rocksdb/table/meta_blocks.cc
Shobhit Dayal b45b1cde3e Feature for sampling and reporting compressibility (#4842)
Summary:
This is a feature to sample data-block compressibility and and report them as stats. 1 in N (tunable) blocks is sampled for compressibility using two algorithms:
1. lz4 or snappy for fast compression
2. zstd or zlib for slow but higher compression.

The stats are reported to the caller as raw-bytes and compressed-bytes. The block continues to be compressed for storage using the specified CompressionType.

The db_bench_tool how has a command line option for specifying the sampling rate. It's default value is 0 (no sampling). To test the overhead for a certain value, users can compare the performance of db_bench_tool, varying the sampling rate. It is unlikely to have a noticeable impact for high values like 20.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4842

Differential Revision: D13629011

Pulled By: shobhitdayal

fbshipit-source-id: 14ca668bcab6499b2a1734edf848eb62a4f4fafa
2019-03-18 12:15:34 -07:00

510 lines
19 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include "table/meta_blocks.h"
#include <map>
#include <string>
#include "db/table_properties_collector.h"
#include "rocksdb/table.h"
#include "rocksdb/table_properties.h"
#include "table/block.h"
#include "table/block_fetcher.h"
#include "table/format.h"
#include "table/internal_iterator.h"
#include "table/persistent_cache_helper.h"
#include "table/table_properties_internal.h"
#include "util/coding.h"
#include "util/file_reader_writer.h"
namespace rocksdb {
MetaIndexBuilder::MetaIndexBuilder()
: meta_index_block_(new BlockBuilder(1 /* restart interval */)) {}
void MetaIndexBuilder::Add(const std::string& key,
const BlockHandle& handle) {
std::string handle_encoding;
handle.EncodeTo(&handle_encoding);
meta_block_handles_.insert({key, handle_encoding});
}
Slice MetaIndexBuilder::Finish() {
for (const auto& metablock : meta_block_handles_) {
meta_index_block_->Add(metablock.first, metablock.second);
}
return meta_index_block_->Finish();
}
// Property block will be read sequentially and cached in a heap located
// object, so there's no need for restart points. Thus we set the restart
// interval to infinity to save space.
PropertyBlockBuilder::PropertyBlockBuilder()
: properties_block_(
new BlockBuilder(port::kMaxInt32 /* restart interval */)) {}
void PropertyBlockBuilder::Add(const std::string& name,
const std::string& val) {
props_.insert({name, val});
}
void PropertyBlockBuilder::Add(const std::string& name, uint64_t val) {
assert(props_.find(name) == props_.end());
std::string dst;
PutVarint64(&dst, val);
Add(name, dst);
}
void PropertyBlockBuilder::Add(
const UserCollectedProperties& user_collected_properties) {
for (const auto& prop : user_collected_properties) {
Add(prop.first, prop.second);
}
}
void PropertyBlockBuilder::AddTableProperty(const TableProperties& props) {
Add(TablePropertiesNames::kRawKeySize, props.raw_key_size);
Add(TablePropertiesNames::kRawValueSize, props.raw_value_size);
Add(TablePropertiesNames::kDataSize, props.data_size);
Add(TablePropertiesNames::kIndexSize, props.index_size);
if (props.index_partitions != 0) {
Add(TablePropertiesNames::kIndexPartitions, props.index_partitions);
Add(TablePropertiesNames::kTopLevelIndexSize, props.top_level_index_size);
}
Add(TablePropertiesNames::kIndexKeyIsUserKey, props.index_key_is_user_key);
Add(TablePropertiesNames::kIndexValueIsDeltaEncoded,
props.index_value_is_delta_encoded);
Add(TablePropertiesNames::kNumEntries, props.num_entries);
Add(TablePropertiesNames::kDeletedKeys, props.num_deletions);
Add(TablePropertiesNames::kMergeOperands, props.num_merge_operands);
Add(TablePropertiesNames::kNumRangeDeletions, props.num_range_deletions);
Add(TablePropertiesNames::kNumDataBlocks, props.num_data_blocks);
Add(TablePropertiesNames::kFilterSize, props.filter_size);
Add(TablePropertiesNames::kFormatVersion, props.format_version);
