0af157f9bf
Summary:
1. Make filter_block.h a base class. Derive block_based_filter_block and full_filter_block. The previous one is the traditional filter block. The full_filter_block is newly added. It would generate a filter block that contain all the keys in SST file.
2. When querying a key, table would first check if full_filter is available. If not, it would go to the exact data block and check using block_based filter.
3. User could choose to use full_filter or tradional(block_based_filter). They would be stored in SST file with different meta index name. "filter.filter_policy" or "full_filter.filter_policy". Then, Table reader is able to know the fllter block type.
4. Some optimizations have been done for full_filter_block, thus it requires a different interface compared to the original one in filter_policy.h.
5. Actual implementation of filter bits coding/decoding is placed in util/bloom_impl.cc
Benchmark: base commit 1d23b5c470
Command:
db_bench --db=/dev/shm/rocksdb --num_levels=6 --key_size=20 --prefix_size=20 --keys_per_prefix=0 --value_size=100 --write_buffer_size=134217728 --max_write_buffer_number=2 --target_file_size_base=33554432 --max_bytes_for_level_base=1073741824 --verify_checksum=false --max_background_compactions=4 --use_plain_table=0 --memtablerep=prefix_hash --open_files=-1 --mmap_read=1 --mmap_write=0 --bloom_bits=10 --bloom_locality=1 --memtable_bloom_bits=500000 --compression_type=lz4 --num=393216000 --use_hash_search=1 --block_size=1024 --block_restart_interval=16 --use_existing_db=1 --threads=1 --benchmarks=readrandom —disable_auto_compactions=1
Read QPS increase for about 30% from 2230002 to 2991411.
Test Plan:
make all check
valgrind db_test
db_stress --use_block_based_filter = 0
./auto_sanity_test.sh
Reviewers: igor, yhchiang, ljin, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D20979
1348 lines
47 KiB
C++
1348 lines
47 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include "table/block_based_table_reader.h"
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#include <string>
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#include <utility>
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#include "db/dbformat.h"
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#include "rocksdb/cache.h"
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#include "rocksdb/comparator.h"
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#include "rocksdb/env.h"
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#include "rocksdb/filter_policy.h"
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#include "rocksdb/iterator.h"
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#include "rocksdb/options.h"
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#include "rocksdb/statistics.h"
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#include "rocksdb/table.h"
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#include "rocksdb/table_properties.h"
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#include "table/block.h"
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#include "table/filter_block.h"
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#include "table/block_based_filter_block.h"
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#include "table/full_filter_block.h"
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#include "table/block_hash_index.h"
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#include "table/block_prefix_index.h"
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#include "table/format.h"
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#include "table/meta_blocks.h"
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#include "table/two_level_iterator.h"
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#include "util/coding.h"
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#include "util/perf_context_imp.h"
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#include "util/stop_watch.h"
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namespace rocksdb {
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extern const uint64_t kBlockBasedTableMagicNumber;
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extern const std::string kHashIndexPrefixesBlock;
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extern const std::string kHashIndexPrefixesMetadataBlock;
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using std::unique_ptr;
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typedef BlockBasedTable::IndexReader IndexReader;
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namespace {
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// The longest the prefix of the cache key used to identify blocks can be.
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// We are using the fact that we know for Posix files the unique ID is three
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// varints.
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// For some reason, compiling for iOS complains that this variable is unused
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const size_t kMaxCacheKeyPrefixSize __attribute__((unused)) =
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kMaxVarint64Length * 3 + 1;
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// Read the block identified by "handle" from "file".
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// The only relevant option is options.verify_checksums for now.
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// On failure return non-OK.
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// On success fill *result and return OK - caller owns *result
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Status ReadBlockFromFile(RandomAccessFile* file, const Footer& footer,
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const ReadOptions& options, const BlockHandle& handle,
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Block** result, Env* env, bool do_uncompress = true) {
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BlockContents contents;
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Status s = ReadBlockContents(file, footer, options, handle, &contents, env,
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do_uncompress);
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if (s.ok()) {
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*result = new Block(contents);
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}
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return s;
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}
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// Delete the resource that is held by the iterator.
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template <class ResourceType>
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void DeleteHeldResource(void* arg, void* ignored) {
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delete reinterpret_cast<ResourceType*>(arg);
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}
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// Delete the entry resided in the cache.
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template <class Entry>
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void DeleteCachedEntry(const Slice& key, void* value) {
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auto entry = reinterpret_cast<Entry*>(value);
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delete entry;
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}
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// Release the cached entry and decrement its ref count.
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void ReleaseCachedEntry(void* arg, void* h) {
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Cache* cache = reinterpret_cast<Cache*>(arg);
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Cache::Handle* handle = reinterpret_cast<Cache::Handle*>(h);
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cache->Release(handle);
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}
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Slice GetCacheKey(const char* cache_key_prefix, size_t cache_key_prefix_size,
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const BlockHandle& handle, char* cache_key) {
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assert(cache_key != nullptr);
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assert(cache_key_prefix_size != 0);
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assert(cache_key_prefix_size <= kMaxCacheKeyPrefixSize);
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memcpy(cache_key, cache_key_prefix, cache_key_prefix_size);
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char* end =
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EncodeVarint64(cache_key + cache_key_prefix_size, handle.offset());
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return Slice(cache_key, static_cast<size_t>(end - cache_key));
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}
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Cache::Handle* GetEntryFromCache(Cache* block_cache, const Slice& key,
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Tickers block_cache_miss_ticker,
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Tickers block_cache_hit_ticker,
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Statistics* statistics) {
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auto cache_handle = block_cache->Lookup(key);
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if (cache_handle != nullptr) {
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PERF_COUNTER_ADD(block_cache_hit_count, 1);
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// overall cache hit
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RecordTick(statistics, BLOCK_CACHE_HIT);
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// block-type specific cache hit
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RecordTick(statistics, block_cache_hit_ticker);
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} else {
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// overall cache miss
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RecordTick(statistics, BLOCK_CACHE_MISS);
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// block-type specific cache miss
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RecordTick(statistics, block_cache_miss_ticker);
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}
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return cache_handle;
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}
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} // namespace
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// -- IndexReader and its subclasses
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// IndexReader is the interface that provide the functionality for index access.
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class BlockBasedTable::IndexReader {
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public:
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explicit IndexReader(const Comparator* comparator)
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: comparator_(comparator) {}
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virtual ~IndexReader() {}
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// Create an iterator for index access.
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// An iter is passed in, if it is not null, update this one and return it
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// If it is null, create a new Iterator
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virtual Iterator* NewIterator(
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BlockIter* iter = nullptr, bool total_order_seek = true) = 0;
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// The size of the index.
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virtual size_t size() const = 0;
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// Report an approximation of how much memory has been used other than memory
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// that was allocated in block cache.
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virtual size_t ApproximateMemoryUsage() const = 0;
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protected:
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const Comparator* comparator_;
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};
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// Index that allows binary search lookup for the first key of each block.
