NextGraph
/
rocksdb
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Integrate block cache tracer in block based table reader. (#5441)

Browse Source 
Summary:
This PR integrates the block cache tracer into block based table reader. The tracer will write the block cache accesses using the trace_writer. The tracer is null in this PR so that nothing will be logged.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5441

Differential Revision: D15772029

Pulled By: HaoyuHuang

fbshipit-source-id: a64adb92642cd23222e0ba8b10d86bf522b42f9b
main
haoyuhuang 6 years ago committed by Facebook Github Bot
parent f1219644ec
commit 7a8d7358bb
7 changed files with 365 additions and 110 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 265
      table/block_based/block_based_table_reader.cc
  2. 18
      table/block_based/block_based_table_reader.h
  3. 5
      tools/block_cache_trace_analyzer.h
  4. 5
      tools/block_cache_trace_analyzer_test.cc
  5. 62
      trace_replay/block_cache_tracer.cc
  6. 89
      trace_replay/block_cache_tracer.h
  7. 31
      trace_replay/block_cache_tracer_test.cc

265
table/block_based/block_based_table_reader.cc
Unescape View File

@ -1877,9 +1877,8 @@ CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
FilePrefetchBuffer* prefetch_buffer, const BlockHandle& filter_blk_handle,
const bool is_a_filter_partition, bool no_io, GetContext* get_context,
BlockCacheLookupContext* /*lookup_context*/,
BlockCacheLookupContext* lookup_context,
const SliceTransform* prefix_extractor) const {
// TODO(haoyu): Trace filter block access here.
// If cache_index_and_filter_blocks is false, filter should be pre-populated.
// We will return rep_->filter anyway. rep_->filter can be nullptr if filter
// read fails at Open() time. We don't want to reload again since it will
@ -1912,17 +1911,22 @@ CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
GetEntryFromCache(block_cache, key, BlockType::kFilter, get_context);
FilterBlockReader* filter = nullptr;
size_t usage = 0;
bool is_cache_hit = false;
bool return_empty_reader = false;
if (cache_handle != nullptr) {
filter =
reinterpret_cast<FilterBlockReader*>(block_cache->Value(cache_handle));
usage = filter->ApproximateMemoryUsage();
is_cache_hit = true;
} else if (no_io) {
// Do not invoke any io.
return CachableEntry<FilterBlockReader>();
return_empty_reader = true;
} else {
filter = ReadFilter(prefetch_buffer, filter_blk_handle,
is_a_filter_partition, prefix_extractor);
if (filter != nullptr) {
size_t usage = filter->ApproximateMemoryUsage();
usage = filter->ApproximateMemoryUsage();
Status s = block_cache->Insert(
key, filter, usage, &DeleteCachedFilterEntry, &cache_handle,
rep_->table_options.cache_index_and_filter_blocks_with_high_priority
@ -1934,19 +1938,36 @@ CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
} else {
RecordTick(rep_->ioptions.statistics, BLOCK_CACHE_ADD_FAILURES);
delete filter;
return CachableEntry<FilterBlockReader>();
return_empty_reader = true;
}
}
}
if (block_cache_tracer_ && lookup_context) {
// Avoid making copy of block_key and cf_name when constructing the access
// record.
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", TraceType::kBlockTraceFilterBlock,
/*block_size=*/usage, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_context->caller, is_cache_hit,
/*no_insert=*/no_io);
block_cache_tracer_->WriteBlockAccess(access_record, key,
rep_->cf_name_for_tracing(),
/*referenced_key=*/nullptr);
}
if (return_empty_reader) {
return CachableEntry<FilterBlockReader>();
}
return {filter, cache_handle ? block_cache : nullptr, cache_handle,
/*own_value=*/false};
}
CachableEntry<UncompressionDict> BlockBasedTable::GetUncompressionDict(
FilePrefetchBuffer* prefetch_buffer, bool no_io, GetContext* get_context,
BlockCacheLookupContext* /*lookup_context*/) const {
// TODO(haoyu): Trace the access on the uncompression dictionary here.