Add(TablePropertiesNames::kFixedKeyLen, props.fixed_key_len);
Add(TablePropertiesNames::kColumnFamilyId, props.column_family_id);
Add(TablePropertiesNames::kCreationTime, props.creation_time);
Add(TablePropertiesNames::kOldestKeyTime, props.oldest_key_time);
if (!props.filter_policy_name.empty()) {
Add(TablePropertiesNames::kFilterPolicy, props.filter_policy_name);
}
if (!props.comparator_name.empty()) {
Add(TablePropertiesNames::kComparator, props.comparator_name);
}
if (!props.merge_operator_name.empty()) {
Add(TablePropertiesNames::kMergeOperator, props.merge_operator_name);
}
if (!props.prefix_extractor_name.empty()) {
Add(TablePropertiesNames::kPrefixExtractorName,
props.prefix_extractor_name);
}
if (!props.property_collectors_names.empty()) {
Add(TablePropertiesNames::kPropertyCollectors,
props.property_collectors_names);
}
if (!props.column_family_name.empty()) {
Add(TablePropertiesNames::kColumnFamilyName, props.column_family_name);
}
if (!props.compression_name.empty()) {
Add(TablePropertiesNames::kCompression, props.compression_name);
}
}
Slice PropertyBlockBuilder::Finish() {
for (const auto& prop : props_) {
properties_block_->Add(prop.first, prop.second);
}
return properties_block_->Finish();
}
void LogPropertiesCollectionError(
Logger* info_log, const std::string& method, const std::string& name) {
assert(method == "Add" || method == "Finish");
std::string msg =
"Encountered error when calling TablePropertiesCollector::" +
method + "() with collector name: " + name;
ROCKS_LOG_ERROR(info_log, "%s", msg.c_str());
}
bool NotifyCollectTableCollectorsOnAdd(
const Slice& key, const Slice& value, uint64_t file_size,
const std::vector<std::unique_ptr<IntTblPropCollector>>& collectors,
Logger* info_log) {
bool all_succeeded = true;
for (auto& collector : collectors) {
Status s = collector->InternalAdd(key, value, file_size);
all_succeeded = all_succeeded && s.ok();
if (!s.ok()) {
LogPropertiesCollectionError(info_log, "Add" /* method */,
collector->Name());
}
}
return all_succeeded;
}
void NotifyCollectTableCollectorsOnBlockAdd(
const std::vector<std::unique_ptr<IntTblPropCollector>>& collectors,
const uint64_t blockRawBytes, const uint64_t blockCompressedBytesFast,
const uint64_t blockCompressedBytesSlow) {
for (auto& collector : collectors) {
collector->BlockAdd(blockRawBytes, blockCompressedBytesFast,
blockCompressedBytesSlow);
}
}
bool NotifyCollectTableCollectorsOnFinish(
const std::vector<std::unique_ptr<IntTblPropCollector>>& collectors,
Logger* info_log, PropertyBlockBuilder* builder) {
bool all_succeeded = true;
for (auto& collector : collectors) {
UserCollectedProperties user_collected_properties;
Status s = collector->Finish(&user_collected_properties);
all_succeeded = all_succeeded && s.ok();
if (!s.ok()) {
LogPropertiesCollectionError(info_log, "Finish" /* method */,
collector->Name());
} else {
builder->Add(user_collected_properties);
}
}
return all_succeeded;
}
Status ReadProperties(const Slice& handle_value, RandomAccessFileReader* file,
FilePrefetchBuffer* prefetch_buffer, const Footer& footer,
const ImmutableCFOptions& ioptions,
TableProperties** table_properties, bool verify_checksum,
BlockHandle* ret_block_handle,
CacheAllocationPtr* verification_buf,
bool /*compression_type_missing*/,
MemoryAllocator* memory_allocator) {
assert(table_properties);
Slice v = handle_value;
BlockHandle handle;
if (!handle.DecodeFrom(&v).ok()) {
return Status::InvalidArgument("Failed to decode properties block handle");
}
BlockContents block_contents;
ReadOptions read_options;
read_options.verify_checksums = verify_checksum;
Status s;
PersistentCacheOptions cache_options;
BlockFetcher block_fetcher(
file, prefetch_buffer, footer, read_options, handle, &block_contents,
ioptions, false /* decompress */, false /*maybe_compressed*/,
UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
s = block_fetcher.ReadBlockContents();
// property block is never compressed. Need to add uncompress logic if we are
// to compress it..
