Summary:
This PR avoids allocations and copies for the result of `GetMergeOperands()` when the average operand size is at least 256 bytes and the total operands size is at least 32KB. The `GetMergeOperands()` already included `PinnableSlice` but was calling `PinSelf()` (i.e., allocating and copying) for each operand. When this optimization takes effect, we instead call `PinSlice()` to skip that allocation and copy. Resources are pinned in order for the `PinnableSlice` to point to valid memory even after `GetMergeOperands()` returns.
The pinned resources include a referenced `SuperVersion`, a `MergingContext`, and a `PinnedIteratorsManager`. They are bundled into a `GetMergeOperandsState`. We use `SharedCleanablePtr` to share that bundle among all `PinnableSlice`s populated by `GetMergeOperands()`. That way, the last `PinnableSlice` to be `Reset()` will cleanup the bundle, including unreferencing the `SuperVersion`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10458
Test Plan:
- new DB level test
- measured benefit/regression in a number of memtable scenarios
Setup command:
```
$ ./db_bench -benchmarks=mergerandom -merge_operator=StringAppendOperator -num=$num -writes=16384 -key_size=16 -value_size=$value_sz -compression_type=none -write_buffer_size=1048576000
```
Benchmark command:
```
./db_bench -threads=$threads -use_existing_db=true -avoid_flush_during_recovery=true -write_buffer_size=1048576000 -benchmarks=readrandomoperands -merge_operator=StringAppendOperator -num=$num -duration=10
```
Worst regression is when a key has many tiny operands:
- Parameters: num=1 (implying 16384 operands per key), value_sz=8, threads=1
- `GetMergeOperands()` latency increases 682 micros -> 800 micros (+17%)
The regression disappears into the noise (<1% difference) if we remove the `Reset()` loop and the size counting loop. The former is arguably needed regardless of this PR as the convention in `Get()` and `MultiGet()` is to `Reset()` the input `PinnableSlice`s at the start. The latter could be optimized to count the size as we accumulate operands rather than after the fact.
Best improvement is when a key has large operands and high concurrency:
- Parameters: num=4 (implying 4096 operands per key), value_sz=2KB, threads=32
- `GetMergeOperands()` latency decreases 11492 micros -> 437 micros (-96%).
Reviewed By: cbi42
Differential Revision: D38336578
Pulled By: ajkr
fbshipit-source-id: 48146d127e04cb7f2d4d2939a2b9dff3aba18258
Summary:
Iterator is not freed after test is done (after the main for
loop), which could cause db close failed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10058
Test Plan:
Able to reproduce consistently with higher thread number,
like 100, make sure it passes after the fix
Reviewed By: ajkr
Differential Revision: D36685823
Pulled By: jay-zhuang
fbshipit-source-id: 4c98b8758d106bfe40cae670e689c3d284765bcf
Summary:
The new microbenchmarks, DBGetMergeOperandsInMemtable and DBGetMergeOperandsInSstFile, correspond to the two different LSMs tested: all data in one memtable and all data in one SST file, respectively. Both cases are parameterized by thread count (1 or 8) and merge operands per key (1, 32, or 1024). The SST file case is additionally parameterized by whether data is in block cache or mmap'd memory.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9971
Test Plan:
```
$ TEST_TMPDIR=/dev/shm/db_basic_bench/ ./db_basic_bench --benchmark_filter=DBGetMergeOperands
The number of inputs is very large. DBGet will be repeated at least 192 times.
The number of inputs is very large. DBGet will be repeated at least 192 times.
2022-05-09T13:15:40-07:00
Running ./db_basic_bench
Run on (36 X 2570.91 MHz CPU s)
CPU Caches:
L1 Data 32 KiB (x18)
L1 Instruction 32 KiB (x18)
L2 Unified 1024 KiB (x18)
L3 Unified 25344 KiB (x1)
Load Average: 4.50, 4.33, 4.37
----------------------------------------------------------------------------------------------------------------------------
Benchmark Time CPU Iterations UserCounters...
