--- /dev/null
+// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
+// This source code is licensed under both the GPLv2 (found in the
+// COPYING file in the root directory) and Apache 2.0 License
+// (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include "table/block_based/block_based_filter_block.h"
+#include <algorithm>
+
+#include "db/dbformat.h"
+#include "monitoring/perf_context_imp.h"
+#include "rocksdb/filter_policy.h"
+#include "table/block_based/block_based_table_reader.h"
+#include "util/coding.h"
+#include "util/string_util.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+namespace {
+
+void AppendItem(std::string* props, const std::string& key,
+ const std::string& value) {
+ char cspace = ' ';
+ std::string value_str("");
+ size_t i = 0;
+ const size_t dataLength = 64;
+ const size_t tabLength = 2;
+ const size_t offLength = 16;
+
+ value_str.append(&value[i], std::min(size_t(dataLength), value.size()));
+ i += dataLength;
+ while (i < value.size()) {
+ value_str.append("\n");
+ value_str.append(offLength, cspace);
+ value_str.append(&value[i], std::min(size_t(dataLength), value.size() - i));
+ i += dataLength;
+ }
+
+ std::string result("");
+ if (key.size() < (offLength - tabLength))
+ result.append(size_t((offLength - tabLength)) - key.size(), cspace);
+ result.append(key);
+
+ props->append(result + ": " + value_str + "\n");
+}
+
+template <class TKey>
+void AppendItem(std::string* props, const TKey& key, const std::string& value) {
+ std::string key_str = ROCKSDB_NAMESPACE::ToString(key);
+ AppendItem(props, key_str, value);
+}
+} // namespace
+
+// See doc/table_format.txt for an explanation of the filter block format.
+
+// Generate new filter every 2KB of data
+static const size_t kFilterBaseLg = 11;
+static const size_t kFilterBase = 1 << kFilterBaseLg;
+
+BlockBasedFilterBlockBuilder::BlockBasedFilterBlockBuilder(
+ const SliceTransform* prefix_extractor,
+ const BlockBasedTableOptions& table_opt)
+ : policy_(table_opt.filter_policy.get()),
+ prefix_extractor_(prefix_extractor),
+ whole_key_filtering_(table_opt.whole_key_filtering),
+ prev_prefix_start_(0),
+ prev_prefix_size_(0),
+ num_added_(0) {
+ assert(policy_);
+}
+
+void BlockBasedFilterBlockBuilder::StartBlock(uint64_t block_offset) {
+ uint64_t filter_index = (block_offset / kFilterBase);
+ assert(filter_index >= filter_offsets_.size());
+ while (filter_index > filter_offsets_.size()) {
+ GenerateFilter();
+ }
+}
+
+void BlockBasedFilterBlockBuilder::Add(const Slice& key) {
+ if (prefix_extractor_ && prefix_extractor_->InDomain(key)) {
+ AddPrefix(key);
+ }
+
+ if (whole_key_filtering_) {
+ AddKey(key);
+ }
+}
+
+// Add key to filter if needed
+inline void BlockBasedFilterBlockBuilder::AddKey(const Slice& key) {
+ num_added_++;
+ start_.push_back(entries_.size());
+ entries_.append(key.data(), key.size());
+}
+
+// Add prefix to filter if needed
+inline void BlockBasedFilterBlockBuilder::AddPrefix(const Slice& key) {
+ // get slice for most recently added entry
+ Slice prev;
+ if (prev_prefix_size_ > 0) {
+ prev = Slice(entries_.data() + prev_prefix_start_, prev_prefix_size_);
+ }
+
+ Slice prefix = prefix_extractor_->Transform(key);
+ // insert prefix only when it's different from the previous prefix.
