diff --git a/db/db_impl.cc b/db/db_impl.cc index cfb523364..23c243471 100644 --- a/db/db_impl.cc +++ b/db/db_impl.cc @@ -1972,9 +1972,9 @@ Status DBImpl::DoCompactionWork(CompactionState* compact) { compaction_filter_value.clear(); bool to_delete = compaction_filter->Filter(compact->compaction->level(), - ikey.user_key, value, - &compaction_filter_value, - &value_changed); + ikey.user_key, value, + &compaction_filter_value, + &value_changed); if (to_delete) { // make a copy of the original key delete_key.assign(key.data(), key.data() + key.size()); diff --git a/db/version_set.h b/db/version_set.h index 3907d9971..f95a89a4f 100644 --- a/db/version_set.h +++ b/db/version_set.h @@ -30,11 +30,9 @@ namespace log { class Writer; } class Compaction; class Iterator; class MemTable; -class TableBuilder; class TableCache; class Version; class VersionSet; -class WritableFile; // Return the smallest index i such that files[i]->largest >= key. // Return files.size() if there is no such file. diff --git a/include/rocksdb/table_stats.h b/include/rocksdb/table_stats.h new file mode 100644 index 000000000..6e2ad2b64 --- /dev/null +++ b/include/rocksdb/table_stats.h @@ -0,0 +1,42 @@ +// Copyright (c) 2013 Facebook +// 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. +#pragma once + +#include +#include + +namespace rocksdb { + +// TableStats contains a bunch of read-only stats of its associated +// table. +struct TableStats { + public: + // TODO(kailiu) we do not support user collected stats yet. + // + // Other than basic table stats, each table may also have the user + // collected stats. + // The value of the user-collected stats are encoded as raw bytes -- + // users have to interprete these values by themselves. + typedef + std::unordered_map + UserCollectedStats; + + // the total size of all data blocks. + uint64_t data_size = 0; + // the total size of all index blocks. + uint64_t index_size = 0; + // total raw key size + uint64_t raw_key_size = 0; + // total raw value size + uint64_t raw_value_size = 0; + // the number of blocks in this table + uint64_t num_data_blocks = 0; + // the number of entries in this table + uint64_t num_entries = 0; + + // user collected stats + UserCollectedStats user_collected_stats; +}; + +} // namespace rocksdb diff --git a/table/table.cc b/table/table.cc index f3c17b6a2..8a4186f6d 100644 --- a/table/table.cc +++ b/table/table.cc @@ -16,6 +16,7 @@ #include "table/block.h" #include "table/filter_block.h" #include "table/format.h" +#include "table/table.h" #include "table/two_level_iterator.h" #include "util/coding.h" @@ -50,6 +51,7 @@ struct Table::Rep { BlockHandle metaindex_handle; // Handle to metaindex_block: saved from footer Block* index_block; + TableStats table_stats; }; // Helper function to setup the cache key's prefix for the Table. @@ -168,11 +170,11 @@ void Table::SetupForCompaction() { compaction_optimized_ = true; } -void Table::ReadMeta(const Footer& footer) { - if (rep_->options.filter_policy == nullptr) { - return; // Do not need any metadata - } +const TableStats& Table::GetTableStats() const { + return rep_->table_stats; +} +void Table::ReadMeta(const Footer& footer) { // 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 @@ -184,12 +186,33 @@ void Table::ReadMeta(const Footer& footer) { } Iterator* iter = meta->NewIterator(BytewiseComparator()); - std::string key = "filter."; - key.append(rep_->options.filter_policy->Name()); - iter->Seek(key); - if (iter->Valid() && iter->key() == Slice(key)) { - ReadFilter(iter->value()); + // read filter + if (rep_->options.filter_policy) { + std::string key = kFilterBlockPrefix; + key.append(rep_->options.filter_policy->Name()); + iter->Seek(key); + + if (iter->Valid() && iter->key() == Slice(key)) { + ReadFilter(iter->value()); + } + } + + // read