BlockCacheLookupContext* lookup_context) const {
if (!rep_->table_options.cache_index_and_filter_blocks) {
// block cache is either disabled or not used for meta-blocks. In either
// case, BlockBasedTableReader is the owner of the uncompression dictionary.
@ -1964,9 +1985,13 @@ CachableEntry<UncompressionDict> BlockBasedTable::GetUncompressionDict(
GetEntryFromCache(rep_->table_options.block_cache.get(), cache_key,
BlockType::kCompressionDictionary, get_context);
UncompressionDict* dict = nullptr;
bool is_cache_hit = false;
size_t usage = 0;
if (cache_handle != nullptr) {
dict = reinterpret_cast<UncompressionDict*>(
rep_->table_options.block_cache->Value(cache_handle));
is_cache_hit = true;
usage = dict->ApproximateMemoryUsage();
} else if (no_io) {
// Do not invoke any io.
} else {
@ -1980,7 +2005,7 @@ CachableEntry<UncompressionDict> BlockBasedTable::GetUncompressionDict(
new UncompressionDict(compression_dict_block->data.ToString(),
rep_->blocks_definitely_zstd_compressed,
rep_->ioptions.statistics));
const size_t usage = uncompression_dict->ApproximateMemoryUsage();
usage = uncompression_dict->ApproximateMemoryUsage();
s = rep_->table_options.block_cache->Insert(
cache_key, uncompression_dict.get(), usage,
&DeleteCachedUncompressionDictEntry, &cache_handle,
@ -2000,6 +2025,20 @@ CachableEntry<UncompressionDict> BlockBasedTable::GetUncompressionDict(
}
}
}
if (block_cache_tracer_ && lookup_context) {
// Avoid making copy of block_key and cf_name when constructing the access
// record.
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", TraceType::kBlockTraceUncompressionDictBlock,
/*block_size=*/usage, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_context->caller, is_cache_hit,
/*no_insert=*/no_io);
block_cache_tracer_->WriteBlockAccess(access_record, cache_key,
rep_->cf_name_for_tracing(),
/*referenced_key=*/nullptr);
}
return {dict, cache_handle ? rep_->table_options.block_cache.get() : nullptr,
cache_handle, false /* own_value */};
}
@ -2116,13 +2155,10 @@ Status BlockBasedTable::MaybeReadBlockAndLoadToCache(
FilePrefetchBuffer* prefetch_buffer, const ReadOptions& ro,
const BlockHandle& handle, const UncompressionDict& uncompression_dict,
CachableEntry<Block>* block_entry, BlockType block_type,
GetContext* get_context,
BlockCacheLookupContext* /*lookup_context*/) const {
// TODO(haoyu): Trace data/index/range deletion block access here.
GetContext* get_context, BlockCacheLookupContext* lookup_context) const {
assert(block_entry != nullptr);
const bool no_io = (ro.read_tier == kBlockCacheTier);
Cache* block_cache = rep_->table_options.block_cache.get();
// No point to cache compressed blocks if it never goes away
Cache* block_cache_compressed =
rep_->immortal_table ? nullptr
@ -2136,6 +2172,8 @@ Status BlockBasedTable::MaybeReadBlockAndLoadToCache(
char compressed_cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
Slice key /* key to the block cache */;
Slice ckey /* key to the compressed block cache */;
bool is_cache_hit = false;
bool no_insert = true;
if (block_cache != nullptr || block_cache_compressed != nullptr) {
// create key for block cache
if (block_cache != nullptr) {
@ -2152,10 +2190,15 @@ Status BlockBasedTable::MaybeReadBlockAndLoadToCache(
s = GetDataBlockFromCache(key, ckey, block_cache, block_cache_compressed,
ro, block_entry, uncompression_dict, block_type,
get_context);
if (block_entry->GetValue()) {
// TODO(haoyu): Differentiate cache hit on uncompressed block cache and
// compressed block cache.
is_cache_hit = true;
}
// Can't find the block from the cache. If I/O is allowed, read from the
// file.
if (block_entry->GetValue() == nullptr && !no_io && ro.fill_cache) {
no_insert = false;
Statistics* statistics = rep_->ioptions.statistics;
bool do_decompress =
block_cache_compressed == nullptr && rep_->blocks_maybe_compressed;
@ -2186,6 +2229,59 @@ Status BlockBasedTable::MaybeReadBlockAndLoadToCache(
}
}
}
// Fill lookup_context.