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// This class can be viewed as a thin wrapper for `Block` class which already
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// supports binary search.
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class BinarySearchIndexReader : public IndexReader {
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public:
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// Read index from the file and create an intance for
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// `BinarySearchIndexReader`.
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// On success, index_reader will be populated; otherwise it will remain
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// unmodified.
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static Status Create(RandomAccessFile* file, const Footer& footer,
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const BlockHandle& index_handle, Env* env,
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const Comparator* comparator,
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IndexReader** index_reader) {
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Block* index_block = nullptr;
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auto s = ReadBlockFromFile(file, footer, ReadOptions(), index_handle,
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&index_block, env);
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if (s.ok()) {
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*index_reader = new BinarySearchIndexReader(comparator, index_block);
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}
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return s;
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}
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virtual Iterator* NewIterator(
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BlockIter* iter = nullptr, bool dont_care = true) override {
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return index_block_->NewIterator(comparator_, iter, true);
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}
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virtual size_t size() const override { return index_block_->size(); }
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virtual size_t ApproximateMemoryUsage() const override {
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assert(index_block_);
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return index_block_->ApproximateMemoryUsage();
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}
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private:
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BinarySearchIndexReader(const Comparator* comparator, Block* index_block)
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: IndexReader(comparator), index_block_(index_block) {
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assert(index_block_ != nullptr);
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}
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std::unique_ptr<Block> index_block_;
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};
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// Index that leverages an internal hash table to quicken the lookup for a given
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// key.
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class HashIndexReader : public IndexReader {
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public:
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static Status Create(const SliceTransform* hash_key_extractor,
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const Footer& footer, RandomAccessFile* file, Env* env,
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const Comparator* comparator,
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const BlockHandle& index_handle,
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Iterator* meta_index_iter, IndexReader** index_reader,
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bool hash_index_allow_collision) {
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Block* index_block = nullptr;
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auto s = ReadBlockFromFile(file, footer, ReadOptions(), index_handle,
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&index_block, env);
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if (!s.ok()) {
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return s;
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}
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// Note, failure to create prefix hash index does not need to be a
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// hard error. We can still fall back to the original binary search index.
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// So, Create will succeed regardless, from this point on.
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auto new_index_reader =
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new HashIndexReader(comparator, index_block);
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*index_reader = new_index_reader;
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// Get prefixes block
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BlockHandle prefixes_handle;
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s = FindMetaBlock(meta_index_iter, kHashIndexPrefixesBlock,
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&prefixes_handle);
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if (!s.ok()) {
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// TODO: log error
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return Status::OK();
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}
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// Get index metadata block
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BlockHandle prefixes_meta_handle;
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s = FindMetaBlock(meta_index_iter, kHashIndexPrefixesMetadataBlock,
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&prefixes_meta_handle);
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if (!s.ok()) {
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// TODO: log error
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return Status::OK();
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}
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// Read contents for the blocks
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BlockContents prefixes_contents;
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s = ReadBlockContents(file, footer, ReadOptions(), prefixes_handle,
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&prefixes_contents, env, true /* do decompression */);
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if (!s.ok()) {
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return s;
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}
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BlockContents prefixes_meta_contents;
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s = ReadBlockContents(file, footer, ReadOptions(), prefixes_meta_handle,
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&prefixes_meta_contents, env,
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true /* do decompression */);
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if (!s.ok()) {
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if (prefixes_contents.heap_allocated) {
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delete[] prefixes_contents.data.data();
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}
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// TODO: log error
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return Status::OK();
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}
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if (!hash_index_allow_collision) {
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// TODO: deprecate once hash_index_allow_collision proves to be stable.
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BlockHashIndex* hash_index = nullptr;
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s = CreateBlockHashIndex(hash_key_extractor,
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prefixes_contents.data,
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prefixes_meta_contents.data,
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&hash_index);
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// TODO: log error
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if (s.ok()) {
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new_index_reader->index_block_->SetBlockHashIndex(hash_index);
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new_index_reader->OwnPrefixesContents(prefixes_contents);
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}
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} else {
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BlockPrefixIndex* prefix_index = nullptr;
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s = BlockPrefixIndex::Create(hash_key_extractor,
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prefixes_contents.data,
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prefixes_meta_contents.data,
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&prefix_index);
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// TODO: log error
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if (s.ok()) {
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new_index_reader->index_block_->SetBlockPrefixIndex(prefix_index);
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}
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}
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// Always release prefix meta block
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if (prefixes_meta_contents.heap_allocated) {
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delete[] prefixes_meta_contents.data.data();
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}
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// Release prefix content block if we don't own it.
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if (!new_index_reader->own_prefixes_contents_) {
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if (prefixes_contents.heap_allocated) {
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delete[] prefixes_contents.data.data();
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}
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}
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return Status::OK();
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}
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virtual Iterator* NewIterator(
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BlockIter* iter = nullptr, bool total_order_seek = true) override {
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return index_block_->NewIterator(comparator_, iter, total_order_seek);
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}
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virtual size_t size() const override { return index_block_->size(); }
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virtual size_t ApproximateMemoryUsage() const override {
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assert(index_block_);
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return index_block_->ApproximateMemoryUsage() +
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prefixes_contents_.data.size();
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}
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private:
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HashIndexReader(const Comparator* comparator, Block* index_block)
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: IndexReader(comparator),
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index_block_(index_block),
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own_prefixes_contents_(false) {
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assert(index_block_ != nullptr);
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}
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~HashIndexReader() {
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if (own_prefixes_contents_ && prefixes_contents_.heap_allocated) {
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delete[] prefixes_contents_.data.data();
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}
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}
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void OwnPrefixesContents(const BlockContents& prefixes_contents) {
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prefixes_contents_ = prefixes_contents;
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own_prefixes_contents_ = true;
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}
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std::unique_ptr<Block> index_block_;
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bool own_prefixes_contents_;
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BlockContents prefixes_contents_;
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};
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struct BlockBasedTable::Rep {
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Rep(const ImmutableCFOptions& ioptions,
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const EnvOptions& env_options,
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const BlockBasedTableOptions& table_opt,
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const InternalKeyComparator& internal_comparator)
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: ioptions(ioptions), env_options(env_options), table_options(table_opt),
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filter_policy(table_opt.filter_policy.get()),
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internal_comparator(internal_comparator) {}
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const ImmutableCFOptions& ioptions;
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const EnvOptions& env_options;
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const BlockBasedTableOptions& table_options;
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const FilterPolicy* const filter_policy;
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const InternalKeyComparator& internal_comparator;
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Status status;
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unique_ptr<RandomAccessFile> file;
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char cache_key_prefix[kMaxCacheKeyPrefixSize];
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size_t cache_key_prefix_size = 0;
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char compressed_cache_key_prefix[kMaxCacheKeyPrefixSize];
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size_t compressed_cache_key_prefix_size = 0;
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// Footer contains the fixed table information
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Footer footer;
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// index_reader and filter will be populated and used only when
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// options.block_cache is nullptr; otherwise we will get the index block via
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// the block cache.
