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rocksdb/db/blob/blob_source_test.cc

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62 KiB

// Copyright (c) Meta Platforms, Inc. and affiliates.
// 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 "db/blob/blob_source.h"
#include <cassert>
#include <cstdint>
#include <cstdio>
#include <memory>
#include <string>
#include "cache/charged_cache.h"
#include "cache/compressed_secondary_cache.h"
#include "db/blob/blob_contents.h"
#include "db/blob/blob_file_cache.h"
#include "db/blob/blob_file_reader.h"
#include "db/blob/blob_log_format.h"
#include "db/blob/blob_log_writer.h"
#include "db/db_test_util.h"
#include "file/filename.h"
#include "file/read_write_util.h"
#include "options/cf_options.h"
#include "rocksdb/options.h"
#include "util/compression.h"
#include "util/random.h"
namespace ROCKSDB_NAMESPACE {
namespace {
// Creates a test blob file with `num` blobs in it.
void WriteBlobFile(const ImmutableOptions& immutable_options,
uint32_t column_family_id, bool has_ttl,
const ExpirationRange& expiration_range_header,
const ExpirationRange& expiration_range_footer,
uint64_t blob_file_number, const std::vector<Slice>& keys,
const std::vector<Slice>& blobs, CompressionType compression,
std::vector<uint64_t>& blob_offsets,
std::vector<uint64_t>& blob_sizes) {
assert(!immutable_options.cf_paths.empty());
size_t num = keys.size();
assert(num == blobs.size());
assert(num == blob_offsets.size());
assert(num == blob_sizes.size());
const std::string blob_file_path =
BlobFileName(immutable_options.cf_paths.front().path, blob_file_number);
std::unique_ptr<FSWritableFile> file;
ASSERT_OK(NewWritableFile(immutable_options.fs.get(), blob_file_path, &file,
FileOptions()));
std::unique_ptr<WritableFileWriter> file_writer(new WritableFileWriter(
std::move(file), blob_file_path, FileOptions(), immutable_options.clock));
constexpr Statistics* statistics = nullptr;
constexpr bool use_fsync = false;
constexpr bool do_flush = false;
BlobLogWriter blob_log_writer(std::move(file_writer), immutable_options.clock,
statistics, blob_file_number, use_fsync,
do_flush);
BlobLogHeader header(column_family_id, compression, has_ttl,
expiration_range_header);
ASSERT_OK(blob_log_writer.WriteHeader(header));
std::vector<std::string> compressed_blobs(num);
std::vector<Slice> blobs_to_write(num);
if (kNoCompression == compression) {
for (size_t i = 0; i < num; ++i) {
blobs_to_write[i] = blobs[i];
blob_sizes[i] = blobs[i].size();
}
} else {
CompressionOptions opts;
CompressionContext context(compression);
constexpr uint64_t sample_for_compression = 0;
CompressionInfo info(opts, context, CompressionDict::GetEmptyDict(),
compression, sample_for_compression);
constexpr uint32_t compression_format_version = 2;
for (size_t i = 0; i < num; ++i) {
ASSERT_TRUE(CompressData(blobs[i], info, compression_format_version,
&compressed_blobs[i]));
blobs_to_write[i] = compressed_blobs[i];
blob_sizes[i] = compressed_blobs[i].size();
}
}
for (size_t i = 0; i < num; ++i) {
uint64_t key_offset = 0;
ASSERT_OK(blob_log_writer.AddRecord(keys[i], blobs_to_write[i], &key_offset,
&blob_offsets[i]));
}
BlobLogFooter footer;
footer.blob_count = num;
footer.expiration_range = expiration_range_footer;
std::string checksum_method;
std::string checksum_value;
ASSERT_OK(
blob_log_writer.AppendFooter(footer, &checksum_method, &checksum_value));
}
} // anonymous namespace
class BlobSourceTest : public DBTestBase {
protected:
public:
explicit BlobSourceTest()
: DBTestBase("blob_source_test", /*env_do_fsync=*/true) {
options_.env = env_;
options_.enable_blob_files = true;
options_.create_if_missing = true;
LRUCacheOptions co;
co.capacity = 8 << 20;
co.num_shard_bits = 2;
co.metadata_charge_policy = kDontChargeCacheMetadata;
co.high_pri_pool_ratio = 0.2;
co.low_pri_pool_ratio = 0.2;
options_.blob_cache = NewLRUCache(co);
options_.lowest_used_cache_tier = CacheTier::kVolatileTier;
assert(db_->GetDbIdentity(db_id_).ok());
assert(db_->GetDbSessionId(db_session_id_).ok());
}
Options options_;
std::string db_id_;
std::string db_session_id_;
};
TEST_F(BlobSourceTest, GetBlobsFromCache) {
options_.cf_paths.emplace_back(
test::PerThreadDBPath(env_, "BlobSourceTest_GetBlobsFromCache"), 0);
options_.statistics = CreateDBStatistics();
Statistics* statistics = options_.statistics.get();
assert(statistics);
DestroyAndReopen(options_);
ImmutableOptions immutable_options(options_);
constexpr uint32_t column_family_id = 1;
constexpr bool has_ttl = false;
constexpr ExpirationRange expiration_range;
constexpr uint64_t blob_file_number = 1;
constexpr size_t num_blobs = 16;
std::vector<std::string> key_strs;
std::vector<std::string> blob_strs;
for (size_t i = 0; i < num_blobs; ++i) {
key_strs.push_back("key" + std::to_string(i));
blob_strs.push_back("blob" + std::to_string(i));
}
std::vector<Slice> keys;
std::vector<Slice> blobs;
uint64_t file_size = BlobLogHeader::kSize;
for (size_t i = 0; i < num_blobs; ++i) {
keys.push_back({key_strs[i]});
blobs.push_back({blob_strs[i]});
file_size += BlobLogRecord::kHeaderSize + keys[i].size() + blobs[i].size();
}
file_size += BlobLogFooter::kSize;
std::vector<uint64_t> blob_offsets(keys.size());
std::vector<uint64_t> blob_sizes(keys.size());
WriteBlobFile(immutable_options, column_family_id, has_ttl, expiration_range,
expiration_range, blob_file_number, keys, blobs, kNoCompression,
blob_offsets, blob_sizes);
constexpr size_t capacity = 1024;
std::shared_ptr<Cache> backing_cache =
NewLRUCache(capacity); // Blob file cache
FileOptions file_options;
constexpr HistogramImpl* blob_file_read_hist = nullptr;
std::unique_ptr<BlobFileCache> blob_file_cache =
std::make_unique<BlobFileCache>(
backing_cache.get(), &immutable_options, &file_options,
column_family_id, blob_file_read_hist, nullptr /*IOTracer*/);
BlobSource blob_source(&immutable_options, db_id_, db_session_id_,
blob_file_cache.get());
ReadOptions read_options;
read_options.verify_checksums = true;
constexpr FilePrefetchBuffer* prefetch_buffer = nullptr;
{
// GetBlob
std::vector<PinnableSlice> values(keys.size());
uint64_t bytes_read = 0;
uint64_t blob_bytes = 0;
uint64_t total_bytes = 0;
read_options.fill_cache = false;
get_perf_context()->Reset();
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_FALSE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
ASSERT_OK(blob_source.GetBlob(read_options, keys[i], blob_file_number,
blob_offsets[i], file_size, blob_sizes[i],
kNoCompression, prefetch_buffer, &values[i],
&bytes_read));
ASSERT_EQ(values[i], blobs[i]);
ASSERT_TRUE(values[i].IsPinned());
ASSERT_EQ(bytes_read,
BlobLogRecord::kHeaderSize + keys[i].size() + blob_sizes[i]);
ASSERT_FALSE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
total_bytes += bytes_read;
}
// Retrieved the blob cache num_blobs * 3 times via TEST_BlobInCache,
// GetBlob, and TEST_BlobInCache.