if (block_cache_tracer_ && lookup_context) {
size_t usage = 0;
uint64_t nkeys = 0;
if (block_entry->GetValue()) {
// Approximate the number of keys in the block using restarts.
nkeys = rep_->table_options.block_restart_interval *
block_entry->GetValue()->NumRestarts();
usage = block_entry->GetValue()->ApproximateMemoryUsage();
}
TraceType trace_block_type = TraceType::kTraceMax;
switch (block_type) {
case BlockType::kIndex:
trace_block_type = TraceType::kBlockTraceIndexBlock;
break;
case BlockType::kData:
trace_block_type = TraceType::kBlockTraceDataBlock;
break;
case BlockType::kRangeDeletion:
trace_block_type = TraceType::kBlockTraceRangeDeletionBlock;
break;
default:
// This cannot happen.
assert(false);
break;
}
if (BlockCacheTraceHelper::ShouldTraceReferencedKey(
trace_block_type, lookup_context->caller)) {
// Defer logging the access to Get() and MultiGet() to trace additional
// information, e.g., the referenced key,
// referenced_key_exist_in_block.
// Make a copy of the block key here since it will be logged later.
lookup_context->FillLookupContext(
is_cache_hit, no_insert, trace_block_type,
/*block_size=*/usage, /*block_key=*/key.ToString(), nkeys);
} else {
// Avoid making copy of block_key and cf_name when constructing the access
// record.
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", trace_block_type,
/*block_size=*/usage, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_context->caller, is_cache_hit,
no_insert);
block_cache_tracer_->WriteBlockAccess(access_record, key,
rep_->cf_name_for_tracing(),
/*referenced_key=*/nullptr);
}
}
assert(s.ok() || block_entry->GetValue() == nullptr);
return s;
}
@ -2874,11 +2970,15 @@ Status BlockBasedTable::Get(const ReadOptions& read_options, const Slice& key,
PERF_COUNTER_BY_LEVEL_ADD(bloom_filter_useful, 1, rep_->level);
break;
} else {
BlockCacheLookupContext lookup_data_block_context{
BlockCacheLookupCaller::kUserGet};
bool does_referenced_key_exist = false;
DataBlockIter biter;
uint64_t referenced_data_size = 0;
NewDataBlockIterator<DataBlockIter>(
read_options, iiter->value(), &biter, BlockType::kData,
/*key_includes_seq=*/true,
/*index_key_is_full=*/true, get_context, &lookup_context,
/*index_key_is_full=*/true, get_context, &lookup_data_block_context,
/*s=*/Status(), /*prefetch_buffer*/ nullptr);
if (read_options.read_tier == kBlockCacheTier &&
@ -2902,25 +3002,47 @@ Status BlockBasedTable::Get(const ReadOptions& read_options, const Slice& key,
// the end of the block, i.e. cannot be in the following blocks
// either. In this case, the seek_key cannot be found, so we break
// from the top level for-loop.
break;
}
// Call the *saver function on each entry/block until it returns false
for (; biter.Valid(); biter.Next()) {
ParsedInternalKey parsed_key;
if (!ParseInternalKey(biter.key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
done = true;
} else {
// Call the *saver function on each entry/block until it returns false
for (; biter.Valid(); biter.Next()) {
ParsedInternalKey parsed_key;
if (!ParseInternalKey(biter.key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (!get_context->SaveValue(
parsed_key, biter.value(), &matched,
biter.IsValuePinned() ? &biter : nullptr)) {
done = true;
break;
if (!get_context->SaveValue(
parsed_key, biter.value(), &matched,
biter.IsValuePinned() ? &biter : nullptr)) {
does_referenced_key_exist = true;
referenced_data_size = biter.key().size() + biter.value().size();
done = true;
break;
}
}
s = biter.status();
}
// Write the block cache access record.
if (block_cache_tracer_) {
// Avoid making copy of block_key, cf_name, and referenced_key when
// constructing the access record.
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", lookup_data_block_context.block_type,
lookup_data_block_context.block_size, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_data_block_context.caller,
lookup_data_block_context.is_cache_hit,