if (!s.ok()) {
return s;
}
Block properties_block(std::move(block_contents),
kDisableGlobalSequenceNumber);
DataBlockIter iter;
properties_block.NewIterator<DataBlockIter>(BytewiseComparator(),
BytewiseComparator(), &iter);
auto new_table_properties = new TableProperties();
// All pre-defined properties of type uint64_t
std::unordered_map<std::string, uint64_t*> predefined_uint64_properties = {
{TablePropertiesNames::kDataSize, &new_table_properties->data_size},
{TablePropertiesNames::kIndexSize, &new_table_properties->index_size},
{TablePropertiesNames::kIndexPartitions,
&new_table_properties->index_partitions},
{TablePropertiesNames::kTopLevelIndexSize,
&new_table_properties->top_level_index_size},
{TablePropertiesNames::kIndexKeyIsUserKey,
&new_table_properties->index_key_is_user_key},
{TablePropertiesNames::kIndexValueIsDeltaEncoded,
&new_table_properties->index_value_is_delta_encoded},
{TablePropertiesNames::kFilterSize, &new_table_properties->filter_size},
{TablePropertiesNames::kRawKeySize, &new_table_properties->raw_key_size},
{TablePropertiesNames::kRawValueSize,
&new_table_properties->raw_value_size},
{TablePropertiesNames::kNumDataBlocks,
&new_table_properties->num_data_blocks},
{TablePropertiesNames::kNumEntries, &new_table_properties->num_entries},
{TablePropertiesNames::kDeletedKeys,
&new_table_properties->num_deletions},
{TablePropertiesNames::kMergeOperands,
&new_table_properties->num_merge_operands},
{TablePropertiesNames::kNumRangeDeletions,
&new_table_properties->num_range_deletions},
{TablePropertiesNames::kFormatVersion,
&new_table_properties->format_version},
{TablePropertiesNames::kFixedKeyLen,
&new_table_properties->fixed_key_len},
{TablePropertiesNames::kColumnFamilyId,
&new_table_properties->column_family_id},
{TablePropertiesNames::kCreationTime,
&new_table_properties->creation_time},
{TablePropertiesNames::kOldestKeyTime,
&new_table_properties->oldest_key_time},
};
std::string last_key;
for (iter.SeekToFirstOrReport(); iter.Valid(); iter.NextOrReport()) {
s = iter.status();
if (!s.ok()) {
break;
}
auto key = iter.key().ToString();
// properties block should be strictly sorted with no duplicate key.
