Materialize the hash index
Summary: Materialize the hash index to avoid the soaring cpu/flash usage when initializing the database. Test Plan: existing unit tests passed Reviewers: sdong, haobo Reviewed By: sdong CC: leveldb Differential Revision: https://reviews.facebook.net/D18339
This commit is contained in:
Kai Liu
parent
4e0602f941
commit
0b3d03d026
@ -5,6 +5,9 @@
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### Public API changes
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* Replaced ColumnFamilyOptions::table_properties_collectors with ColumnFamilyOptions::table_properties_collector_factories
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### New Features
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* Hash index for block-based table will be materialized and reconstructed more efficiently. Previously hash index is constructed by scanning the whole table during every table open.
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## 3.0.0 (05/05/2014)
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### Public API changes
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@ -15,6 +15,8 @@
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#include <map>
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#include <memory>
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#include <string>
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#include <unordered_map>
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#include "db/dbformat.h"
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@ -41,6 +43,8 @@
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namespace rocksdb {
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extern const std::string kHashIndexPrefixesBlock;
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extern const std::string kHashIndexPrefixesMetadataBlock;
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namespace {
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typedef BlockBasedTableOptions::IndexType IndexType;
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@ -57,6 +61,14 @@ typedef BlockBasedTableOptions::IndexType IndexType;
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// design that just works.
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class IndexBuilder {
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public:
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// Index builder will construct a set of blocks which contain:
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// 1. One primary index block.
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// 2. (Optional) a set of metablocks that contains the metadata of the
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// primary index.
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struct IndexBlocks {
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Slice index_block_contents;
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std::unordered_map<std::string, Slice> meta_blocks;
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};
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explicit IndexBuilder(const Comparator* comparator)
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: comparator_(comparator) {}
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@ -72,15 +84,19 @@ class IndexBuilder {
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// the last one in the table
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//
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// REQUIRES: Finish() has not yet been called.
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virtual void AddEntry(std::string* last_key_in_current_block,
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virtual void AddIndexEntry(std::string* last_key_in_current_block,
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const Slice* first_key_in_next_block,
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const BlockHandle& block_handle) = 0;
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// This method will be called whenever a key is added. The subclasses may
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// override OnKeyAdded() if they need to collect additional information.
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virtual void OnKeyAdded(const Slice& key) {}
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// Inform the index builder that all entries has been written. Block builder
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// may therefore perform any operation required for block finalization.
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//
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// REQUIRES: Finish() has not yet been called.
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virtual Slice Finish() = 0;
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virtual Status Finish(IndexBlocks* index_blocks) = 0;
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// Get the estimated size for index block.
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virtual size_t EstimatedSize() const = 0;
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@ -103,7 +119,7 @@ class ShortenedIndexBuilder : public IndexBuilder {
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: IndexBuilder(comparator),
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index_block_builder_(1 /* block_restart_interval == 1 */, comparator) {}
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virtual void AddEntry(std::string* last_key_in_current_block,
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virtual void AddIndexEntry(std::string* last_key_in_current_block,
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const Slice* first_key_in_next_block,
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const BlockHandle& block_handle) override {
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if (first_key_in_next_block != nullptr) {
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@ -118,7 +134,10 @@ class ShortenedIndexBuilder : public IndexBuilder {
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index_block_builder_.Add(*last_key_in_current_block, handle_encoding);
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}
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virtual Slice Finish() override { return index_block_builder_.Finish(); }
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virtual Status Finish(IndexBlocks* index_blocks) {
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index_blocks->index_block_contents = index_block_builder_.Finish();
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return Status::OK();
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}
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virtual size_t EstimatedSize() const {
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return index_block_builder_.CurrentSizeEstimate();
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@ -128,38 +147,125 @@ class ShortenedIndexBuilder : public IndexBuilder {
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BlockBuilder index_block_builder_;
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};
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// FullKeyIndexBuilder is also based on BlockBuilder. It works pretty much like
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// ShortenedIndexBuilder, but preserves the full key instead the substitude key.
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class FullKeyIndexBuilder : public IndexBuilder {
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// HashIndexBuilder contains a binary-searchable primary index and the
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// metadata for secondary hash index construction.
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// The metadata for hash index consists two parts:
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// - a metablock that compactly contains a sequence of prefixes. All prefixes
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// are stored consectively without any metadata (like, prefix sizes) being
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// stored, which is kept in the other metablock.
