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2016 Commits (7d36bc42735824f116bf538a43507d6be47d785d)
| Author | SHA1 | Message | Date |
|---|---|---|---|
Jaepil Jeong
|
4eb7b35f6d |
Fix compile error in Clang 13 (#10033)
Summary:
This PR fixes the following compilation error in Clang 13, which was tested on macOS 12.4.
```
❯ ninja clean && ninja
[1/1] Cleaning all built files...
Cleaning... 0 files.
[198/315] Building CXX object CMakeFiles/rocksdb.dir/util/cleanable.cc.o
FAILED: CMakeFiles/rocksdb.dir/util/cleanable.cc.o
ccache /opt/homebrew/opt/llvm/bin/clang++ -DGFLAGS=1 -DGFLAGS_IS_A_DLL=0 -DHAVE_FULLFSYNC -DJEMALLOC_NO_DEMANGLE -DLZ4 -DOS_MACOSX -DROCKSDB_JEMALLOC -DROCKSDB_LIB_IO_POSIX -DROCKSDB_NO_DYNAMIC_EXTENSION -DROCKSDB_PLATFORM_POSIX -DSNAPPY -DTBB -DZLIB -DZSTD -I/Users/jaepil/work/deepsearch/deps/cpp/rocksdb -I/Users/jaepil/work/deepsearch/deps/cpp/rocksdb/include -I/Users/jaepil/app/include -I/opt/homebrew/include -I/opt/homebrew/opt/llvm/include -W -Wextra -Wall -pthread -Wsign-compare -Wshadow -Wno-unused-parameter -Wno-unused-variable -Woverloaded-virtual -Wnon-virtual-dtor -Wno-missing-field-initializers -Wno-strict-aliasing -Wno-invalid-offsetof -fno-omit-frame-pointer -momit-leaf-frame-pointer -march=armv8-a+crc+crypto -Wno-unused-function -Werror -O3 -DNDEBUG -DROCKSDB_USE_RTTI -arch arm64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX12.3.sdk -std=gnu++17 -MD -MT CMakeFiles/rocksdb.dir/util/cleanable.cc.o -MF CMakeFiles/rocksdb.dir/util/cleanable.cc.o.d -o CMakeFiles/rocksdb.dir/util/cleanable.cc.o -c /Users/jaepil/work/deepsearch/deps/cpp/rocksdb/util/cleanable.cc
/Users/jaepil/work/deepsearch/deps/cpp/rocksdb/util/cleanable.cc:24:65: error: no member named 'move' in namespace 'std'
Cleanable::Cleanable(Cleanable&& other) noexcept { *this = std::move(other); }
~~~~~^
/Users/jaepil/work/deepsearch/deps/cpp/rocksdb/util/cleanable.cc:126:16: error: no member named 'move' in namespace 'std'
*this = std::move(from);
~~~~~^
2 errors generated.
[209/315] Building CXX object CMakeFiles/rocksdb.dir/tools/block_cache_analyzer/block_cache_trace_analyzer.cc.o
ninja: build stopped: subcommand failed.
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10033
Reviewed By: jay-zhuang
Differential Revision: D36580562
Pulled By: ajkr
fbshipit-source-id: 0f6b241d186ed528ad62d259af2857d2c2b4ded1
|
3 years ago |
|
tagliavini
|
6c50082654 |
Remove code that only compiles for Visual Studio versions older than 2015 (#10065)
Summary: There are currently some preprocessor checks that assume support for Visual Studio versions older than 2015 (i.e., 0 < _MSC_VER < 1900), although we don't support them any more. We removed all code that only compiles on those older versions, except third-party/ files. The ROCKSDB_NOEXCEPT symbol is now obsolete, since it now always gets replaced by noexcept. We removed it. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10065 Reviewed By: pdillinger Differential Revision: D36721901 Pulled By: guidotag fbshipit-source-id: a2892d365ef53cce44a0a7d90dd6b72ee9b5e5f2 |
3 years ago |
|
Levi Tamasi
|
af7ae912e2 |
Fix potential ambiguities in/around port/sys_time.h (#10045)
Summary:
There are some time-related POSIX APIs that are not available on Windows
(e.g. `localtime_r`), which we have worked around by providing our own
implementations in `port/sys_time.h`. This workaround actually relies on
some ambiguity: on Windows, a call to `localtime_r` calls
`ROCKSDB_NAMESPACE::port::localtime_r` (which is pulled into
`ROCKSDB_NAMESPACE` by a using-declaration), while on other platforms
it calls the global `localtime_r`. This works fine as long as there is only one
candidate function; however, it breaks down when there is more than one
`localtime_r` visible in a scope.
The patch fixes this by introducing `ROCKSDB_NAMESPACE::port::{TimeVal, GetTimeOfDay, LocalTimeR}`
to eliminate any ambiguity.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10045
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D36639372
Pulled By: ltamasi
fbshipit-source-id: fc13dbfa421b7c8918111a6d9e24ce77e91a7c50
|
3 years ago |
|
Changyu Bi
|
8515bd50c9 |
Support read rate-limiting in SequentialFileReader (#9973)
Summary: Added rate limiter and read rate-limiting support to SequentialFileReader. I've updated call sites to SequentialFileReader::Read with appropriate IO priority (or left a TODO and specified IO_TOTAL for now). The PR is separated into four commits: the first one added the rate-limiting support, but with some fixes in the unit test since the number of request bytes from rate limiter in SequentialFileReader are not accurate (there is overcharge at EOF). The second commit fixed this by allowing SequentialFileReader to check file size and determine how many bytes are left in the file to read. The third commit added benchmark related code. The fourth commit moved the logic of using file size to avoid overcharging the rate limiter into backup engine (the main user of SequentialFileReader). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9973 Test Plan: - `make check`, backup_engine_test covers usage of SequentialFileReader with rate limiter. - Run db_bench to check if rate limiting is throttling as expected: Verified that reads and writes are together throttled at 2MB/s, and at 0.2MB chunks that are 100ms apart. - Set up: `./db_bench --benchmarks=fillrandom -db=/dev/shm/test_rocksdb` - Benchmark: ``` strace -ttfe read,write ./db_bench --benchmarks=backup -db=/dev/shm/test_rocksdb --backup_rate_limit=2097152 --use_existing_db strace -ttfe read,write ./db_bench --benchmarks=restore -db=/dev/shm/test_rocksdb --restore_rate_limit=2097152 --use_existing_db ``` - db bench on backup and restore to ensure no performance regression. - backup (avg over 50 runs): pre-change: 1.90443e+06 micros/op; post-change: 1.8993e+06 micros/op (improve by 0.2%) - restore (avg over 50 runs): pre-change: 1.79105e+06 micros/op; post-change: 1.78192e+06 micros/op (improve by 0.5%) ``` # Set up ./db_bench --benchmarks=fillrandom -db=/tmp/test_rocksdb -num=10000000 # benchmark TEST_TMPDIR=/tmp/test_rocksdb NUM_RUN=50 for ((j=0;j<$NUM_RUN;j++)) do ./db_bench -db=$TEST_TMPDIR -num=10000000 -benchmarks=backup -use_existing_db | egrep 'backup' # Restore #./db_bench -db=$TEST_TMPDIR -num=10000000 -benchmarks=restore -use_existing_db done > rate_limit.txt && awk -v NUM_RUN=$NUM_RUN '{sum+=$3;sum_sqrt+=$3^2}END{print sum/NUM_RUN, sqrt(sum_sqrt/NUM_RUN-(sum/NUM_RUN)^2)}' rate_limit.txt >> rate_limit_2.txt ``` Reviewed By: hx235 Differential Revision: D36327418 Pulled By: cbi42 fbshipit-source-id: e75d4307cff815945482df5ba630c1e88d064691 |
3 years ago |
|
anand76
|
8e9d9156b0 |
Fix fbcode internal build failure (#10041)
Summary: The build failed due to different namespaces for coroutines (std::experimental vs std) based on compiler version. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10041 Reviewed By: ltamasi Differential Revision: D36617212 Pulled By: anand1976 fbshipit-source-id: dfb25320788d32969317d5651173059e2cbd8bd5 |
3 years ago |
|
Changyu Bi
|
cc23b46da1 |
Support using ZDICT_finalizeDictionary to generate zstd dictionary (#9857)
Summary:
An untrained dictionary is currently simply the concatenation of several samples. The ZSTD API, ZDICT_finalizeDictionary(), can improve such a dictionary's effectiveness at low cost. This PR changes how dictionary is created by calling the ZSTD ZDICT_finalizeDictionary() API instead of creating raw content dictionary (when max_dict_buffer_bytes > 0), and pass in all buffered uncompressed data blocks as samples.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9857
Test Plan:
#### db_bench test for cpu/memory of compression+decompression and space saving on synthetic data:
Set up: change the parameter [here](
|
3 years ago |
|
anand76
|
57997ddaaf |
Multi file concurrency in MultiGet using coroutines and async IO (#9968)