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, 0);
ASSERT_EQ((int)get_perf_context()->blob_read_count, num_blobs);
ASSERT_EQ((int)get_perf_context()->blob_read_byte, total_bytes);
ASSERT_GE((int)get_perf_context()->blob_checksum_time, 0);
ASSERT_EQ((int)get_perf_context()->blob_decompress_time, 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS), num_blobs * 3);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE), 0);
read_options.fill_cache = true;
blob_bytes = 0;
total_bytes = 0;
get_perf_context()->Reset();
statistics->Reset().PermitUncheckedError();
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_FALSE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
ASSERT_OK(blob_source.GetBlob(read_options, keys[i], blob_file_number,
blob_offsets[i], file_size, blob_sizes[i],
kNoCompression, prefetch_buffer, &values[i],
&bytes_read));
ASSERT_EQ(values[i], blobs[i]);
ASSERT_TRUE(values[i].IsPinned());
ASSERT_EQ(bytes_read,
BlobLogRecord::kHeaderSize + keys[i].size() + blob_sizes[i]);
blob_bytes += blob_sizes[i];
total_bytes += bytes_read;
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, i);
ASSERT_EQ((int)get_perf_context()->blob_read_count, i + 1);
ASSERT_EQ((int)get_perf_context()->blob_read_byte, total_bytes);
ASSERT_TRUE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, i + 1);
ASSERT_EQ((int)get_perf_context()->blob_read_count, i + 1);
ASSERT_EQ((int)get_perf_context()->blob_read_byte, total_bytes);
}
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, num_blobs);
ASSERT_EQ((int)get_perf_context()->blob_read_count, num_blobs);
ASSERT_EQ((int)get_perf_context()->blob_read_byte, total_bytes);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS), num_blobs * 2);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT), num_blobs);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD), num_blobs);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ), blob_bytes);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE),
blob_bytes);
read_options.fill_cache = true;
total_bytes = 0;
blob_bytes = 0;
get_perf_context()->Reset();
statistics->Reset().PermitUncheckedError();
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_TRUE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
ASSERT_OK(blob_source.GetBlob(read_options, keys[i], blob_file_number,
blob_offsets[i], file_size, blob_sizes[i],
kNoCompression, prefetch_buffer, &values[i],
&bytes_read));
ASSERT_EQ(values[i], blobs[i]);
ASSERT_TRUE(values[i].IsPinned());
ASSERT_EQ(bytes_read,
BlobLogRecord::kHeaderSize + keys[i].size() + blob_sizes[i]);
ASSERT_TRUE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
total_bytes += bytes_read; // on-disk blob record size
blob_bytes += blob_sizes[i]; // cached blob value size
}
// Retrieved the blob cache num_blobs * 3 times via TEST_BlobInCache,
// GetBlob, and TEST_BlobInCache.
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, num_blobs * 3);
ASSERT_EQ((int)get_perf_context()->blob_read_count, 0); // without i/o
ASSERT_EQ((int)get_perf_context()->blob_read_byte, 0); // without i/o
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT), num_blobs * 3);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ),
blob_bytes * 3);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE), 0);
// Cache-only GetBlob
read_options.read_tier = ReadTier::kBlockCacheTier;
total_bytes = 0;
blob_bytes = 0;
get_perf_context()->Reset();
statistics->Reset().PermitUncheckedError();
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_TRUE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
ASSERT_OK(blob_source.GetBlob(read_options, keys[i], blob_file_number,
blob_offsets[i], file_size, blob_sizes[i],
kNoCompression, prefetch_buffer, &values[i],
&bytes_read));
ASSERT_EQ(values[i], blobs[i]);
ASSERT_TRUE(values[i].IsPinned());
ASSERT_EQ(bytes_read,
BlobLogRecord::kHeaderSize + keys[i].size() + blob_sizes[i]);
ASSERT_TRUE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
total_bytes += bytes_read;
blob_bytes += blob_sizes[i];
}
// Retrieved the blob cache num_blobs * 3 times via TEST_BlobInCache,
// GetBlob, and TEST_BlobInCache.
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, num_blobs * 3);
ASSERT_EQ((int)get_perf_context()->blob_read_count, 0); // without i/o
ASSERT_EQ((int)get_perf_context()->blob_read_byte, 0); // without i/o
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT), num_blobs * 3);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ),
blob_bytes * 3);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE), 0);
}
options_.blob_cache->EraseUnRefEntries();
{
// Cache-only GetBlob
std::vector<PinnableSlice> values(keys.size());
uint64_t bytes_read = 0;
read_options.read_tier = ReadTier::kBlockCacheTier;
read_options.fill_cache = true;
get_perf_context()->Reset();
statistics->Reset().PermitUncheckedError();
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_FALSE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
ASSERT_TRUE(blob_source
.GetBlob(read_options, keys[i], blob_file_number,
blob_offsets[i], file_size, blob_sizes[i],
kNoCompression, prefetch_buffer, &values[i],
&bytes_read)
.IsIncomplete());
ASSERT_TRUE(values[i].empty());
ASSERT_FALSE(values[i].IsPinned());
ASSERT_EQ(bytes_read, 0);
ASSERT_FALSE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
}
// Retrieved the blob cache num_blobs * 3 times via TEST_BlobInCache,
// GetBlob, and TEST_BlobInCache.
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, 0);
ASSERT_EQ((int)get_perf_context()->blob_read_count, 0);
ASSERT_EQ((int)get_perf_context()->blob_read_byte, 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS), num_blobs * 3);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE), 0);
}
{
// GetBlob from non-existing file
std::vector<PinnableSlice> values(keys.size());
uint64_t bytes_read = 0;
uint64_t file_number = 100; // non-existing file
read_options.read_tier = ReadTier::kReadAllTier;
read_options.fill_cache = true;
get_perf_context()->Reset();
statistics->Reset().PermitUncheckedError();
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_FALSE(blob_source.TEST_BlobInCache(file_number, file_size,
blob_offsets[i]));
ASSERT_TRUE(blob_source
.GetBlob(read_options, keys[i], file_number,
blob_offsets[i], file_size, blob_sizes[i],
kNoCompression, prefetch_buffer, &values[i],
&bytes_read)
.IsIOError());
ASSERT_TRUE(values[i].empty());
ASSERT_FALSE(values[i].IsPinned());
ASSERT_EQ(bytes_read, 0);
ASSERT_FALSE(blob_source.TEST_BlobInCache(file_number, file_size,
blob_offsets[i]));
}
// Retrieved the blob cache num_blobs * 3 times via TEST_BlobInCache,
// GetBlob, and TEST_BlobInCache.