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unique_ptr<IndexReader> index_reader;
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unique_ptr<FilterBlockReader> filter;
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std::shared_ptr<const TableProperties> table_properties;
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BlockBasedTableOptions::IndexType index_type;
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bool hash_index_allow_collision;
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// TODO(kailiu) It is very ugly to use internal key in table, since table
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// module should not be relying on db module. However to make things easier
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// and compatible with existing code, we introduce a wrapper that allows
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// block to extract prefix without knowing if a key is internal or not.
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unique_ptr<SliceTransform> internal_prefix_transform;
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};
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BlockBasedTable::~BlockBasedTable() {
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delete rep_;
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}
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// CachableEntry represents the entries that *may* be fetched from block cache.
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// field `value` is the item we want to get.
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// field `cache_handle` is the cache handle to the block cache. If the value
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// was not read from cache, `cache_handle` will be nullptr.
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template <class TValue>
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struct BlockBasedTable::CachableEntry {
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CachableEntry(TValue* value, Cache::Handle* cache_handle)
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: value(value)
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, cache_handle(cache_handle) {
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}
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CachableEntry(): CachableEntry(nullptr, nullptr) { }
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void Release(Cache* cache) {
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if (cache_handle) {
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cache->Release(cache_handle);
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value = nullptr;
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cache_handle = nullptr;
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}
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}
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TValue* value = nullptr;
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// if the entry is from the cache, cache_handle will be populated.
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Cache::Handle* cache_handle = nullptr;
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};
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// Helper function to setup the cache key's prefix for the Table.
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void BlockBasedTable::SetupCacheKeyPrefix(Rep* rep) {
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assert(kMaxCacheKeyPrefixSize >= 10);
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rep->cache_key_prefix_size = 0;
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rep->compressed_cache_key_prefix_size = 0;
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if (rep->table_options.block_cache != nullptr) {
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GenerateCachePrefix(rep->table_options.block_cache.get(), rep->file.get(),
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&rep->cache_key_prefix[0],
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&rep->cache_key_prefix_size);
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}
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if (rep->table_options.block_cache_compressed != nullptr) {
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GenerateCachePrefix(rep->table_options.block_cache_compressed.get(),
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rep->file.get(), &rep->compressed_cache_key_prefix[0],
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&rep->compressed_cache_key_prefix_size);
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}
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}
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void BlockBasedTable::GenerateCachePrefix(Cache* cc,
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RandomAccessFile* file, char* buffer, size_t* size) {
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// generate an id from the file
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*size = file->GetUniqueId(buffer, kMaxCacheKeyPrefixSize);
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// If the prefix wasn't generated or was too long,
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// create one from the cache.
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if (*size == 0) {
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char* end = EncodeVarint64(buffer, cc->NewId());
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*size = static_cast<size_t>(end - buffer);
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}
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}
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void BlockBasedTable::GenerateCachePrefix(Cache* cc,
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WritableFile* file, char* buffer, size_t* size) {
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// generate an id from the file
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*size = file->GetUniqueId(buffer, kMaxCacheKeyPrefixSize);
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// If the prefix wasn't generated or was too long,
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// create one from the cache.
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if (*size == 0) {
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char* end = EncodeVarint64(buffer, cc->NewId());
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*size = static_cast<size_t>(end - buffer);
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}
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}
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Status BlockBasedTable::Open(const ImmutableCFOptions& ioptions,
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const EnvOptions& env_options,
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const BlockBasedTableOptions& table_options,
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const InternalKeyComparator& internal_comparator,
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unique_ptr<RandomAccessFile>&& file,
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uint64_t file_size,
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unique_ptr<TableReader>* table_reader) {
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table_reader->reset();
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Footer footer(kBlockBasedTableMagicNumber);
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auto s = ReadFooterFromFile(file.get(), file_size, &footer);
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if (!s.ok()) return s;
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// We've successfully read the footer and the index block: we're
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// ready to serve requests.
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Rep* rep = new BlockBasedTable::Rep(
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|
ioptions, env_options, table_options, internal_comparator);
|
|
rep->file = std::move(file);
|
|
rep->footer = footer;
|
|
rep->index_type = table_options.index_type;
|
|
rep->hash_index_allow_collision = table_options.hash_index_allow_collision;
|
|
SetupCacheKeyPrefix(rep);
|
|
unique_ptr<BlockBasedTable> new_table(new BlockBasedTable(rep));
|
|
|
|
// Read meta index
|
|
std::unique_ptr<Block> meta;
|
|
std::unique_ptr<Iterator> meta_iter;
|
|
s = ReadMetaBlock(rep, &meta, &meta_iter);
|
|
|
|
// Read the properties
|
|
bool found_properties_block = true;
|
|
s = SeekToPropertiesBlock(meta_iter.get(), &found_properties_block);
|
|
|
|
if (found_properties_block) {
|
|
s = meta_iter->status();
|
|
TableProperties* table_properties = nullptr;
|
|
if (s.ok()) {
|
|
s = ReadProperties(meta_iter->value(), rep->file.get(), rep->footer,
|
|
rep->ioptions.env, rep->ioptions.info_log,
|
|
&table_properties);
|
|
}
|
|
|
|
if (!s.ok()) {
|
|
auto err_msg =
|
|
"[Warning] Encountered error while reading data from properties "
|
|
"block " + s.ToString();
|
|
Log(rep->ioptions.info_log, "%s", err_msg.c_str());
|
|
} else {
|
|
rep->table_properties.reset(table_properties);
|
|
}
|
|
} else {
|
|
Log(WARN_LEVEL, rep->ioptions.info_log,
|
|
"Cannot find Properties block from file.");
|
|
}
|
|
|
|
// Will use block cache for index/filter blocks access?
|
|
if (table_options.block_cache &&
|
|
table_options.cache_index_and_filter_blocks) {
|
|
// Hack: Call NewIndexIterator() to implicitly add index to the block_cache
|
|
unique_ptr<Iterator> iter(new_table->NewIndexIterator(ReadOptions()));
|
|
s = iter->status();
|
|
|
|
if (s.ok()) {
|
|
// Hack: Call GetFilter() to implicitly add filter to the block_cache
|
|
auto filter_entry = new_table->GetFilter();
|
|
filter_entry.Release(table_options.block_cache.get());
|
|
}
|
|
} else {
|
|
// If we don't use block cache for index/filter blocks access, we'll
|
|
// pre-load these blocks, which will kept in member variables in Rep
|
|
// and with a same life-time as this table object.
