fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
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221 lines
7.9 KiB
221 lines
7.9 KiB
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root 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/partitioned_index_reader.h"
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#include "block_cache.h"
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#include "file/random_access_file_reader.h"
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#include "table/block_based/block_based_table_reader.h"
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#include "table/block_based/partitioned_index_iterator.h"
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namespace ROCKSDB_NAMESPACE {
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Status PartitionIndexReader::Create(
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const BlockBasedTable* table, const ReadOptions& ro,
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FilePrefetchBuffer* prefetch_buffer, bool use_cache, bool prefetch,
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bool pin, BlockCacheLookupContext* lookup_context,
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std::unique_ptr<IndexReader>* index_reader) {
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assert(table != nullptr);
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assert(table->get_rep());
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assert(!pin || prefetch);
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assert(index_reader != nullptr);
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CachableEntry<Block> index_block;
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if (prefetch || !use_cache) {
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const Status s =
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ReadIndexBlock(table, prefetch_buffer, ro, use_cache,
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/*get_context=*/nullptr, lookup_context, &index_block);
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if (!s.ok()) {
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return s;
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}
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if (use_cache && !pin) {
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index_block.Reset();
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}
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}
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index_reader->reset(new PartitionIndexReader(table, std::move(index_block)));
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return Status::OK();
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}
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InternalIteratorBase<IndexValue>* PartitionIndexReader::NewIterator(
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const ReadOptions& read_options, bool /* disable_prefix_seek */,
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IndexBlockIter* iter, GetContext* get_context,
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BlockCacheLookupContext* lookup_context) {
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const bool no_io = (read_options.read_tier == kBlockCacheTier);
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CachableEntry<Block> index_block;
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const Status s =
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GetOrReadIndexBlock(no_io, read_options.rate_limiter_priority,
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get_context, lookup_context, &index_block);
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if (!s.ok()) {
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if (iter != nullptr) {
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iter->Invalidate(s);
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return iter;
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}
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return NewErrorInternalIterator<IndexValue>(s);
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}
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const BlockBasedTable::Rep* rep = table()->rep_;
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InternalIteratorBase<IndexValue>* it = nullptr;
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Statistics* kNullStats = nullptr;
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// Filters are already checked before seeking the index
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if (!partition_map_.empty()) {
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// We don't return pinned data from index blocks, so no need
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// to set `block_contents_pinned`.
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it = NewTwoLevelIterator(
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new BlockBasedTable::PartitionedIndexIteratorState(table(),
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&partition_map_),
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index_block.GetValue()->NewIndexIterator(
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internal_comparator()->user_comparator(),
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rep->get_global_seqno(BlockType::kIndex), nullptr, kNullStats, true,
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index_has_first_key(), index_key_includes_seq(),
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index_value_is_full()));
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} else {
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ReadOptions ro;
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ro.fill_cache = read_options.fill_cache;
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ro.deadline = read_options.deadline;
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ro.io_timeout = read_options.io_timeout;
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ro.adaptive_readahead = read_options.adaptive_readahead;
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ro.async_io = read_options.async_io;
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ro.rate_limiter_priority = read_options.rate_limiter_priority;
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// We don't return pinned data from index blocks, so no need
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// to set `block_contents_pinned`.
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std::unique_ptr<InternalIteratorBase<IndexValue>> index_iter(
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index_block.GetValue()->NewIndexIterator(
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internal_comparator()->user_comparator(),
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rep->get_global_seqno(BlockType::kIndex), nullptr, kNullStats, true,
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index_has_first_key(), index_key_includes_seq(),
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index_value_is_full()));
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it = new PartitionedIndexIterator(
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table(), ro, *internal_comparator(), std::move(index_iter),
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lookup_context ? lookup_context->caller
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: TableReaderCaller::kUncategorized);
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}
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assert(it != nullptr);
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index_block.TransferTo(it);
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return it;
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// TODO(myabandeh): Update TwoLevelIterator to be able to make use of
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// on-stack BlockIter while the state is on heap. Currentlly it assumes
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// the first level iter is always on heap and will attempt to delete it
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// in its destructor.