+ if (prev.size() == 0 || prefix != prev) {
+ prev_prefix_start_ = entries_.size();
+ prev_prefix_size_ = prefix.size();
+ AddKey(prefix);
+ }
+}
+
+Slice BlockBasedFilterBlockBuilder::Finish(const BlockHandle& /*tmp*/,
+ Status* status) {
+ // In this impl we ignore BlockHandle
+ *status = Status::OK();
+ if (!start_.empty()) {
+ GenerateFilter();
+ }
+
+ // Append array of per-filter offsets
+ const uint32_t array_offset = static_cast<uint32_t>(result_.size());
+ for (size_t i = 0; i < filter_offsets_.size(); i++) {
+ PutFixed32(&result_, filter_offsets_[i]);
+ }
+
+ PutFixed32(&result_, array_offset);
+ result_.push_back(kFilterBaseLg); // Save encoding parameter in result
+ return Slice(result_);
+}
+
+void BlockBasedFilterBlockBuilder::GenerateFilter() {
+ const size_t num_entries = start_.size();
+ if (num_entries == 0) {
+ // Fast path if there are no keys for this filter
+ filter_offsets_.push_back(static_cast<uint32_t>(result_.size()));
+ return;
+ }
+
+ // Make list of keys from flattened key structure
+ start_.push_back(entries_.size()); // Simplify length computation
+ tmp_entries_.resize(num_entries);
+ for (size_t i = 0; i < num_entries; i++) {
+ const char* base = entries_.data() + start_[i];
+ size_t length = start_[i + 1] - start_[i];
+ tmp_entries_[i] = Slice(base, length);
+ }
+
+ // Generate filter for current set of keys and append to result_.
+ filter_offsets_.push_back(static_cast<uint32_t>(result_.size()));
+ policy_->CreateFilter(&tmp_entries_[0], static_cast<int>(num_entries),
+ &result_);
+
+ tmp_entries_.clear();
+ entries_.clear();
+ start_.clear();
+ prev_prefix_start_ = 0;
+ prev_prefix_size_ = 0;
+}
+
+BlockBasedFilterBlockReader::BlockBasedFilterBlockReader(
+ const BlockBasedTable* t, CachableEntry<BlockContents>&& filter_block)
+ : FilterBlockReaderCommon(t, std::move(filter_block)) {
+ assert(table());
+ assert(table()->get_rep());
+ assert(table()->get_rep()->filter_policy);
+}
+
+std::unique_ptr<FilterBlockReader> BlockBasedFilterBlockReader::Create(
+ const BlockBasedTable* table, FilePrefetchBuffer* prefetch_buffer,
+ bool use_cache, bool prefetch, bool pin,
+ BlockCacheLookupContext* lookup_context) {
+ assert(table);
+ assert(table->get_rep());
+ assert(!pin || prefetch);
+
+ CachableEntry<BlockContents> filter_block;
+ if (prefetch || !use_cache) {
+ const Status s = ReadFilterBlock(table, prefetch_buffer, ReadOptions(),
+ use_cache, nullptr /* get_context */,
+ lookup_context, &filter_block);
+ if (!s.ok()) {
+ return std::unique_ptr<FilterBlockReader>();
+ }
+
+ if (use_cache && !pin) {
+ filter_block.Reset();
+ }
+ }
+
+ return std::unique_ptr<FilterBlockReader>(
+ new BlockBasedFilterBlockReader(table, std::move(filter_block)));
+}
+
+bool BlockBasedFilterBlockReader::KeyMayMatch(
+ const Slice& key, const SliceTransform* /* prefix_extractor */,
+ uint64_t block_offset, const bool no_io,
+ const Slice* const /*const_ikey_ptr*/, GetContext* get_context,
+ BlockCacheLookupContext* lookup_context) {
+ assert(block_offset != kNotValid);
+ if (!whole_key_filtering()) {
+ return true;
+ }
+ return MayMatch(key, block_offset, no_io, get_context, lookup_context);
+}
+
+bool BlockBasedFilterBlockReader::PrefixMayMatch(
+ const Slice& prefix, const SliceTransform* /* prefix_extractor */,
+ uint64_t block_offset, const bool no_io,
+ const Slice* const /*const_ikey_ptr*/, GetContext* get_context,
+ BlockCacheLookupContext* lookup_context) {
+ assert(block_offset != kNotValid);
+ return MayMatch(prefix, block_offset, no_io, get_context, lookup_context);
+}
+
+bool BlockBasedFilterBlockReader::ParseFieldsFromBlock(
+ const BlockContents& contents, const char** data, const char** offset,