|
|
IndexReader* index_reader = nullptr;
|
|
// TODO: we never really verify check sum for index block
|
|
s = new_table->CreateIndexReader(&index_reader, meta_iter.get());
|
|
|
|
if (s.ok()) {
|
|
rep->index_reader.reset(index_reader);
|
|
|
|
// Set filter block
|
|
if (rep->filter_policy) {
|
|
// First try reading full_filter, then reading block_based_filter
|
|
for (auto filter_block_prefix : { kFullFilterBlockPrefix,
|
|
kFilterBlockPrefix }) {
|
|
std::string key = filter_block_prefix;
|
|
key.append(rep->filter_policy->Name());
|
|
|
|
BlockHandle handle;
|
|
if (FindMetaBlock(meta_iter.get(), key, &handle).ok()) {
|
|
rep->filter.reset(ReadFilter(handle, rep,
|
|
filter_block_prefix, nullptr));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
delete index_reader;
|
|
}
|
|
}
|
|
|
|
if (s.ok()) {
|
|
*table_reader = std::move(new_table);
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
void BlockBasedTable::SetupForCompaction() {
|
|
/*
|
|
switch (.access_hint_on_compaction_start) {
|
|
case Options::NONE:
|
|
break;
|
|
case Options::NORMAL:
|
|
rep_->file->Hint(RandomAccessFile::NORMAL);
|
|
break;
|
|
case Options::SEQUENTIAL:
|
|
rep_->file->Hint(RandomAccessFile::SEQUENTIAL);
|
|
break;
|
|
case Options::WILLNEED:
|
|
rep_->file->Hint(RandomAccessFile::WILLNEED);
|
|
break;
|
|
default:
|
|
assert(false);
|
|
}
|
|
compaction_optimized_ = true;
|
|
*/
|
|
}
|
|
|
|
std::shared_ptr<const TableProperties> BlockBasedTable::GetTableProperties()
|
|
const {
|
|
return rep_->table_properties;
|
|
}
|
|
|
|
size_t BlockBasedTable::ApproximateMemoryUsage() const {
|
|
size_t usage = 0;
|
|
if (rep_->filter) {
|
|
usage += rep_->filter->ApproximateMemoryUsage();
|
|
}
|
|
if (rep_->index_reader) {
|
|
usage += rep_->index_reader->ApproximateMemoryUsage();
|
|
}
|
|
return usage;
|
|
}
|
|
|
|
// Load the meta-block from the file. On success, return the loaded meta block
|
|
// and its iterator.
|
|
Status BlockBasedTable::ReadMetaBlock(
|
|
Rep* rep,
|
|
std::unique_ptr<Block>* meta_block,
|
|
std::unique_ptr<Iterator>* iter) {
|
|
// TODO(sanjay): Skip this if footer.metaindex_handle() size indicates
|
|
// it is an empty block.
|
|
// TODO: we never really verify check sum for meta index block
|
|
Block* meta = nullptr;
|
|
Status s = ReadBlockFromFile(
|
|
rep->file.get(),
|
|
rep->footer,
|
|
ReadOptions(),
|
|
rep->footer.metaindex_handle(),
|
|
&meta,
|
|
rep->ioptions.env);
|
|
|
|
if (!s.ok()) {
|
|
auto err_msg =
|
|
"[Warning] Encountered error while reading data from properties"
|
|
"block " + s.ToString();
|
|
Log(rep->ioptions.info_log, "%s", err_msg.c_str());
|
|
}
|
|
if (!s.ok()) {
|
|
delete meta;
|
|
return s;
|
|
}
|
|
|
|
meta_block->reset(meta);
|
|
// meta block uses bytewise comparator.
|
|
iter->reset(meta->NewIterator(BytewiseComparator()));
|
|
return Status::OK();
|
|
}
|
|
|
|
Status BlockBasedTable::GetDataBlockFromCache(
|
|
const Slice& block_cache_key, const Slice& compressed_block_cache_key,
|
|
Cache* block_cache, Cache* block_cache_compressed, Statistics* statistics,
|
|
const ReadOptions& read_options,
|
|
BlockBasedTable::CachableEntry<Block>* block) {
|
|
Status s;
|
|
Block* compressed_block = nullptr;
|
|
Cache::Handle* block_cache_compressed_handle = nullptr;
|
|
|
|
// Lookup uncompressed cache first
|
|
if (block_cache != nullptr) {
|
|
block->cache_handle =
|
|
GetEntryFromCache(block_cache, block_cache_key, BLOCK_CACHE_DATA_MISS,
|
|
BLOCK_CACHE_DATA_HIT, statistics);
|
|
if (block->cache_handle != nullptr) {
|
|
block->value =
|
|
reinterpret_cast<Block*>(block_cache->Value(block->cache_handle));
|
|
return s;
|
|
}
|
|
}
|
|
|
|
// If not found, search from the compressed block cache.
|
|
assert(block->cache_handle == nullptr && block->value == nullptr);
|
|
|
|
if (block_cache_compressed == nullptr) {
|
|
return s;
|
|
}
|
|
|
|
assert(!compressed_block_cache_key.empty());
|
|
block_cache_compressed_handle =
|
|
block_cache_compressed->Lookup(compressed_block_cache_key);
|
|
// if we found in the compressed cache, then uncompress and insert into
|
|
// uncompressed cache
|
|
if (block_cache_compressed_handle == nullptr) {
|
|
RecordTick(statistics, BLOCK_CACHE_COMPRESSED_MISS);
|
|
return s;
|
|
}
|
|
|
|
// found compressed block
|
|
RecordTick(statistics, BLOCK_CACHE_COMPRESSED_HIT);
|
|
compressed_block = reinterpret_cast<Block*>(
|
|
block_cache_compressed->Value(block_cache_compressed_handle));
|
|
assert(compressed_block->compression_type() != kNoCompression);
|
|
|
|
// Retrieve the uncompressed contents into a new buffer
|
|
BlockContents contents;
|
|
s = UncompressBlockContents(compressed_block->data(),
|
|
compressed_block->size(), &contents);
|
|
|
|
// Insert uncompressed block into block cache
|
|
if (s.ok()) {
|
|
block->value = new Block(contents); // uncompressed block
|
|
assert(block->value->compression_type() == kNoCompression);
|
|
if (block_cache != nullptr && block->value->cachable() &&
|
|
read_options.fill_cache) {
|
|
block->cache_handle =
|
|
block_cache->Insert(block_cache_key, block->value,
|
|
block->value->size(), &DeleteCachedEntry<Block>);
|
|
assert(reinterpret_cast<Block*>(
|
|
block_cache->Value(block->cache_handle)) == block->value);
|
|
}
|
|
}
|
|
|
|
// Release hold on compressed cache entry
|
|
block_cache_compressed->Release(block_cache_compressed_handle);
|
|
return s;
|
|
}
|
|
|
|
Status BlockBasedTable::PutDataBlockToCache(
|
|
const Slice& block_cache_key, const Slice& compressed_block_cache_key,
|
|
Cache* block_cache, Cache* block_cache_compressed,
|
|
const ReadOptions& read_options, Statistics* statistics,
|
|
CachableEntry<Block>* block, Block* raw_block) {
|
|
assert(raw_block->compression_type() == kNoCompression ||
|
|
block_cache_compressed != nullptr);
|
|
|
|
Status s;
|
|
// Retrieve the uncompressed contents into a new buffer
|
|
BlockContents contents;
|
|
if (raw_block->compression_type() != kNoCompression) {
|
|
s = UncompressBlockContents(raw_block->data(), raw_block->size(),
|
|
&contents);
|
|
}
|
|
if (!s.ok()) {
|
|
delete raw_block;
|
|
return s;
|
|
}
|
|
|
|
if (raw_block->compression_type() != kNoCompression) {
|
|
block->value = new Block(contents); // uncompressed block
|
|
} else {
|
|
block->value = raw_block;
|
|
raw_block = nullptr;
|
|
}
|
|
|
|
// Insert compressed block into compressed block cache.