Summary: This PR implements a coroutine version of batched MultiGet in order to concurrently read from multiple SST files in a level using async IO, thus reducing the latency of the MultiGet. The API from the user perspective is still synchronous and single threaded, with the RocksDB part of the processing happening in the context of the caller's thread. In Version::MultiGet, the decision is made whether to call synchronous or coroutine code. A good way to review this PR is to review the first 4 commits in order - de773b3, 70c2f70, 10b50e1, and 377a597 - before reviewing the rest. TODO: 1. Figure out how to build it in CircleCI (requires some dependencies to be installed) 2. Do some stress testing with coroutines enabled No regression in synchronous MultiGet between this branch and main - ``` ./db_bench -use_existing_db=true --db=/data/mysql/rocksdb/prefix_scan -benchmarks="readseq,multireadrandom" -key_size=32 -value_size=512 -num=5000000 -batch_size=64 -multiread_batched=true -use_direct_reads=false -duration=60 -ops_between_duration_checks=1 -readonly=true -adaptive_readahead=true -threads=16 -cache_size=10485760000 -async_io=false -multiread_stride=40000 -statistics ``` Branch - ```multireadrandom : 4.025 micros/op 3975111 ops/sec 60.001 seconds 238509056 operations; 2062.3 MB/s (14767808 of 14767808 found)``` Main - ```multireadrandom : 3.987 micros/op 4013216 ops/sec 60.001 seconds 240795392 operations; 2082.1 MB/s (15231040 of 15231040 found)``` More benchmarks in various scenarios are given below. The measurements were taken with ```async_io=false``` (no coroutines) and ```async_io=true``` (use coroutines). For an IO bound workload (with every key requiring an IO), the coroutines version shows a clear benefit, being ~2.6X faster. For CPU bound workloads, the coroutines version has ~6-15% higher CPU utilization, depending on how many keys overlap an SST file. 1. Single thread IO bound workload on remote storage with sparse MultiGet batch keys (~1 key overlap/file) - No coroutines - ```multireadrandom : 831.774 micros/op 1202 ops/sec 60.001 seconds 72136 operations; 0.6 MB/s (72136 of 72136 found)``` Using coroutines - ```multireadrandom : 318.742 micros/op 3137 ops/sec 60.003 seconds 188248 operations; 1.6 MB/s (188248 of 188248 found)``` 2. Single thread CPU bound workload (all data cached) with ~1 key overlap/file - No coroutines - ```multireadrandom : 4.127 micros/op 242322 ops/sec 60.000 seconds 14539384 operations; 125.7 MB/s (14539384 of 14539384 found)``` Using coroutines - ```multireadrandom : 4.741 micros/op 210935 ops/sec 60.000 seconds 12656176 operations; 109.4 MB/s (12656176 of 12656176 found)``` 3. Single thread CPU bound workload with ~2 key overlap/file - No coroutines - ```multireadrandom : 3.717 micros/op 269000 ops/sec 60.000 seconds 16140024 operations; 139.6 MB/s (16140024 of 16140024 found)``` Using coroutines - ```multireadrandom : 4.146 micros/op 241204 ops/sec 60.000 seconds 14472296 operations; 125.1 MB/s (14472296 of 14472296 found)``` 4. CPU bound multi-threaded (16 threads) with ~4 key overlap/file - No coroutines - ```multireadrandom : 4.534 micros/op 3528792 ops/sec 60.000 seconds 211728728 operations; 1830.7 MB/s (12737024 of 12737024 found) ``` Using coroutines - ```multireadrandom : 4.872 micros/op 3283812 ops/sec 60.000 seconds 197030096 operations; 1703.6 MB/s (12548032 of 12548032 found) ``` Pull Request resolved: https://github.com/facebook/rocksdb/pull/9968 Reviewed By: akankshamahajan15 Differential Revision: D36348563 Pulled By: anand1976 fbshipit-source-id: c0ce85a505fd26ebfbb09786cbd7f25202038696 |
3 years ago |
|
Yaroslav Stepanchuk
|
0a43061f8d |
Remove ROCKSDB_SUPPORT_THREAD_LOCAL define because it's a part of C++11 (#10015)
Summary: ROCKSDB_SUPPORT_THREAD_LOCAL definition has been removed. `__thread`(#define) has been replaced with `thread_local`(C++ keyword) across the code base. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10015 Reviewed By: siying Differential Revision: D36485491 Pulled By: pdillinger fbshipit-source-id: 6522d212514ee190b90b4e2750c80c7e34013c78 |
3 years ago |
|
gitbw95
|
05c678e135 |
Set Write rate limiter priority dynamically and pass it to FS (#9988)
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. From the RocksDB perspective, there can be two kinds of rate limiters, the internal (native) one and the external one. - The internal (native) rate limiter is introduced in [the wiki](https://github.com/facebook/rocksdb/wiki/Rate-Limiter). Currently, only IO_LOW and IO_HIGH are used and they are set statically. - For the external rate limiter, in FSWritableFile functions, IOOptions is open for end users to set and get rate_limiter_priority for their own rate limiter. Currently, RocksDB doesn’t pass the rate_limiter_priority through IOOptions to the file system. ### Solution During the User Read, Flush write, Compaction read/write, the WriteController is used to determine whether DB writes are stalled or slowed down. The rate limiter priority (Env::IOPriority) can be determined accordingly. We decided to always pass the priority in IOOptions. What the file system does with it should be a contract between the user and the file system. We would like to set the rate limiter priority at file level, since the Flush/Compaction job level may be too coarse with multiple files and block IO level is too granular. **This PR is for the Write path.** The **Write:** dynamic priority for different state are listed as follows: | State | Normal | Delayed | Stalled | | ----- | ------ | ------- | ------- | | Flush | IO_HIGH | IO_USER | IO_USER | | Compaction | IO_LOW | IO_USER | IO_USER | Flush and Compaction writes share the same call path through BlockBaseTableWriter, WritableFileWriter, and FSWritableFile. When a new FSWritableFile object is created, its io_priority_ can be set dynamically based on the state of the WriteController. In WritableFileWriter, before the call sites of FSWritableFile functions, WritableFileWriter::DecideRateLimiterPriority() determines the rate_limiter_priority. The options (IOOptions) argument of FSWritableFile functions will be updated with the rate_limiter_priority. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9988 Test Plan: Add unit tests. Reviewed By: anand1976 Differential Revision: D36395159 Pulled By: gitbw95 fbshipit-source-id: a7c82fc29759139a1a07ec46c37dbf7e753474cf |
3 years ago |
|
Hui Xiao
|
3573558ec5 |
Rewrite memory-charging feature's option API (#9926)
Summary: **Context:** Previous PR https://github.com/facebook/rocksdb/pull/9748, https://github.com/facebook/rocksdb/pull/9073, https://github.com/facebook/rocksdb/pull/8428 added separate flag for each charged memory area. Such API design is not scalable as we charge more and more memory areas. Also, we foresee an opportunity to consolidate this feature with other cache usage related features such as `cache_index_and_filter_blocks` using `CacheEntryRole`. Therefore we decided to consolidate all these flags with `CacheUsageOptions cache_usage_options` and this PR serves as the first step by consolidating memory-charging related flags. **Summary:** - Replaced old API reference with new ones, including making `kCompressionDictionaryBuildingBuffer` opt-out and added a unit test for that - Added missing db bench/stress test for some memory charging features - Renamed related test suite to indicate they are under the same theme of memory charging - Refactored a commonly used mocked cache component in memory charging related tests to reduce code duplication - Replaced the phrases "memory tracking" / "cache reservation" (other than CacheReservationManager-related ones) with "memory charging" for standard description of this feature. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9926 Test Plan: - New unit test for opt-out `kCompressionDictionaryBuildingBuffer` `TEST_F(ChargeCompressionDictionaryBuildingBufferTest, Basic)` - New unit test for option validation/sanitization `TEST_F(CacheUsageOptionsOverridesTest, SanitizeAndValidateOptions)` - CI - db bench (in case querying new options introduces regression) **+0.5% micros/op**: `TEST_TMPDIR=/dev/shm/testdb ./db_bench -benchmarks=fillseq -db=$TEST_TMPDIR -charge_compression_dictionary_building_buffer=1(remove this for comparison) -compression_max_dict_bytes=10000 -disable_auto_compactions=1 -write_buffer_size=100000 -num=4000000 | egrep 'fillseq'` #-run | (pre-PR) avg micros/op | std micros/op | (post-PR) micros/op | std micros/op | change (%) -- | -- | -- | -- | -- | -- 10 | 3.9711 | 0.264408 | 3.9914 | 0.254563 | 0.5111933721 20 | 3.83905 | 0.0664488 | 3.8251 | 0.0695456 | **-0.3633711465** 40 | 3.86625 | 0.136669 | 3.8867 | 0.143765 | **0.5289363078** - db_stress: `python3 tools/db_crashtest.py blackbox -charge_compression_dictionary_building_buffer=1 -charge_filter_construction=1 -charge_table_reader=1 -cache_size=1` killed as normal Reviewed By: ajkr Differential Revision: D36054712 Pulled By: hx235 fbshipit-source-id: d406e90f5e0c5ea4dbcb585a484ad9302d4302af |
3 years ago |
|
mrambacher
|
b11ff347b4 |
Use STATIC_AVOID_DESTRUCTION for static objects with non-trivial destructors (#9958)
Summary: Changed the static objects that had non-trivial destructors to use the STATIC_AVOID_DESTRUCTION construct. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9958 Reviewed By: pdillinger Differential Revision: D36442982 Pulled By: mrambacher fbshipit-source-id: 029d47b1374d30d198bfede369a4c0ae7a4eb519 |
3 years ago |
|
Qingyou Meng
|
7b55b50839 |
util/ribbon_alg.h: removed duplicate word "vector" (#9216)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/9216 Reviewed By: riversand963 Differential Revision: D36219934 fbshipit-source-id: 8253b4e3eacceb8b040eeaa45cd5a50570a4eba6 |
3 years ago |
|
sdong
|
736a7b5433 |
Remove own ToString() (#9955)
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 |
3 years ago |
|
sdong
|
49628c9a83 |
Use std::numeric_limits<> (#9954)