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// - a metablock contains the metadata of the prefixes, including prefix size,
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// restart index and number of block it spans. The format looks like:
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//
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// +-----------------+---------------------------+---------------------+ <=prefix 1
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// | length: 4 bytes | restart interval: 4 bytes | num-blocks: 4 bytes |
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// +-----------------+---------------------------+---------------------+ <=prefix 2
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// | length: 4 bytes | restart interval: 4 bytes | num-blocks: 4 bytes |
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// +-----------------+---------------------------+---------------------+
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// | |
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// | .... |
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// | |
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// +-----------------+---------------------------+---------------------+ <=prefix n
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// | length: 4 bytes | restart interval: 4 bytes | num-blocks: 4 bytes |
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// +-----------------+---------------------------+---------------------+
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//
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// The reason of separating these two metablocks is to enable the efficiently
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// reuse the first metablock during hash index construction without unnecessary
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// data copy or small heap allocations for prefixes.
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class HashIndexBuilder : public IndexBuilder {
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public:
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explicit FullKeyIndexBuilder(const Comparator* comparator)
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explicit HashIndexBuilder(const Comparator* comparator,
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const SliceTransform* hash_key_extractor)
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: IndexBuilder(comparator),
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index_block_builder_(1 /* block_restart_interval == 1 */, comparator) {}
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primary_index_builder(comparator),
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hash_key_extractor_(hash_key_extractor) {}
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virtual void AddEntry(std::string* last_key_in_current_block,
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virtual void AddIndexEntry(std::string* last_key_in_current_block,
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const Slice* first_key_in_next_block,
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const BlockHandle& block_handle) override {
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std::string handle_encoding;
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block_handle.EncodeTo(&handle_encoding);
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index_block_builder_.Add(*last_key_in_current_block, handle_encoding);
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++current_restart_index_;
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primary_index_builder.AddIndexEntry(last_key_in_current_block,
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first_key_in_next_block, block_handle);
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}
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virtual Slice Finish() override { return index_block_builder_.Finish(); }
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virtual void OnKeyAdded(const Slice& key) override {
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auto key_prefix = hash_key_extractor_->Transform(key);
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bool is_first_entry = pending_block_num_ == 0;
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// Keys may share the prefix
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if (is_first_entry || pending_entry_prefix_ != key_prefix) {
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if (!is_first_entry) {
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FlushPendingPrefix();
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}
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// need a hard copy otherwise the underlying data changes all the time.
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// TODO(kailiu) ToString() is expensive. We may speed up can avoid data
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// copy.
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pending_entry_prefix_ = key_prefix.ToString();
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pending_block_num_ = 1;
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pending_entry_index_ = current_restart_index_;
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} else {
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// entry number increments when keys share the prefix reside in
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// differnt data blocks.
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auto last_restart_index = pending_entry_index_ + pending_block_num_ - 1;
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assert(last_restart_index <= current_restart_index_);
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if (last_restart_index != current_restart_index_) {
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++pending_block_num_;
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}
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}
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}
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virtual Status Finish(IndexBlocks* index_blocks) {
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FlushPendingPrefix();
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primary_index_builder.Finish(index_blocks);
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index_blocks->meta_blocks.insert(
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{kHashIndexPrefixesBlock.c_str(), prefix_block_});
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index_blocks->meta_blocks.insert(
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{kHashIndexPrefixesMetadataBlock.c_str(), prefix_meta_block_});
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return Status::OK();
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}
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virtual size_t EstimatedSize() const {
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return index_block_builder_.CurrentSizeEstimate();
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return primary_index_builder.EstimatedSize() + prefix_block_.size() +
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prefix_meta_block_.size();
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}
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private:
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BlockBuilder index_block_builder_;
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void FlushPendingPrefix() {
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prefix_block_.append(pending_entry_prefix_.data(),
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pending_entry_prefix_.size());
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PutVarint32(&prefix_meta_block_, pending_entry_prefix_.size());
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PutVarint32(&prefix_meta_block_, pending_entry_index_);
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PutVarint32(&prefix_meta_block_, pending_block_num_);
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}
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ShortenedIndexBuilder primary_index_builder;
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const SliceTransform* hash_key_extractor_;
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// stores a sequence of prefixes
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std::string prefix_block_;
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// stores the metadata of prefixes
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std::string prefix_meta_block_;
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// The following 3 variables keeps unflushed prefix and its metadata.
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// The details of block_num and entry_index can be found in
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// "block_hash_index.{h,cc}"
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uint32_t pending_block_num_ = 0;
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uint32_t pending_entry_index_ = 0;
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std::string pending_entry_prefix_;
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uint64_t current_restart_index_ = 0;
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};
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// Create a index builder based on its type.
