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4da34b97ee
Summary: ### Context: Background compactions and flush generate large reads and writes, and can be long running, especially for universal compaction. In some cases, this can impact foreground reads and writes by users. ### Solution User, Flush, and Compaction reads share some code path. For this task, we update the rate_limiter_priority in ReadOptions for code paths (e.g. FindTable (mainly in BlockBasedTable::Open()) and various iterators), and eventually update the rate_limiter_priority in IOOptions for FSRandomAccessFile. **This PR is for the Read path.** The **Read:** dynamic priority for different state are listed as follows: | State | Normal | Delayed | Stalled | | ----- | ------ | ------- | ------- | | Flush (verification read in BuildTable()) | IO_USER | IO_USER | IO_USER | | Compaction | IO_LOW | IO_USER | IO_USER | | User | User provided | User provided | User provided | We will respect the read_options that the user provided and will not set it. The only sst read for Flush is the verification read in BuildTable(). It claims to be "regard as user read". **Details** 1. Set read_options.rate_limiter_priority dynamically: - User: Do not update the read_options. Use the read_options that the user provided. - Compaction: Update read_options in CompactionJob::ProcessKeyValueCompaction(). - Flush: Update read_options in BuildTable(). 2. Pass the rate limiter priority to FSRandomAccessFile functions: - After calling the FindTable(), read_options is passed through GetTableReader(table_cache.cc), BlockBasedTableFactory::NewTableReader(block_based_table_factory.cc), and BlockBasedTable::Open(). The Open() needs some updates for the ReadOptions variable and the updates are also needed for the called functions, including PrefetchTail(), PrepareIOOptions(), ReadFooterFromFile(), ReadMetaIndexblock(), ReadPropertiesBlock(), PrefetchIndexAndFilterBlocks(), and ReadRangeDelBlock(). - In RandomAccessFileReader, the functions to be updated include Read(), MultiRead(), ReadAsync(), and Prefetch(). - Update the downstream functions of NewIndexIterator(), NewDataBlockIterator(), and BlockBasedTableIterator(). ### Test Plans Add unit tests. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9996 Reviewed By: anand1976 Differential Revision: D36452483 Pulled By: gitbw95 fbshipit-source-id: 60978204a4f849bb9261cb78d9bc1cb56d6008cf
57 lines
2.1 KiB
C++
57 lines
2.1 KiB
C++
// 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/index_reader_common.h"
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namespace ROCKSDB_NAMESPACE {
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Status BlockBasedTable::IndexReaderCommon::ReadIndexBlock(
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const BlockBasedTable* table, FilePrefetchBuffer* prefetch_buffer,
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const ReadOptions& read_options, bool use_cache, GetContext* get_context,
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BlockCacheLookupContext* lookup_context,
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CachableEntry<Block>* index_block) {
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PERF_TIMER_GUARD(read_index_block_nanos);
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assert(table != nullptr);
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assert(index_block != nullptr);
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assert(index_block->IsEmpty());
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const Rep* const rep = table->get_rep();
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assert(rep != nullptr);
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const Status s = table->RetrieveBlock(
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prefetch_buffer, read_options, rep->footer.index_handle(),
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UncompressionDict::GetEmptyDict(), index_block, BlockType::kIndex,
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get_context, lookup_context, /* for_compaction */ false, use_cache,
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/* wait_for_cache */ true);
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return s;
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}
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Status BlockBasedTable::IndexReaderCommon::GetOrReadIndexBlock(
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bool no_io, Env::IOPriority rate_limiter_priority, GetContext* get_context,
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BlockCacheLookupContext* lookup_context,
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CachableEntry<Block>* index_block) const {
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assert(index_block != nullptr);
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if (!index_block_.IsEmpty()) {
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index_block->SetUnownedValue(index_block_.GetValue());
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return Status::OK();
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}
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ReadOptions read_options;
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read_options.rate_limiter_priority = rate_limiter_priority;
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if (no_io) {
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read_options.read_tier = kBlockCacheTier;
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}
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return ReadIndexBlock(table_, /*prefetch_buffer=*/nullptr, read_options,
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cache_index_blocks(), get_context, lookup_context,
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index_block);
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}
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} // namespace ROCKSDB_NAMESPACE
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