Summary: Right now we still don't fully use std::numeric_limits but use a macro, mainly for supporting VS 2013. Right now we only support VS 2017 and up so it is not a problem. The code comment claims that MinGW still needs it. We don't have a CI running MinGW so it's hard to validate. since we now require C++17, it's hard to imagine MinGW would still build RocksDB but doesn't support std::numeric_limits<>. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9954 Test Plan: See CI Runs. Reviewed By: riversand963 Differential Revision: D36173954 fbshipit-source-id: a35a73af17cdcae20e258cdef57fcf29a50b49e0 |
3 years ago |
|
Hui Xiao
|
de537dcaf1 |
Fix a comment in RateLimiter::RequestToken (#9933)
Summary: **Context/Summary:** - As titled Pull Request resolved: https://github.com/facebook/rocksdb/pull/9933 Test Plan: - No code change Reviewed By: ajkr Differential Revision: D36086544 Pulled By: hx235 fbshipit-source-id: 2bdd19f67e45df1e3af4121b0c1a5e866a57826d |
3 years ago |
|
Peter Dillinger
|
9d0cae7104 |
Eliminate unnecessary (slow) block cache Ref()ing in MultiGet (#9899)
Summary: When MultiGet() determines that multiple query keys can be served by examining the same data block in block cache (one Lookup()), each PinnableSlice referring to data in that data block needs to hold on to the block in cache so that they can be released at arbitrary times by the API user. Historically this is accomplished with extra calls to Ref() on the Handle from Lookup(), with each PinnableSlice cleanup calling Release() on the Handle, but this creates extra contention on the block cache for the extra Ref()s and Release()es, especially because they hit the same cache shard repeatedly. In the case of merge operands (possibly more cases?), the problem was compounded by doing an extra Ref()+eventual Release() for each merge operand for a key reusing a block (which could be the same key!), rather than one Ref() per key. (Note: the non-shared case with `biter` was already one per key.) This change optimizes MultiGet not to rely on these extra, contentious Ref()+Release() calls by instead, in the shared block case, wrapping the cache Release() cleanup in a refcounted object referenced by the PinnableSlices, such that after the last wrapped reference is released, the cache entry is Release()ed. Relaxed atomic refcounts should be much faster than mutex-guarded Ref() and Release(), and much less prone to a performance cliff when MultiGet() does a lot of block sharing. Note that I did not use std::shared_ptr, because that would require an extra indirection object (shared_ptr itself new/delete) in order to associate a ref increment/decrement with a Cleanable cleanup entry. (If I assumed it was the size of two pointers, I could do some hackery to make it work without the extra indirection, but that's too fragile.) Some details: * Fixed (removed) extra block cache tracing entries in cases of cache entry reuse in MultiGet, but it's likely that in some other cases traces are missing (XXX comment inserted) * Moved existing implementations for cleanable.h from iterator.cc to new cleanable.cc * Improved API comments on Cleanable * Added a public SharedCleanablePtr class to cleanable.h in case others could benefit from the same pattern (potentially many Cleanables and/or smart pointers referencing a shared Cleanable) * Add a typedef for MultiGetContext::Mask * Some variable renaming for clarity Pull Request resolved: https://github.com/facebook/rocksdb/pull/9899 Test Plan: Added unit tests for SharedCleanablePtr. Greatly enhanced ability of existing tests to detect cache use-after-free. * Release PinnableSlices from MultiGet as they are read rather than in bulk (in db_test_util wrapper). * In ASAN build, default to using a trivially small LRUCache for block_cache so that entries are immediately erased when unreferenced. (Updated two tests that depend on caching.) New ASAN testsuite running time seems OK to me. If I introduce a bug into my implementation where we skip the shared cleanups on block reuse, ASAN detects the bug in `db_basic_test *MultiGet*`. If I remove either of the above testing enhancements, the bug is not detected. Consider for follow-up work: manipulate or randomize ordering of PinnableSlice use and release from MultiGet db_test_util wrapper. But in typical cases, natural ordering gives pretty good functional coverage. Performance test: In the extreme (but possible) case of MultiGetting the same or adjacent keys in a batch, throughput can improve by an order of magnitude. `./db_bench -benchmarks=multireadrandom -db=/dev/shm/testdb -readonly -num=5 -duration=10 -threads=20 -multiread_batched -batch_size=200` Before ops/sec, num=5: 1,384,394 Before ops/sec, num=500: 6,423,720 After ops/sec, num=500: 10,658,794 After ops/sec, num=5: 16,027,257 Also note that previously, with high parallelism, having query keys concentrated in a single block was worse than spreading them out a bit. Now concentrated in a single block is faster than spread out, which is hopefully consistent with natural expectation. Random query performance: with num=1000000, over 999 x 10s runs running before & after simultaneously (each -threads=12): Before: multireadrandom [AVG 999 runs] : 1088699 (± 7344) ops/sec; 120.4 (± 0.8 ) MB/sec After: multireadrandom [AVG 999 runs] : 1090402 (± 7230) ops/sec; 120.6 (± 0.8 ) MB/sec Possibly better, possibly in the noise. Reviewed By: anand1976 Differential Revision: D35907003 Pulled By: pdillinger fbshipit-source-id: bbd244d703649a8ca12d476f2d03853ed9d1a17e |
3 years ago |
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Jonathan Albrecht
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844a35108b |
Fix minimum libzstd version that supports ZSTD_STREAMING (#9841)
Summary: The minimum libzstd version that has `ZSTD_compressStream2` is 1.4.0 so only define ZSTD_STREAMING in that case. Fixes building on Ubuntu 18.04 which has libzstd 1.3.3 as its repository version. Fixes https://github.com/facebook/rocksdb/issues/9795 Pull Request resolved: https://github.com/facebook/rocksdb/pull/9841 Test Plan: Build and test on Ubuntu 18.04 with: apt-get install libsnappy-dev zlib1g-dev libbz2-dev liblz4-dev \ libzstd-dev libgflags-dev g++ make curl Reviewed By: ajkr Differential Revision: D35648738 Pulled By: jay-zhuang fbshipit-source-id: 2a9e969bcc17a7dc10172f3817283409de885811 |
3 years ago |
|
Peter Dillinger
|
efd035164b |
Meta-internal folly integration with F14FastMap (#9546)
Summary: Especially after updating to C++17, I don't see a compelling case for *requiring* any folly components in RocksDB. I was able to purge the existing hard dependencies, and it can be quite difficult to strip out non-trivial components from folly for use in RocksDB. (The prospect of doing that on F14 has changed my mind on the best approach here.) But this change creates an optional integration where we can plug in components from folly at compile time, starting here with F14FastMap to replace std::unordered_map when possible (probably no public APIs for example). I have replaced the biggest CPU users of std::unordered_map with compile-time pluggable UnorderedMap which will use F14FastMap when USE_FOLLY is set. USE_FOLLY is always set in the Meta-internal buck build, and a simulation of that is in the Makefile for public CI testing. A full folly build is not needed, but checking out the full folly repo is much simpler for getting the dependency, and anything else we might want to optionally integrate in the future. Some picky details: * I don't think the distributed mutex stuff is actually used, so it was easy to remove. * I implemented an alternative to `folly::constexpr_log2` (which is much easier in C++17 than C++11) so that I could pull out the hard dependencies on `ConstexprMath.h` * I had to add noexcept move constructors/operators to some types to make F14's complainUnlessNothrowMoveAndDestroy check happy, and I added a macro to make that easier in some common cases. * Updated Meta-internal buck build to use folly F14Map (always) No updates to HISTORY.md nor INSTALL.md as this is not (yet?) considered a production integration for open source users. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9546 Test Plan: CircleCI tests updated so that a couple of them use folly. Most internal unit & stress/crash tests updated to use Meta-internal latest folly. (Note: they should probably use buck but they currently use Makefile.) Example performance improvement: when filter partitions are pinned in cache, they are tracked by PartitionedFilterBlockReader::filter_map_ and we can build a test that exercises that heavily. Build DB with ``` TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks=fillrandom -num=10000000 -disable_wal=1 -write_buffer_size=30000000 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -partition_index_and_filters ``` and test with (simultaneous runs with & without folly, ~20 times each to see convergence) ``` TEST_TMPDIR=/dev/shm/rocksdb ./db_bench_folly -readonly -use_existing_db -benchmarks=readrandom -num=10000000 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -partition_index_and_filters -duration=40 -pin_l0_filter_and_index_blocks_in_cache ``` Average ops/s no folly: 26229.2 Average ops/s with folly: 26853.3 (+2.4%) Reviewed By: ajkr Differential Revision: D34181736 Pulled By: pdillinger fbshipit-source-id: ffa6ad5104c2880321d8a1aa7187e00ab0d02e94 |