lookup_data_block_context.no_insert,
/*referenced_key=*/"", referenced_data_size,
lookup_data_block_context.num_keys_in_block,
does_referenced_key_exist);
block_cache_tracer_->WriteBlockAccess(
access_record, lookup_data_block_context.block_key,
rep_->cf_name_for_tracing(), key);
}
s = biter.status();
}
if (done) {
// Avoid the extra Next which is expensive in two-level indexes
break;
@ -2992,14 +3114,18 @@ void BlockBasedTable::MultiGet(const ReadOptions& read_options,
bool done = false;
for (iiter->Seek(key); iiter->Valid() && !done; iiter->Next()) {
bool reusing_block = true;
uint64_t referenced_data_size = 0;
bool does_referenced_key_exist = false;
BlockCacheLookupContext lookup_data_block_context(
BlockCacheLookupCaller::kUserMGet);
if (iiter->value().offset() != offset) {
offset = iiter->value().offset();
biter.Invalidate(Status::OK());
NewDataBlockIterator<DataBlockIter>(
read_options, iiter->value(), &biter, BlockType::kData,
/*key_includes_seq=*/false,
/*index_key_is_full=*/true, get_context, &lookup_context,
Status(), nullptr);
/*index_key_is_full=*/true, get_context,
&lookup_data_block_context, Status(), nullptr);
reusing_block = false;
}
if (read_options.read_tier == kBlockCacheTier &&
@ -3021,38 +3147,59 @@ void BlockBasedTable::MultiGet(const ReadOptions& read_options,
// the end of the block, i.e. cannot be in the following blocks
// either. In this case, the seek_key cannot be found, so we break
// from the top level for-loop.
break;
}
// Call the *saver function on each entry/block until it returns false
for (; biter.Valid(); biter.Next()) {
ParsedInternalKey parsed_key;
Cleanable dummy;
Cleanable* value_pinner = nullptr;
if (!ParseInternalKey(biter.key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (biter.IsValuePinned()) {
if (reusing_block) {
Cache* block_cache = rep_->table_options.block_cache.get();
assert(biter.cache_handle() != nullptr);
block_cache->Ref(biter.cache_handle());
dummy.RegisterCleanup(&ReleaseCachedEntry, block_cache,
biter.cache_handle());
value_pinner = &dummy;
} else {
value_pinner = &biter;
done = true;
} else {
// Call the *saver function on each entry/block until it returns false
for (; biter.Valid(); biter.Next()) {
ParsedInternalKey parsed_key;
Cleanable dummy;
Cleanable* value_pinner = nullptr;
if (!ParseInternalKey(biter.key(), &parsed_key)) {
s = Status::Corruption(Slice());
}
if (biter.IsValuePinned()) {
if (reusing_block) {
Cache* block_cache = rep_->table_options.block_cache.get();
assert(biter.cache_handle() != nullptr);
block_cache->Ref(biter.cache_handle());
dummy.RegisterCleanup(&ReleaseCachedEntry, block_cache,
biter.cache_handle());
value_pinner = &dummy;
} else {
value_pinner = &biter;
}
}
}
if (!get_context->SaveValue(
parsed_key, biter.value(), &matched, value_pinner)) {
done = true;
break;
if (!get_context->SaveValue(parsed_key, biter.value(), &matched,
value_pinner)) {
does_referenced_key_exist = true;
referenced_data_size = biter.key().size() + biter.value().size();
done = true;
break;
}
}
s = biter.status();
}
// Write the block cache access.
if (block_cache_tracer_) {
// Avoid making copy of block_key, cf_name, and referenced_key when
// constructing the access record.
BlockCacheTraceRecord access_record(
rep_->ioptions.env->NowMicros(),
/*block_key=*/"", lookup_data_block_context.block_type,
lookup_data_block_context.block_size, rep_->cf_id_for_tracing(),
/*cf_name=*/"", rep_->level_for_tracing(),
rep_->sst_number_for_tracing(), lookup_data_block_context.caller,
lookup_data_block_context.is_cache_hit,
lookup_data_block_context.no_insert,
/*referenced_key=*/"", referenced_data_size,
lookup_data_block_context.num_keys_in_block,
does_referenced_key_exist);
block_cache_tracer_->WriteBlockAccess(
access_record, lookup_data_block_context.block_key,
rep_->cf_name_for_tracing(), key);
}
s = biter.status();
if (done) {
// Avoid the extra Next which is expensive in two-level indexes
break;

