BLOCK_CACHE_ADD));
EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD_REDUNDANT));
EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD_REDUNDANT));
EXPECT_EQ(0, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD_REDUNDANT));
// --------
EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_ADD_REDUNDANT));
// Access just data, forcing redundant load+insert
ReadOptions read_options;
std::unique_ptr<Iterator> iter{db_->NewIterator(read_options)};
cache->SetNthLookupNotFound(1);
iter->SeekToFirst();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(iter->key(), "bar");
EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD));
EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD));
EXPECT_EQ(2, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD));
// --------
EXPECT_EQ(6, TestGetTickerCount(options, BLOCK_CACHE_ADD));
EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_INDEX_ADD_REDUNDANT));
EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_FILTER_ADD_REDUNDANT));
EXPECT_EQ(1, TestGetTickerCount(options, BLOCK_CACHE_DATA_ADD_REDUNDANT));
// --------
EXPECT_EQ(3, TestGetTickerCount(options, BLOCK_CACHE_ADD_REDUNDANT));
}
EXPECT_GE(iterations_tested, 1);
}
TEST_F(DBBlockCacheTest, ParanoidFileChecks) {
Options options = CurrentOptions();
options.create_if_missing = true;
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
options.level0_file_num_compaction_trigger = 2;
options.paranoid_file_checks = true;
BlockBasedTableOptions table_options;
table_options.cache_index_and_filter_blocks = false;
table_options.filter_policy.reset(NewBloomFilterPolicy(20));
options.table_factory.reset(new BlockBasedTableFactory(table_options));
CreateAndReopenWithCF({"pikachu"}, options);
ASSERT_OK(Put(1, "1_key", "val"));
ASSERT_OK(Put(1, "9_key", "val"));
// Create a new table.
ASSERT_OK(Flush(1));
ASSERT_EQ(1, /* read and cache data block */
TestGetTickerCount(options, BLOCK_CACHE_ADD));
ASSERT_OK(Put(1, "1_key2", "val2"));
ASSERT_OK(Put(1, "9_key2", "val2"));
// Create a new SST file. This will further trigger a compaction
// and generate another file.
ASSERT_OK(Flush(1));
dbfull()->TEST_WaitForCompact();
ASSERT_EQ(3, /* Totally 3 files created up to now */
TestGetTickerCount(options, BLOCK_CACHE_ADD));
// After disabling options.paranoid_file_checks. NO further block
// is added after generating a new file.
ASSERT_OK(
dbfull()->SetOptions(handles_[1], {{"paranoid_file_checks", "false"}}));
ASSERT_OK(Put(1, "1_key3", "val3"));
ASSERT_OK(Put(1, "9_key3", "val3"));
ASSERT_OK(Flush(1));
ASSERT_OK(Put(1, "1_key4", "val4"));
ASSERT_OK(Put(1, "9_key4", "val4"));
ASSERT_OK(Flush(1));
dbfull()->TEST_WaitForCompact();
ASSERT_EQ(3, /* Totally 3 files created up to now */
TestGetTickerCount(options, BLOCK_CACHE_ADD));
}
TEST_F(DBBlockCacheTest, CompressedCache) {
if (!Snappy_Supported()) {
return;
}
int num_iter = 80;
// Run this test three iterations.