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IndexBuilder* CreateIndexBuilder(IndexType type, const Comparator* comparator) {
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IndexBuilder* CreateIndexBuilder(IndexType type, const Comparator* comparator,
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const SliceTransform* prefix_extractor) {
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switch (type) {
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case BlockBasedTableOptions::kBinarySearch: {
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return new ShortenedIndexBuilder(comparator);
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}
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case BlockBasedTableOptions::kHashSearch: {
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return new HashIndexBuilder(comparator, prefix_extractor);
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}
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default: {
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assert(!"Do not recognize the index type ");
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return nullptr;
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@ -249,7 +355,7 @@ extern const uint64_t kLegacyBlockBasedTableMagicNumber = 0xdb4775248b80fb57ull;
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class BlockBasedTableBuilder::BlockBasedTablePropertiesCollector
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: public TablePropertiesCollector {
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public:
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BlockBasedTablePropertiesCollector(
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explicit BlockBasedTablePropertiesCollector(
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BlockBasedTableOptions::IndexType index_type)
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: index_type_(index_type) {}
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@ -288,6 +394,8 @@ struct BlockBasedTableBuilder::Rep {
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uint64_t offset = 0;
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Status status;
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BlockBuilder data_block;
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InternalKeySliceTransform internal_prefix_transform;
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std::unique_ptr<IndexBuilder> index_builder;
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std::string last_key;
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@ -316,8 +424,9 @@ struct BlockBasedTableBuilder::Rep {
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internal_comparator(icomparator),
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file(f),
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data_block(options, &internal_comparator),
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index_builder(
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CreateIndexBuilder(index_block_type, &internal_comparator)),
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internal_prefix_transform(options.prefix_extractor.get()),
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index_builder(CreateIndexBuilder(index_block_type, &internal_comparator,
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&this->internal_prefix_transform)),
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compression_type(compression_type),
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checksum_type(checksum_type),
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filter_block(opt.filter_policy == nullptr
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@ -335,16 +444,13 @@ struct BlockBasedTableBuilder::Rep {
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}
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};
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// TODO(sdong): Currently only write out binary search index. In
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// BlockBasedTableReader, Hash index will be built using binary search index.
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BlockBasedTableBuilder::BlockBasedTableBuilder(
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const Options& options, const BlockBasedTableOptions& table_options,
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const InternalKeyComparator& internal_comparator, WritableFile* file,
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CompressionType compression_type)
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: rep_(new Rep(options, internal_comparator, file,
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table_options.flush_block_policy_factory.get(),
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compression_type,
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BlockBasedTableOptions::IndexType::kBinarySearch,
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compression_type, table_options.index_type,
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table_options.checksum)) {
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if (rep_->filter_block != nullptr) {
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rep_->filter_block->StartBlock(0);
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@ -370,7 +476,7 @@ void BlockBasedTableBuilder::Add(const Slice& key, const Slice& value) {
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if (r->props.num_entries > 0) {
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assert(r->internal_comparator.Compare(key, Slice(r->last_key)) > 0);
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}
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r->index_builder->OnKeyAdded(key);
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auto should_flush = r->flush_block_policy->Update(key, value);
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if (should_flush) {
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assert(!r->data_block.empty());
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@ -385,7 +491,7 @@ void BlockBasedTableBuilder::Add(const Slice& key, const Slice& value) {
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// entries in the first block and < all entries in subsequent
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// blocks.
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if (ok()) {
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r->index_builder->AddEntry(&r->last_key, &key, r->pending_handle);
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r->index_builder->AddIndexEntry(&r->last_key, &key, r->pending_handle);
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}
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}
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@ -561,24 +667,36 @@ Status BlockBasedTableBuilder::Finish() {
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// block, we will finish writing all index entries here and flush them
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// to storage after metaindex block is written.
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if (ok() && !empty_data_block) {
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r->index_builder->AddEntry(&r->last_key, nullptr /* no next data block */,
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r->pending_handle);
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r->index_builder->AddIndexEntry(
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&r->last_key, nullptr /* no next data block */, r->pending_handle);
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}
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IndexBuilder::IndexBlocks index_blocks;
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auto s = r->index_builder->Finish(&index_blocks);
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if (!s.ok()) {
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return s;
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}
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// Write meta blocks and metaindex block with the following order.
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// 1. [meta block: filter]
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// 2. [meta block: properties]
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// 3. [metaindex block]
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if (ok()) {
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MetaIndexBuilder meta_index_builer;
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// 2. [other meta blocks]
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// 3. [meta block: properties]
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// 4. [metaindex block]
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// write meta blocks
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MetaIndexBuilder meta_index_builder;
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for (const auto& item : index_blocks.meta_blocks) {
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BlockHandle block_handle;
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WriteBlock(item.second, &block_handle);
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meta_index_builder.Add(item.first, block_handle);
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}
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// Write filter block.
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if (ok()) {
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if (r->filter_block != nullptr) {
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// Add mapping from "<filter_block_prefix>.Name" to location
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// of filter data.
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std::string key = BlockBasedTable::kFilterBlockPrefix;
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key.append(r->options.filter_policy->Name());
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meta_index_builer.Add(key, filter_block_handle);
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meta_index_builder.Add(key, filter_block_handle);
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}
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// Write properties block.