----------------------------------------------------------------------------------------------------------------------------
DBGetMergeOperandsInMemtable/entries_per_key:1/threads:1 846 ns 846 ns 849893 db_size=0
DBGetMergeOperandsInMemtable/entries_per_key:32/threads:1 2436 ns 2436 ns 305779 db_size=0
DBGetMergeOperandsInMemtable/entries_per_key:1024/threads:1 77226 ns 77224 ns 8152 db_size=0
DBGetMergeOperandsInMemtable/entries_per_key:1/threads:8 116 ns 929 ns 779368 db_size=0
DBGetMergeOperandsInMemtable/entries_per_key:32/threads:8 330 ns 2644 ns 280824 db_size=0
DBGetMergeOperandsInMemtable/entries_per_key:1024/threads:8 12466 ns 99718 ns 7200 db_size=0
DBGetMergeOperandsInSstFile/entries_per_key:1/mmap:0/threads:1 1640 ns 1640 ns 461262 db_size=21.7826M
DBGetMergeOperandsInSstFile/entries_per_key:1/mmap:1/threads:1 1693 ns 1693 ns 439936 db_size=21.7826M
DBGetMergeOperandsInSstFile/entries_per_key:32/mmap:0/threads:1 3999 ns 3999 ns 172881 db_size=19.6981M
DBGetMergeOperandsInSstFile/entries_per_key:32/mmap:1/threads:1 5544 ns 5543 ns 135657 db_size=19.6981M
DBGetMergeOperandsInSstFile/entries_per_key:1024/mmap:0/threads:1 78767 ns 78761 ns 8395 db_size=19.6389M
DBGetMergeOperandsInSstFile/entries_per_key:1024/mmap:1/threads:1 157242 ns 157238 ns 4495 db_size=19.6389M
DBGetMergeOperandsInSstFile/entries_per_key:1/mmap:0/threads:8 231 ns 1848 ns 347768 db_size=21.7826M
DBGetMergeOperandsInSstFile/entries_per_key:1/mmap:1/threads:8 214 ns 1715 ns 393312 db_size=21.7826M
DBGetMergeOperandsInSstFile/entries_per_key:32/mmap:0/threads:8 596 ns 4767 ns 142088 db_size=19.6981M
DBGetMergeOperandsInSstFile/entries_per_key:32/mmap:1/threads:8 720 ns 5757 ns 118200 db_size=19.6981M
DBGetMergeOperandsInSstFile/entries_per_key:1024/mmap:0/threads:8 11613 ns 92460 ns 7344 db_size=19.6389M
DBGetMergeOperandsInSstFile/entries_per_key:1024/mmap:1/threads:8 19989 ns 159908 ns 4440 db_size=19.6389M
```
Reviewed By: jay-zhuang
Differential Revision: D36258861
Pulled By: ajkr
fbshipit-source-id: 04b733e1cc3a4a70ed9baa894c50fdf96c0d6064
Summary:
ToString() is created as some platform doesn't support std::to_string(). However, we've already used std::to_string() by mistake for 16 months (in db/db_info_dumper.cc). This commit just remove ToString().
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9955
Test Plan: Watch CI tests
Reviewed By: riversand963
Differential Revision: D36176799
fbshipit-source-id: bdb6dcd0e3a3ab96a1ac810f5d0188f684064471
Summary:
Use `unique_ptr<DB>` to make sure the DB object is deleted. Previously it was not, which led to accumulating file descriptors for deleted directories because a `DBImpl::db_dir_` from each test remained alive.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9939
Test Plan: run `lsof -p $(pidof db_basic_bench)` while benchmark runs; verify no FDs for deleted directories.
Reviewed By: jay-zhuang
Differential Revision: D36108761
Pulled By: ajkr
fbshipit-source-id: cfe02646b038a445af7d5db8989eb1f40d658359
Summary:
I tried evaluating https://github.com/facebook/rocksdb/issues/9611 using DBGet microbenchmarks but mostly found the change is well within the noise even for hundreds of repetitions; meanwhile, the InternalKeyComparator CPU it saves is 1-2% according to perf so it should be measurable. In this PR I tried adding a mmap mode that will bypass compression/checksum/block cache/file read to focus more on the block lookup paths, and also increased the Get() count.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9903
Reviewed By: jay-zhuang, riversand963
Differential Revision: D35907375
Pulled By: ajkr
fbshipit-source-id: 69490d5040ef0863e1ce296724104d0aa7667215
Summary:
This commit was generated using `mgt import`.
pristine code for third-party libraries:
third-party/benchmark
upgrade google benchmark to v1.6.1
contains a local patch that reverts [this](https://github.com/google/benchmark/pull/1227?fbclid=IwAR2CCmIJmjU62SPPQQf_t8kdAsMjYv_Pa_GxabYUOdQpGPZUHKwbnYS_1oE) and changs `enum Flags` to be `enum Flags : uint32_t`.
Reviewed By: chadaustin
Differential Revision: D35136540
fbshipit-source-id: f3662f953cd87956e5e9b767e55e3697f99d3b49
Summary:
DBGet p95 and p99 have high variation, remove them for now.
Also increase the iteration to 3 to avoid false positive.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9742
Test Plan: Internal CI
Reviewed By: ajkr
Differential Revision: D35082820
Pulled By: jay-zhuang
fbshipit-source-id: facc1d56b94e54aa8c8852c207aae2ae4e4924b0
Summary:
* Add more micro-benchmark tests
* Expose an API in DBImpl for waiting for compactions (still not visible to the user)
* Add argument name for ribbon_bench
* remove benchmark run from CI, as it runs too long.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9436
Test Plan: CI
Reviewed By: riversand963
Differential Revision: D33777836
Pulled By: jay-zhuang
fbshipit-source-id: c05de3bc082cc05b5d019f00b324e774bf4bbd96
Summary:
Directory fsync might be expensive on btrfs and it may not be needed.
Here are 4 directory fsync cases:
1. creating a new file: dir-fsync is not needed on btrfs, as long as the
new file itself is synced.
2. renaming a file: dir-fsync is not needed if the renamed file is
synced. So an API `FsyncAfterFileRename(filename, ...)` is provided
to sync the file on btrfs. By default, it just calls dir-fsync.
3. deleting files: dir-fsync is forced by set
`IOOptions.force_dir_fsync = true`
4. renaming multiple files (like backup and checkpoint): dir-fsync is
forced, the same as above.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8903
Test Plan: run tests on btrfs and non btrfs
Reviewed By: ajkr
Differential Revision: D30885059
Pulled By: jay-zhuang
fbshipit-source-id: dd2730b31580b0bcaedffc318a762d7dbf25de4a
Andrew Kryczka