// Iteration 1: only a uncompressed block cache
// Iteration 2: only a compressed block cache
// Iteration 3: both block cache and compressed cache
// Iteration 4: both block cache and compressed cache, but DB is not
// compressed
for (int iter = 0; iter < 4; iter++) {
Options options = CurrentOptions();
options.write_buffer_size = 64 * 1024; // small write buffer
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
BlockBasedTableOptions table_options;
switch (iter) {
case 0:
// only uncompressed block cache
table_options.block_cache = NewLRUCache(8 * 1024);
table_options.block_cache_compressed = nullptr;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
break;
case 1:
// no block cache, only compressed cache
table_options.no_block_cache = true;
table_options.block_cache = nullptr;
table_options.block_cache_compressed = NewLRUCache(8 * 1024);
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
break;
case 2:
// both compressed and uncompressed block cache
table_options.block_cache = NewLRUCache(1024);
table_options.block_cache_compressed = NewLRUCache(8 * 1024);
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
break;
case 3:
// both block cache and compressed cache, but DB is not compressed
// also, make block cache sizes bigger, to trigger block cache hits
table_options.block_cache = NewLRUCache(1024 * 1024);
table_options.block_cache_compressed = NewLRUCache(8 * 1024 * 1024);
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
options.compression = kNoCompression;
break;
default:
FAIL();
}
CreateAndReopenWithCF({"pikachu"}, options);
// default column family doesn't have block cache
Options no_block_cache_opts;
no_block_cache_opts.statistics = options.statistics;
no_block_cache_opts = CurrentOptions(no_block_cache_opts);
BlockBasedTableOptions table_options_no_bc;
table_options_no_bc.no_block_cache = true;
no_block_cache_opts.table_factory.reset(
NewBlockBasedTableFactory(table_options_no_bc));
ReopenWithColumnFamilies(
{"default", "pikachu"},
std::vector<Options>({no_block_cache_opts, options}));
Random rnd(301);
// Write 8MB (80 values, each 100K)
ASSERT_EQ(NumTableFilesAtLevel(0, 1), 0);
std::vector<std::string> values;
std::string str;
for (int i = 0; i < num_iter; i++) {
if (i % 4 == 0) { // high compression ratio
str = RandomString(&rnd, 1000);
}
values.push_back(str);
ASSERT_OK(Put(1, Key(i), values[i]));
}
// flush all data from memtable so that reads are from block cache
ASSERT_OK(Flush(1));
for (int i = 0; i < num_iter; i++) {
ASSERT_EQ(Get(1, Key(i)), values[i]);
}
// check that we triggered the appropriate code paths in the cache
switch (iter) {
case 0:
// only uncompressed block cache
ASSERT_GT(TestGetTickerCount(options, BLOCK_CACHE_MISS), 0);
ASSERT_EQ(TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_MISS), 0);
break;
case 1:
// no block cache, only compressed cache
ASSERT_EQ(TestGetTickerCount(options, BLOCK_CACHE_MISS), 0);
ASSERT_GT(TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_MISS), 0);
break;
case 2:
// both compressed and uncompressed block cache
ASSERT_GT(TestGetTickerCount(options, BLOCK_CACHE_MISS), 0);
ASSERT_GT(TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_MISS), 0);
break;
case 3:
// both compressed and uncompressed block cache
ASSERT_GT(TestGetTickerCount(options, BLOCK_CACHE_MISS), 0);
ASSERT_GT(TestGetTickerCount(options, BLOCK_CACHE_HIT), 0);
ASSERT_GT(TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_MISS), 0);
// compressed doesn't have any hits since blocks are not compressed on
// storage
ASSERT_EQ(TestGetTickerCount(options, BLOCK_CACHE_COMPRESSED_HIT), 0);
break;
default:
FAIL();
}
options.create_if_missing = true;
DestroyAndReopen(options);
}
}
TEST_F(DBBlockCacheTest, CacheCompressionDict) {
const int kNumFiles = 4;