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@ -605,20 +723,16 @@ Status BlockBasedTableBuilder::Finish() {
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&properties_block_handle
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);
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meta_index_builer.Add(kPropertiesBlock,
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properties_block_handle);
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meta_index_builder.Add(kPropertiesBlock, properties_block_handle);
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} // end of properties block writing
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WriteRawBlock(
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meta_index_builer.Finish(),
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kNoCompression,
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&metaindex_block_handle
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);
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} // meta blocks and metaindex block.
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} // meta blocks
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// Write index block
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if (ok()) {
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WriteBlock(r->index_builder->Finish(), &index_block_handle);
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// flush the meta index block
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WriteRawBlock(meta_index_builder.Finish(), kNoCompression,
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&metaindex_block_handle);
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WriteBlock(index_blocks.index_block_contents, &index_block_handle);
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}
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// Write footer
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@ -685,7 +799,6 @@ uint64_t BlockBasedTableBuilder::FileSize() const {
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return rep_->offset;
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}
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const std::string BlockBasedTable::kFilterBlockPrefix =
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"filter.";
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const std::string BlockBasedTable::kFilterBlockPrefix = "filter.";
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} // namespace rocksdb
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@ -56,5 +56,8 @@ TableFactory* NewBlockBasedTableFactory(
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const std::string BlockBasedTablePropertyNames::kIndexType =
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"rocksdb.block.based.table.index.type";
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const std::string kHashIndexPrefixesBlock = "rocksdb.hashindex.prefixes";
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const std::string kHashIndexPrefixesMetadataBlock =
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"rocksdb.hashindex.metadata";
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} // namespace rocksdb
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@ -8,9 +8,11 @@
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include <memory>
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#include <stdint.h>
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#include <memory>
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#include <string>
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#include "rocksdb/flush_block_policy.h"
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#include "rocksdb/options.h"
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#include "rocksdb/table.h"
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@ -45,4 +47,7 @@ class BlockBasedTableFactory : public TableFactory {
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BlockBasedTableOptions table_options_;
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};
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extern const std::string kHashIndexPrefixesBlock;
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extern const std::string kHashIndexPrefixesMetadataBlock;
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} // namespace rocksdb
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@ -38,6 +38,8 @@
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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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@ -186,19 +188,13 @@ class BinarySearchIndexReader : public IndexReader {
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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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// @param data_iter_gen, equavalent to BlockBasedTable::NewIterator(). But that
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// functions requires index to be initalized. To avoid this problem external
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// caller will pass a function that can create the iterator over the entries
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// without the table to be fully initialized.
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class HashIndexReader : public IndexReader {
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public:
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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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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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std::function<Iterator*(Iterator*)> data_iter_gen,
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const SliceTransform* prefix_extractor,
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IndexReader** index_reader) {
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assert(prefix_extractor);
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const BlockHandle& index_handle,