|
|
// Release the hold on the compressed cache entry immediately.
|
|
if (block_cache_compressed != nullptr && raw_block != nullptr &&
|
|
raw_block->cachable()) {
|
|
auto cache_handle = block_cache_compressed->Insert(
|
|
compressed_block_cache_key, raw_block, raw_block->size(),
|
|
&DeleteCachedEntry<Block>);
|
|
block_cache_compressed->Release(cache_handle);
|
|
RecordTick(statistics, BLOCK_CACHE_COMPRESSED_MISS);
|
|
// Avoid the following code to delete this cached block.
|
|
raw_block = nullptr;
|
|
}
|
|
delete raw_block;
|
|
|
|
// insert into uncompressed block cache
|
|
assert((block->value->compression_type() == kNoCompression));
|
|
if (block_cache != nullptr && block->value->cachable()) {
|
|
block->cache_handle =
|
|
block_cache->Insert(block_cache_key, block->value, block->value->size(),
|
|
&DeleteCachedEntry<Block>);
|
|
RecordTick(statistics, BLOCK_CACHE_ADD);
|
|
assert(reinterpret_cast<Block*>(block_cache->Value(block->cache_handle)) ==
|
|
block->value);
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
FilterBlockReader* BlockBasedTable::ReadFilter(
|
|
const BlockHandle& filter_handle, BlockBasedTable::Rep* rep,
|
|
const std::string& filter_block_prefix, size_t* filter_size) {
|
|
// TODO: We might want to unify with ReadBlockFromFile() if we start
|
|
// requiring checksum verification in Table::Open.
|
|
ReadOptions opt;
|
|
BlockContents block;
|
|
if (!ReadBlockContents(rep->file.get(), rep->footer, opt, filter_handle,
|
|
&block, rep->ioptions.env, false).ok()) {
|
|
return nullptr;
|
|
}
|
|
|
|
if (filter_size) {
|
|
*filter_size = block.data.size();
|
|
}
|
|
|
|
assert(rep->filter_policy);
|
|
if (kFilterBlockPrefix == filter_block_prefix) {
|
|
return new BlockBasedFilterBlockReader(rep->ioptions.prefix_extractor,
|
|
rep->table_options, block.data, block.heap_allocated);
|
|
} else if (kFullFilterBlockPrefix == filter_block_prefix) {
|
|
auto filter_bits_reader = rep->filter_policy->
|
|
GetFilterBitsReader(block.data);
|
|
|
|
if (filter_bits_reader != nullptr) {
|
|
return new FullFilterBlockReader(rep->ioptions.prefix_extractor,
|
|
rep->table_options, block.data, filter_bits_reader,
|
|
block.heap_allocated);
|
|
}
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
BlockBasedTable::CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
|
|
bool no_io) const {
|
|
// filter pre-populated
|
|
if (rep_->filter != nullptr) {
|
|
return {rep_->filter.get(), nullptr /* cache handle */};
|
|
}
|
|
|
|
Cache* block_cache = rep_->table_options.block_cache.get();
|
|
if (rep_->filter_policy == nullptr /* do not use filter */ ||
|
|
block_cache == nullptr /* no block cache at all */) {
|
|
return {nullptr /* filter */, nullptr /* cache handle */};
|
|
}
|
|
|
|
// Fetching from the cache
|
|
char cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
|
|
auto key = GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
|
|
rep_->footer.metaindex_handle(),
|
|
cache_key
|
|
);
|
|
|
|
Statistics* statistics = rep_->ioptions.statistics;
|
|
auto cache_handle =
|
|
GetEntryFromCache(block_cache, key, BLOCK_CACHE_FILTER_MISS,
|
|
BLOCK_CACHE_FILTER_HIT, statistics);
|
|
|
|
FilterBlockReader* filter = nullptr;
|
|
if (cache_handle != nullptr) {
|
|
filter = reinterpret_cast<FilterBlockReader*>(
|
|
block_cache->Value(cache_handle));
|
|
} else if (no_io) {
|
|
// Do not invoke any io.
|
|
return CachableEntry<FilterBlockReader>();
|
|
} else {
|
|
size_t filter_size = 0;
|
|
std::unique_ptr<Block> meta;
|
|
std::unique_ptr<Iterator> iter;
|
|
auto s = ReadMetaBlock(rep_, &meta, &iter);
|
|
|
|
if (s.ok()) {
|
|
// First try reading full_filter, then reading block_based_filter
|
|
for (auto filter_block_prefix : {kFullFilterBlockPrefix,
|
|
kFilterBlockPrefix}) {
|
|
std::string filter_block_key = filter_block_prefix;
|
|
filter_block_key.append(rep_->filter_policy->Name());
|
|
BlockHandle handle;
|
|
if (FindMetaBlock(iter.get(), filter_block_key, &handle).ok()) {
|
|
filter = ReadFilter(handle, rep_, filter_block_prefix, &filter_size);
|
|
|
|
if (filter == nullptr) break; // err happen in ReadFilter
|
|
assert(filter_size > 0);
|
|
cache_handle = block_cache->Insert(
|
|
key, filter, filter_size, &DeleteCachedEntry<FilterBlockReader>);
|
|
RecordTick(statistics, BLOCK_CACHE_ADD);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return { filter, cache_handle };
|
|
}
|
|
|
|
Iterator* BlockBasedTable::NewIndexIterator(const ReadOptions& read_options,
|
|
BlockIter* input_iter) {
|
|
// index reader has already been pre-populated.
|
|
if (rep_->index_reader) {
|
|
return rep_->index_reader->NewIterator(
|
|
input_iter, read_options.total_order_seek);
|
|
}
|
|
|
|
bool no_io = read_options.read_tier == kBlockCacheTier;
|
|
Cache* block_cache = rep_->table_options.block_cache.get();
|
|
char cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
|
|
auto key = GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
|
|
rep_->footer.index_handle(), cache_key);
|
|
Statistics* statistics = rep_->ioptions.statistics;
|
|
auto cache_handle =
|
|
GetEntryFromCache(block_cache, key, BLOCK_CACHE_INDEX_MISS,
|
|
BLOCK_CACHE_INDEX_HIT, statistics);
|
|
|
|
if (cache_handle == nullptr && no_io) {
|
|
if (input_iter != nullptr) {
|
|
input_iter->SetStatus(Status::Incomplete("no blocking io"));
|
|
return input_iter;
|
|
} else {
|
|
return NewErrorIterator(Status::Incomplete("no blocking io"));
|
|
}
|
|
}
|
|
|
|
IndexReader* index_reader = nullptr;
|
|
if (cache_handle != nullptr) {
|
|
index_reader =
|
|
reinterpret_cast<IndexReader*>(block_cache->Value(cache_handle));
|
|
} else {
|
|
// Create index reader and put it in the cache.