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, 0);
ASSERT_EQ((int)get_perf_context()->blob_read_count, 0);
ASSERT_EQ((int)get_perf_context()->blob_read_byte, 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS), num_blobs * 3);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE), 0);
}
}
TEST_F(BlobSourceTest, GetCompressedBlobs) {
if (!Snappy_Supported()) {
return;
}
const CompressionType compression = kSnappyCompression;
options_.cf_paths.emplace_back(
test::PerThreadDBPath(env_, "BlobSourceTest_GetCompressedBlobs"), 0);
DestroyAndReopen(options_);
ImmutableOptions immutable_options(options_);
constexpr uint32_t column_family_id = 1;
constexpr bool has_ttl = false;
constexpr ExpirationRange expiration_range;
constexpr size_t num_blobs = 256;
std::vector<std::string> key_strs;
std::vector<std::string> blob_strs;
for (size_t i = 0; i < num_blobs; ++i) {
key_strs.push_back("key" + std::to_string(i));
blob_strs.push_back("blob" + std::to_string(i));
}
std::vector<Slice> keys;
std::vector<Slice> blobs;
for (size_t i = 0; i < num_blobs; ++i) {
keys.push_back({key_strs[i]});
blobs.push_back({blob_strs[i]});
}
std::vector<uint64_t> blob_offsets(keys.size());
std::vector<uint64_t> blob_sizes(keys.size());
constexpr size_t capacity = 1024;
auto backing_cache = NewLRUCache(capacity); // Blob file cache
FileOptions file_options;
std::unique_ptr<BlobFileCache> blob_file_cache =
std::make_unique<BlobFileCache>(
backing_cache.get(), &immutable_options, &file_options,
column_family_id, nullptr /*HistogramImpl*/, nullptr /*IOTracer*/);
BlobSource blob_source(&immutable_options, db_id_, db_session_id_,
blob_file_cache.get());
ReadOptions read_options;
read_options.verify_checksums = true;
uint64_t bytes_read = 0;
std::vector<PinnableSlice> values(keys.size());
{
// Snappy Compression
const uint64_t file_number = 1;
read_options.read_tier = ReadTier::kReadAllTier;
WriteBlobFile(immutable_options, column_family_id, has_ttl,
expiration_range, expiration_range, file_number, keys, blobs,
compression, blob_offsets, blob_sizes);
CacheHandleGuard<BlobFileReader> blob_file_reader;
ASSERT_OK(blob_source.GetBlobFileReader(file_number, &blob_file_reader));
ASSERT_NE(blob_file_reader.GetValue(), nullptr);
const uint64_t file_size = blob_file_reader.GetValue()->GetFileSize();
ASSERT_EQ(blob_file_reader.GetValue()->GetCompressionType(), compression);
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_NE(blobs[i].size() /*uncompressed size*/,
blob_sizes[i] /*compressed size*/);
}
read_options.fill_cache = true;
read_options.read_tier = ReadTier::kReadAllTier;
get_perf_context()->Reset();
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_FALSE(blob_source.TEST_BlobInCache(file_number, file_size,
blob_offsets[i]));
ASSERT_OK(blob_source.GetBlob(read_options, keys[i], file_number,
blob_offsets[i], file_size, blob_sizes[i],
compression, nullptr /*prefetch_buffer*/,
&values[i], &bytes_read));
ASSERT_EQ(values[i], blobs[i] /*uncompressed blob*/);
ASSERT_NE(values[i].size(), blob_sizes[i] /*compressed size*/);
ASSERT_EQ(bytes_read,
BlobLogRecord::kHeaderSize + keys[i].size() + blob_sizes[i]);
ASSERT_TRUE(blob_source.TEST_BlobInCache(file_number, file_size,
blob_offsets[i]));
}
ASSERT_GE((int)get_perf_context()->blob_decompress_time, 0);
read_options.read_tier = ReadTier::kBlockCacheTier;
get_perf_context()->Reset();
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_TRUE(blob_source.TEST_BlobInCache(file_number, file_size,
blob_offsets[i]));
// Compressed blob size is passed in GetBlob
ASSERT_OK(blob_source.GetBlob(read_options, keys[i], file_number,
blob_offsets[i], file_size, blob_sizes[i],
compression, nullptr /*prefetch_buffer*/,
&values[i], &bytes_read));
ASSERT_EQ(values[i], blobs[i] /*uncompressed blob*/);
ASSERT_NE(values[i].size(), blob_sizes[i] /*compressed size*/);
ASSERT_EQ(bytes_read,
BlobLogRecord::kHeaderSize + keys[i].size() + blob_sizes[i]);
ASSERT_TRUE(blob_source.TEST_BlobInCache(file_number, file_size,
blob_offsets[i]));
}
ASSERT_EQ((int)get_perf_context()->blob_decompress_time, 0);
}
}
TEST_F(BlobSourceTest, MultiGetBlobsFromMultiFiles) {
options_.cf_paths.emplace_back(
test::PerThreadDBPath(env_, "BlobSourceTest_MultiGetBlobsFromMultiFiles"),
0);
options_.statistics = CreateDBStatistics();
Statistics* statistics = options_.statistics.get();
assert(statistics);
DestroyAndReopen(options_);
ImmutableOptions immutable_options(options_);
constexpr uint32_t column_family_id = 1;
constexpr bool has_ttl = false;
constexpr ExpirationRange expiration_range;
constexpr uint64_t blob_files = 2;
constexpr size_t num_blobs = 32;
std::vector<std::string> key_strs;
std::vector<std::string> blob_strs;
for (size_t i = 0; i < num_blobs; ++i) {
key_strs.push_back("key" + std::to_string(i));
blob_strs.push_back("blob" + std::to_string(i));
}
std::vector<Slice> keys;
std::vector<Slice> blobs;
uint64_t file_size = BlobLogHeader::kSize;
uint64_t blob_value_bytes = 0;
for (size_t i = 0; i < num_blobs; ++i) {
keys.push_back({key_strs[i]});
blobs.push_back({blob_strs[i]});
blob_value_bytes += blobs[i].size();
file_size += BlobLogRecord::kHeaderSize + keys[i].size() + blobs[i].size();
}
file_size += BlobLogFooter::kSize;
const uint64_t blob_records_bytes =
file_size - BlobLogHeader::kSize - BlobLogFooter::kSize;
std::vector<uint64_t> blob_offsets(keys.size());
std::vector<uint64_t> blob_sizes(keys.size());
{
// Write key/blob pairs to multiple blob files.
for (size_t i = 0; i < blob_files; ++i) {
const uint64_t file_number = i + 1;
WriteBlobFile(immutable_options, column_family_id, has_ttl,
expiration_range, expiration_range, file_number, keys,
blobs, kNoCompression, blob_offsets, blob_sizes);
}
}
constexpr size_t capacity = 10;
std::shared_ptr<Cache> backing_cache =
NewLRUCache(capacity); // Blob file cache
FileOptions file_options;
constexpr HistogramImpl* blob_file_read_hist = nullptr;
std::unique_ptr<BlobFileCache> blob_file_cache =
std::make_unique<BlobFileCache>(
backing_cache.get(), &immutable_options, &file_options,
column_family_id, blob_file_read_hist, nullptr /*IOTracer*/);
BlobSource blob_source(&immutable_options, db_id_, db_session_id_,
blob_file_cache.get());
ReadOptions read_options;
read_options.verify_checksums = true;
uint64_t bytes_read = 0;
{
// MultiGetBlob
read_options.fill_cache = true;
read_options.read_tier = ReadTier::kReadAllTier;
autovector<BlobFileReadRequests> blob_reqs;
std::array<autovector<BlobReadRequest>, blob_files> blob_reqs_in_file;
std::array<PinnableSlice, num_blobs * blob_files> value_buf;
std::array<Status, num_blobs * blob_files> statuses_buf;
for (size_t i = 0; i < blob_files; ++i) {
const uint64_t file_number = i + 1;
for (size_t j = 0; j < num_blobs; ++j) {
blob_reqs_in_file[i].emplace_back(
keys[j], blob_offsets[j], blob_sizes[j], kNoCompression,
&value_buf[i * num_blobs + j], &statuses_buf[i * num_blobs + j]);
}
blob_reqs.emplace_back(file_number, file_size, blob_reqs_in_file[i]);
}
get_perf_context()->Reset();
statistics->Reset().PermitUncheckedError();
blob_source.MultiGetBlob(read_options, blob_reqs, &bytes_read);
for (size_t i = 0; i < blob_files; ++i) {
const uint64_t file_number = i + 1;
for (size_t j = 0; j < num_blobs; ++j) {
ASSERT_OK(statuses_buf[i * num_blobs + j]);
ASSERT_EQ(value_buf[i * num_blobs + j], blobs[j]);
ASSERT_TRUE(blob_source.TEST_BlobInCache(file_number, file_size,
blob_offsets[j]));
}
}
// Retrieved all blobs from 2 blob files twice via MultiGetBlob and
// TEST_BlobInCache.
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count,
num_blobs * blob_files);
ASSERT_EQ((int)get_perf_context()->blob_read_count,
num_blobs * blob_files); // blocking i/o
ASSERT_EQ((int)get_perf_context()->blob_read_byte,
blob_records_bytes * blob_files); // blocking i/o
ASSERT_GE((int)get_perf_context()->blob_checksum_time, 0);
ASSERT_EQ((int)get_perf_context()->blob_decompress_time, 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS),
num_blobs * blob_files); // MultiGetBlob
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT),
num_blobs * blob_files); // TEST_BlobInCache
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD),
num_blobs * blob_files); // MultiGetBlob
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ),
blob_value_bytes * blob_files); // TEST_BlobInCache
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE),
blob_value_bytes * blob_files); // MultiGetBlob
get_perf_context()->Reset();
statistics->Reset().PermitUncheckedError();
autovector<BlobReadRequest> fake_blob_reqs_in_file;
std::array<PinnableSlice, num_blobs> fake_value_buf;
std::array<Status, num_blobs> fake_statuses_buf;
const uint64_t fake_file_number = 100;
for (size_t i = 0; i < num_blobs; ++i) {
fake_blob_reqs_in_file.emplace_back(
keys[i], blob_offsets[i], blob_sizes[i], kNoCompression,
&fake_value_buf[i], &fake_statuses_buf[i]);
}
// Add a fake multi-get blob request.
blob_reqs.emplace_back(fake_file_number, file_size, fake_blob_reqs_in_file);
blob_source.MultiGetBlob(read_options, blob_reqs, &bytes_read);
// Check the real blob read requests.
for (size_t i = 0; i < blob_files; ++i) {
const uint64_t file_number = i + 1;
for (size_t j = 0; j < num_blobs; ++j) {
ASSERT_OK(statuses_buf[i * num_blobs + j]);
ASSERT_EQ(value_buf[i * num_blobs + j], blobs[j]);
ASSERT_TRUE(blob_source.TEST_BlobInCache(file_number, file_size,
blob_offsets[j]));
}
}
// Check the fake blob request.