stats + iter->Seek(kStatsBlock); + if (iter->Valid() && iter->key() == Slice(kStatsBlock)) { + auto s = iter->status(); + if (s.ok()) { + s = ReadStats(iter->value(), rep_); + } + + if (!s.ok()) { + auto err_msg = + "[Warning] Encountered error while reading data from stats block " + + s.ToString(); + Log(rep_->options.info_log, err_msg.c_str()); + } } + delete iter; delete meta; } @@ -215,6 +238,82 @@ void Table::ReadFilter(const Slice& filter_handle_value) { rep_->filter = new FilterBlockReader(rep_->options, block.data); } +Status Table::ReadStats(const Slice& handle_value, Rep* rep) { + Slice v = handle_value; + BlockHandle handle; + if (!handle.DecodeFrom(&v).ok()) { + return Status::InvalidArgument("Failed to decode stats block handle"); + } + + BlockContents block_contents; + Status s = ReadBlockContents( + rep->file.get(), + ReadOptions(), + handle, + &block_contents, + rep->options.env + ); + + if (!s.ok()) { + return s; + } + + Block stats_block(block_contents); + std::unique_ptr iter( + stats_block.NewIterator(BytewiseComparator()) + ); + + auto& table_stats = rep->table_stats; + std::unordered_map predefined_name_stat_map = { + { TableStatsNames::kDataSize, &table_stats.data_size }, + { TableStatsNames::kIndexSize, &table_stats.index_size }, + { TableStatsNames::kRawKeySize, &table_stats.raw_key_size }, + { TableStatsNames::kRawValueSize, &table_stats.raw_value_size }, + { TableStatsNames::kNumDataBlocks, &table_stats.num_data_blocks }, + { TableStatsNames::kNumEntries, &table_stats.num_entries }, + }; + + std::string last_key; + for (iter->SeekToFirst(); iter->Valid(); iter->Next()) { + s = iter->status(); + if (!s.ok()) { + break; + } + + auto key = iter->key().ToString(); + // stats block is strictly sorted with no duplicate key. + assert( + last_key.empty() || + BytewiseComparator()->Compare(key, last_key) > 0 + ); + last_key = key; + + auto raw_val = iter->value(); + auto pos = predefined_name_stat_map.find(key); + + if (pos == predefined_name_stat_map.end()) { + // handle user-collected + table_stats.user_collected_stats.insert( + std::make_pair(iter->key().ToString(), raw_val.ToString()) + ); + } else { + // handle predefined rocksdb stats + uint64_t val; + if (!GetVarint64(&raw_val, &val)) { + // skip malformed value + auto error_msg = + "[Warning] detect malformed value in stats meta-block:" + "\tkey: " + key + "\tval: " + raw_val.ToString(); + Log(rep->options.info_log, error_msg.c_str()); + continue; + } + *(pos->second) = val; + } + } + + return s; +} + Table::~Table() { delete rep_; } @@ -495,4 +594,14 @@ uint64_t Table::ApproximateOffsetOf(const Slice& key) const { return result; } +const std::string Table::kFilterBlockPrefix = "filter."; +const std::string Table::kStatsBlock = "rocksdb.stats"; + +const std::string TableStatsNames::kDataSize = "rocksdb.data.size"; +const std::string TableStatsNames::kIndexSize = "rocksdb.index.size"; +const std::string TableStatsNames::kRawKeySize = "rocksdb.raw.key.size"; +const std::string TableStatsNames::kRawValueSize = "rocksdb.raw.value.size"; +const std::string TableStatsNames::kNumDataBlocks = "rocksdb.num.data.blocks"; +const std::string TableStatsNames::kNumEntries = "rocksdb.num.entries"; + } // namespace rocksdb diff --git a/table/table.h b/table/table.h index 6300dbd16..6e7f85747 100644 --- a/table/table.h +++ b/table/table.h @@ -5,8 +5,9 @@ #pragma once #include #include -#include "rocksdb/iterator.h" #include "rocksdb/env.h" +#include "rocksdb/iterator.h" +#include "rocksdb/table_stats.h" namespace rocksdb { @@ -25,6 +26,9 @@ using std::unique_ptr; // multiple threads without external synchronization. class Table { public: + static const std::string kFilterBlockPrefix; + static