|
|
Status s;
|
|
s = CreateIndexReader(&index_reader);
|
|
|
|
if (!s.ok()) {
|
|
// make sure if something goes wrong, index_reader shall remain intact.
|
|
assert(index_reader == nullptr);
|
|
if (input_iter != nullptr) {
|
|
input_iter->SetStatus(s);
|
|
return input_iter;
|
|
} else {
|
|
return NewErrorIterator(s);
|
|
}
|
|
}
|
|
|
|
cache_handle = block_cache->Insert(key, index_reader, index_reader->size(),
|
|
&DeleteCachedEntry<IndexReader>);
|
|
RecordTick(statistics, BLOCK_CACHE_ADD);
|
|
}
|
|
|
|
assert(cache_handle);
|
|
auto* iter = index_reader->NewIterator(
|
|
input_iter, read_options.total_order_seek);
|
|
iter->RegisterCleanup(&ReleaseCachedEntry, block_cache, cache_handle);
|
|
return iter;
|
|
}
|
|
|
|
// Convert an index iterator value (i.e., an encoded BlockHandle)
|
|
// into an iterator over the contents of the corresponding block.
|
|
// If input_iter is null, new a iterator
|
|
// If input_iter is not null, update this iter and return it
|
|
Iterator* BlockBasedTable::NewDataBlockIterator(Rep* rep,
|
|
const ReadOptions& ro, const Slice& index_value,
|
|
BlockIter* input_iter) {
|
|
const bool no_io = (ro.read_tier == kBlockCacheTier);
|
|
Cache* block_cache = rep->table_options.block_cache.get();
|
|
Cache* block_cache_compressed =
|
|
rep->table_options.block_cache_compressed.get();
|
|
CachableEntry<Block> block;
|
|
|
|
BlockHandle handle;
|
|
Slice input = index_value;
|
|
// We intentionally allow extra stuff in index_value so that we
|
|
// can add more features in the future.
|
|
Status s = handle.DecodeFrom(&input);
|
|
|
|
if (!s.ok()) {
|
|
if (input_iter != nullptr) {
|
|
input_iter->SetStatus(s);
|
|
return input_iter;
|
|
} else {
|
|
return NewErrorIterator(s);
|
|
}
|
|
}
|
|
|
|
// If either block cache is enabled, we'll try to read from it.
|
|
if (block_cache != nullptr || block_cache_compressed != nullptr) {
|
|
Statistics* statistics = rep->ioptions.statistics;
|
|
char cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
|
|
char compressed_cache_key[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
|
|
Slice key, /* key to the block cache */
|
|
ckey /* key to the compressed block cache */;
|
|
|
|
// create key for block cache
|
|
if (block_cache != nullptr) {
|
|
key = GetCacheKey(rep->cache_key_prefix, rep->cache_key_prefix_size,
|
|
handle, cache_key);
|
|
}
|
|
|
|
if (block_cache_compressed != nullptr) {
|
|
ckey = GetCacheKey(rep->compressed_cache_key_prefix,
|
|
rep->compressed_cache_key_prefix_size, handle,
|
|
compressed_cache_key);
|
|
}
|
|
|
|
s = GetDataBlockFromCache(key, ckey, block_cache, block_cache_compressed,
|
|
statistics, ro, &block);
|
|
|
|
if (block.value == nullptr && !no_io && ro.fill_cache) {
|
|
Block* raw_block = nullptr;
|
|
{
|
|
StopWatch sw(rep->ioptions.env, statistics, READ_BLOCK_GET_MICROS);
|
|
s = ReadBlockFromFile(rep->file.get(), rep->footer, ro, handle,
|
|
&raw_block, rep->ioptions.env,
|
|
block_cache_compressed == nullptr);
|
|
}
|
|
|
|
if (s.ok()) {
|
|
s = PutDataBlockToCache(key, ckey, block_cache, block_cache_compressed,
|
|
ro, statistics, &block, raw_block);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Didn't get any data from block caches.
|
|
if (block.value == nullptr) {
|
|
if (no_io) {
|
|
// Could not read from block_cache and can't do IO
|
|
if (input_iter != nullptr) {
|
|
input_iter->SetStatus(Status::Incomplete("no blocking io"));
|
|
return input_iter;
|
|
} else {
|
|
return NewErrorIterator(Status::Incomplete("no blocking io"));
|
|
}
|
|
}
|
|
s = ReadBlockFromFile(rep->file.get(), rep->footer, ro, handle,
|
|
&block.value, rep->ioptions.env);
|
|
}
|
|
|
|
Iterator* iter;
|
|
if (block.value != nullptr) {
|
|
iter = block.value->NewIterator(&rep->internal_comparator, input_iter);
|
|
if (block.cache_handle != nullptr) {
|
|
iter->RegisterCleanup(&ReleaseCachedEntry, block_cache,
|
|
block.cache_handle);
|
|
} else {
|
|
iter->RegisterCleanup(&DeleteHeldResource<Block>, block.value, nullptr);
|
|
}
|
|
} else {
|
|
if (input_iter != nullptr) {
|
|
input_iter->SetStatus(s);
|
|
iter = input_iter;
|
|
} else {
|
|
iter = NewErrorIterator(s);
|
|
}
|
|
}
|
|
return iter;
|
|
}
|
|
|
|
class BlockBasedTable::BlockEntryIteratorState : public TwoLevelIteratorState {
|
|
public:
|
|
BlockEntryIteratorState(BlockBasedTable* table,
|
|
const ReadOptions& read_options)
|
|
: TwoLevelIteratorState(
|
|
table->rep_->ioptions.prefix_extractor != nullptr),
|
|
table_(table),
|
|
read_options_(read_options) {}
|
|
|
|
Iterator* NewSecondaryIterator(const Slice& index_value) override {
|
|
return NewDataBlockIterator(table_->rep_, read_options_, index_value);
|
|
}
|
|
|
|
bool PrefixMayMatch(const Slice& internal_key) override {
|
|
if (read_options_.total_order_seek) {
|
|
return true;
|
|
}
|
|
return table_->PrefixMayMatch(internal_key);
|
|
}
|
|
|
|
private:
|
|
// Don't own table_
|
|
BlockBasedTable* table_;
|
|
const ReadOptions read_options_;
|
|
};
|
|
|
|
// This will be broken if the user specifies an unusual implementation
|
|
// of Options.comparator, or if the user specifies an unusual
|
|
// definition of prefixes in BlockBasedTableOptions.filter_policy.