18
table/block_based/block_based_table_reader.h
Unescape View File

@ -17,6 +17,7 @@
#include <vector>
#include "db/range_tombstone_fragmenter.h"
#include "file/filename.h"
#include "options/cf_options.h"
#include "rocksdb/options.h"
#include "rocksdb/persistent_cache.h"
@ -571,6 +572,23 @@ struct BlockBasedTable::Rep {
? kDisableGlobalSequenceNumber
: global_seqno;
}
uint64_t cf_id_for_tracing() const {
return table_properties ? table_properties->column_family_id
: rocksdb::TablePropertiesCollectorFactory::
Context::kUnknownColumnFamily;
}
Slice cf_name_for_tracing() const {
return table_properties ? table_properties->column_family_name
: BlockCacheTraceHelper::kUnknownColumnFamilyName;
}
uint32_t level_for_tracing() const { return level >= 0 ? level : UINT32_MAX; }
uint64_t sst_number_for_tracing() const {
return file ? TableFileNameToNumber(file->file_name()) : UINT64_MAX;
}
};
// Iterates over the contents of BlockBasedTable.

5
tools/block_cache_trace_analyzer.h
Unescape View File

@ -35,10 +35,11 @@ struct BlockAccessInfo {
block_size = access.block_size;
caller_num_access_map[access.caller]++;
num_accesses++;
if (ShouldTraceReferencedKey(access)) {
if (BlockCacheTraceHelper::ShouldTraceReferencedKey(access.block_type,
access.caller)) {
num_keys = access.num_keys_in_block;
if (access.is_referenced_key_exist_in_block == Boolean::kTrue) {
if (access.referenced_key_exist_in_block == Boolean::kTrue) {
key_num_access_map[access.referenced_key]++;
num_referenced_key_exist_in_block++;
} else {

5
tools/block_cache_trace_analyzer_test.cc
Unescape View File

@ -89,9 +89,10 @@ class BlockCacheTracerTest : public testing::Test {
// The writer should only write these fields for data blocks and the
// caller is either GET or MGET.
record.referenced_key = kRefKeyPrefix + std::to_string(key_id);
record.is_referenced_key_exist_in_block = Boolean::kTrue;
record.referenced_key_exist_in_block = Boolean::kTrue;
record.num_keys_in_block = kNumKeysInBlock;
ASSERT_OK(writer->WriteBlockAccess(record));
ASSERT_OK(writer->WriteBlockAccess(
record, record.block_key, record.cf_name, record.referenced_key));
}
}