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_TRUE(fake_statuses_buf[i].IsIOError());
ASSERT_TRUE(fake_value_buf[i].empty());
ASSERT_FALSE(blob_source.TEST_BlobInCache(fake_file_number, file_size,
blob_offsets[i]));
}
// Retrieved all blobs from 3 blob files (including the fake one) twice
// via MultiGetBlob and TEST_BlobInCache.
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count,
num_blobs * blob_files * 2);
ASSERT_EQ((int)get_perf_context()->blob_read_count,
0); // blocking i/o
ASSERT_EQ((int)get_perf_context()->blob_read_byte,
0); // blocking i/o
ASSERT_GE((int)get_perf_context()->blob_checksum_time, 0);
ASSERT_EQ((int)get_perf_context()->blob_decompress_time, 0);
// Fake blob requests: MultiGetBlob and TEST_BlobInCache
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS), num_blobs * 2);
// Real blob requests: MultiGetBlob and TEST_BlobInCache
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT),
num_blobs * blob_files * 2);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD), 0);
// Real blob requests: MultiGetBlob and TEST_BlobInCache
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ),
blob_value_bytes * blob_files * 2);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE), 0);
}
}
TEST_F(BlobSourceTest, MultiGetBlobsFromCache) {
options_.cf_paths.emplace_back(
test::PerThreadDBPath(env_, "BlobSourceTest_MultiGetBlobsFromCache"), 0);
options_.statistics = CreateDBStatistics();
Statistics* statistics = options_.statistics.get();
assert(statistics);
DestroyAndReopen(options_);
ImmutableOptions immutable_options(options_);
constexpr uint32_t column_family_id = 1;
constexpr bool has_ttl = false;
constexpr ExpirationRange expiration_range;
constexpr uint64_t blob_file_number = 1;
constexpr size_t num_blobs = 16;
std::vector<std::string> key_strs;
std::vector<std::string> blob_strs;
for (size_t i = 0; i < num_blobs; ++i) {
key_strs.push_back("key" + std::to_string(i));
blob_strs.push_back("blob" + std::to_string(i));
}
std::vector<Slice> keys;
std::vector<Slice> blobs;
uint64_t file_size = BlobLogHeader::kSize;
for (size_t i = 0; i < num_blobs; ++i) {
keys.push_back({key_strs[i]});
blobs.push_back({blob_strs[i]});
file_size += BlobLogRecord::kHeaderSize + keys[i].size() + blobs[i].size();
}
file_size += BlobLogFooter::kSize;
std::vector<uint64_t> blob_offsets(keys.size());
std::vector<uint64_t> blob_sizes(keys.size());
WriteBlobFile(immutable_options, column_family_id, has_ttl, expiration_range,
expiration_range, blob_file_number, keys, blobs, kNoCompression,
blob_offsets, blob_sizes);
constexpr size_t capacity = 10;
std::shared_ptr<Cache> backing_cache =
NewLRUCache(capacity); // Blob file cache
FileOptions file_options;
constexpr HistogramImpl* blob_file_read_hist = nullptr;
std::unique_ptr<BlobFileCache> blob_file_cache =
std::make_unique<BlobFileCache>(
backing_cache.get(), &immutable_options, &file_options,
column_family_id, blob_file_read_hist, nullptr /*IOTracer*/);
BlobSource blob_source(&immutable_options, db_id_, db_session_id_,
blob_file_cache.get());
ReadOptions read_options;
read_options.verify_checksums = true;
constexpr FilePrefetchBuffer* prefetch_buffer = nullptr;
{
// MultiGetBlobFromOneFile
uint64_t bytes_read = 0;
std::array<Status, num_blobs> statuses_buf;
std::array<PinnableSlice, num_blobs> value_buf;
autovector<BlobReadRequest> blob_reqs;
for (size_t i = 0; i < num_blobs; i += 2) { // even index
blob_reqs.emplace_back(keys[i], blob_offsets[i], blob_sizes[i],
kNoCompression, &value_buf[i], &statuses_buf[i]);
ASSERT_FALSE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
}
read_options.fill_cache = true;
read_options.read_tier = ReadTier::kReadAllTier;
get_perf_context()->Reset();
statistics->Reset().PermitUncheckedError();
// Get half of blobs
blob_source.MultiGetBlobFromOneFile(read_options, blob_file_number,
file_size, blob_reqs, &bytes_read);
uint64_t fs_read_bytes = 0;
uint64_t ca_read_bytes = 0;
for (size_t i = 0; i < num_blobs; ++i) {
if (i % 2 == 0) {
ASSERT_OK(statuses_buf[i]);
ASSERT_EQ(value_buf[i], blobs[i]);
ASSERT_TRUE(value_buf[i].IsPinned());
fs_read_bytes +=
blob_sizes[i] + keys[i].size() + BlobLogRecord::kHeaderSize;
ASSERT_TRUE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
ca_read_bytes += blob_sizes[i];
} else {
statuses_buf[i].PermitUncheckedError();
ASSERT_TRUE(value_buf[i].empty());
ASSERT_FALSE(value_buf[i].IsPinned());
ASSERT_FALSE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
}
}
constexpr int num_even_blobs = num_blobs / 2;
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, num_even_blobs);
ASSERT_EQ((int)get_perf_context()->blob_read_count,
num_even_blobs); // blocking i/o
ASSERT_EQ((int)get_perf_context()->blob_read_byte,
fs_read_bytes); // blocking i/o
ASSERT_GE((int)get_perf_context()->blob_checksum_time, 0);
ASSERT_EQ((int)get_perf_context()->blob_decompress_time, 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS), num_blobs);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT), num_even_blobs);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD), num_even_blobs);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ),
ca_read_bytes);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE),
ca_read_bytes);
// Get the rest of blobs
for (size_t i = 1; i < num_blobs; i += 2) { // odd index
ASSERT_FALSE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
ASSERT_OK(blob_source.GetBlob(read_options, keys[i], blob_file_number,
blob_offsets[i], file_size, blob_sizes[i],
kNoCompression, prefetch_buffer,
&value_buf[i], &bytes_read));
ASSERT_EQ(value_buf[i], blobs[i]);
ASSERT_TRUE(value_buf[i].IsPinned());
ASSERT_EQ(bytes_read,
BlobLogRecord::kHeaderSize + keys[i].size() + blob_sizes[i]);
ASSERT_TRUE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
}
// Cache-only MultiGetBlobFromOneFile
read_options.read_tier = ReadTier::kBlockCacheTier;
get_perf_context()->Reset();
statistics->Reset().PermitUncheckedError();
blob_reqs.clear();
for (size_t i = 0; i < num_blobs; ++i) {
blob_reqs.emplace_back(keys[i], blob_offsets[i], blob_sizes[i],
kNoCompression, &value_buf[i], &statuses_buf[i]);
}
blob_source.MultiGetBlobFromOneFile(read_options, blob_file_number,
file_size, blob_reqs, &bytes_read);
uint64_t blob_bytes = 0;
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_OK(statuses_buf[i]);
ASSERT_EQ(value_buf[i], blobs[i]);
ASSERT_TRUE(value_buf[i].IsPinned());
ASSERT_TRUE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
blob_bytes += blob_sizes[i];
}
// Retrieved the blob cache num_blobs * 2 times via GetBlob and
// TEST_BlobInCache.