|
|
// In particular, we require the following three properties:
|
|
//
|
|
// 1) key.starts_with(prefix(key))
|
|
// 2) Compare(prefix(key), key) <= 0.
|
|
// 3) If Compare(key1, key2) <= 0, then Compare(prefix(key1), prefix(key2)) <= 0
|
|
//
|
|
// Otherwise, this method guarantees no I/O will be incurred.
|
|
//
|
|
// REQUIRES: this method shouldn't be called while the DB lock is held.
|
|
bool BlockBasedTable::PrefixMayMatch(const Slice& internal_key) {
|
|
if (!rep_->filter_policy) {
|
|
return true;
|
|
}
|
|
|
|
assert(rep_->ioptions.prefix_extractor != nullptr);
|
|
auto prefix = rep_->ioptions.prefix_extractor->Transform(
|
|
ExtractUserKey(internal_key));
|
|
InternalKey internal_key_prefix(prefix, 0, kTypeValue);
|
|
auto internal_prefix = internal_key_prefix.Encode();
|
|
|
|
bool may_match = true;
|
|
Status s;
|
|
|
|
// To prevent any io operation in this method, we set `read_tier` to make
|
|
// sure we always read index or filter only when they have already been
|
|
// loaded to memory.
|
|
ReadOptions no_io_read_options;
|
|
no_io_read_options.read_tier = kBlockCacheTier;
|
|
|
|
// First, try check with full filter
|
|
auto filter_entry = GetFilter(true /* no io */);
|
|
FilterBlockReader* filter = filter_entry.value;
|
|
if (filter != nullptr && !filter->IsBlockBased()) {
|
|
may_match = filter->PrefixMayMatch(prefix);
|
|
}
|
|
|
|
// Then, try find it within each block
|
|
if (may_match) {
|
|
unique_ptr<Iterator> iiter(NewIndexIterator(no_io_read_options));
|
|
iiter->Seek(internal_prefix);
|
|
|
|
if (!iiter->Valid()) {
|
|
// we're past end of file
|
|
// if it's incomplete, it means that we avoided I/O
|
|
// and we're not really sure that we're past the end
|
|
// of the file
|
|
may_match = iiter->status().IsIncomplete();
|
|
} else if (ExtractUserKey(iiter->key()).starts_with(
|
|
ExtractUserKey(internal_prefix))) {
|
|
// we need to check for this subtle case because our only
|
|
// guarantee is that "the key is a string >= last key in that data
|
|
// block" according to the doc/table_format.txt spec.
|
|
//
|
|
// Suppose iiter->key() starts with the desired prefix; it is not
|
|
// necessarily the case that the corresponding data block will
|
|
// contain the prefix, since iiter->key() need not be in the
|
|
// block. However, the next data block may contain the prefix, so
|
|
// we return true to play it safe.
|
|
may_match = true;
|
|
} else if (filter != nullptr && filter->IsBlockBased()) {
|
|
// iiter->key() does NOT start with the desired prefix. Because
|
|
// Seek() finds the first key that is >= the seek target, this
|
|
// means that iiter->key() > prefix. Thus, any data blocks coming
|
|
// after the data block corresponding to iiter->key() cannot
|
|
// possibly contain the key. Thus, the corresponding data block
|
|
// is the only on could potentially contain the prefix.
|
|
Slice handle_value = iiter->value();
|
|
BlockHandle handle;
|
|
s = handle.DecodeFrom(&handle_value);
|
|
assert(s.ok());
|
|
may_match = filter->PrefixMayMatch(prefix, handle.offset());
|
|
}
|
|
}
|
|
|
|
Statistics* statistics = rep_->ioptions.statistics;
|
|
RecordTick(statistics, BLOOM_FILTER_PREFIX_CHECKED);
|
|
if (!may_match) {
|
|
RecordTick(statistics, BLOOM_FILTER_PREFIX_USEFUL);
|
|
}
|
|
|
|
filter_entry.Release(rep_->table_options.block_cache.get());
|
|
return may_match;
|
|
}
|
|
|
|
Iterator* BlockBasedTable::NewIterator(const ReadOptions& read_options,
|
|
Arena* arena) {
|
|
return NewTwoLevelIterator(new BlockEntryIteratorState(this, read_options),
|
|
NewIndexIterator(read_options), arena);
|
|
}
|
|
|
|
Status BlockBasedTable::Get(
|
|
const ReadOptions& read_options, const Slice& key, void* handle_context,
|
|
bool (*result_handler)(void* handle_context, const ParsedInternalKey& k,
|
|
const Slice& v),
|
|
void (*mark_key_may_exist_handler)(void* handle_context)) {
|
|
Status s;
|
|
auto filter_entry = GetFilter(read_options.read_tier == kBlockCacheTier);
|
|
FilterBlockReader* filter = filter_entry.value;
|
|
|
|
// First check the full filter
|
|
// If full filter not useful, Then go into each block
|
|
if (filter != nullptr && !filter->IsBlockBased()
|
|
&& !filter->KeyMayMatch(ExtractUserKey(key))) {
|
|
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_USEFUL);
|
|
} else {
|
|
BlockIter iiter;
|
|
NewIndexIterator(read_options, &iiter);
|
|
|
|
bool done = false;
|
|
for (iiter.Seek(key); iiter.Valid() && !done; iiter.Next()) {
|
|
Slice handle_value = iiter.value();
|
|
|
|
BlockHandle handle;
|
|
bool not_exist_in_filter =
|
|
filter != nullptr && filter->IsBlockBased() == true &&
|
|
handle.DecodeFrom(&handle_value).ok() &&
|
|
!filter->KeyMayMatch(ExtractUserKey(key), handle.offset());
|
|
|
|
if (not_exist_in_filter) {
|
|
// Not found
|
|
// TODO: think about interaction with Merge. If a user key cannot
|
|
// cross one data block, we should be fine.