const std::string kStatsBlock; + // Attempt to open the table that is stored in bytes [0..file_size) // of "file", and read the metadata entries necessary to allow // retrieving data from the table. @@ -68,10 +72,13 @@ class Table { // posix_fadvise void SetupForCompaction(); + const TableStats& GetTableStats() const; + private: struct Rep; Rep* rep_; bool compaction_optimized_; + explicit Table(Rep* rep) : compaction_optimized_(false) { rep_ = rep; } static Iterator* BlockReader(void*, const ReadOptions&, const EnvOptions& soptions, const Slice&, @@ -92,6 +99,7 @@ class Table { void ReadMeta(const Footer& footer); void ReadFilter(const Slice& filter_handle_value); + static Status ReadStats(const Slice& handle_value, Rep* rep); static void SetupCacheKeyPrefix(Rep* rep); @@ -100,4 +108,13 @@ class Table { void operator=(const Table&); }; +struct TableStatsNames { + static const std::string kDataSize; + static const std::string kIndexSize; + static const std::string kRawKeySize; + static const std::string kRawValueSize; + static const std::string kNumDataBlocks; + static const std::string kNumEntries; +}; + } // namespace rocksdb diff --git a/table/table_builder.cc b/table/table_builder.cc index d42ef0d2f..b187b70e7 100644 --- a/table/table_builder.cc +++ b/table/table_builder.cc @@ -5,6 +5,8 @@ #include "rocksdb/table_builder.h" #include +#include + #include "rocksdb/comparator.h" #include "rocksdb/env.h" #include "rocksdb/filter_policy.h" @@ -12,23 +14,63 @@ #include "table/block_builder.h" #include "table/filter_block.h" #include "table/format.h" +#include "table/table.h" #include "util/coding.h" #include "util/crc32c.h" #include "util/stop_watch.h" namespace rocksdb { +namespace { + +struct BytewiseLessThan { + bool operator()(const std::string& key1, const std::string& key2) { + // smaller entries will be placed in front. + return comparator->Compare(key1, key2) <= 0; + } + const Comparator* comparator = BytewiseComparator(); +}; + +// When writing to a block that requires entries to be sorted by +// `BytewiseComparator`, we can buffer the content to `BytewiseSortedMap` +// before writng to store. +typedef std::map BytewiseSortedMap; + +void AddStats(BytewiseSortedMap& stats, std::string name, uint64_t val) { + assert(stats.find(name) == stats.end()); + + std::string dst; + PutVarint64(&dst, val); + + stats.insert( + std::make_pair(name, dst) + ); +} + +static bool GoodCompressionRatio(size_t compressed_size, size_t raw_size) { + // Check to see if compressed less than 12.5% + return compressed_size < raw_size - (raw_size / 8u); +} + +} // anonymous namespace + struct TableBuilder::Rep { Options options; Options index_block_options; WritableFile* file; - uint64_t offset; + uint64_t offset = 0; Status status; BlockBuilder data_block; BlockBuilder index_block; std::string last_key; - int64_t num_entries; - bool closed; // Either Finish() or Abandon() has been called. + + uint64_t num_entries = 0; + uint64_t num_data_blocks = 0; + uint64_t raw_key_size = 0; + uint64_t raw_value_size = 0; + uint64_t data_size = 0; + + bool closed = false; // Either Finish() or Abandon() has been called. FilterBlockBuilder* filter_block; // We do not emit the index entry for a block until we have seen the @@ -49,11 +91,8 @@ struct TableBuilder::Rep { : options(opt), index_block_options(opt), file(f), - offset(0), data_block(&options), index_block(&index_block_options), - num_entries(0), - closed(false), filter_block(opt.filter_policy == nullptr ? nullptr : new FilterBlockBuilder(opt)), pending_index_entry(false) { @@ -129,8 +168,10 @@ void TableBuilder::Add(const Slice& key, const Slice& value) { } r->last_key.assign(key.data(), key.size()); - r->num_entries++; r->data_block.Add(key, value); + r->num_entries++; + r->raw_key_size += key.size(); + r->raw_value_size += value.size(); } void TableBuilder::Flush() { @@ -147,11 +188,8 @@ void TableBuilder::Flush() { if (r->filter_block != nullptr) { r->filter_block->StartBlock(r->offset); } -} - -static bool GoodCompressionRatio(size_t compressed_size, size_t raw_size) { - // Check to see if compressed less than 12.5% - return compressed_size < raw_size - (raw_size / 8u); + r->data_size = r->offset; + ++r->num_data_blocks; } void TableBuilder::WriteBlock(BlockBuilder* block, BlockHandle* handle) { @@ -267,35 +305,88 @@ Status TableBuilder::Finish() { &filter_block_handle); } - // Write metaindex block + // To make sure stats block is able to keep the accurate size of index + // block, we will finish writing all index entries here and flush them + // to storage after metaindex block is written. + if (ok() && (r->pending_index_entry)) { + r->options.comparator->FindShortSuccessor(&r->last_key); + std::string handle_encoding; + r->pending_handle.EncodeTo(&handle_encoding); + r->index_block.Add(r->last_key, Slice(handle_encoding)); + r->pending_index_entry = false; + } + + // Write meta blocks and metaindex block with the following order. + // 1. [meta block: filter] + // 2. [meta block: stats] + // 3. [metaindex block] if (ok()) { // We use `BytewiseComparator` as the comparator for meta block. BlockBuilder meta_index_block( r->options.block_restart_interval, BytewiseComparator() ); + // Key: meta block name + // Value: block handle to that meta block + BytewiseSortedMap meta_block_handles; + + // Write filter block. if (r->filter_block != nullptr) { - // Add mapping from "filter.Name" to location of filter data - std::string key = "filter."; + // Add mapping from ".Name" to location + // of filter data. + std::string key = Table::kFilterBlockPrefix; key.append(r->options.filter_policy->Name()); std::string handle_encoding; filter_block_handle.EncodeTo(&handle_encoding); - meta_index_block.Add(key, handle_encoding); + meta_block_handles.insert( + std::make_pair(key, handle_encoding) + ); + } + + // Write stats block. + { + BlockBuilder stats_block( + r->options.block_restart_interval, + BytewiseComparator() + ); + + BytewiseSortedMap stats; + + // Add basic stats + AddStats(stats, TableStatsNames::kRawKeySize, r->raw_key_size); + AddStats(stats, TableStatsNames::kRawValueSize, r->raw_value_size); + AddStats(stats, TableStatsNames::kDataSize, r->data_size); + AddStats( + stats, + TableStatsNames::kIndexSize, + r->index_block.CurrentSizeEstimate() + kBlockTrailerSize + ); + AddStats(stats, TableStatsNames::kNumEntries, r->num_entries); + AddStats(stats, TableStatsNames::kNumDataBlocks, r->num_data_blocks); + + for (const auto& stat : stats) { + stats_block.Add(stat.first, stat.second); + } + + BlockHandle stats_block_handle; + WriteBlock(&stats_block, &stats_block_handle); + + std::string handle_encoding; + stats_block_handle.EncodeTo(&handle_encoding); + meta_block_handles.insert( + std::make_pair(Table::kStatsBlock, handle_encoding) + ); + } // end of stats block writing + + for (const auto& metablock : meta_block_handles) { + meta_index_block.Add(metablock.first, metablock.second); } - // TODO(postrelease): Add stats and other meta blocks WriteBlock(&meta_index_block, &metaindex_block_handle); - } + } // meta blocks and metaindex block. // Write index block if (ok()) { - if (r->pending_index_entry) { - r->options.comparator->FindShortSuccessor(&r->last_key); - std::string handle_encoding; - r->pending_handle.EncodeTo(&handle_encoding); - r->index_block.Add(r->last_key, Slice(handle_encoding)); - r->pending_index_entry = false; - } WriteBlock(&r->index_block, &index_block_handle); } diff --git a/table/table_test.cc b/table/table_test.cc index 