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, num_blobs * 2);
ASSERT_EQ((int)get_perf_context()->blob_read_count, 0); // blocking i/o
ASSERT_EQ((int)get_perf_context()->blob_read_byte, 0); // blocking i/o
ASSERT_GE((int)get_perf_context()->blob_checksum_time, 0);
ASSERT_EQ((int)get_perf_context()->blob_decompress_time, 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT), num_blobs * 2);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ),
blob_bytes * 2);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE), 0);
}
options_.blob_cache->EraseUnRefEntries();
{
// Cache-only MultiGetBlobFromOneFile
uint64_t bytes_read = 0;
read_options.read_tier = ReadTier::kBlockCacheTier;
std::array<Status, num_blobs> statuses_buf;
std::array<PinnableSlice, num_blobs> value_buf;
autovector<BlobReadRequest> blob_reqs;
for (size_t i = 0; i < num_blobs; i++) {
blob_reqs.emplace_back(keys[i], blob_offsets[i], blob_sizes[i],
kNoCompression, &value_buf[i], &statuses_buf[i]);
ASSERT_FALSE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
}
get_perf_context()->Reset();
statistics->Reset().PermitUncheckedError();
blob_source.MultiGetBlobFromOneFile(read_options, blob_file_number,
file_size, blob_reqs, &bytes_read);
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_TRUE(statuses_buf[i].IsIncomplete());
ASSERT_TRUE(value_buf[i].empty());
ASSERT_FALSE(value_buf[i].IsPinned());
ASSERT_FALSE(blob_source.TEST_BlobInCache(blob_file_number, file_size,
blob_offsets[i]));
}
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, 0);
ASSERT_EQ((int)get_perf_context()->blob_read_count, 0); // blocking i/o
ASSERT_EQ((int)get_perf_context()->blob_read_byte, 0); // blocking i/o
ASSERT_EQ((int)get_perf_context()->blob_checksum_time, 0);
ASSERT_EQ((int)get_perf_context()->blob_decompress_time, 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS), num_blobs * 2);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE), 0);
}
{
// MultiGetBlobFromOneFile from non-existing file
uint64_t bytes_read = 0;
uint64_t non_existing_file_number = 100;
read_options.read_tier = ReadTier::kReadAllTier;
std::array<Status, num_blobs> statuses_buf;
std::array<PinnableSlice, num_blobs> value_buf;
autovector<BlobReadRequest> blob_reqs;
for (size_t i = 0; i < num_blobs; i++) {
blob_reqs.emplace_back(keys[i], blob_offsets[i], blob_sizes[i],
kNoCompression, &value_buf[i], &statuses_buf[i]);
ASSERT_FALSE(blob_source.TEST_BlobInCache(non_existing_file_number,
file_size, blob_offsets[i]));
}
get_perf_context()->Reset();
statistics->Reset().PermitUncheckedError();
blob_source.MultiGetBlobFromOneFile(read_options, non_existing_file_number,
file_size, blob_reqs, &bytes_read);
for (size_t i = 0; i < num_blobs; ++i) {
ASSERT_TRUE(statuses_buf[i].IsIOError());
ASSERT_TRUE(value_buf[i].empty());
ASSERT_FALSE(value_buf[i].IsPinned());
ASSERT_FALSE(blob_source.TEST_BlobInCache(non_existing_file_number,
file_size, blob_offsets[i]));
}
ASSERT_EQ((int)get_perf_context()->blob_cache_hit_count, 0);
ASSERT_EQ((int)get_perf_context()->blob_read_count, 0); // blocking i/o
ASSERT_EQ((int)get_perf_context()->blob_read_byte, 0); // blocking i/o
ASSERT_EQ((int)get_perf_context()->blob_checksum_time, 0);
ASSERT_EQ((int)get_perf_context()->blob_decompress_time, 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_MISS), num_blobs * 2);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_HIT), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_ADD), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_READ), 0);
ASSERT_EQ(statistics->getTickerCount(BLOB_DB_CACHE_BYTES_WRITE), 0);
}
}
class BlobSecondaryCacheTest : public DBTestBase {
protected:
public:
explicit BlobSecondaryCacheTest()
: DBTestBase("blob_secondary_cache_test", /*env_do_fsync=*/true) {
options_.env = env_;
options_.enable_blob_files = true;
options_.create_if_missing = true;
// Set a small cache capacity to evict entries from the cache, and to test
// that secondary cache is used properly.
lru_cache_opts_.capacity = 1024;
lru_cache_opts_.num_shard_bits = 0;
lru_cache_opts_.strict_capacity_limit = true;
lru_cache_opts_.metadata_charge_policy = kDontChargeCacheMetadata;
lru_cache_opts_.high_pri_pool_ratio = 0.2;
lru_cache_opts_.low_pri_pool_ratio = 0.2;
secondary_cache_opts_.capacity = 8 << 20; // 8 MB
secondary_cache_opts_.num_shard_bits = 0;
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
secondary_cache_opts_.metadata_charge_policy =
kDefaultCacheMetadataChargePolicy;
// Read blobs from the secondary cache if they are not in the primary cache
options_.lowest_used_cache_tier = CacheTier::kNonVolatileBlockTier;
assert(db_->GetDbIdentity(db_id_).ok());
assert(db_->GetDbSessionId(db_session_id_).ok());
}
Options options_;
LRUCacheOptions lru_cache_opts_;
CompressedSecondaryCacheOptions secondary_cache_opts_;
std::string db_id_;
std::string db_session_id_;
};
TEST_F(BlobSecondaryCacheTest, GetBlobsFromSecondaryCache) {
if (!Snappy_Supported()) {
return;
}
secondary_cache_opts_.compression_type = kSnappyCompression;
lru_cache_opts_.secondary_cache =
NewCompressedSecondaryCache(secondary_cache_opts_);
options_.blob_cache = NewLRUCache(lru_cache_opts_);
options_.cf_paths.emplace_back(
test::PerThreadDBPath(
env_, "BlobSecondaryCacheTest_GetBlobsFromSecondaryCache"),
0);
options_.statistics = CreateDBStatistics();
Statistics* statistics = options_.statistics.get();
assert(statistics);
DestroyAndReopen(options_);
ImmutableOptions immutable_options(options_);
constexpr uint32_t column_family_id = 1;
constexpr bool has_ttl = false;
constexpr ExpirationRange expiration_range;
constexpr uint64_t file_number = 1;
Random rnd(301);
std::vector<std::string> key_strs{"key0", "key1"};
std::vector<std::string> blob_strs{rnd.RandomString(512),
rnd.RandomString(768)};
std::vector<Slice> keys{key_strs[0], key_strs[1]};
std::vector<Slice> blobs{blob_strs[0], blob_strs[1]};
std::vector<uint64_t> blob_offsets(keys.size());
std::vector<uint64_t> blob_sizes(keys.size());
WriteBlobFile(immutable_options, column_family_id, has_ttl, expiration_range,
expiration_range, file_number, keys, blobs, kNoCompression,
blob_offsets, blob_sizes);
constexpr size_t capacity = 1024;
std::shared_ptr<Cache> backing_cache = NewLRUCache(capacity);
FileOptions file_options;
constexpr HistogramImpl* blob_file_read_hist = nullptr;
std::unique_ptr<BlobFileCache> blob_file_cache(new BlobFileCache(
backing_cache.get(), &immutable_options, &file_options, column_family_id,
blob_file_read_hist, nullptr /*IOTracer*/));
BlobSource blob_source(&immutable_options, db_id_, db_session_id_,
blob_file_cache.get());
CacheHandleGuard<BlobFileReader> file_reader;
ASSERT_OK(blob_source.GetBlobFileReader(file_number, &file_reader));
ASSERT_NE(file_reader.GetValue(), nullptr);
const uint64_t file_size = file_reader.GetValue()->GetFileSize();
ASSERT_EQ(file_reader.GetValue()->GetCompressionType(), kNoCompression);
ReadOptions read_options;
read_options.verify_checksums = true;
auto blob_cache = options_.blob_cache;
auto secondary_cache = lru_cache_opts_.secondary_cache;
Cache::CreateCallback create_cb = [](const void* buf, size_t size,
void** out_obj,
size_t* charge) -> Status {
CacheAllocationPtr allocation(new char[size]);
return BlobContents::CreateCallback(std::move(allocation), buf, size,
out_obj, charge);
};
{
// GetBlob
std::vector<PinnableSlice> values(keys.size());
read_options.fill_cache = true;
get_perf_context()->Reset();
// key0 should be filled to the primary cache from the blob file.