+ size_t* num, size_t* base_lg) {
+ assert(data);
+ assert(offset);
+ assert(num);
+ assert(base_lg);
+
+ const size_t n = contents.data.size();
+ if (n < 5) { // 1 byte for base_lg and 4 for start of offset array
+ return false;
+ }
+
+ const uint32_t last_word = DecodeFixed32(contents.data.data() + n - 5);
+ if (last_word > n - 5) {
+ return false;
+ }
+
+ *data = contents.data.data();
+ *offset = (*data) + last_word;
+ *num = (n - 5 - last_word) / 4;
+ *base_lg = contents.data[n - 1];
+
+ return true;
+}
+
+bool BlockBasedFilterBlockReader::MayMatch(
+ const Slice& entry, uint64_t block_offset, bool no_io,
+ GetContext* get_context, BlockCacheLookupContext* lookup_context) const {
+ CachableEntry<BlockContents> filter_block;
+
+ const Status s =
+ GetOrReadFilterBlock(no_io, get_context, lookup_context, &filter_block);
+ if (!s.ok()) {
+ return true;
+ }
+
+ assert(filter_block.GetValue());
+
+ const char* data = nullptr;
+ const char* offset = nullptr;
+ size_t num = 0;
+ size_t base_lg = 0;
+ if (!ParseFieldsFromBlock(*filter_block.GetValue(), &data, &offset, &num,
+ &base_lg)) {
+ return true; // Errors are treated as potential matches
+ }
+
+ const uint64_t index = block_offset >> base_lg;
+ if (index < num) {
+ const uint32_t start = DecodeFixed32(offset + index * 4);
+ const uint32_t limit = DecodeFixed32(offset + index * 4 + 4);
+ if (start <= limit && limit <= (uint32_t)(offset - data)) {
+ const Slice filter = Slice(data + start, limit - start);
+
+ assert(table());
+ assert(table()->get_rep());
+ const FilterPolicy* const policy = table()->get_rep()->filter_policy;
+
+ const bool may_match = policy->KeyMayMatch(entry, filter);
+ if (may_match) {
+ PERF_COUNTER_ADD(bloom_sst_hit_count, 1);
+ return true;
+ } else {
+ PERF_COUNTER_ADD(bloom_sst_miss_count, 1);
+ return false;
+ }
+ } else if (start == limit) {
+ // Empty filters do not match any entries
+ return false;
+ }
+ }
+ return true; // Errors are treated as potential matches
+}
+
+size_t BlockBasedFilterBlockReader::ApproximateMemoryUsage() const {
+ size_t usage = ApproximateFilterBlockMemoryUsage();
+#ifdef ROCKSDB_MALLOC_USABLE_SIZE
+ usage += malloc_usable_size(const_cast<BlockBasedFilterBlockReader*>(this));
+#else
+ usage += sizeof(*this);
+#endif // ROCKSDB_MALLOC_USABLE_SIZE
+ return usage;
+}
+
+std::string BlockBasedFilterBlockReader::ToString() const {
+ CachableEntry<BlockContents> filter_block;
+
+ const Status s =
+ GetOrReadFilterBlock(false /* no_io */, nullptr /* get_context */,
+ nullptr /* lookup_context */, &filter_block);
+ if (!s.ok()) {
+ return std::string("Unable to retrieve filter block");
+ }
+
+ assert(filter_block.GetValue());
+
+ const char* data = nullptr;
+ const char* offset = nullptr;
+ size_t num = 0;
+ size_t base_lg = 0;
+ if (!ParseFieldsFromBlock(*filter_block.GetValue(), &data, &offset, &num,
+ &base_lg)) {
+ return std::string("Error parsing filter block");
+ }
+
+ std::string result;
+ result.reserve(1024);
+
+ std::string s_bo("Block offset"), s_hd("Hex dump"), s_fb("# filter blocks");
+ AppendItem(&result, s_fb, ROCKSDB_NAMESPACE::ToString(num));
+ AppendItem(&result, s_bo, s_hd);
+
+ for (size_t index = 0; index < num; index++) {
+ uint32_t start = DecodeFixed32(offset + index * 4);
+ uint32_t limit = DecodeFixed32(offset + index * 4 + 4);
+
+ if (start != limit) {
+ result.append(" filter block # " +
+ ROCKSDB_NAMESPACE::ToString(index + 1) + "\n");
+ Slice filter = Slice(data + start, limit - start);
+ AppendItem(&result, start, filter.ToString(true));
+ }
+ }
+ return result;
+}
+
+} // namespace ROCKSDB_NAMESPACE
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