62
trace_replay/block_cache_tracer.cc
Unescape View File

@ -15,13 +15,6 @@ namespace rocksdb {
namespace {
const unsigned int kCharSize = 1;
} // namespace
bool ShouldTraceReferencedKey(const BlockCacheTraceRecord& record) {
return (record.block_type == TraceType::kBlockTraceDataBlock) &&
(record.caller == BlockCacheLookupCaller::kUserGet ||
record.caller == BlockCacheLookupCaller::kUserMGet);
}
bool ShouldTrace(const BlockCacheTraceRecord& record,
const TraceOptions& trace_options) {
@ -34,6 +27,17 @@ bool ShouldTrace(const BlockCacheTraceRecord& record,
const uint64_t hash = GetSliceNPHash64(Slice(record.block_key));
return hash % trace_options.sampling_frequency == 0;
}
} // namespace
const std::string BlockCacheTraceHelper::kUnknownColumnFamilyName =
"UnknownColumnFamily";
bool BlockCacheTraceHelper::ShouldTraceReferencedKey(
TraceType block_type, BlockCacheLookupCaller caller) {
return (block_type == TraceType::kBlockTraceDataBlock) &&
(caller == BlockCacheLookupCaller::kUserGet ||
caller == BlockCacheLookupCaller::kUserMGet);
}
BlockCacheTraceWriter::BlockCacheTraceWriter(
Env* env, const TraceOptions& trace_options,
@ -43,7 +47,8 @@ BlockCacheTraceWriter::BlockCacheTraceWriter(
trace_writer_(std::move(trace_writer)) {}
Status BlockCacheTraceWriter::WriteBlockAccess(
const BlockCacheTraceRecord& record) {
const BlockCacheTraceRecord& record, const Slice& block_key,
const Slice& cf_name, const Slice& referenced_key) {
uint64_t trace_file_size = trace_writer_->GetFileSize();
if (trace_file_size > trace_options_.max_trace_file_size) {
return Status::OK();
@ -51,19 +56,21 @@ Status BlockCacheTraceWriter::WriteBlockAccess(
Trace trace;
trace.ts = record.access_timestamp;
trace.type = record.block_type;
PutLengthPrefixedSlice(&trace.payload, record.block_key);
PutLengthPrefixedSlice(&trace.payload, block_key);
PutFixed64(&trace.payload, record.block_size);
PutFixed32(&trace.payload, record.cf_id);
PutLengthPrefixedSlice(&trace.payload, record.cf_name);
PutFixed64(&trace.payload, record.cf_id);
PutLengthPrefixedSlice(&trace.payload, cf_name);
PutFixed32(&trace.payload, record.level);
PutFixed32(&trace.payload, record.sst_fd_number);
PutFixed64(&trace.payload, record.sst_fd_number);
trace.payload.push_back(record.caller);
trace.payload.push_back(record.is_cache_hit);
trace.payload.push_back(record.no_insert);
if (ShouldTraceReferencedKey(record)) {
PutLengthPrefixedSlice(&trace.payload, record.referenced_key);
if (BlockCacheTraceHelper::ShouldTraceReferencedKey(record.block_type,
record.caller)) {
PutLengthPrefixedSlice(&trace.payload, referenced_key);
PutFixed64(&trace.payload, record.referenced_data_size);
PutFixed64(&trace.payload, record.num_keys_in_block);
trace.payload.push_back(record.is_referenced_key_exist_in_block);
trace.payload.push_back(record.referenced_key_exist_in_block);
}
std::string encoded_trace;
TracerHelper::EncodeTrace(trace, &encoded_trace);
@ -143,6 +150,7 @@ Status BlockCacheTraceReader::ReadAccess(BlockCacheTraceRecord* record) {
record->access_timestamp = trace.ts;
record->block_type = trace.type;
Slice enc_slice = Slice(trace.payload);
Slice block_key;
if (!GetLengthPrefixedSlice(&enc_slice, &block_key)) {
return Status::Incomplete(
@ -153,7 +161,7 @@ Status BlockCacheTraceReader::ReadAccess(BlockCacheTraceRecord* record) {
return Status::Incomplete(
"Incomplete access record: Failed to read block size.");
}
if (!GetFixed32(&enc_slice, &record->cf_id)) {
if (!GetFixed64(&enc_slice, &record->cf_id)) {
return Status::Incomplete(
"Incomplete access record: Failed to read column family ID.");
}
@ -167,7 +175,7 @@ Status BlockCacheTraceReader::ReadAccess(BlockCacheTraceRecord* record) {
return Status::Incomplete(
"Incomplete access record: Failed to read level.");
}
if (!GetFixed32(&enc_slice, &record->sst_fd_number)) {
if (!GetFixed64(&enc_slice, &record->sst_fd_number)) {
return Status::Incomplete(
"Incomplete access record: Failed to read SST file number.");
}
@ -190,13 +198,18 @@ Status BlockCacheTraceReader::ReadAccess(BlockCacheTraceRecord* record) {
record->no_insert = static_cast<Boolean>(enc_slice[0]);
enc_slice.remove_prefix(kCharSize);
if (ShouldTraceReferencedKey(*record)) {
if (BlockCacheTraceHelper::ShouldTraceReferencedKey(record->block_type,
record->caller)) {
Slice referenced_key;
if (!GetLengthPrefixedSlice(&enc_slice, &referenced_key)) {
return Status::Incomplete(
"Incomplete access record: Failed to read the referenced key.");
}
record->referenced_key = referenced_key.ToString();
if (!GetFixed64(&enc_slice, &record->referenced_data_size)) {
return Status::Incomplete(
"Incomplete access record: Failed to read the referenced data size.");
}
if (!GetFixed64(&enc_slice, &record->num_keys_in_block)) {
return Status::Incomplete(
"Incomplete access record: Failed to read the number of keys in the "
@ -205,10 +218,9 @@ Status BlockCacheTraceReader::ReadAccess(BlockCacheTraceRecord* record) {
if (enc_slice.empty()) {
return Status::Incomplete(
"Incomplete access record: Failed to read "
"is_referenced_key_exist_in_block.");
"referenced_key_exist_in_block.");
}
record->is_referenced_key_exist_in_block =
static_cast<Boolean>(enc_slice[0]);
record->referenced_key_exist_in_block = static_cast<Boolean>(enc_slice[0]);
}
return Status::OK();
}
@ -239,7 +251,10 @@ void BlockCacheTracer::EndTrace() {
writer_.store(nullptr);
}
Status BlockCacheTracer::WriteBlockAccess(const BlockCacheTraceRecord& record) {
Status BlockCacheTracer::WriteBlockAccess(const BlockCacheTraceRecord& record,
const Slice& block_key,
const Slice& cf_name,
const Slice& referenced_key) {
if (!writer_.load() || !ShouldTrace(record, trace_options_)) {
return Status::OK();
}
@ -247,7 +262,8 @@ Status BlockCacheTracer::WriteBlockAccess(const BlockCacheTraceRecord& record) {
if (!writer_.load()) {
return Status::OK();
}
return writer_.load()->WriteBlockAccess(record);
return writer_.load()->WriteBlockAccess(record, block_key, cf_name,
referenced_key);
}
} // namespace rocksdb