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
ASSERT_OK(blob_source.GetBlob(read_options, keys[0], file_number,
blob_offsets[0], file_size, blob_sizes[0],
kNoCompression, nullptr /* prefetch_buffer */,
&values[0], nullptr /* bytes_read */));
// Release cache handle
values[0].Reset();
// key0 should be evicted and key0's dummy item is inserted into secondary
// cache. key1 should be filled to the primary cache from the blob file.
ASSERT_OK(blob_source.GetBlob(read_options, keys[1], file_number,
blob_offsets[1], file_size, blob_sizes[1],
kNoCompression, nullptr /* prefetch_buffer */,
&values[1], nullptr /* bytes_read */));
// Release cache handle
values[1].Reset();
// key0 should be filled to the primary cache from the blob file. key1
// should be evicted and key1's dummy item is inserted into secondary cache.
ASSERT_OK(blob_source.GetBlob(read_options, keys[0], file_number,
blob_offsets[0], file_size, blob_sizes[0],
kNoCompression, nullptr /* prefetch_buffer */,
&values[0], nullptr /* bytes_read */));
ASSERT_EQ(values[0], blobs[0]);
ASSERT_TRUE(
blob_source.TEST_BlobInCache(file_number, file_size, blob_offsets[0]));
// Release cache handle
values[0].Reset();
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
// key0 should be evicted and is inserted into secondary cache.
// key1 should be filled to the primary cache from the blob file.
ASSERT_OK(blob_source.GetBlob(read_options, keys[1], file_number,
blob_offsets[1], file_size, blob_sizes[1],
kNoCompression, nullptr /* prefetch_buffer */,
&values[1], nullptr /* bytes_read */));
ASSERT_EQ(values[1], blobs[1]);
ASSERT_TRUE(
blob_source.TEST_BlobInCache(file_number, file_size, blob_offsets[1]));
// Release cache handle
values[1].Reset();
Derive cache keys from SST unique IDs (#10394) Summary: ... so that cache keys can be derived from DB manifest data before reading the file from storage--so that every part of the file can potentially go in a persistent cache. See updated comments in cache_key.cc for technical details. Importantly, the new cache key encoding uses some fancy but efficient math to pack data into the cache key without depending on the sizes of the various pieces. This simplifies some existing code creating cache keys, like cache warming before the file size is known. This should provide us an essentially permanent mapping between SST unique IDs and base cache keys, with the ability to "upgrade" SST unique IDs (and thus cache keys) with new SST format_versions. These cache keys are of similar, perhaps indistinguishable quality to the previous generation. Before this change (see "corrected" days between collision): ``` ./cache_bench -stress_cache_key -sck_keep_bits=43 18 collisions after 2 x 90 days, est 10 days between (1.15292e+19 corrected) ``` After this change (keep 43 bits, up through 50, to validate "trajectory" is ok on "corrected" days between collision): ``` 19 collisions after 3 x 90 days, est 14.2105 days between (1.63836e+19 corrected) 16 collisions after 5 x 90 days, est 28.125 days between (1.6213e+19 corrected) 15 collisions after 7 x 90 days, est 42 days between (1.21057e+19 corrected) 15 collisions after 17 x 90 days, est 102 days between (1.46997e+19 corrected) 15 collisions after 49 x 90 days, est 294 days between (2.11849e+19 corrected) 15 collisions after 62 x 90 days, est 372 days between (1.34027e+19 corrected) 15 collisions after 53 x 90 days, est 318 days between (5.72858e+18 corrected) 15 collisions after 309 x 90 days, est 1854 days between (1.66994e+19 corrected) ``` However, the change does modify (probably weaken) the "guaranteed unique" promise from this > SST files generated in a single process are guaranteed to have unique cache keys, unless/until number session ids * max file number = 2**86 to this (see https://github.com/facebook/rocksdb/issues/10388) > With the DB id limitation, we only have nice guaranteed unique cache keys for files generated in a single process until biggest session_id_counter and offset_in_file reach combined 64 bits I don't think this is a practical concern, though. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10394 Test Plan: unit tests updated, see simulation results above Reviewed By: jay-zhuang Differential Revision: D38667529 Pulled By: pdillinger fbshipit-source-id: 49af3fe7f47e5b61162809a78b76c769fd519fba
2 years ago
OffsetableCacheKey base_cache_key(db_id_, db_session_id_, file_number);
// blob_cache here only looks at the primary cache since we didn't provide
// the cache item helper for the secondary cache. However, since key0 is
// demoted to the secondary cache, we shouldn't be able to find it in the
// primary cache.
{
CacheKey cache_key = base_cache_key.WithOffset(blob_offsets[0]);
const Slice key0 = cache_key.AsSlice();
auto handle0 = blob_cache->Lookup(key0, statistics);
ASSERT_EQ(handle0, nullptr);
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
// key0's item should be in the secondary cache.
bool is_in_sec_cache = false;
auto sec_handle0 =
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
secondary_cache->Lookup(key0, create_cb, true,
/*advise_erase=*/true, is_in_sec_cache);
ASSERT_FALSE(is_in_sec_cache);
ASSERT_NE(sec_handle0, nullptr);
ASSERT_TRUE(sec_handle0->IsReady());
auto value = static_cast<BlobContents*>(sec_handle0->Value());
ASSERT_NE(value, nullptr);
ASSERT_EQ(value->data(), blobs[0]);
delete value;
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
// key0 doesn't exist in the blob cache although key0's dummy
// item exist in the secondary cache.
ASSERT_FALSE(blob_source.TEST_BlobInCache(file_number, file_size,
blob_offsets[0]));
}
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
// key1 should exists in the primary cache. key1's dummy item exists
// in the secondary cache.
{
CacheKey cache_key = base_cache_key.WithOffset(blob_offsets[1]);
const Slice key1 = cache_key.AsSlice();
auto handle1 = blob_cache->Lookup(key1, statistics);
ASSERT_NE(handle1, nullptr);
blob_cache->Release(handle1);
bool is_in_sec_cache = false;
auto sec_handle1 =
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
secondary_cache->Lookup(key1, create_cb, true,
/*advise_erase=*/true, is_in_sec_cache);
ASSERT_FALSE(is_in_sec_cache);
ASSERT_EQ(sec_handle1, nullptr);
ASSERT_TRUE(blob_source.TEST_BlobInCache(file_number, file_size,
blob_offsets[1]));
}
{
// fetch key0 from the blob file to the primary cache.
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
// key1 is evicted and inserted into the secondary cache.
ASSERT_OK(blob_source.GetBlob(
read_options, keys[0], file_number, blob_offsets[0], file_size,
blob_sizes[0], kNoCompression, nullptr /* prefetch_buffer */,
&values[0], nullptr /* bytes_read */));
ASSERT_EQ(values[0], blobs[0]);
// Release cache handle
values[0].Reset();
// key0 should be in the primary cache.
CacheKey cache_key0 = base_cache_key.WithOffset(blob_offsets[0]);
const Slice key0 = cache_key0.AsSlice();
auto handle0 = blob_cache->Lookup(key0, statistics);
ASSERT_NE(handle0, nullptr);
auto value = static_cast<BlobContents*>(blob_cache->Value(handle0));
ASSERT_NE(value, nullptr);
ASSERT_EQ(value->data(), blobs[0]);
blob_cache->Release(handle0);
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
// key1 is not in the primary cache and is in the secondary cache.
CacheKey cache_key1 = base_cache_key.WithOffset(blob_offsets[1]);
const Slice key1 = cache_key1.AsSlice();
auto handle1 = blob_cache->Lookup(key1, statistics);
ASSERT_EQ(handle1, nullptr);
// erase key0 from the primary cache.
blob_cache->Erase(key0);
handle0 = blob_cache->Lookup(key0, statistics);
ASSERT_EQ(handle0, nullptr);
// key1 promotion should succeed due to the primary cache being empty. we
// did't call secondary cache's Lookup() here, because it will remove the
// key but it won't be able to promote the key to the primary cache.