Reduce scope of compression dictionary to single SST (#4952) Summary: Our previous approach was to train one compression dictionary per compaction, using the first output SST to train a dictionary, and then applying it on subsequent SSTs in the same compaction. While this was great for minimizing CPU/memory/I/O overhead, it did not achieve good compression ratios in practice. In our most promising potential use case, moderate reductions in a dictionary's scope make a major difference on compression ratio. So, this PR changes compression dictionary to be scoped per-SST. It accepts the tradeoff during table building to use more memory and CPU. Important changes include: - The `BlockBasedTableBuilder` has a new state when dictionary compression is in-use: `kBuffered`. In that state it accumulates uncompressed data in-memory whenever `Add` is called. - After accumulating target file size bytes or calling `BlockBasedTableBuilder::Finish`, a `BlockBasedTableBuilder` moves to the `kUnbuffered` state. The transition (`EnterUnbuffered()`) involves sampling the buffered data, training a dictionary, and compressing/writing out all buffered data. In the `kUnbuffered` state, a `BlockBasedTableBuilder` behaves the same as before -- blocks are compressed/written out as soon as they fill up. - Samples are now whole uncompressed data blocks, except the final sample may be a partial data block so we don't breach the user's configured `max_dict_bytes` or `zstd_max_train_bytes`. The dictionary trainer is supposed to work better when we pass it real units of compression. Previously we were passing 64-byte KV samples which was not realistic. Pull Request resolved: https://github.com/facebook/rocksdb/pull/4952 Differential Revision: D13967980 Pulled By: ajkr fbshipit-source-id: 82bea6f7537e1529c7a1a4cdee84585f5949300f
2019-02-12 04:42:25 +01:00
const int kNumEntriesPerFile = 128;
const int kNumBytesPerEntry = 1024;
// Try all the available libraries that support dictionary compression
std::vector<CompressionType> compression_types;
if (Zlib_Supported()) {
compression_types.push_back(kZlibCompression);
}
if (LZ4_Supported()) {
compression_types.push_back(kLZ4Compression);
compression_types.push_back(kLZ4HCCompression);
}
if (ZSTD_Supported()) {
compression_types.push_back(kZSTD);
} else if (ZSTDNotFinal_Supported()) {
compression_types.push_back(kZSTDNotFinalCompression);
}
Random rnd(301);
for (auto compression_type : compression_types) {
Options options = CurrentOptions();
options.compression = compression_type;
options.compression_opts.max_dict_bytes = 4096;
options.create_if_missing = true;
options.num_levels = 2;
options.statistics = ROCKSDB_NAMESPACE::CreateDBStatistics();
options.target_file_size_base = kNumEntriesPerFile * kNumBytesPerEntry;
BlockBasedTableOptions table_options;
table_options.cache_index_and_filter_blocks = true;
table_options.block_cache.reset(new MockCache());
options.table_factory.reset(new BlockBasedTableFactory(table_options));
DestroyAndReopen(options);
RecordCacheCountersForCompressionDict(options);
for (int i = 0; i < kNumFiles; ++i) {
ASSERT_EQ(i, NumTableFilesAtLevel(0, 0));
for (int j = 0; j < kNumEntriesPerFile; ++j) {
std::string value = RandomString(&rnd, kNumBytesPerEntry);
ASSERT_OK(Put(Key(j * kNumFiles + i), value.c_str()));
}
ASSERT_OK(Flush());
}
dbfull()->TEST_WaitForCompact();
ASSERT_EQ(0, NumTableFilesAtLevel(0));
ASSERT_EQ(kNumFiles, NumTableFilesAtLevel(1));
// Compression dictionary blocks are preloaded.
CheckCacheCountersForCompressionDict(
options, kNumFiles /* expected_compression_dict_misses */,
0 /* expected_compression_dict_hits */,
kNumFiles /* expected_compression_dict_inserts */);
// Seek to a key in a file. It should cause the SST's dictionary meta-block
// to be read.
RecordCacheCounters(options);
RecordCacheCountersForCompressionDict(options);
ReadOptions read_options;
ASSERT_NE("NOT_FOUND", Get(Key(kNumFiles * kNumEntriesPerFile - 1)));
// Two block hits: index and dictionary since they are prefetched
// One block missed/added: data block
CheckCacheCounters(options, 1 /* expected_misses */, 2 /* expected_hits */,
1 /* expected_inserts */, 0 /* expected_failures */);
CheckCacheCountersForCompressionDict(
options, 0 /* expected_compression_dict_misses */,
1 /* expected_compression_dict_hits */,
0 /* expected_compression_dict_inserts */);
}
}
#endif // ROCKSDB_LITE
} // namespace ROCKSDB_NAMESPACE
int main(int argc, char** argv) {
ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}