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Iterator* meta_index_iter, 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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@ -207,14 +203,57 @@ class HashIndexReader : public IndexReader {
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return s;
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}
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*index_reader = new HashIndexReader(comparator, index_block);
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std::unique_ptr<Iterator> index_iter(index_block->NewIterator(nullptr));
|
||||
std::unique_ptr<Iterator> data_iter(
|
||||
data_iter_gen(index_block->NewIterator(nullptr)));
|
||||
auto hash_index = CreateBlockHashIndex(index_iter.get(), data_iter.get(),
|
||||
index_block->NumRestarts(),
|
||||
comparator, prefix_extractor);
|
||||
index_block->SetBlockHashIndex(hash_index);
|
||||
// Get prefixes block
|
||||
BlockHandle prefixes_handle;
|
||||
s = FindMetaBlock(meta_index_iter, kHashIndexPrefixesBlock,
|
||||
&prefixes_handle);
|
||||
if (!s.ok()) {
|
||||
return s;
|
||||
}
|
||||
|
||||
// Get index metadata block
|
||||
BlockHandle prefixes_meta_handle;
|
||||
s = FindMetaBlock(meta_index_iter, kHashIndexPrefixesMetadataBlock,
|
||||
&prefixes_meta_handle);
|
||||
if (!s.ok()) {
|
||||
return s;
|
||||
}
|
||||
|
||||
// Read contents for the blocks
|
||||
BlockContents prefixes_contents;
|
||||
s = ReadBlockContents(file, footer, ReadOptions(), prefixes_handle,
|
||||
&prefixes_contents, env, true /* do decompression */);
|
||||
if (!s.ok()) {
|
||||
return s;
|
||||
}
|
||||
BlockContents prefixes_meta_contents;
|
||||
s = ReadBlockContents(file, footer, ReadOptions(), prefixes_meta_handle,
|
||||
&prefixes_meta_contents, env,
|
||||
true /* do decompression */);
|
||||
if (!s.ok()) {
|
||||
if (prefixes_contents.heap_allocated) {
|
||||
delete[] prefixes_contents.data.data();
|
||||
}
|
||||
return s;
|
||||
}
|
||||
|
||||
auto new_index_reader =
|
||||
new HashIndexReader(comparator, index_block, prefixes_contents);
|
||||
BlockHashIndex* hash_index = nullptr;
|
||||
s = CreateBlockHashIndex(hash_key_extractor, prefixes_contents.data,
|
||||
prefixes_meta_contents.data, &hash_index);
|
||||
if (!s.ok()) {
|
||||
return s;
|
||||
}
|
||||
|
||||
new_index_reader->index_block_->SetBlockHashIndex(hash_index);
|
||||
|
||||
*index_reader = new_index_reader;
|
||||
|
||||
// release resources
|
||||
if (prefixes_meta_contents.heap_allocated) {
|
||||
delete[] prefixes_meta_contents.data.data();
|
||||
}
|
||||
return s;
|
||||
}
|
||||
|
||||
@ -225,11 +264,22 @@ class HashIndexReader : public IndexReader {
|
||||
virtual size_t size() const override { return index_block_->size(); }
|
||||
|
||||
private:
|
||||
HashIndexReader(const Comparator* comparator, Block* index_block)
|
||||
: IndexReader(comparator), index_block_(index_block) {
|
||||
HashIndexReader(const Comparator* comparator, Block* index_block,
|
||||
const BlockContents& prefixes_contents)
|
||||
: IndexReader(comparator),
|
||||
index_block_(index_block),
|
||||
prefixes_contents_(prefixes_contents) {
|
||||
assert(index_block_ != nullptr);
|
||||
}
|
||||
|
||||
~HashIndexReader() {
|
||||
if (prefixes_contents_.heap_allocated) {
|
||||
delete[] prefixes_contents_.data.data();
|
||||
}
|
||||
}
|
||||
|
||||
std::unique_ptr<Block> index_block_;
|
||||
BlockContents prefixes_contents_;
|
||||
};
|
||||
|
||||
|
||||
@ -408,7 +458,7 @@ Status BlockBasedTable::Open(const Options& options, const EnvOptions& soptions,
|
||||
// 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);
|
||||
s = new_table->CreateIndexReader(&index_reader, meta_iter.get());
|
||||
|
||||
if (s.ok()) {
|
||||
rep->index_reader.reset(index_reader);
|
||||
@ -417,10 +467,9 @@ Status BlockBasedTable::Open(const Options& options, const EnvOptions& soptions,
|
||||
if (rep->options.filter_policy) {
|
||||
std::string key = kFilterBlockPrefix;
|
||||
key.append(rep->options.filter_policy->Name());
|
||||
meta_iter->Seek(key);
|
||||
|
||||
if (meta_iter->Valid() && meta_iter->key() == Slice(key)) {
|
||||
rep->filter.reset(ReadFilter(meta_iter->value(), rep));
|
||||
BlockHandle handle;
|
||||
if (FindMetaBlock(meta_iter.get(), key, &handle).ok()) {
|
||||
rep->filter.reset(ReadFilter(handle, rep));
|
||||
}
|
||||
}
|
||||
} else {
|
||||
@ -617,16 +666,9 @@ Status BlockBasedTable::PutDataBlockToCache(
|
||||
return s;
|
||||
}
|
||||
|
||||
FilterBlockReader* BlockBasedTable::ReadFilter (
|
||||
const Slice& filter_handle_value,
|
||||
FilterBlockReader* BlockBasedTable::ReadFilter(const BlockHandle& filter_handle,
|
||||
BlockBasedTable::Rep* rep,
|
||||
size_t* filter_size) {
|
||||
Slice v = filter_handle_value;
|
||||
BlockHandle filter_handle;
|
||||
if (!filter_handle.DecodeFrom(&v).ok()) {
|
||||
return nullptr;
|
||||
}
|
||||
|
||||
// TODO: We might want to unify with ReadBlockFromFile() if we start
|
||||
// requiring checksum verification in Table::Open.
|
||||
ReadOptions opt;
|
||||
@ -687,10 +729,9 @@ BlockBasedTable::CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
|
||||
if (s.ok()) {
|
||||
std::string filter_block_key = kFilterBlockPrefix;
|
||||
filter_block_key.append(rep_->options.filter_policy->Name());
|
||||
iter->Seek(filter_block_key);
|
||||
|
||||
if (iter->Valid() && iter->key() == Slice(filter_block_key)) {
|
||||
filter = ReadFilter(iter->value(), rep_, &filter_size);
|
||||
BlockHandle handle;
|
||||
if (FindMetaBlock(iter.get(), filter_block_key, &handle).ok()) {
|
||||
filter = ReadFilter(handle, rep_, &filter_size);
|
||||
assert(filter);
|
||||
assert(filter_size > 0);
|
||||
|
||||
@ -1032,7 +1073,8 @@ bool BlockBasedTable::TEST_KeyInCache(const ReadOptions& options,
|
||||
// 3. options
|
||||
// 4. internal_comparator
|
||||
// 5. index_type
|
||||
Status BlockBasedTable::CreateIndexReader(IndexReader** index_reader) {
|
||||
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;
|
||||
@ -1045,41 +1087,45 @@ Status BlockBasedTable::CreateIndexReader(IndexReader** index_reader) {
|
||||
}
|
||||
}
|
||||
|
||||
// TODO(sdong): Currently binary index is the only index type we support in
|
||||
// files. Hash index is built on top of binary index too.
