Skip to main content

Browse the archive

Revision 80de9004649753d87fa1b2d41127b1401a4c0065 authored by Levi Tamasi on 13 December 2019, 20:45:49 UTC, committed by Levi Tamasi on 17 December 2019, 15:52:22 UTC 
Do not create/install new SuperVersion if nothing was deleted during memtable trim (#6169)
 
Summary:
We have observed an increase in CPU load caused by frequent calls to
`ColumnFamilyData::InstallSuperVersion` from `DBImpl::TrimMemtableHistory`
when using `max_write_buffer_size_to_maintain` to limit the amount of
memtable history maintained for transaction conflict checking. As it turns out,
this is caused by the code creating and installing a new `SuperVersion` even if
no memtables were actually trimmed. The patch adds a check to avoid this.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6169

Test Plan:
Compared `perf` output for

```
./db_bench -benchmarks=randomtransaction -optimistic_transaction_db=1 -statistics -stats_interval_seconds=1 -duration=90 -num=500000 --max_write_buffer_size_to_maintain=16000000 --transaction_set_snapshot=1 --threads=32
```

before and after the change. With the fix, the call chain `rocksdb::DBImpl::TrimMemtableHistory` ->
`rocksdb::ColumnFamilyData::InstallSuperVersion` -> `rocksdb::ThreadLocalPtr::StaticMeta::Scrape`
no longer registers in the `perf` report.

Differential Revision: D19031509

Pulled By: ltamasi

fbshipit-source-id: 02686fce594e5b50eba0710e4b28a9b808c8aa20
1 parent 1d9eae3
Raw File
options_sanity_check.h 
// 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).

#pragma once

#include <string>
#include <unordered_map>

#ifndef ROCKSDB_LITE
namespace rocksdb {
// This enum defines the RocksDB options sanity level.
enum OptionsSanityCheckLevel : unsigned char {
  // Performs no sanity check at all.
  kSanityLevelNone = 0x00,
  // Performs minimum check to ensure the RocksDB instance can be
  // opened without corrupting / mis-interpreting the data.
  kSanityLevelLooselyCompatible = 0x01,
  // Perform exact match sanity check.
  kSanityLevelExactMatch = 0xFF,
};

// The sanity check level for DB options
static const std::unordered_map<std::string, OptionsSanityCheckLevel>
    sanity_level_db_options {};

// The sanity check level for column-family options
static const std::unordered_map<std::string, OptionsSanityCheckLevel>
    sanity_level_cf_options = {
        {"comparator", kSanityLevelLooselyCompatible},
        {"table_factory", kSanityLevelLooselyCompatible},
        {"merge_operator", kSanityLevelLooselyCompatible}};

// The sanity check level for block-based table options
static const std::unordered_map<std::string, OptionsSanityCheckLevel>
    sanity_level_bbt_options {};

OptionsSanityCheckLevel DBOptionSanityCheckLevel(
    const std::string& options_name);
OptionsSanityCheckLevel CFOptionSanityCheckLevel(
    const std::string& options_name);
OptionsSanityCheckLevel BBTOptionSanityCheckLevel(
    const std::string& options_name);

}  // namespace rocksdb

#endif  // !ROCKSDB_LITE
back to top