1d24e9228..859488619 100644 --- a/table/table_test.cc +++ b/table/table_test.cc @@ -4,6 +4,8 @@ #include #include #include +#include + #include "db/dbformat.h" #include "db/memtable.h" #include "db/write_batch_internal.h" @@ -232,7 +234,8 @@ class BlockConstructor: public Constructor { class TableConstructor: public Constructor { public: - explicit TableConstructor(const Comparator* cmp) + explicit TableConstructor( + const Comparator* cmp) : Constructor(cmp) { } ~TableConstructor() { @@ -846,6 +849,118 @@ static bool Between(uint64_t val, uint64_t low, uint64_t high) { class TableTest { }; +// This test include all the basic checks except those for index size and block +// size, which will be conducted in separated unit tests. +TEST(TableTest, BasicTableStats) { + TableConstructor c(BytewiseComparator()); + + c.Add("a1", "val1"); + c.Add("b2", "val2"); + c.Add("c3", "val3"); + c.Add("d4", "val4"); + c.Add("e5", "val5"); + c.Add("f6", "val6"); + c.Add("g7", "val7"); + c.Add("h8", "val8"); + c.Add("j9", "val9"); + + std::vector keys; + KVMap kvmap; + Options options; + options.compression = kNoCompression; + options.block_restart_interval = 1; + + c.Finish(options, &keys, &kvmap); + + auto& stats = c.table()->GetTableStats(); + ASSERT_EQ(kvmap.size(), stats.num_entries); + + auto raw_key_size = kvmap.size() * 2ul; + auto raw_value_size = kvmap.size() * 4ul; + + ASSERT_EQ(raw_key_size, stats.raw_key_size); + ASSERT_EQ(raw_value_size, stats.raw_value_size); + ASSERT_EQ(1ul, stats.num_data_blocks); + + // Verify data size. + BlockBuilder block_builder(&options); + for (const auto& item : kvmap) { + block_builder.Add(item.first, item.second); + } + Slice content = block_builder.Finish(); + ASSERT_EQ( + content.size() + kBlockTrailerSize, + stats.data_size + ); +} + +static std::string RandomString(Random* rnd, int len) { + std::string r; + test::RandomString(rnd, len, &r); + return r; +} + +// It's very hard to figure out the index block size of a block accurately. +// To make sure we get the index size, we just make sure as key number +// grows, the filter block size also grows. +TEST(TableTest, IndexSizeStat) { + uint64_t last_index_size = 0; + + // we need to use random keys since the pure human readable texts + // may be well compressed, resulting insignifcant change of index + // block size. + Random rnd(test::RandomSeed()); + std::vector keys; + + for (int i = 0; i < 100; ++i) { + keys.push_back(RandomString(&rnd, 10000)); + } + + // Each time we load one more key to the table. the table index block + // size is expected to be larger than last time's. + for (size_t i = 1; i < keys.size(); ++i) { + TableConstructor c(BytewiseComparator()); + for (size_t j = 0; j < i; ++j) { + c.Add(keys[j], "val"); + } + + std::vector ks; + KVMap kvmap; + Options options; + options.compression = kNoCompression; + options.block_restart_interval = 1; + + c.Finish(options, &ks, &kvmap); + auto index_size = + c.table()->GetTableStats().index_size; + ASSERT_GT(index_size, last_index_size); + last_index_size = index_size; + } +} + +TEST(TableTest, NumBlockStat) { + Random rnd(test::RandomSeed()); + TableConstructor c(BytewiseComparator()); + Options options; + options.compression = kNoCompression; + options.block_restart_interval = 1; + options.block_size = 1000; + + for (int i = 0; i < 10; ++i) { + // the key/val are slightly smaller than block size, so that each block + // holds roughly one key/value pair. + c.Add(RandomString(&rnd, 900), "val"); + } + + std::vector ks; + KVMap kvmap; + c.Finish(options, &ks, &kvmap); + ASSERT_EQ( + kvmap.size(), + c.table()->GetTableStats().num_data_blocks + ); +} + TEST(TableTest, ApproximateOffsetOfPlain) { TableConstructor c(BytewiseComparator()); c.Add("k01", "hello");