|
||||
if (index_type_on_file != BlockBasedTableOptions::kBinarySearch) {
|
||||
return Status::NotSupported("File Contains not supported index type: ",
|
||||
std::to_string(index_type_on_file));
|
||||
}
|
||||
|
||||
auto file = rep_->file.get();
|
||||
auto env = rep_->options.env;
|
||||
auto comparator = &rep_->internal_comparator;
|
||||
const Footer& footer = rep_->footer;
|
||||
|
||||
switch (rep_->index_type) {
|
||||
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()) {
|
||||
return Status::Corruption("Unable to read the metaindex block");
|
||||
}
|
||||
meta_index_iter = meta_iter_guard.get();
|
||||
}
|
||||
|
||||
// We need to wrap data with internal_prefix_transform to make sure it can
|
||||
// handle prefix correctly.
|
||||
if (rep_->options.prefix_extractor == nullptr) {
|
||||
return Status::InvalidArgument(
|
||||
"BlockBasedTableOptions::kHashSearch requires "
|
||||
"options.prefix_extractor to be set.");
|
||||
}
|
||||
|
||||
rep_->internal_prefix_transform.reset(
|
||||
new InternalKeySliceTransform(rep_->options.prefix_extractor.get()));
|
||||
return HashIndexReader::Create(
|
||||
file, footer, footer.index_handle(), env, comparator,
|
||||
[&](Iterator* index_iter) {
|
||||
return NewTwoLevelIterator(new BlockEntryIteratorState(this,
|
||||
ReadOptions(), nullptr), index_iter);
|
||||
},
|
||||
rep_->internal_prefix_transform.get(), index_reader);
|
||||
rep_->internal_prefix_transform.get(), footer, file, env, comparator,
|
||||
footer.index_handle(), meta_index_iter, index_reader);
|
||||
}
|
||||
default: {
|
||||
std::string error_message =
|
||||
"Unrecognized index type: " + std::to_string(rep_->index_type);
|
||||
// equivalent to assert(false), but more informative.
|
||||
assert(!error_message.c_str());
|
||||
return Status::InvalidArgument(error_message.c_str());
|
||||
}
|
||||
}
|
||||
|
||||
@ -160,8 +160,13 @@ class BlockBasedTable : public TableReader {
|
||||
friend class BlockBasedTableBuilder;
|
||||
|
||||
void ReadMeta(const Footer& footer);
|
||||
void ReadFilter(const Slice& filter_handle_value);
|
||||
Status CreateIndexReader(IndexReader** index_reader);
|
||||
|
||||
// Create a index reader based on the index type stored in the table.
|
||||
// Optionally, user can pass a preloaded meta_index_iter for the index that
|
||||
// need to access extra meta blocks for index construction. This parameter
|
||||
// helps avoid re-reading meta index block if caller already created one.
|
||||
Status CreateIndexReader(IndexReader** index_reader,
|
||||
Iterator* preloaded_meta_index_iter = nullptr);
|
||||
|
||||
// Read the meta block from sst.
|
||||
static Status ReadMetaBlock(
|
||||
@ -170,10 +175,8 @@ class BlockBasedTable : public TableReader {
|
||||
std::unique_ptr<Iterator>* iter);
|
||||
|
||||
// Create the filter from the filter block.
|
||||
static FilterBlockReader* ReadFilter(
|
||||
const Slice& filter_handle_value,
|
||||
Rep* rep,
|
||||
size_t* filter_size = nullptr);
|
||||
static FilterBlockReader* ReadFilter(const BlockHandle& filter_handle,
|
||||
Rep* rep, size_t* filter_size = nullptr);
|
||||
|
||||
static void SetupCacheKeyPrefix(Rep* rep);
|
||||
|
||||
|
||||
@ -3,21 +3,62 @@
|
||||
// LICENSE file in the root directory of this source tree. An additional grant
|
||||
// of patent rights can be found in the PATENTS file in the same directory.