3 years ago |
|
mrambacher
|
b7db7eae26 |
Plugin Registry (#7949)
Summary: Added a Plugin class to the ObjectRegistry. Enabled compile-time and program-time addition of plugins to the Registry. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7949 Reviewed By: mrambacher Differential Revision: D33517674 Pulled By: pdillinger fbshipit-source-id: c3e3270aab76a489bfa9e85d78cdfca951912557 |
3 years ago |
|
Hui Xiao
|
49623f9c8e |
Account memory of big memory users in BlockBasedTable in global memory limit (#9748)
Summary: **Context:** Through heap profiling, we discovered that `BlockBasedTableReader` objects can accumulate and lead to high memory usage (e.g, `max_open_file = -1`). These memories are currently not saved, not tracked, not constrained and not cache evict-able. As a first step to improve this, similar to https://github.com/facebook/rocksdb/pull/8428, this PR is to track an estimate of `BlockBasedTableReader` object's memory in block cache and fail future creation if the memory usage exceeds the available space of cache at the time of creation. **Summary:** - Approximate big memory users (`BlockBasedTable::Rep` and `TableProperties` )' memory usage in addition to the existing estimated ones (filter block/index block/un-compression dictionary) - Charge all of these memory usages to block cache on `BlockBasedTable::Open()` and release them on `~BlockBasedTable()` as there is no memory usage fluctuation of concern in between - Refactor on CacheReservationManager (and its call-sites) to add concurrent support for BlockBasedTable used in this PR. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9748 Test Plan: - New unit tests - db bench: `OpenDb` : **-0.52% in ms** - Setup `./db_bench -benchmarks=fillseq -db=/dev/shm/testdb -disable_auto_compactions=1 -write_buffer_size=1048576` - Repeated run with pre-change w/o feature and post-change with feature, benchmark `OpenDb`: `./db_bench -benchmarks=readrandom -use_existing_db=1 -db=/dev/shm/testdb -reserve_table_reader_memory=true (remove this when running w/o feature) -file_opening_threads=3 -open_files=-1 -report_open_timing=true| egrep 'OpenDb:'` #-run | (feature-off) avg milliseconds | std milliseconds | (feature-on) avg milliseconds | std milliseconds | change (%) -- | -- | -- | -- | -- | -- 10 | 11.4018 | 5.95173 | 9.47788 | 1.57538 | -16.87382694 20 | 9.23746 | 0.841053 | 9.32377 | 1.14074 | 0.9343477536 40 | 9.0876 | 0.671129 | 9.35053 | 1.11713 | 2.893283155 80 | 9.72514 | 2.28459 | 9.52013 | 1.0894 | -2.108041632 160 | 9.74677 | 0.991234 | 9.84743 | 1.73396 | 1.032752389 320 | 10.7297 | 5.11555 | 10.547 | 1.97692 | **-1.70275031** 640 | 11.7092 | 2.36565 | 11.7869 | 2.69377 | **0.6635807741** - db bench on write with cost to cache in WriteBufferManager (just in case this PR's CRM refactoring accidentally slows down anything in WBM) : `fillseq` : **+0.54% in micros/op** `./db_bench -benchmarks=fillseq -db=/dev/shm/testdb -disable_auto_compactions=1 -cost_write_buffer_to_cache=true -write_buffer_size=10000000000 | egrep 'fillseq'` #-run | (pre-PR) avg micros/op | std micros/op | (post-PR) avg micros/op | std micros/op | change (%) -- | -- | -- | -- | -- | -- 10 | 6.15 | 0.260187 | 6.289 | 0.371192 | 2.260162602 20 | 7.28025 | 0.465402 | 7.37255 | 0.451256 | 1.267813605 40 | 7.06312 | 0.490654 | 7.13803 | 0.478676 | **1.060579461** 80 | 7.14035 | 0.972831 | 7.14196 | 0.92971 | **0.02254791432** - filter bench: `bloom filter`: **-0.78% in ms/key** - ` ./filter_bench -impl=2 -quick -reserve_table_builder_memory=true | grep 'Build avg'` #-run | (pre-PR) avg ns/key | std ns/key | (post-PR) ns/key | std ns/key | change (%) -- | -- | -- | -- | -- | -- 10 | 26.4369 | 0.442182 | 26.3273 | 0.422919 | **-0.4145720565** 20 | 26.4451 | 0.592787 | 26.1419 | 0.62451 | **-1.1465262** - Crash test `python3 tools/db_crashtest.py blackbox --reserve_table_reader_memory=1 --cache_size=1` killed as normal Reviewed By: ajkr Differential Revision: D35136549 Pulled By: hx235 fbshipit-source-id: 146978858d0f900f43f4eb09bfd3e83195e3be28 |
3 years ago |
|
Peter Dillinger
|
a8a422e962 |
Add manifest fix-up utility for file temperatures (#9683)
Summary: The goal of this change is to allow changes to the "current" (in FileSystem) file temperatures to feed back into DB metadata, so that they can inform decisions and stats reporting. In part because of modular code factoring, it doesn't seem easy to do this automagically, where opening an SST file and observing current Temperature different from expected would trigger a change in metadata and DB manifest write (essentially giving the deep read path access to the write path). It is also difficult to do this while the DB is open because of the limitations of LogAndApply. This change allows updating file temperature metadata on a closed DB using an experimental utility function UpdateManifestForFilesState() or `ldb update_manifest --update_temperatures`. This should suffice for "migration" scenarios where outside tooling has placed or re-arranged DB files into a (different) tiered configuration without going through RocksDB itself (currently, only compaction can change temperature metadata). Some details: * Refactored and added unit test for `ldb unsafe_remove_sst_file` because of shared functionality * Pulled in autovector.h changes from https://github.com/facebook/rocksdb/issues/9546 to fix SuperVersionContext move constructor (related to an older draft of this change) Possible follow-up work: * Support updating manifest with file checksums, such as when a new checksum function is used and want existing DB metadata updated for it. * It's possible that for some repair scenarios, lighter weight than full repair, we might want to support UpdateManifestForFilesState() to modify critical file details like size or checksum using same algorithm. But let's make sure these are differentiated from modifying file details in ways that don't suspect corruption (or require extreme trust). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9683 Test Plan: unit tests added Reviewed By: jay-zhuang Differential Revision: D34798828 Pulled By: pdillinger fbshipit-source-id: cfd83e8fb10761d8c9e7f9c020d68c9106a95554 |
3 years ago |
|
Jay Zhuang
|
2586585b0c |
Minor fix for Windows build with zlib (#9699)
Summary: ``` conversion from 'size_t' to 'uLong', possible loss of data ``` Fix https://github.com/facebook/rocksdb/issues/9688 Pull Request resolved: https://github.com/facebook/rocksdb/pull/9699 Reviewed By: riversand963 Differential Revision: D34901116 Pulled By: jay-zhuang fbshipit-source-id: 969148a7a8c023449bd85055a1f0eec71d0a9b3f |
3 years ago |
|
Jay Zhuang
|
09b0e8f2c7 |
Fix a timer crash caused by invalid memory management (#9656)
Summary: Timer crash when multiple DB instances doing heavy DB open and close operations concurrently. Which is caused by adding a timer task with smaller timestamp than the current running task. Fix it by moving the getting new task timestamp part within timer mutex protection. And other fixes: - Disallow adding duplicated function name to timer - Fix a minor memory leak in timer when a running task is cancelled Pull Request resolved: https://github.com/facebook/rocksdb/pull/9656 Reviewed By: ajkr Differential Revision: D34626296 Pulled By: jay-zhuang fbshipit-source-id: 6b6d96a5149746bf503546244912a9e41a0c5f6b |
3 years ago |
|
Andrew Kryczka
|
062396af15 |
Avoid popcnt on Windows when unavailable and in portable builds (#9680)
Summary: Fixes https://github.com/facebook/rocksdb/issues/9560. Only use popcnt intrinsic when HAVE_SSE42 is set. Also avoid setting it based on compiler test in portable builds because such test will pass on MSVC even without proper arch flags (ref: https://devblogs.microsoft.com/oldnewthing/20201026-00/?p=104397). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9680 Test Plan: verified the combinations of -DPORTABLE and -DFORCE_SSE42 produce expected compiler flags on Linux. Verified MSVC build using PORTABLE=1 (in CircleCI) does not set HAVE_SSE42. Reviewed By: pdillinger Differential Revision: D34739033 Pulled By: ajkr fbshipit-source-id: d10456f3392945fc3e59430a1777840f7b60b276 |
3 years ago |
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Siddhartha Roychowdhury
|
fec4403ff1 |
Integrate WAL compression into log reader/writer. (#9642)