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
// Instead we use the end-to-end blob source API to read key1.
// In function TEST_BlobInCache, key1's dummy item is inserted into the
// primary cache and a standalone handle is checked by GetValue().
ASSERT_TRUE(blob_source.TEST_BlobInCache(file_number, file_size,
blob_offsets[1]));
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
// key1's dummy handle is in the primary cache and key1's item is still
// in the secondary cache. So, the primary cache's Lookup() can only
// get a dummy handle.
handle1 = blob_cache->Lookup(key1, statistics);
ASSERT_NE(handle1, nullptr);
Avoid recompressing cold block in CompressedSecondaryCache (#10527) Summary: **Summary:** When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache. When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache. **Implementation Details** Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true) The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache: 1. If a handle is found in primary cache: 1.1. If the handle's value is not nullptr, it is returned immediately. 1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache. - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache. 2. If a handle is not found in primary cache: 2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr. 2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle. The behaviors of `LRUCacheShard::Promote()` are updated as follows: 1. If `e->sec_handle` has value, one of the following steps can happen: 1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle. 1.2. Insert the item into the primary cache and return the handle to caller. 1.3. Exception handling. 3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released. The behavior of `CompressedSecondaryCache::Insert()` is updated: 1. If a block is evicted from the primary cache for the first time, a dummy item is inserted. 4. If a dummy item is found for a block, the block is inserted into the secondary cache. The behavior of `CompressedSecondaryCache:::Lookup()` is updated: 1. If a handle is not found or it is a dummy item, a nullptr is returned. 2. If `erase_handle` is true, the handle is erased. The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527 Test Plan: 1. stress tests. 5. unit tests. 6. CPU profiling for db_bench. Reviewed By: siying Differential Revision: D38747613 Pulled By: gitbw95 fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2 years ago
// handl1 is a dummy handle.
ASSERT_EQ(blob_cache->Value(handle1), nullptr);
blob_cache->Release(handle1);
}
}
}
class BlobSourceCacheReservationTest : public DBTestBase {
public:
explicit BlobSourceCacheReservationTest()
: DBTestBase("blob_source_cache_reservation_test",
/*env_do_fsync=*/true) {
options_.env = env_;
options_.enable_blob_files = true;
options_.create_if_missing = true;
LRUCacheOptions co;
co.capacity = kCacheCapacity;
co.num_shard_bits = kNumShardBits;
co.metadata_charge_policy = kDontChargeCacheMetadata;
co.high_pri_pool_ratio = 0.0;
co.low_pri_pool_ratio = 0.0;
std::shared_ptr<Cache> blob_cache = NewLRUCache(co);
co.high_pri_pool_ratio = 0.5;
co.low_pri_pool_ratio = 0.5;
std::shared_ptr<Cache> block_cache = NewLRUCache(co);
options_.blob_cache = blob_cache;
options_.lowest_used_cache_tier = CacheTier::kVolatileTier;
BlockBasedTableOptions block_based_options;
block_based_options.no_block_cache = false;
block_based_options.block_cache = block_cache;
block_based_options.cache_usage_options.options_overrides.insert(
{CacheEntryRole::kBlobCache,
{/* charged = */ CacheEntryRoleOptions::Decision::kEnabled}});
options_.table_factory.reset(
NewBlockBasedTableFactory(block_based_options));
assert(db_->GetDbIdentity(db_id_).ok());
assert(db_->GetDbSessionId(db_session_id_).ok());
}
void GenerateKeysAndBlobs() {
for (size_t i = 0; i < kNumBlobs; ++i) {
key_strs_.push_back("key" + std::to_string(i));
blob_strs_.push_back("blob" + std::to_string(i));
}
blob_file_size_ = BlobLogHeader::kSize;
for (size_t i = 0; i < kNumBlobs; ++i) {
keys_.push_back({key_strs_[i]});
blobs_.push_back({blob_strs_[i]});
blob_file_size_ +=
BlobLogRecord::kHeaderSize + keys_[i].size() + blobs_[i].size();
}
blob_file_size_ += BlobLogFooter::kSize;
}
static constexpr std::size_t kSizeDummyEntry = CacheReservationManagerImpl<
CacheEntryRole::kBlobCache>::GetDummyEntrySize();
static constexpr std::size_t kCacheCapacity = 1 * kSizeDummyEntry;
static constexpr int kNumShardBits = 0; // 2^0 shard
static constexpr uint32_t kColumnFamilyId = 1;
static constexpr bool kHasTTL = false;
static constexpr uint64_t kBlobFileNumber = 1;
static constexpr size_t kNumBlobs = 16;
std::vector<Slice> keys_;
std::vector<Slice> blobs_;
std::vector<std::string> key_strs_;
std::vector<std::string> blob_strs_;
uint64_t blob_file_size_;
Options options_;
std::string db_id_;
std::string db_session_id_;
};
#ifndef ROCKSDB_LITE
TEST_F(BlobSourceCacheReservationTest, SimpleCacheReservation) {
options_.cf_paths.emplace_back(
test::PerThreadDBPath(
env_, "BlobSourceCacheReservationTest_SimpleCacheReservation"),
0);
GenerateKeysAndBlobs();
DestroyAndReopen(options_);
ImmutableOptions immutable_options(options_);
constexpr ExpirationRange expiration_range;
std::vector<uint64_t> blob_offsets(keys_.size());
std::vector<uint64_t> blob_sizes(keys_.size());
WriteBlobFile(immutable_options, kColumnFamilyId, kHasTTL, expiration_range,
expiration_range, kBlobFileNumber, keys_, blobs_,
kNoCompression, blob_offsets, blob_sizes);
constexpr size_t capacity = 10;
std::shared_ptr<Cache> backing_cache = NewLRUCache(capacity);
FileOptions file_options;
constexpr HistogramImpl* blob_file_read_hist = nullptr;
std::unique_ptr<BlobFileCache> blob_file_cache =
std::make_unique<BlobFileCache>(
backing_cache.get(), &immutable_options, &file_options,
kColumnFamilyId, blob_file_read_hist, nullptr /*IOTracer*/);
BlobSource blob_source(&immutable_options, db_id_, db_session_id_,
blob_file_cache.get());
ConcurrentCacheReservationManager* cache_res_mgr =
static_cast<ChargedCache*>(blob_source.GetBlobCache())
->TEST_GetCacheReservationManager();
ASSERT_NE(cache_res_mgr, nullptr);
ReadOptions read_options;
read_options.verify_checksums = true;
{
read_options.fill_cache = false;
std::vector<PinnableSlice> values(keys_.size());
for (size_t i = 0; i < kNumBlobs; ++i) {
ASSERT_OK(blob_source.GetBlob(
read_options, keys_[i], kBlobFileNumber, blob_offsets[i],
blob_file_size_, blob_sizes[i], kNoCompression,
nullptr /* prefetch_buffer */, &values[i], nullptr /* bytes_read */));
ASSERT_EQ(cache_res_mgr->GetTotalReservedCacheSize(), 0);
ASSERT_EQ(cache_res_mgr->GetTotalMemoryUsed(), 0);
}
}
{
read_options.fill_cache = true;
std::vector<PinnableSlice> values(keys_.size());
// num_blobs is 16, so the total blob cache usage is less than a single
// dummy entry. Therefore, cache reservation manager only reserves one dummy
// entry here.