89
trace_replay/block_cache_tracer.h
Unescape View File

@ -49,28 +49,80 @@ struct BlockCacheLookupContext {
BlockCacheLookupContext(const BlockCacheLookupCaller& _caller)
: caller(_caller) {}
const BlockCacheLookupCaller caller;
// These are populated when we perform lookup/insert on block cache. The block
// cache tracer uses these inforation when logging the block access at
// BlockBasedTable::GET and BlockBasedTable::MultiGet.
bool is_cache_hit = false;
bool no_insert = false;
TraceType block_type = TraceType::kTraceMax;
uint64_t block_size = 0;
std::string block_key;
uint64_t num_keys_in_block = 0;
void FillLookupContext(bool _is_cache_hit, bool _no_insert,
TraceType _block_type, uint64_t _block_size,
const std::string& _block_key,
uint64_t _num_keys_in_block) {
is_cache_hit = _is_cache_hit;
no_insert = _no_insert;
block_type = _block_type;
block_size = _block_size;
block_key = _block_key;
num_keys_in_block = _num_keys_in_block;
}
};
enum Boolean : char { kTrue = 1, kFalse = 0 };
struct BlockCacheTraceRecord {
// Required fields for all accesses.
uint64_t access_timestamp;
uint64_t access_timestamp = 0;
std::string block_key;
TraceType block_type;
uint64_t block_size;
uint32_t cf_id;
TraceType block_type = TraceType::kTraceMax;
uint64_t block_size = 0;
uint64_t cf_id = 0;
std::string cf_name;
uint32_t level;
uint32_t sst_fd_number;
BlockCacheLookupCaller caller;
Boolean is_cache_hit;
Boolean no_insert;
uint32_t level = 0;
uint64_t sst_fd_number = 0;
BlockCacheLookupCaller caller =
BlockCacheLookupCaller::kMaxBlockCacheLookupCaller;
Boolean is_cache_hit = Boolean::kFalse;
Boolean no_insert = Boolean::kFalse;
// Required fields for data block and user Get/Multi-Get only.
std::string referenced_key;
uint64_t referenced_data_size = 0;
uint64_t num_keys_in_block = 0;
Boolean is_referenced_key_exist_in_block = Boolean::kFalse;
Boolean referenced_key_exist_in_block = Boolean::kFalse;
BlockCacheTraceRecord() {}
BlockCacheTraceRecord(uint64_t _access_timestamp, std::string _block_key,
TraceType _block_type, uint64_t _block_size,
uint64_t _cf_id, std::string _cf_name, uint32_t _level,
uint64_t _sst_fd_number, BlockCacheLookupCaller _caller,
bool _is_cache_hit, bool _no_insert,
std::string _referenced_key = "",
uint64_t _referenced_data_size = 0,
uint64_t _num_keys_in_block = 0,
bool _referenced_key_exist_in_block = false)
: access_timestamp(_access_timestamp),
block_key(_block_key),
block_type(_block_type),
block_size(_block_size),
cf_id(_cf_id),
cf_name(_cf_name),
level(_level),
sst_fd_number(_sst_fd_number),
caller(_caller),
is_cache_hit(_is_cache_hit ? Boolean::kTrue : Boolean::kFalse),
no_insert(_no_insert ? Boolean::kTrue : Boolean::kFalse),
referenced_key(_referenced_key),
referenced_data_size(_referenced_data_size),
num_keys_in_block(_num_keys_in_block),
referenced_key_exist_in_block(
_referenced_key_exist_in_block ? Boolean::kTrue : Boolean::kFalse) {
}
};
struct BlockCacheTraceHeader {
@ -79,7 +131,13 @@ struct BlockCacheTraceHeader {
uint32_t rocksdb_minor_version;
};
bool ShouldTraceReferencedKey(const BlockCacheTraceRecord& record);
class BlockCacheTraceHelper {
public:
static bool ShouldTraceReferencedKey(TraceType block_type,
BlockCacheLookupCaller caller);
static const std::string kUnknownColumnFamilyName;
};
// BlockCacheTraceWriter captures all RocksDB block cache accesses using a
// user-provided TraceWriter. Every RocksDB operation is written as a single
@ -96,7 +154,10 @@ class BlockCacheTraceWriter {
BlockCacheTraceWriter(BlockCacheTraceWriter&&) = delete;
BlockCacheTraceWriter& operator=(BlockCacheTraceWriter&&) = delete;
Status WriteBlockAccess(const BlockCacheTraceRecord& record);
// Pass Slice references to avoid copy.
Status WriteBlockAccess(const BlockCacheTraceRecord& record,
const Slice& block_key, const Slice& cf_name,
const Slice& referenced_key);
// Write a trace header at the beginning, typically on initiating a trace,
// with some metadata like a magic number and RocksDB version.
@ -148,7 +209,9 @@ class BlockCacheTracer {
// Stop writing block cache accesses to the trace_writer.
void EndTrace();
Status WriteBlockAccess(const BlockCacheTraceRecord& record);
Status WriteBlockAccess(const BlockCacheTraceRecord& record,
const Slice& block_key, const Slice& cf_name,
const Slice& referenced_key);
private:
TraceOptions trace_options_;