Summary: Integrate the streaming compress/uncompress API into WAL compression. The streaming compression object is stored in the log_writer along with a reusable output buffer to store the compressed buffer(s). The streaming uncompress object is stored in the log_reader along with a reusable output buffer to store the uncompressed buffer(s). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9642 Test Plan: Added unit tests to verify different scenarios - large buffers, split compressed buffers, etc. Future optimizations: The overhead for small records is quite high, so it makes sense to compress only buffers above a certain threshold and use a separate record type to indicate that those records are compressed. Reviewed By: anand1976 Differential Revision: D34709167 Pulled By: sidroyc fbshipit-source-id: a37a3cd1301adff6152fb3fcd23726106af07dd4 |
3 years ago |
|
jingkai.yuan
|
926ee13811 |
Fix corruption error when compressing blob data with zlib. (#9572)
Summary: The plain data length may not be big enough if the compression actually expands data. So use deflateBound() to get the upper limit on the compressed output before deflate(). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9572 Reviewed By: riversand963 Differential Revision: D34326475 Pulled By: ajkr fbshipit-source-id: 4b679cb7a83a62782a127785b4d5eb9aa4646449 |
3 years ago |
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Siddhartha Roychowdhury
|
21345d2823 |
Streaming Compression API for WAL compression. (#9619)
Summary: Implement a streaming compression API (compress/uncompress) to use for WAL compression. The log_writer would use the compress class/API to compress a record before writing it out in chunks. The log_reader would use the uncompress class/API to uncompress the chunks and combine into a single record. Added unit test to verify the API for different sizes/compression types. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9619 Test Plan: make -j24 check Reviewed By: anand1976 Differential Revision: D34437346 Pulled By: sidroyc fbshipit-source-id: b180569ad2ddcf3106380f8758b556cc0ad18382 |
3 years ago |
|
anand76
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d795a730be |
Combine data members of IOStatus with Status (#9549)
Summary: Combine the data members retryable_, data_loss_ and scope_ of IOStatus with Status, as protected members. IOStatus is now defined as a derived class of Status with no new data, but additional methods. This will allow us to eventually track the result of FileSystem calls in RocksDB with one variable instead of two. Benchmark commands and results are below. The performance after changes seems slightly better. ```./db_bench -db=/data/mysql/rocksdb/prefix_scan -benchmarks="fillseq" -key_size=32 -value_size=512 -num=5000000 -use_direct_io_for_flush_and_compaction=true -target_file_size_base=16777216``` ```./db_bench -use_existing_db=true --db=/data/mysql/rocksdb/prefix_scan -benchmarks="readseq,seekrandom,readseq" -key_size=32 -value_size=512 -num=5000000 -seek_nexts=10000 -use_direct_reads=true -duration=60 -ops_between_duration_checks=1 -readonly=true -adaptive_readahead=false -threads=1 -cache_size=10485760000``` Before - seekrandom : 3715.432 micros/op 269 ops/sec; 1394.9 MB/s (16149 of 16149 found) seekrandom : 3687.177 micros/op 271 ops/sec; 1405.6 MB/s (16273 of 16273 found) seekrandom : 3709.646 micros/op 269 ops/sec; 1397.1 MB/s (16175 of 16175 found) readseq : 0.369 micros/op 2711321 ops/sec; 1406.6 MB/s readseq : 0.363 micros/op 2754092 ops/sec; 1428.8 MB/s readseq : 0.372 micros/op 2688046 ops/sec; 1394.6 MB/s After - seekrandom : 3606.830 micros/op 277 ops/sec; 1436.9 MB/s (16636 of 16636 found) seekrandom : 3594.467 micros/op 278 ops/sec; 1441.9 MB/s (16693 of 16693 found) seekrandom : 3597.919 micros/op 277 ops/sec; 1440.5 MB/s (16677 of 16677 found) readseq : 0.354 micros/op 2822809 ops/sec; 1464.5 MB/s readseq : 0.358 micros/op 2795080 ops/sec; 1450.1 MB/s readseq : 0.354 micros/op 2822889 ops/sec; 1464.5 MB/s Pull Request resolved: https://github.com/facebook/rocksdb/pull/9549 Reviewed By: pdillinger Differential Revision: D34310362 Pulled By: anand1976 fbshipit-source-id: 54b27756edf9c9ecfe730a2dce542a7a46743096 |
3 years ago |
|
mrambacher
|
30b08878d8 |
Make FilterPolicy Customizable (#9590)
Summary: Make FilterPolicy into a Customizable class. Allow new FilterPolicy to be discovered through the ObjectRegistry Pull Request resolved: https://github.com/facebook/rocksdb/pull/9590 Reviewed By: pdillinger Differential Revision: D34327367 Pulled By: mrambacher fbshipit-source-id: 37e7edac90ec9457422b72f359ab8ef48829c190 |
3 years ago |
|
Siddhartha Roychowdhury
|
39b0d92153 |
Add record to set WAL compression type if enabled (#9556)
Summary: When WAL compression is enabled, add a record (new record type) to store the compression type to indicate that all subsequent records are compressed. The log reader will store the compression type when this record is encountered and use the type to uncompress the subsequent records. Compress and uncompress to be implemented in subsequent diffs. Enabled WAL compression in some WAL tests to check for regressions. Some tests that rely on offsets have been disabled. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9556 Reviewed By: anand1976 Differential Revision: D34308216 Pulled By: sidroyc fbshipit-source-id: 7f10595e46f3277f1ea2d309fbf95e2e935a8705 |
3 years ago |
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Peter Dillinger
|
8c681087c7 |
Refactor FilterPolicies toward Customizable (#9567)
Summary: Some changes to make it easier to make FilterPolicy customizable. Especially, create distinct classes for the different testing-only and user-facing built-in FilterPolicy modes. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9567 Test Plan: tests updated, with no intended difference in functionality tested. No difference in test performance seen as a result of moving to string-based filter type configuration. Reviewed By: mrambacher Differential Revision: D34234694 Pulled By: pdillinger fbshipit-source-id: 8a94931a9e04c3bcca863a4f524cfd064aaf0122 |
3 years ago |
|
mrambacher
|
fe9d495112 |
Return different Status based on ObjectRegistry::NewObject calls (#9333)
Summary: This fix addresses https://github.com/facebook/rocksdb/issues/9299. If attempting to create a new object via the ObjectRegistry and a factory is not found, the ObjectRegistry will return a "NotSupported" status. This is the same behavior as previously. If the factory is found but could not successfully create the object, an "InvalidArgument" status is returned. If the factory returned a reason why (in the errmsg), this message will be in the returned status. In practice, there are two options in the ConfigOptions that control how these errors are propagated: - If "ignore_unknown_options=true", then both InvalidArgument and NotSupported status codes will be swallowed internally. Both cases will return success - If "ignore_unsupported_options=true", then having no factory will return success but a failing factory will return an error - If both options are false, both cases (no and failing factory) will return errors. In practice this likely only changes Customizable that may be partially available. For example, the JEMallocMemoryAllocator is a built-in allocator that is registered with the system but may not be compiled in. In this case, the status code for this allocator changed from NotSupported("JEMalloc not available") to InvalidArgumen("JEMalloc not available"). Other Customizable builtins/plugins would have the same semantics. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9333 Reviewed By: pdillinger Differential Revision: D33517681 Pulled By: mrambacher fbshipit-source-id: 8033052d4a4a7b88c2d9f90147b1b4467e51f6fd |
3 years ago |
|
Peter Dillinger
|
68a9c186d0 |
FilterPolicy API changes for 7.0 (#9501)