uint64_t blob_bytes = 0;
for (size_t i = 0; i < kNumBlobs; ++i) {
ASSERT_OK(blob_source.GetBlob(
read_options, keys_[i], kBlobFileNumber, blob_offsets[i],
blob_file_size_, blob_sizes[i], kNoCompression,
nullptr /* prefetch_buffer */, &values[i], nullptr /* bytes_read */));
size_t charge = 0;
ASSERT_TRUE(blob_source.TEST_BlobInCache(kBlobFileNumber, blob_file_size_,
blob_offsets[i], &charge));
blob_bytes += charge;
ASSERT_EQ(cache_res_mgr->GetTotalReservedCacheSize(), kSizeDummyEntry);
ASSERT_EQ(cache_res_mgr->GetTotalMemoryUsed(), blob_bytes);
ASSERT_EQ(cache_res_mgr->GetTotalMemoryUsed(),
options_.blob_cache->GetUsage());
}
}
{
Derive cache keys from SST unique IDs (#10394) Summary: ... so that cache keys can be derived from DB manifest data before reading the file from storage--so that every part of the file can potentially go in a persistent cache. See updated comments in cache_key.cc for technical details. Importantly, the new cache key encoding uses some fancy but efficient math to pack data into the cache key without depending on the sizes of the various pieces. This simplifies some existing code creating cache keys, like cache warming before the file size is known. This should provide us an essentially permanent mapping between SST unique IDs and base cache keys, with the ability to "upgrade" SST unique IDs (and thus cache keys) with new SST format_versions. These cache keys are of similar, perhaps indistinguishable quality to the previous generation. Before this change (see "corrected" days between collision): ``` ./cache_bench -stress_cache_key -sck_keep_bits=43 18 collisions after 2 x 90 days, est 10 days between (1.15292e+19 corrected) ``` After this change (keep 43 bits, up through 50, to validate "trajectory" is ok on "corrected" days between collision): ``` 19 collisions after 3 x 90 days, est 14.2105 days between (1.63836e+19 corrected) 16 collisions after 5 x 90 days, est 28.125 days between (1.6213e+19 corrected) 15 collisions after 7 x 90 days, est 42 days between (1.21057e+19 corrected) 15 collisions after 17 x 90 days, est 102 days between (1.46997e+19 corrected) 15 collisions after 49 x 90 days, est 294 days between (2.11849e+19 corrected) 15 collisions after 62 x 90 days, est 372 days between (1.34027e+19 corrected) 15 collisions after 53 x 90 days, est 318 days between (5.72858e+18 corrected) 15 collisions after 309 x 90 days, est 1854 days between (1.66994e+19 corrected) ``` However, the change does modify (probably weaken) the "guaranteed unique" promise from this > SST files generated in a single process are guaranteed to have unique cache keys, unless/until number session ids * max file number = 2**86 to this (see https://github.com/facebook/rocksdb/issues/10388) > With the DB id limitation, we only have nice guaranteed unique cache keys for files generated in a single process until biggest session_id_counter and offset_in_file reach combined 64 bits I don't think this is a practical concern, though. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10394 Test Plan: unit tests updated, see simulation results above Reviewed By: jay-zhuang Differential Revision: D38667529 Pulled By: pdillinger fbshipit-source-id: 49af3fe7f47e5b61162809a78b76c769fd519fba
2 years ago
OffsetableCacheKey base_cache_key(db_id_, db_session_id_, kBlobFileNumber);
size_t blob_bytes = options_.blob_cache->GetUsage();
for (size_t i = 0; i < kNumBlobs; ++i) {
size_t charge = 0;
ASSERT_TRUE(blob_source.TEST_BlobInCache(kBlobFileNumber, blob_file_size_,
blob_offsets[i], &charge));
CacheKey cache_key = base_cache_key.WithOffset(blob_offsets[i]);
// We didn't call options_.blob_cache->Erase() here, this is because
// the cache wrapper's Erase() method must be called to update the
// cache usage after erasing the cache entry.
blob_source.GetBlobCache()->Erase(cache_key.AsSlice());
if (i == kNumBlobs - 1) {
// All the blobs got removed from the cache. cache_res_mgr should not
// reserve any space for them.
ASSERT_EQ(cache_res_mgr->GetTotalReservedCacheSize(), 0);
} else {
ASSERT_EQ(cache_res_mgr->GetTotalReservedCacheSize(), kSizeDummyEntry);
}
blob_bytes -= charge;
ASSERT_EQ(cache_res_mgr->GetTotalMemoryUsed(), blob_bytes);
ASSERT_EQ(cache_res_mgr->GetTotalMemoryUsed(),
options_.blob_cache->GetUsage());
}
}
}
TEST_F(BlobSourceCacheReservationTest, IncreaseCacheReservationOnFullCache) {
options_.cf_paths.emplace_back(
test::PerThreadDBPath(
env_,
"BlobSourceCacheReservationTest_IncreaseCacheReservationOnFullCache"),
0);
GenerateKeysAndBlobs();
DestroyAndReopen(options_);
ImmutableOptions immutable_options(options_);
constexpr size_t blob_size = kSizeDummyEntry / (kNumBlobs / 2);
for (size_t i = 0; i < kNumBlobs; ++i) {
blob_file_size_ -= blobs_[i].size(); // old blob size
blob_strs_[i].resize(blob_size, '@');
blobs_[i] = Slice(blob_strs_[i]);
blob_file_size_ += blobs_[i].size(); // new blob size
}
std::vector<uint64_t> blob_offsets(keys_.size());
std::vector<uint64_t> blob_sizes(keys_.size());
constexpr ExpirationRange expiration_range;
WriteBlobFile(immutable_options, kColumnFamilyId, kHasTTL, expiration_range,
expiration_range, kBlobFileNumber, keys_, blobs_,
kNoCompression, blob_offsets, blob_sizes);
constexpr size_t capacity = 10;
std::shared_ptr<Cache> backing_cache = NewLRUCache(capacity);
FileOptions file_options;
constexpr HistogramImpl* blob_file_read_hist = nullptr;
std::unique_ptr<BlobFileCache> blob_file_cache =
std::make_unique<BlobFileCache>(
backing_cache.get(), &immutable_options, &file_options,
kColumnFamilyId, blob_file_read_hist, nullptr /*IOTracer*/);
BlobSource blob_source(&immutable_options, db_id_, db_session_id_,
blob_file_cache.get());
ConcurrentCacheReservationManager* cache_res_mgr =
static_cast<ChargedCache*>(blob_source.GetBlobCache())
->TEST_GetCacheReservationManager();
ASSERT_NE(cache_res_mgr, nullptr);
ReadOptions read_options;
read_options.verify_checksums = true;
{
read_options.fill_cache = false;
std::vector<PinnableSlice> values(keys_.size());
for (size_t i = 0; i < kNumBlobs; ++i) {
ASSERT_OK(blob_source.GetBlob(
read_options, keys_[i], kBlobFileNumber, blob_offsets[i],
blob_file_size_, blob_sizes[i], kNoCompression,
nullptr /* prefetch_buffer */, &values[i], nullptr /* bytes_read */));
ASSERT_EQ(cache_res_mgr->GetTotalReservedCacheSize(), 0);
ASSERT_EQ(cache_res_mgr->GetTotalMemoryUsed(), 0);
}
}
{
read_options.fill_cache = true;
std::vector<PinnableSlice> values(keys_.size());
// Since we resized each blob to be kSizeDummyEntry / (num_blobs / 2), we
// can't fit all the blobs in the cache at the same time, which means we
// should observe cache evictions once we reach the cache's capacity.
// Due to the overhead of the cache and the BlobContents objects, as well as
// jemalloc bin sizes, this happens after inserting seven blobs.
uint64_t blob_bytes = 0;
for (size_t i = 0; i < kNumBlobs; ++i) {
ASSERT_OK(blob_source.GetBlob(
read_options, keys_[i], kBlobFileNumber, blob_offsets[i],
blob_file_size_, blob_sizes[i], kNoCompression,
nullptr /* prefetch_buffer */, &values[i], nullptr /* bytes_read */));
// Release cache handle
values[i].Reset();
if (i < kNumBlobs / 2 - 1) {
size_t charge = 0;
ASSERT_TRUE(blob_source.TEST_BlobInCache(
kBlobFileNumber, blob_file_size_, blob_offsets[i], &charge));
blob_bytes += charge;
}
ASSERT_EQ(cache_res_mgr->GetTotalReservedCacheSize(), kSizeDummyEntry);
ASSERT_EQ(cache_res_mgr->GetTotalMemoryUsed(), blob_bytes);
ASSERT_EQ(cache_res_mgr->GetTotalMemoryUsed(),
options_.blob_cache->GetUsage());
}
}
}
#endif // ROCKSDB_LITE
} // namespace ROCKSDB_NAMESPACE
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}