|
||||
|
||||
#include "table/block_hash_index.h"
|
||||
|
||||
#include <algorithm>
|
||||
|
||||
#include "table/block_hash_index.h"
|
||||
#include "rocksdb/comparator.h"
|
||||
#include "rocksdb/iterator.h"
|
||||
#include "rocksdb/slice_transform.h"
|
||||
#include "util/coding.h"
|
||||
|
||||
namespace rocksdb {
|
||||
|
||||
BlockHashIndex* CreateBlockHashIndex(Iterator* index_iter, Iterator* data_iter,
|
||||
const uint32_t num_restarts,
|
||||
const Comparator* comparator,
|
||||
const SliceTransform* hash_key_extractor) {
|
||||
Status CreateBlockHashIndex(const SliceTransform* hash_key_extractor,
|
||||
const Slice& prefixes, const Slice& prefix_meta,
|
||||
BlockHashIndex** hash_index) {
|
||||
uint64_t pos = 0;
|
||||
auto meta_pos = prefix_meta;
|
||||
Status s;
|
||||
*hash_index = new BlockHashIndex(
|
||||
hash_key_extractor,
|
||||
false /* external module manages memory space for prefixes */);
|
||||
|
||||
while (!meta_pos.empty()) {
|
||||
uint32_t prefix_size = 0;
|
||||
uint32_t entry_index = 0;
|
||||
uint32_t num_blocks = 0;
|
||||
if (!GetVarint32(&meta_pos, &prefix_size) ||
|
||||
!GetVarint32(&meta_pos, &entry_index) ||
|
||||
!GetVarint32(&meta_pos, &num_blocks)) {
|
||||
s = Status::Corruption(
|
||||
"Corrupted prefix meta block: unable to read from it.");
|
||||
break;
|
||||
}
|
||||
Slice prefix(prefixes.data() + pos, prefix_size);
|
||||
(*hash_index)->Add(prefix, entry_index, num_blocks);
|
||||
|
||||
pos += prefix_size;
|
||||
}
|
||||
|
||||
if (s.ok() && pos != prefixes.size()) {
|
||||
s = Status::Corruption("Corrupted prefix meta block");
|
||||
}
|
||||
|
||||
if (!s.ok()) {
|
||||
delete *hash_index;
|
||||
}
|
||||
|
||||
return s;
|
||||
}
|
||||
|
||||
BlockHashIndex* CreateBlockHashIndexOnTheFly(
|
||||
Iterator* index_iter, Iterator* data_iter, const uint32_t num_restarts,
|
||||
const Comparator* comparator, const SliceTransform* hash_key_extractor) {
|
||||
assert(hash_key_extractor);
|
||||
auto hash_index = new BlockHashIndex(hash_key_extractor);
|
||||
auto hash_index = new BlockHashIndex(
|
||||
hash_key_extractor,
|
||||
true /* hash_index will copy prefix when Add() is called */);
|
||||
uint64_t current_restart_index = 0;
|
||||
|
||||
std::string pending_entry_prefix;
|
||||
@ -88,12 +129,16 @@ BlockHashIndex* CreateBlockHashIndex(Iterator* index_iter, Iterator* data_iter,
|
||||
|
||||
bool BlockHashIndex::Add(const Slice& prefix, uint32_t restart_index,
|
||||
uint32_t num_blocks) {
|
||||
auto prefix_to_insert = prefix;
|
||||
if (kOwnPrefixes) {
|
||||
auto prefix_ptr = arena_.Allocate(prefix.size());
|
||||
std::copy(prefix.data() /* begin */, prefix.data() + prefix.size() /* end */,
|
||||
std::copy(prefix.data() /* begin */,
|
||||
prefix.data() + prefix.size() /* end */,
|
||||
prefix_ptr /* destination */);
|
||||
auto result =
|
||||
restart_indices_.insert({Slice(prefix_ptr, prefix.size()),
|
||||
RestartIndex(restart_index, num_blocks)});
|
||||
prefix_to_insert = Slice(prefix_ptr, prefix.size());
|
||||
}
|
||||
auto result = restart_indices_.insert(
|
||||
{prefix_to_insert, RestartIndex(restart_index, num_blocks)});
|
||||
return result.second;
|
||||
}
|
||||
|
||||
|
||||
@ -7,6 +7,7 @@
|
||||
#include <string>
|
||||
#include <unordered_map>
|
||||
|
||||
#include "rocksdb/status.h"
|
||||
#include "util/arena.h"
|
||||
#include "util/murmurhash.h"
|
||||
|
||||
@ -35,8 +36,12 @@ class BlockHashIndex {
|
||||
uint32_t num_blocks = 1;
|
||||
};
|
||||
|
||||
explicit BlockHashIndex(const SliceTransform* hash_key_extractor)
|
||||
: hash_key_extractor_(hash_key_extractor) {}
|
||||
// @params own_prefixes indicate if we should take care the memory space for
|
||||
// the `key_prefix`
|
||||
// passed by Add()
|
||||
explicit BlockHashIndex(const SliceTransform* hash_key_extractor,
|
||||
bool own_prefixes)
|
||||
: hash_key_extractor_(hash_key_extractor), kOwnPrefixes(own_prefixes) {}
|
||||
|
||||
// Maps a key to its restart first_index.