Summary: * Inefficient block-based filter is no longer customizable in the public API, though (for now) can still be enabled. * Removed deprecated FilterPolicy::CreateFilter() and FilterPolicy::KeyMayMatch() * Removed `rocksdb_filterpolicy_create()` from C API * Change meaning of nullptr return from GetBuilderWithContext() from "use block-based filter" to "generate no filter in this case." This is a cleaner solution to the proposal in https://github.com/facebook/rocksdb/issues/8250. * Also, when user specifies bits_per_key < 0.5, we now round this down to "no filter" because we expect a filter with >= 80% FP rate is unlikely to be worth the CPU cost of accessing it (esp with cache_index_and_filter_blocks=1 or partition_filters=1). * bits_per_key >= 0.5 and < 1.0 is still rounded up to 1.0 (for 62% FP rate) * This also gives us some support for configuring filters from OPTIONS file as currently saved: `filter_policy=rocksdb.BuiltinBloomFilter`. Opening from such an options file will enable reading filters (an improvement) but not writing new ones. (See Customizable follow-up below.) * Also removed deprecated functions * FilterBitsBuilder::CalculateNumEntry() * FilterPolicy::GetFilterBitsBuilder() * NewExperimentalRibbonFilterPolicy() * Remove default implementations of * FilterBitsBuilder::EstimateEntriesAdded() * FilterBitsBuilder::ApproximateNumEntries() * FilterPolicy::GetBuilderWithContext() * Remove support for "filter_policy=experimental_ribbon" configuration string. * Allow "filter_policy=bloomfilter:n" without bool to discourage use of block-based filter. Some pieces for https://github.com/facebook/rocksdb/issues/9389 Likely follow-up (later PRs): * Refactoring toward FilterPolicy Customizable, so that we can generate filters with same configuration as before when configuring from options file. * Remove support for user enabling block-based filter (ignore `bool use_block_based_builder`) * Some months after this change, we could even remove read support for block-based filter, because it is not critical to DB data preservation. * Make FilterBitsBuilder::FinishV2 to avoid `using FilterBitsBuilder::Finish` mess and add support for specifying a MemoryAllocator (for cache warming) Pull Request resolved: https://github.com/facebook/rocksdb/pull/9501 Test Plan: A number of obsolete tests deleted and new tests or test cases added or updated. Reviewed By: hx235 Differential Revision: D34008011 Pulled By: pdillinger fbshipit-source-id: a39a720457c354e00d5b59166b686f7f59e392aa |
3 years ago |
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satyajanga
|
036bbab6f7 |
Use the comparator from the sst file table properties in sst_dump_tool (#9491)
Summary: We introduced a new Comparator for timestamp in user keys. In the sst_dump_tool by default we use BytewiseComparator to read sst files. This change allows us to read comparator_name from table properties in meta data block and use it to read. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9491 Test Plan: added unittests for new functionality. make check   Reviewed By: riversand963 Differential Revision: D33993614 Pulled By: satyajanga fbshipit-source-id: 4b5cf938e6d2cb3931d763bef5baccc900b8c536 |
3 years ago |
|
Peter Dillinger
|
5cb137a860 |
Work around some new clang-analyze failures (#9515)
Summary: ... seen only in internal clang-analyze runs after https://github.com/facebook/rocksdb/issues/9481 * Mostly, this works around falsely reported leaks by using std::unique_ptr in some places where clang-analyze was getting confused. (I didn't see any changes in C++17 that could make our Status implementation leak memory.) * Also fixed SetBGError returning address of a stack variable. * Also fixed another false null deref report by adding an assert. Also, use SKIP_LINK=1 to speed up `make analyze` Pull Request resolved: https://github.com/facebook/rocksdb/pull/9515 Test Plan: Was able to reproduce the reported errors locally and verify they're fixed (except SetBGError). Otherwise, existing tests Reviewed By: hx235 Differential Revision: D34054630 Pulled By: pdillinger fbshipit-source-id: 38600ef3da75ddca307dff96b7a1a523c2885c2e |
3 years ago |
|
Peter Dillinger
|
fd3e0f43b3 |
Require C++17 (#9481)
Summary: Drop support for some old compilers by requiring C++17 standard (or higher). See https://github.com/facebook/rocksdb/issues/9388 First modification based on this is to remove some conditional compilation in slice.h (also better for ODR) Also in this PR: * Fix some Makefile formatting that seems to affect ASSERT_STATUS_CHECKED config in some cases * Add c_test to NON_PARALLEL_TEST in Makefile * Fix a clang-analyze reported "potential leak" in lru_cache_test * Better "compatibility" definition of DEFINE_uint32 for old versions of gflags * Fix a linking problem with shared libraries in Makefile (`./random_test: error while loading shared libraries: librocksdb.so.6.29: cannot open shared object file: No such file or directory`) * Always set ROCKSDB_SUPPORT_THREAD_LOCAL and use thread_local (from C++11) * TODO in later PR: clean up that obsolete flag * Fix a cosmetic typo in c.h (https://github.com/facebook/rocksdb/issues/9488) Pull Request resolved: https://github.com/facebook/rocksdb/pull/9481 Test Plan: CircleCI config substantially updated. * Upgrade to latest Ubuntu images for each release * Generally prefer Ubuntu 20, but keep a couple Ubuntu 16 builds with oldest supported compilers, to ensure compatibility * Remove .circleci/cat_ignore_eagain except for Ubuntu 16 builds, because this is to work around a kernel bug that should not affect anything but Ubuntu 16. * Remove designated gcc-9 build, because the default linux build now uses GCC 9 from Ubuntu 20. * Add some `apt-key add` to fix some apt "couldn't be verified" errors * Generally drop SKIP_LINK=1; work-around no longer needed * Generally `add-apt-repository` before `apt-get update` as manual testing indicated the reverse might not work. Travis: * Use gcc-7 by default (remove specific gcc-7 and gcc-4.8 builds) * TODO in later PR: fix s390x "Assembler messages: Error: invalid switch -march=z14" failure AppVeyor: * Completely dropped because we are dropping VS2015 support and CircleCI covers VS >= 2017 Also local testing with old gflags (out of necessity when using ROCKSDB_NO_FBCODE=1). Reviewed By: mrambacher Differential Revision: D33946377 Pulled By: pdillinger fbshipit-source-id: ae077c823905b45370a26c0103ada119459da6c1 |
3 years ago |
|
Hui Xiao
|
920386f2b7 |
Detect (new) Bloom/Ribbon Filter construction corruption (#9342)
Summary: Note: rebase on and merge after https://github.com/facebook/rocksdb/pull/9349, https://github.com/facebook/rocksdb/pull/9345, (optional) https://github.com/facebook/rocksdb/pull/9393 **Context:** (Quoted from pdillinger) Layers of information during new Bloom/Ribbon Filter construction in building block-based tables includes the following: a) set of keys to add to filter b) set of hashes to add to filter (64-bit hash applied to each key) c) set of Bloom indices to set in filter, with duplicates d) set of Bloom indices to set in filter, deduplicated e) final filter and its checksum This PR aims to detect corruption (e.g, unexpected hardware/software corruption on data structures residing in the memory for a long time) from b) to e) and leave a) as future works for application level. - b)'s corruption is detected by verifying the xor checksum of the hash entries calculated as the entries accumulate before being added to the filter. (i.e, `XXPH3FilterBitsBuilder::MaybeVerifyHashEntriesChecksum()`) - c) - e)'s corruption is detected by verifying the hash entries indeed exists in the constructed filter by re-querying these hash entries in the filter (i.e, `FilterBitsBuilder::MaybePostVerify()`) after computing the block checksum (except for PartitionFilter, which is done right after each `FilterBitsBuilder::Finish` for impl simplicity - see code comment for more). For this stage of detection, we assume hash entries are not corrupted after checking on b) since the time interval from b) to c) is relatively short IMO. Option to enable this feature of detection is `BlockBasedTableOptions::detect_filter_construct_corruption` which is false by default. **Summary:** - Implemented new functions `XXPH3FilterBitsBuilder::MaybeVerifyHashEntriesChecksum()` and `FilterBitsBuilder::MaybePostVerify()` - Ensured hash entries, final filter and banding and their [cache reservation ](https://github.com/facebook/rocksdb/issues/9073) are released properly despite corruption - See [Filter.construction.artifacts.release.point.pdf ](https://github.com/facebook/rocksdb/files/7923487/Design.Filter.construction.artifacts.release.point.pdf) for high-level design - Bundled and refactored hash entries's related artifact in XXPH3FilterBitsBuilder into `HashEntriesInfo` for better control on lifetime of these artifact during `SwapEntires`, `ResetEntries` - Ensured RocksDB block-based table builder calls `FilterBitsBuilder::MaybePostVerify()` after constructing the filter by `FilterBitsBuilder::Finish()` - When encountering such filter construction corruption, stop writing the filter content to files and mark such a block-based table building non-ok by storing the corruption status in the builder. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9342 Test Plan: - Added new unit test `DBFilterConstructionCorruptionTestWithParam.DetectCorruption` - Included this new feature in `DBFilterConstructionReserveMemoryTestWithParam.ReserveMemory` as this feature heavily touch ReserveMemory's impl - For fallback case, I run `./filter_bench -impl=3 -detect_filter_construct_corruption=true -reserve_table_builder_memory=true -strict_capacity_limit=true -quick -runs 10 | grep 'Build avg'` to make sure nothing break. - Added to `filter_bench`: increased filter construction time by **30%**, mostly by `MaybePostVerify()` - FastLocalBloom - Before change: `./filter_bench -impl=2 -quick -runs 10 | grep 'Build avg'`: **28.86643s** - After change: - `./filter_bench -impl=2 -detect_filter_construct_corruption=false -quick -runs 10 | grep 'Build avg'` (expect a tiny increase due to MaybePostVerify is always called regardless): **27.6644s (-4% perf improvement might be due to now we don't drop bloom hash entry in `AddAllEntries` along iteration but in bulk later, same with the bypassing-MaybePostVerify case below)** - `./filter_bench -impl=2 -detect_filter_construct_corruption=true -quick -runs 10 | grep 'Build avg'` (expect acceptable increase): **34.41159s (+20%)** - `./filter_bench -impl=2 -detect_filter_construct_corruption=true -quick -runs 10 | grep 'Build avg'` (by-passing MaybePostVerify, expect minor increase): **27.13431s (-6%)** - Standard128Ribbon - Before change: `./filter_bench -impl=3 -quick -runs 10 | grep 'Build avg'`: **122.5384s** - After change: - `./filter_bench -impl=3 -detect_filter_construct_corruption=false -quick -runs 10 | grep 'Build avg'` (expect a tiny increase due to MaybePostVerify is always called regardless - verified by removing MaybePostVerify under this case and found only +-1ns difference): **124.3588s (+2%)** - `./filter_bench -impl=3 -detect_filter_construct_corruption=true -quick -runs 10 | grep 'Build avg'`(expect acceptable increase): **159.4946s (+30%)** - `./filter_bench -impl=3 -detect_filter_construct_corruption=true -quick -runs 10 | grep 'Build avg'`(by-passing MaybePostVerify, expect minor increase) : **125.258s (+2%)** - Added to `db_stress`: `make crash_test`, `./db_stress --detect_filter_construct_corruption=true` - Manually smoke-tested: manually corrupted the filter construction in some db level tests with basic PUT and background flush. As expected, the error did get returned to users in subsequent PUT and Flush status. Reviewed By: pdillinger Differential Revision: D33746928 Pulled By: hx235 fbshipit-source-id: cb056426be5a7debc1cd16f23bc250f36a08ca57 |
3 years ago |
|
Andrew Kryczka
|
272ce445d6 |
remove unused instance variable in GenericRateLimiter (#9484)
Summary: As reported in https://github.com/facebook/rocksdb/pull/2899#issuecomment-1001467021, `prev_num_drains_` is confusing as we never set it to nonzero. So this PR removes it. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9484 Test Plan: `make check -j24` Reviewed By: hx235 Differential Revision: D33923203 Pulled By: ajkr fbshipit-source-id: 6277d50a198b90646583ee8094c2e6a1bbdadc7b |
3 years ago |
|
Yanqin Jin
|
dd203ed604 |
Disallow a combination of options (#9348)
Summary: Disallow `immutable_db_opts.use_direct_io_for_flush_and_compaction == true` and `mutable_db_opts.writable_file_max_buffer_size == 0`, since it causes `WritableFileWriter::Append()` to loop forever and does not make much sense in direct IO. This combination of options itself does not make much sense: asking RocksDB to do direct IO but not allowing RocksDB to allocate a buffer. We should detect this false combination and warn user early, no matter whether the application is running on a platform that supports direct IO or not. In the case of platform **not** supporting direct IO, it's ok if the user learns about this and then finds that direct IO is not supported. One tricky thing: the constructor of `WritableFileWriter` is being used in our unit tests, and it's impossible to return status code from constructor. Since we do not throw, I put an assertion for now. Fortunately, the constructor is not exposed to external applications. Closing https://github.com/facebook/rocksdb/issues/7109 Pull Request resolved: https://github.com/facebook/rocksdb/pull/9348 Test Plan: make check Reviewed By: ajkr Differential Revision: D33371924 Pulled By: riversand963 fbshipit-source-id: 2a3701ab541cee23bffda8a36cdf37b2d235edfa |
3 years ago |
|
mrambacher
|
7d7085c4e8 |
Fix LITE build for SliceTransform::AsString (#9460)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/9460 Reviewed By: pdillinger Differential Revision: D33830275 Pulled By: mrambacher fbshipit-source-id: 65dd1496e0291013085fdc3cce6ae3bf6dc955b5 |
3 years ago |
|
Peter Dillinger
|
ea89c77f27 |
Fix major bug with MultiGet, DeleteRange, and memtable Bloom (#9453)
Summary: MemTable::MultiGet was not considering range tombstones before querying Bloom filter. This means range tombstones would be skipped for keys (or prefixes) with no other entries in the memtable. This could cause old values for a key (in SST files) to still show up until the range tombstone covering it has been flushed. This is fixed by essentially disabling the memtable Bloom filter when there are any range tombstones. (This could be better optimized in the future, but good enough for now.) Did some other cleanup/optimization in the same code to (more than) offset the cost of checking on range tombstones in more cases. There is now notable improvement when memtable_whole_key_filtering and prefix_extractor are used together (unusual), and this makes MultiGet closer to the Get implementation. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9453 Test Plan: new unit test added. Added memtable Bloom to crash test. Performance testing -------------------- Build WAL-only DB (recovers to memtable): ``` TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks=fillrandom -num=1000000 -write_buffer_size=250000000 ``` Query test command, to maximize sensitivity to the changed code: ``` TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -use_existing_db -readonly -benchmarks=multireadrandom -num=10000000 -write_buffer_size=250000000 -memtable_bloom_size_ratio=0.015 -multiread_batched -batch_size=24 -threads=8 -memtable_whole_key_filtering=$MWKF -prefix_size=$PXS ``` (Note -num here is 10x larger for mostly memtable misses) Before & after run simultaneously, average over 10 iterations per data point, ops/sec. MWKF=0 PXS=0 (Bloom disabled) Before: 5724844 After: 6722066 MWKF=0 PXS=7 (prefixes hardly unique; Bloom not useful) Before: 9981319 After: 10237990 MWKF=0 PXS=8 (prefixes unique; Bloom useful) Before: 12081715 After: 12117603 MWKF=1 PXS=0 (whole key Bloom useful) Before: 11944354 After: 12096085 MWKF=1 PXS=7 (whole key Bloom useful in new version; prefixes not useful in old version) Before: 9444299 After: 11826029 MWKF=1 PXS=7 (whole key Bloom useful in new version; prefixes useful in old version) Before: 11784465 After: 11778591 Only in this last case is the 'before' *slightly* faster, perhaps because hashing prefixes is slightly faster than hashing whole keys. Otherwise, 'after' is faster. Reviewed By: ajkr Differential Revision: D33805025 Pulled By: pdillinger fbshipit-source-id: 597523cae4f4eafdf6ae6bb2bc6cb46f83b017bf |
3 years ago |
|
mrambacher
|
37ec9d0c12 |
Improve performance of SliceTransform::AsString (#9401)
Summary: 1. Removed the options from the Capped/Fixed SliceTransforms. Instead these classes are created with id.number. This allows the GetID() id to be calculated and stored at class construction time. This change puts the construction back to similar to how it was prior to the Customizable changes for SliceTransform. 2. Improve the performance of AsString by using the ID only if there are no option properties (which is the case for all of the builtin transforms). Ran tests of calling AsString in a loop 5M times and found approximately a 10x performance increase vs the original code. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9401 Reviewed By: pdillinger Differential Revision: D33668672 Pulled By: mrambacher fbshipit-source-id: d0075912c6ece8ed754ee543bc6b0b49a169b309 |
3 years ago |
|
Peter Dillinger
|
449029f865 |
Remove deprecated ObjectLibrary::Register() (and Regex public API) (#9439)
Summary: Regexes are considered potentially problematic for use in registering RocksDB extensions, so we are removing ObjectLibrary::Register() and the Regex public API it depended on (now unused). In reference to https://github.com/facebook/rocksdb/issues/9389 Why? * The power of Regexes can make it hard to reason about which extension will match what. (The replacement API isn't perfect, but we are at least "holding the line" on patterns we have seen in practice.) * It is easy to make regexes that don't quite mean what you think they mean, such as forgetting that the `.` in `foo.bar` can match any character or that matching is nondeterministic, as in `a🅱️42` matching `.*:[0-9]+`. * Some regexes and implementations can have disastrously bad performance. This might not be much practical concern for ObjectLibray here, but we don't want to encourage potentially dangerous further use in production code. (Testing code is fine. See TestRegex.) Pull Request resolved: https://github.com/facebook/rocksdb/pull/9439 Test Plan: CI Reviewed By: mrambacher Differential Revision: D33792342 Pulled By: pdillinger fbshipit-source-id: 4f64dcb04764e639162c8977a5fa196f67754cec |
3 years ago |
|
Peter Dillinger
|
fc9d4071f0 |
Fast path for detecting unchanged prefix_extractor (#9407)