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}
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Status PartitionIndexReader::CacheDependencies(const ReadOptions& ro,
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bool pin) {
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if (!partition_map_.empty()) {
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// The dependencies are already cached since `partition_map_` is filled in
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// an all-or-nothing manner.
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return Status::OK();
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}
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// Before read partitions, prefetch them to avoid lots of IOs
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BlockCacheLookupContext lookup_context{TableReaderCaller::kPrefetch};
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const BlockBasedTable::Rep* rep = table()->rep_;
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IndexBlockIter biter;
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BlockHandle handle;
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Statistics* kNullStats = nullptr;
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CachableEntry<Block> index_block;
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{
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Status s = GetOrReadIndexBlock(false /* no_io */, ro.rate_limiter_priority,
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nullptr /* get_context */, &lookup_context,
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&index_block);
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if (!s.ok()) {
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return s;
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}
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}
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// We don't return pinned data from index blocks, so no need
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// to set `block_contents_pinned`.
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index_block.GetValue()->NewIndexIterator(
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internal_comparator()->user_comparator(),
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rep->get_global_seqno(BlockType::kIndex), &biter, kNullStats, true,
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index_has_first_key(), index_key_includes_seq(), index_value_is_full());
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// Index partitions are assumed to be consecuitive. Prefetch them all.
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// Read the first block offset
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biter.SeekToFirst();
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if (!biter.Valid()) {
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// Empty index.
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return biter.status();
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}
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handle = biter.value().handle;
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uint64_t prefetch_off = handle.offset();
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// Read the last block's offset
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biter.SeekToLast();
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if (!biter.Valid()) {
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// Empty index.
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return biter.status();
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}
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handle = biter.value().handle;
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uint64_t last_off =
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handle.offset() + BlockBasedTable::BlockSizeWithTrailer(handle);
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uint64_t prefetch_len = last_off - prefetch_off;
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std::unique_ptr<FilePrefetchBuffer> prefetch_buffer;
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rep->CreateFilePrefetchBuffer(
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0, 0, &prefetch_buffer, false /*Implicit auto readahead*/,
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0 /*num_reads_*/, 0 /*num_file_reads_for_auto_readahead*/);
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IOOptions opts;
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{
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Status s = rep->file->PrepareIOOptions(ro, opts);
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if (s.ok()) {
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s = prefetch_buffer->Prefetch(opts, rep->file.get(), prefetch_off,
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static_cast<size_t>(prefetch_len),
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ro.rate_limiter_priority);
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}
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if (!s.ok()) {
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return s;
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}
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}
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// For saving "all or nothing" to partition_map_
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UnorderedMap<uint64_t, CachableEntry<Block>> map_in_progress;
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// After prefetch, read the partitions one by one
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biter.SeekToFirst();
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size_t partition_count = 0;
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for (; biter.Valid(); biter.Next()) {
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handle = biter.value().handle;
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CachableEntry<Block> block;
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++partition_count;
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// TODO: Support counter batch update for partitioned index and
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// filter blocks
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Status s = table()->MaybeReadBlockAndLoadToCache(
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prefetch_buffer.get(), ro, handle, UncompressionDict::GetEmptyDict(),
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/*for_compaction=*/false, &block.As<Block_kIndex>(),
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/*get_context=*/nullptr, &lookup_context, /*contents=*/nullptr,
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/*async_read=*/false);
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if (!s.ok()) {
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return s;
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}
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if (block.GetValue() != nullptr) {
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// Might need to "pin" some mmap-read blocks (GetOwnValue) if some
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// partitions are successfully compressed (cached) and some are not
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// compressed (mmap eligible)
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if (block.IsCached() || block.GetOwnValue()) {
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if (pin) {
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map_in_progress[handle.offset()] = std::move(block);
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}
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}
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}
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}
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Status s = biter.status();
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// Save (pin) them only if everything checks out
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if (map_in_progress.size() == partition_count && s.ok()) {
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std::swap(partition_map_, map_in_progress);
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}
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return s;
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}
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} // namespace ROCKSDB_NAMESPACE
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