|
|
RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_USEFUL);
|
|
break;
|
|
} else {
|
|
BlockIter biter;
|
|
NewDataBlockIterator(rep_, read_options, iiter.value(), &biter);
|
|
|
|
if (read_options.read_tier && biter.status().IsIncomplete()) {
|
|
// couldn't get block from block_cache
|
|
// Update Saver.state to Found because we are only looking for whether
|
|
// we can guarantee the key is not there when "no_io" is set
|
|
(*mark_key_may_exist_handler)(handle_context);
|
|
break;
|
|
}
|
|
if (!biter.status().ok()) {
|
|
s = biter.status();
|
|
break;
|
|
}
|
|
|
|
// Call the *saver function on each entry/block until it returns false
|
|
for (biter.Seek(key); biter.Valid(); biter.Next()) {
|
|
ParsedInternalKey parsed_key;
|
|
if (!ParseInternalKey(biter.key(), &parsed_key)) {
|
|
s = Status::Corruption(Slice());
|
|
}
|
|
|
|
if (!(*result_handler)(handle_context, parsed_key,
|
|
biter.value())) {
|
|
done = true;
|
|
break;
|
|
}
|
|
}
|
|
s = biter.status();
|
|
}
|
|
}
|
|
if (s.ok()) {
|
|
s = iiter.status();
|
|
}
|
|
}
|
|
|
|
filter_entry.Release(rep_->table_options.block_cache.get());
|
|
return s;
|
|
}
|
|
|
|
bool BlockBasedTable::TEST_KeyInCache(const ReadOptions& options,
|
|
const Slice& key) {
|
|
std::unique_ptr<Iterator> iiter(NewIndexIterator(options));
|
|
iiter->Seek(key);
|
|
assert(iiter->Valid());
|
|
CachableEntry<Block> block;
|
|
|
|
BlockHandle handle;
|
|
Slice input = iiter->value();
|
|
Status s = handle.DecodeFrom(&input);
|
|
assert(s.ok());
|
|
Cache* block_cache = rep_->table_options.block_cache.get();
|
|
assert(block_cache != nullptr);
|
|
|
|
char cache_key_storage[kMaxCacheKeyPrefixSize + kMaxVarint64Length];
|
|
Slice cache_key =
|
|
GetCacheKey(rep_->cache_key_prefix, rep_->cache_key_prefix_size,
|
|
handle, cache_key_storage);
|
|
Slice ckey;
|
|
|
|
s = GetDataBlockFromCache(cache_key, ckey, block_cache, nullptr, nullptr,
|
|
options, &block);
|
|
assert(s.ok());
|
|
bool in_cache = block.value != nullptr;
|
|
if (in_cache) {
|
|
ReleaseCachedEntry(block_cache, block.cache_handle);
|
|
}
|
|
return in_cache;
|
|
}
|
|
|
|
// REQUIRES: The following fields of rep_ should have already been populated:
|
|
// 1. file
|
|
// 2. index_handle,
|
|
// 3. options
|
|
// 4. internal_comparator
|
|
// 5. index_type
|
|
Status BlockBasedTable::CreateIndexReader(IndexReader** index_reader,
|
|
Iterator* preloaded_meta_index_iter) {
|
|
// Some old version of block-based tables don't have index type present in
|
|
// table properties. If that's the case we can safely use the kBinarySearch.
|
|
auto index_type_on_file = BlockBasedTableOptions::kBinarySearch;
|
|
if (rep_->table_properties) {
|
|
auto& props = rep_->table_properties->user_collected_properties;
|
|
auto pos = props.find(BlockBasedTablePropertyNames::kIndexType);
|
|
if (pos != props.end()) {
|
|
index_type_on_file = static_cast<BlockBasedTableOptions::IndexType>(
|
|
DecodeFixed32(pos->second.c_str()));
|
|
}
|
|
}
|
|
|
|
auto file = rep_->file.get();
|
|
auto env = rep_->ioptions.env;
|
|
auto comparator = &rep_->internal_comparator;
|
|
const Footer& footer = rep_->footer;
|
|
|
|
if (index_type_on_file == BlockBasedTableOptions::kHashSearch &&
|
|
rep_->ioptions.prefix_extractor == nullptr) {
|
|
Log(rep_->ioptions.info_log,
|
|
"BlockBasedTableOptions::kHashSearch requires "
|
|
"options.prefix_extractor to be set."
|
|
" Fall back to binary seach index.");
|
|
index_type_on_file = BlockBasedTableOptions::kBinarySearch;
|
|
}
|
|
|
|
switch (index_type_on_file) {
|
|
case BlockBasedTableOptions::kBinarySearch: {
|
|
return BinarySearchIndexReader::Create(
|
|
file, footer, footer.index_handle(), env, comparator, index_reader);
|
|
}
|
|
case BlockBasedTableOptions::kHashSearch: {
|
|
std::unique_ptr<Block> meta_guard;
|
|
std::unique_ptr<Iterator> meta_iter_guard;
|
|
auto meta_index_iter = preloaded_meta_index_iter;
|
|
if (meta_index_iter == nullptr) {
|
|
auto s = ReadMetaBlock(rep_, &meta_guard, &meta_iter_guard);
|
|
if (!s.ok()) {
|
|
// we simply fall back to binary search in case there is any
|
|
// problem with prefix hash index loading.
|
|
Log(rep_->ioptions.info_log,
|
|
"Unable to read the metaindex block."
|
|
" Fall back to binary seach index.");
|
|
return BinarySearchIndexReader::Create(
|
|
file, footer, footer.index_handle(), env, comparator, index_reader);
|
|
}
|
|
meta_index_iter = meta_iter_guard.get();
|
|
}
|
|
|
|
// We need to wrap data with internal_prefix_transform to make sure it can
|
|
// handle prefix correctly.
|
|
rep_->internal_prefix_transform.reset(
|
|
new InternalKeySliceTransform(rep_->ioptions.prefix_extractor));
|
|
return HashIndexReader::Create(
|
|
rep_->internal_prefix_transform.get(), footer, file, env, comparator,
|
|
footer.index_handle(), meta_index_iter, index_reader,
|
|
rep_->hash_index_allow_collision);
|
|
}
|
|
default: {
|
|
std::string error_message =
|
|
"Unrecognized index type: " + std::to_string(rep_->index_type);
|
|
return Status::InvalidArgument(error_message.c_str());
|
|
}
|
|
}
|
|
}
|
|
|
|
uint64_t BlockBasedTable::ApproximateOffsetOf(const Slice& key) {
|
|
unique_ptr<Iterator> index_iter(NewIndexIterator(ReadOptions()));
|
|
|
|
index_iter->Seek(key);
|
|
uint64_t result;
|
|
if (index_iter->Valid()) {
|
|
BlockHandle handle;
|
|
Slice input = index_iter->value();
|
|
Status s = handle.DecodeFrom(&input);
|
|
if (s.ok()) {
|
|
result = handle.offset();
|
|
} else {
|
|
// Strange: we can't decode the block handle in the index block.
|
|
// We'll just return the offset of the metaindex block, which is
|
|
// close to the whole file size for this case.
|
|
result = rep_->footer.metaindex_handle().offset();
|
|
}
|
|
} else {
|
|
// key is past the last key in the file. If table_properties is not
|
|
// available, approximate the offset by returning the offset of the
|
|
// metaindex block (which is right near the end of the file).
|
|
result = 0;
|
|
if (rep_->table_properties) {
|
|
result = rep_->table_properties->data_size;
|
|
}
|
|
// table_properties is not present in the table.
|
|
if (result == 0) {
|
|
result = rep_->footer.metaindex_handle().offset();
|
|
}
|
|
}
|
|
return result;
|
|
}
|
|
|
|
bool BlockBasedTable::TEST_filter_block_preloaded() const {
|
|
return rep_->filter != nullptr;
|
|
}
|
|
|
|
bool BlockBasedTable::TEST_index_reader_preloaded() const {
|
|
return rep_->index_reader != nullptr;
|
|
}
|
|
|
|
} // namespace rocksdb
|