if (!last_key.empty() &&
BytewiseComparator()->Compare(key, last_key) <= 0) {
s = Status::Corruption("properties unsorted");
break;
}
last_key = key;
auto raw_val = iter.value();
auto pos = predefined_uint64_properties.find(key);
new_table_properties->properties_offsets.insert(
{key, handle.offset() + iter.ValueOffset()});
if (pos != predefined_uint64_properties.end()) {
if (key == TablePropertiesNames::kDeletedKeys ||
key == TablePropertiesNames::kMergeOperands) {
// Insert in user-collected properties for API backwards compatibility
new_table_properties->user_collected_properties.insert(
{key, raw_val.ToString()});
}
// handle predefined rocksdb properties
uint64_t val;
if (!GetVarint64(&raw_val, &val)) {
// skip malformed value
auto error_msg =
"Detect malformed value in properties meta-block:"
"\tkey: " + key + "\tval: " + raw_val.ToString();
ROCKS_LOG_ERROR(ioptions.info_log, "%s", error_msg.c_str());
continue;
}
*(pos->second) = val;
} else if (key == TablePropertiesNames::kFilterPolicy) {
new_table_properties->filter_policy_name = raw_val.ToString();
} else if (key == TablePropertiesNames::kColumnFamilyName) {
new_table_properties->column_family_name = raw_val.ToString();
} else if (key == TablePropertiesNames::kComparator) {
new_table_properties->comparator_name = raw_val.ToString();
} else if (key == TablePropertiesNames::kMergeOperator) {
new_table_properties->merge_operator_name = raw_val.ToString();
} else if (key == TablePropertiesNames::kPrefixExtractorName) {
new_table_properties->prefix_extractor_name = raw_val.ToString();
} else if (key == TablePropertiesNames::kPropertyCollectors) {
new_table_properties->property_collectors_names = raw_val.ToString();
} else if (key == TablePropertiesNames::kCompression) {
new_table_properties->compression_name = raw_val.ToString();
} else {
// handle user-collected properties
new_table_properties->user_collected_properties.insert(
{key, raw_val.ToString()});
}
}
if (s.ok()) {
*table_properties = new_table_properties;
if (ret_block_handle != nullptr) {
*ret_block_handle = handle;
}
if (verification_buf != nullptr) {
size_t len = handle.size() + kBlockTrailerSize;
*verification_buf = rocksdb::AllocateBlock(len, memory_allocator);
if (verification_buf->get() != nullptr) {
memcpy(verification_buf->get(), block_contents.data.data(), len);
}
}
} else {
delete new_table_properties;
}
return s;
}
Status ReadTableProperties(RandomAccessFileReader* file, uint64_t file_size,
uint64_t table_magic_number,
const ImmutableCFOptions& ioptions,
TableProperties** properties,
bool compression_type_missing,
MemoryAllocator* memory_allocator) {
// -- Read metaindex block
Footer footer;
auto s = ReadFooterFromFile(file, nullptr /* prefetch_buffer */, file_size,
&footer, table_magic_number);
if (!s.ok()) {
return s;
}
auto metaindex_handle = footer.metaindex_handle();
BlockContents metaindex_contents;
ReadOptions read_options;
read_options.verify_checksums = false;
PersistentCacheOptions cache_options;
BlockFetcher block_fetcher(
file, nullptr /* prefetch_buffer */, footer, read_options,
metaindex_handle, &metaindex_contents, ioptions, false /* decompress */,
false /*maybe_compressed*/, UncompressionDict::GetEmptyDict(),
cache_options, memory_allocator);
s = block_fetcher.ReadBlockContents();
if (!s.ok()) {
return s;
}
// property blocks are never compressed. Need to add uncompress logic if we
// are to compress it.