|
||||
// Returns nullptr if the restart first_index is found
|
||||
@ -52,9 +57,18 @@ class BlockHashIndex {
|
||||
private:
|
||||
const SliceTransform* hash_key_extractor_;
|
||||
std::unordered_map<Slice, RestartIndex, murmur_hash> restart_indices_;
|
||||
|
||||
Arena arena_;
|
||||
bool kOwnPrefixes;
|
||||
};
|
||||
|
||||
// Create hash index by reading from the metadata blocks.
|
||||
// @params prefixes: a sequence of prefixes.
|
||||
// @params prefix_meta: contains the "metadata" to of the prefixes.
|
||||
Status CreateBlockHashIndex(const SliceTransform* hash_key_extractor,
|
||||
const Slice& prefixes, const Slice& prefix_meta,
|
||||
BlockHashIndex** hash_index);
|
||||
|
||||
// Create hash index by scanning the entries in index as well as the whole
|
||||
// dataset.
|
||||
// @params index_iter: an iterator with the pointer to the first entry in a
|
||||
@ -64,9 +78,8 @@ class BlockHashIndex {
|
||||
// @params num_restarts: used for correctness verification.
|
||||
// @params hash_key_extractor: extract the hashable part of a given key.
|
||||
// On error, nullptr will be returned.
|
||||
BlockHashIndex* CreateBlockHashIndex(Iterator* index_iter, Iterator* data_iter,
|
||||
const uint32_t num_restarts,
|
||||
const Comparator* comparator,
|
||||
const SliceTransform* hash_key_extractor);
|
||||
BlockHashIndex* CreateBlockHashIndexOnTheFly(
|
||||
Iterator* index_iter, Iterator* data_iter, const uint32_t num_restarts,
|
||||
const Comparator* comparator, const SliceTransform* hash_key_extractor);
|
||||
|
||||
} // namespace rocksdb
|
||||
|
||||
@ -81,9 +81,9 @@ TEST(BlockTest, BasicTest) {
|
||||
MapIterator index_iter(index_entries);
|
||||
|
||||
auto prefix_extractor = NewFixedPrefixTransform(prefix_size);
|
||||
std::unique_ptr<BlockHashIndex> block_hash_index(
|
||||
CreateBlockHashIndex(&index_iter, &data_iter, index_entries.size(),
|
||||
BytewiseComparator(), prefix_extractor));
|
||||
std::unique_ptr<BlockHashIndex> block_hash_index(CreateBlockHashIndexOnTheFly(
|
||||
&index_iter, &data_iter, index_entries.size(), BytewiseComparator(),
|
||||
prefix_extractor));
|
||||
|
||||
std::map<std::string, BlockHashIndex::RestartIndex> expected = {
|
||||
{"01xx", BlockHashIndex::RestartIndex(0, 1)},
|
||||
|
||||
@ -163,8 +163,8 @@ void CheckBlockContents(BlockContents contents, const int max_key,
|
||||
{
|
||||
auto iter1 = reader1.NewIterator(nullptr);
|
||||
auto iter2 = reader1.NewIterator(nullptr);
|
||||
reader1.SetBlockHashIndex(CreateBlockHashIndex(iter1, iter2, keys.size(),
|
||||
BytewiseComparator(),
|
||||
reader1.SetBlockHashIndex(CreateBlockHashIndexOnTheFly(
|
||||
iter1, iter2, keys.size(), BytewiseComparator(),
|
||||
prefix_extractor.get()));
|
||||
|
||||
delete iter1;
|
||||
|
||||
@ -254,11 +254,23 @@ Status ReadTableProperties(RandomAccessFile* file, uint64_t file_size,
|
||||
properties);
|
||||
} else {
|
||||
s = Status::Corruption("Unable to read the property block.");
|
||||
Log(WARN_LEVEL, info_log,
|
||||
"Cannot find Properties block from file.");
|
||||
Log(WARN_LEVEL, info_log, "Cannot find Properties block from file.");
|
||||
}
|
||||
|
||||
return s;
|
||||
}
|
||||
|
||||
Status FindMetaBlock(Iterator* 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);
|
||||
}
|
||||
}
|
||||
|
||||
} // namespace rocksdb
|
||||
|
||||
@ -123,4 +123,9 @@ Status ReadTableProperties(RandomAccessFile* file, uint64_t file_size,
|
||||
// set to true.
|
||||
extern Status SeekToPropertiesBlock(Iterator* meta_iter, bool* is_found);
|
||||
|
||||
// Find the meta block from the meta index block.
|
||||
Status FindMetaBlock(Iterator* meta_index_iter,
|
||||
const std::string& meta_block_name,
|
||||
BlockHandle* block_handle);
|
||||
|
||||
} // namespace rocksdb
|
||||
|
||||
Loading…
Reference in New Issue
Block a user