31
trace_replay/block_cache_tracer_test.cc
Unescape View File

@ -20,6 +20,7 @@ const uint32_t kLevel = 1;
const uint64_t kSSTFDNumber = 100;
const std::string kRefKeyPrefix = "test-get-";
const uint64_t kNumKeysInBlock = 1024;
const uint64_t kReferencedDataSize = 10;
} // namespace
class BlockCacheTracerTest : public testing::Test {
@ -61,7 +62,7 @@ class BlockCacheTracerTest : public testing::Test {
BlockCacheTraceRecord record;
record.block_type = block_type;
record.block_size = kBlockSize + key_id;
record.block_key = kBlockKeyPrefix + std::to_string(key_id);
record.block_key = (kBlockKeyPrefix + std::to_string(key_id));
record.access_timestamp = env_->NowMicros();
record.cf_id = kCFId;
record.cf_name = kDefaultColumnFamilyName;
@ -73,10 +74,12 @@ class BlockCacheTracerTest : public testing::Test {
// Provide these fields for all block types.
// The writer should only write these fields for data blocks and the
// caller is either GET or MGET.
record.referenced_key = kRefKeyPrefix + std::to_string(key_id);
record.is_referenced_key_exist_in_block = Boolean::kTrue;
record.referenced_key = (kRefKeyPrefix + std::to_string(key_id));
record.referenced_key_exist_in_block = Boolean::kTrue;
record.num_keys_in_block = kNumKeysInBlock;
ASSERT_OK(writer->WriteBlockAccess(record));
record.referenced_data_size = kReferencedDataSize + key_id;
ASSERT_OK(writer->WriteBlockAccess(
record, record.block_key, record.cf_name, record.referenced_key));
}
}
@ -95,7 +98,7 @@ class BlockCacheTracerTest : public testing::Test {
record.is_cache_hit = Boolean::kFalse;
record.no_insert = Boolean::kFalse;
record.referenced_key = kRefKeyPrefix + std::to_string(key_id);
record.is_referenced_key_exist_in_block = Boolean::kTrue;
record.referenced_key_exist_in_block = Boolean::kTrue;
record.num_keys_in_block = kNumKeysInBlock;
return record;
}
@ -122,13 +125,15 @@ class BlockCacheTracerTest : public testing::Test {
record.caller == BlockCacheLookupCaller::kUserMGet)) {
ASSERT_EQ(kRefKeyPrefix + std::to_string(key_id),
record.referenced_key);
ASSERT_EQ(Boolean::kTrue, record.is_referenced_key_exist_in_block);
ASSERT_EQ(Boolean::kTrue, record.referenced_key_exist_in_block);
ASSERT_EQ(kNumKeysInBlock, record.num_keys_in_block);
ASSERT_EQ(kReferencedDataSize + key_id, record.referenced_data_size);
continue;
}
ASSERT_EQ("", record.referenced_key);
ASSERT_EQ(Boolean::kFalse, record.is_referenced_key_exist_in_block);
ASSERT_EQ(Boolean::kFalse, record.referenced_key_exist_in_block);
ASSERT_EQ(0, record.num_keys_in_block);
ASSERT_EQ(0, record.referenced_data_size);
}
}
@ -147,7 +152,8 @@ TEST_F(BlockCacheTracerTest, AtomicWriteBeforeStartTrace) {
BlockCacheTracer writer;
// The record should be written to the trace_file since StartTrace is not
// called.
ASSERT_OK(writer.WriteBlockAccess(record));
ASSERT_OK(writer.WriteBlockAccess(record, record.block_key, record.cf_name,
record.referenced_key));
ASSERT_OK(env_->FileExists(trace_file_path_));
}
{
@ -170,7 +176,8 @@ TEST_F(BlockCacheTracerTest, AtomicWrite) {
&trace_writer));
BlockCacheTracer writer;
ASSERT_OK(writer.StartTrace(env_, trace_opt, std::move(trace_writer)));
ASSERT_OK(writer.WriteBlockAccess(record));
ASSERT_OK(writer.WriteBlockAccess(record, record.block_key, record.cf_name,
record.referenced_key));
ASSERT_OK(env_->FileExists(trace_file_path_));
}
{
@ -197,11 +204,13 @@ TEST_F(BlockCacheTracerTest, AtomicNoWriteAfterEndTrace) {
&trace_writer));
BlockCacheTracer writer;
ASSERT_OK(writer.StartTrace(env_, trace_opt, std::move(trace_writer)));
ASSERT_OK(writer.WriteBlockAccess(record));
ASSERT_OK(writer.WriteBlockAccess(record, record.block_key, record.cf_name,
record.referenced_key));
writer.EndTrace();
// Write the record again. This time the record should not be written since
// EndTrace is called.
ASSERT_OK(writer.WriteBlockAccess(record));
ASSERT_OK(writer.WriteBlockAccess(record, record.block_key, record.cf_name,
record.referenced_key));
ASSERT_OK(env_->FileExists(trace_file_path_));
}
{

Write Preview
Loading…
Cancel
Save