Block metaindex_block(std::move(metaindex_contents),
kDisableGlobalSequenceNumber);
std::unique_ptr<InternalIterator> meta_iter(
metaindex_block.NewIterator<DataBlockIter>(BytewiseComparator(),
BytewiseComparator()));
// -- Read property block
bool found_properties_block = true;
s = SeekToPropertiesBlock(meta_iter.get(), &found_properties_block);
if (!s.ok()) {
return s;
}
TableProperties table_properties;
if (found_properties_block == true) {
s = ReadProperties(
meta_iter->value(), file, nullptr /* prefetch_buffer */, footer,
ioptions, properties, false /* verify_checksum */,
nullptr /* ret_block_hanel */, nullptr /* ret_block_contents */,
compression_type_missing, memory_allocator);
} else {
s = Status::NotFound();
}
return s;
}
Status FindMetaBlock(InternalIterator* meta_index_iter,
const std::string& meta_block_name,
BlockHandle* block_handle) {
meta_index_iter->Seek(meta_block_name);
if (meta_index_iter->status().ok() && meta_index_iter->Valid() &&
meta_index_iter->key() == meta_block_name) {
Slice v = meta_index_iter->value();
return block_handle->DecodeFrom(&v);
} else {
return Status::Corruption("Cannot find the meta block", meta_block_name);
}
}
Status FindMetaBlock(RandomAccessFileReader* file, uint64_t file_size,
uint64_t table_magic_number,
const ImmutableCFOptions& ioptions,
const std::string& meta_block_name,
BlockHandle* block_handle,
bool /*compression_type_missing*/,
MemoryAllocator* memory_allocator) {
Footer footer;
auto s = ReadFooterFromFile(file, nullptr /* prefetch_buffer */, file_size,
&footer, table_magic_number);
if (!s.ok()) {
return s;
}
auto metaindex_handle = footer.metaindex_handle();
BlockContents metaindex_contents;
ReadOptions read_options;
read_options.verify_checksums = false;
PersistentCacheOptions cache_options;
BlockFetcher block_fetcher(
file, nullptr /* prefetch_buffer */, footer, read_options,
metaindex_handle, &metaindex_contents, ioptions,
false /* do decompression */, false /*maybe_compressed*/,
UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
s = block_fetcher.ReadBlockContents();
if (!s.ok()) {
return s;
}
// meta blocks are never compressed. Need to add uncompress logic if we are to
// compress it.
Block metaindex_block(std::move(metaindex_contents),
kDisableGlobalSequenceNumber);
std::unique_ptr<InternalIterator> meta_iter;
meta_iter.reset(metaindex_block.NewIterator<DataBlockIter>(
BytewiseComparator(), BytewiseComparator()));
return FindMetaBlock(meta_iter.get(), meta_block_name, block_handle);
}
Status ReadMetaBlock(RandomAccessFileReader* file,
FilePrefetchBuffer* prefetch_buffer, uint64_t file_size,
uint64_t table_magic_number,
const ImmutableCFOptions& ioptions,
const std::string& meta_block_name,
BlockContents* contents, bool /*compression_type_missing*/,
MemoryAllocator* memory_allocator) {
Status status;
Footer footer;
status = ReadFooterFromFile(file, prefetch_buffer, file_size, &footer,
table_magic_number);
if (!status.ok()) {
return status;
}
// Reading metaindex block
auto metaindex_handle = footer.metaindex_handle();
BlockContents metaindex_contents;
ReadOptions read_options;
read_options.verify_checksums = false;
PersistentCacheOptions cache_options;
BlockFetcher block_fetcher(file, prefetch_buffer, footer, read_options,
metaindex_handle, &metaindex_contents, ioptions,
false /* decompress */, false /*maybe_compressed*/,
UncompressionDict::GetEmptyDict(), cache_options,
memory_allocator);
status = block_fetcher.ReadBlockContents();
if (!status.ok()) {
return status;
}
// meta block is never compressed. Need to add uncompress logic if we are to
// compress it.
// Finding metablock
Block metaindex_block(std::move(metaindex_contents),
kDisableGlobalSequenceNumber);
std::unique_ptr<InternalIterator> meta_iter;
meta_iter.reset(metaindex_block.NewIterator<DataBlockIter>(
BytewiseComparator(), BytewiseComparator()));
BlockHandle block_handle;
status = FindMetaBlock(meta_iter.get(), meta_block_name, &block_handle);
if (!status.ok()) {
return status;
}
// Reading metablock
BlockFetcher block_fetcher2(
file, prefetch_buffer, footer, read_options, block_handle, contents,
ioptions, false /* decompress */, false /*maybe_compressed*/,
UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
return block_fetcher2.ReadBlockContents();
}
} // namespace rocksdb