// 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) 2011 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/partitioned_index_reader.h" #include "block_cache.h" #include "file/random_access_file_reader.h" #include "table/block_based/block_based_table_reader.h" #include "table/block_based/partitioned_index_iterator.h" namespace ROCKSDB_NAMESPACE { Status PartitionIndexReader::Create( const BlockBasedTable* table, const ReadOptions& ro, FilePrefetchBuffer* prefetch_buffer, bool use_cache, bool prefetch, bool pin, BlockCacheLookupContext* lookup_context, std::unique_ptr* index_reader) { assert(table != nullptr); assert(table->get_rep()); assert(!pin || prefetch); assert(index_reader != nullptr); CachableEntry index_block; if (prefetch || !use_cache) { const Status s = ReadIndexBlock(table, prefetch_buffer, ro, use_cache, /*get_context=*/nullptr, lookup_context, &index_block); if (!s.ok()) { return s; } if (use_cache && !pin) { index_block.Reset(); } } index_reader->reset(new PartitionIndexReader(table, std::move(index_block))); return Status::OK(); } InternalIteratorBase* PartitionIndexReader::NewIterator( const ReadOptions& read_options, bool /* disable_prefix_seek */, IndexBlockIter* iter, GetContext* get_context, BlockCacheLookupContext* lookup_context) { const bool no_io = (read_options.read_tier == kBlockCacheTier); CachableEntry index_block; const Status s = GetOrReadIndexBlock(no_io, get_context, lookup_context, &index_block, read_options); if (!s.ok()) { if (iter != nullptr) { iter->Invalidate(s); return iter; } return NewErrorInternalIterator(s); } const BlockBasedTable::Rep* rep = table()->rep_; InternalIteratorBase* it = nullptr; Statistics* kNullStats = nullptr; // Filters are already checked before seeking the index if (!partition_map_.empty()) { // We don't return pinned data from index blocks, so no need // to set `block_contents_pinned`. it = NewTwoLevelIterator( new BlockBasedTable::PartitionedIndexIteratorState(table(), &partition_map_), index_block.GetValue()->NewIndexIterator( internal_comparator()->user_comparator(), rep->get_global_seqno(BlockType::kIndex), nullptr, kNullStats, true, index_has_first_key(), index_key_includes_seq(), index_value_is_full())); } else { ReadOptions ro; ro.fill_cache = read_options.fill_cache; ro.deadline = read_options.deadline; ro.io_timeout = read_options.io_timeout; ro.adaptive_readahead = read_options.adaptive_readahead; ro.async_io = read_options.async_io; ro.rate_limiter_priority = read_options.rate_limiter_priority; ro.verify_checksums = read_options.verify_checksums; ro.io_activity = read_options.io_activity; // We don't return pinned data from index blocks, so no need // to set `block_contents_pinned`. std::unique_ptr> index_iter( index_block.GetValue()->NewIndexIterator( internal_comparator()->user_comparator(), rep->get_global_seqno(BlockType::kIndex), nullptr, kNullStats, true, index_has_first_key(), index_key_includes_seq(), index_value_is_full())); it = new PartitionedIndexIterator( table(), ro, *internal_comparator(), std::move(index_iter), lookup_context ? lookup_context->caller : TableReaderCaller::kUncategorized); } assert(it != nullptr); index_block.TransferTo(it); return it; // TODO(myabandeh): Update TwoLevelIterator to be able to make use of // on-stack BlockIter while the state is on heap. Currentlly it assumes // the first level iter is always on heap and will attempt to delete it // in its destructor. } Status PartitionIndexReader::CacheDependencies(const ReadOptions& ro, bool pin) { if (!partition_map_.empty()) { // The dependencies are already cached since `partition_map_` is filled in // an all-or-nothing manner. return Status::OK(); } // Before read partitions, prefetch them to avoid lots of IOs BlockCacheLookupContext lookup_context{TableReaderCaller::kPrefetch}; const BlockBasedTable::Rep* rep = table()->rep_; IndexBlockIter biter; BlockHandle handle; Statistics* kNullStats = nullptr; CachableEntry index_block; { Status s = GetOrReadIndexBlock(false /* no_io */, nullptr /* get_context */, &lookup_context, &index_block, ro); if (!s.ok()) { return s; } } // We don't return pinned data from index blocks, so no need // to set `block_contents_pinned`. index_block.GetValue()->NewIndexIterator( internal_comparator()->user_comparator(), rep->get_global_seqno(BlockType::kIndex), &biter, kNullStats, true, index_has_first_key(), index_key_includes_seq(), index_value_is_full()); // Index partitions are assumed to be consecuitive. Prefetch them all. // Read the first block offset biter.SeekToFirst(); if (!biter.Valid()) { // Empty index. return biter.status(); } handle = biter.value().handle; uint64_t prefetch_off = handle.offset(); // Read the last block's offset biter.SeekToLast(); if (!biter.Valid()) { // Empty index. return biter.status(); } handle = biter.value().handle; uint64_t last_off = handle.offset() + BlockBasedTable::BlockSizeWithTrailer(handle); uint64_t prefetch_len = last_off - prefetch_off; std::unique_ptr prefetch_buffer; rep->CreateFilePrefetchBuffer( 0, 0, &prefetch_buffer, false /*Implicit auto readahead*/, 0 /*num_reads_*/, 0 /*num_file_reads_for_auto_readahead*/); IOOptions opts; { Status s = rep->file->PrepareIOOptions(ro, opts); if (s.ok()) { s = prefetch_buffer->Prefetch(opts, rep->file.get(), prefetch_off, static_cast(prefetch_len), ro.rate_limiter_priority); } if (!s.ok()) { return s; } } // For saving "all or nothing" to partition_map_ UnorderedMap> map_in_progress; // After prefetch, read the partitions one by one biter.SeekToFirst(); size_t partition_count = 0; for (; biter.Valid(); biter.Next()) { handle = biter.value().handle; CachableEntry block; ++partition_count; // TODO: Support counter batch update for partitioned index and // filter blocks Status s = table()->MaybeReadBlockAndLoadToCache( prefetch_buffer.get(), ro, handle, UncompressionDict::GetEmptyDict(), /*for_compaction=*/false, &block.As(), /*get_context=*/nullptr, &lookup_context, /*contents=*/nullptr, /*async_read=*/false); if (!s.ok()) { return s; } if (block.GetValue() != nullptr) { // Might need to "pin" some mmap-read blocks (GetOwnValue) if some // partitions are successfully compressed (cached) and some are not // compressed (mmap eligible) if (block.IsCached() || block.GetOwnValue()) { if (pin) { map_in_progress[handle.offset()] = std::move(block); } } } } Status s = biter.status(); // Save (pin) them only if everything checks out if (map_in_progress.size() == partition_count && s.ok()) { std::swap(partition_map_, map_in_progress); } return s; } } // namespace ROCKSDB_NAMESPACE