Summary: Fixes a major performance regression in 6.26, where extra CPU is spent in SliceTransform::AsString when reads involve a prefix_extractor (Get, MultiGet, Seek). Common case performance is now better than 6.25. This change creates a "fast path" for verifying that the current prefix extractor is unchanged and compatible with what was used to generate a table file. This fast path detects the common case by pointer comparison on the current prefix_extractor and a "known good" prefix extractor (if applicable) that is saved at the time the table reader is opened. The "known good" prefix extractor is saved as another shared_ptr copy (in an existing field, however) to ensure the pointer is not recycled. When the prefix_extractor has changed to a different instance but same compatible configuration (rare, odd), performance is still a regression compared to 6.25, but this is likely acceptable because of the oddity of such a case. The performance of incompatible prefix_extractor is essentially unchanged. Also fixed a minor case (ForwardIterator) where a prefix_extractor could be used via a raw pointer after being freed as a shared_ptr, if replaced via SetOptions. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9407 Test Plan: ## Performance Populate DB with `TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks=fillrandom -num=10000000 -disable_wal=1 -write_buffer_size=10000000 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -prefix_size=12` Running head-to-head comparisons simultaneously with `TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -use_existing_db -readonly -benchmarks=seekrandom -num=10000000 -duration=20 -disable_wal=1 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -prefix_size=12` Below each is compared by ops/sec vs. baseline which is version 6.25 (multiple baseline runs because of variable machine load) v6.26: 4833 vs. 6698 (<- major regression!) v6.27: 4737 vs. 6397 (still) New: 6704 vs. 6461 (better than baseline in common case) Disabled fastpath: 4843 vs. 6389 (e.g. if prefix extractor instance changes but is still compatible) Changed prefix size (no usable filter) in new: 787 vs. 5927 Changed prefix size (no usable filter) in new & baseline: 773 vs. 784 Reviewed By: mrambacher Differential Revision: D33677812 Pulled By: pdillinger fbshipit-source-id: 571d9711c461fb97f957378a061b7e7dbc4d6a76 |
3 years ago |
|
Yanqin Jin
|
0376869f05 |
Remove using namespace (#9369)
Summary: As title. This is part of an fb-internal task. First, remove all `using namespace` statements if applicable. Next, utilize multiple build platforms and see if anything is broken. Should anything become broken, fix the compilation errors with as little extra change as possible. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9369 Test Plan: internal build and make check make clean && make static_lib && cd examples && make all Reviewed By: pdillinger Differential Revision: D33517260 Pulled By: riversand963 fbshipit-source-id: 3fc4ce6402a073421dfd9a9b2d1c79441dca7a40 |
3 years ago |
|
mrambacher
|
1973fcba11 |
Restore Regex support for ObjectLibrary::Register, rename new APIs to allow old one to be deprecated in the future (#9362)
Summary: In order to support old-style regex function registration, restored the original "Register<T>(string, Factory)" method using regular expressions. The PatternEntry methods were left in place but renamed to AddFactory. The goal is to allow for the deprecation of the original regex Registry method in an upcoming release. Added modes to the PatternEntry kMatchZeroOrMore and kMatchAtLeastOne to match * or +, respectively (kMatchAtLeastOne was the original behavior). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9362 Reviewed By: pdillinger Differential Revision: D33432562 Pulled By: mrambacher fbshipit-source-id: ed88ab3f9a2ad0d525c7bd1692873f9bb3209d02 |
3 years ago |
|
Hui Xiao
|
9110685e8c |
Release cache reservation of hash entries of the fall-back Ribbon Filter earlier (#9345)
Summary: Note: rebase on and merge after https://github.com/facebook/rocksdb/pull/9349, as part of https://github.com/facebook/rocksdb/pull/9342 **Context:** https://github.com/facebook/rocksdb/pull/9073 charged the hash entries' memory in block cache with `CacheReservationHandle`. However, in the edge case where Ribbon Filter falls back to Bloom Filter and swaps its hash entries to the embedded bloom filter object, the handles associated with those entries are not swapped and thus not released as soon as those entries are cleared during Bloom Filter's finish process. Although this is a minor issue since RocksDB internal calls `FilterBitsBuilder->Reset()` right after `FilterBitsBuilder->Finish()` on the main path, which releases all the cache reservation related to both the Ribbon Filter and its embedded Bloom Filter, it still worths this fix to avoid confusion. **Summary:** - Swapped the `CacheReservationHandle` associated with the hash entries on Ribbon Filter's fallback Pull Request resolved: https://github.com/facebook/rocksdb/pull/9345 Test Plan: - Added a unit test to verify the number of cache reservation after clearing hash entries, which failed before the change and now succeeds Reviewed By: pdillinger Differential Revision: D33377225 Pulled By: hx235 fbshipit-source-id: 7487f4c40dfb6ee7928232021f93ef2c5329cffa |
3 years ago |
|
mrambacher
|
1c39b7952b |
Remove/Reduce use of Regex in ObjectRegistry/Library (#9264)
Summary: Added new ObjectLibrary::Entry classes to replace/reduce the use of Regex. For simple factories that only do name matching, there are "StringEntry" and "AltStringEntry" classes. For classes that use some semblance of regular expressions, there is a PatternEntry class that can match a name and prefixes. There is also a class for Customizable::IndividualId format matches. Added tests for the new derivative classes and got all unit tests to pass. Resolves https://github.com/facebook/rocksdb/issues/9225. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9264 Reviewed By: pdillinger Differential Revision: D33062001 Pulled By: mrambacher fbshipit-source-id: c2d2143bd2d38bdf522705c8280c35381b135c03 |
3 years ago |
|
Kefu Chai
|
cc1d4e3d33 |
gcc-11 and cmake related cleanup (#9286)
Summary:
in hope to get rockdb compiled with GCC-11 without warning
* util/bloom_test: init a variable before using it
to silence the GCC warning like
```
util/bloom_test.cc:1253:31: error: ‘<anonymous>’ may be used uninitialized [-Werror=maybe-uninitialized]
1253 | Slice key_slice{key_bytes, 8};
| ^
...
include/rocksdb/slice.h:41:3: note: by argument 2 of type ‘const char*’ to ‘rocksdb::Slice::Slice(const char*, size_t)’ declared here
41 | Slice(const char* d, size_t n) : data_(d), size_(n) {}
| ^~~~~
util/bloom_test.cc:1249:3: note: ‘<anonymous>’ declared here
1249 | };
| ^
cc1plus: all warnings being treated as errors
```
* cmake: add find_package(uring ...)
find liburing in a more consistent way. also it is the encouraged way for finding a library.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9286
Reviewed By: mrambacher
Differential Revision: D33165241
Pulled By: jay-zhuang
fbshipit-source-id: 9f3487e11b4e40fd8f1c97c8facb24a190e5ce31
|
3 years ago |
|
Peter Dillinger
|
0050a73a4f |
New stable, fixed-length cache keys (#9126)
Summary: This change standardizes on a new 16-byte cache key format for block cache (incl compressed and secondary) and persistent cache (but not table cache and row cache). The goal is a really fast cache key with practically ideal stability and uniqueness properties without external dependencies (e.g. from FileSystem). A fixed key size of 16 bytes should enable future optimizations to the concurrent hash table for block cache, which is a heavy CPU user / bottleneck, but there appears to be measurable performance improvement even with no changes to LRUCache. This change replaces a lot of disjointed and ugly code handling cache keys with calls to a simple, clean new internal API (cache_key.h). (Preserving the old cache key logic under an option would be very ugly and likely negate the performance gain of the new approach. Complete replacement carries some inherent risk, but I think that's acceptable with sufficient analysis and testing.) The scheme for encoding new cache keys is complicated but explained in cache_key.cc. Also: EndianSwapValue is moved to math.h to be next to other bit operations. (Explains some new include "math.h".) ReverseBits operation added and unit tests added to hash_test for both. Fixes https://github.com/facebook/rocksdb/issues/7405 (presuming a root cause) Pull Request resolved: https://github.com/facebook/rocksdb/pull/9126 Test Plan: ### Basic correctness Several tests needed updates to work with the new functionality, mostly because we are no longer relying on filesystem for stable cache keys so table builders & readers need more context info to agree on cache keys. This functionality is so core, a huge number of existing tests exercise the cache key functionality. ### Performance Create db with `TEST_TMPDIR=/dev/shm ./db_bench -bloom_bits=10 -benchmarks=fillrandom -num=3000000 -partition_index_and_filters` And test performance with `TEST_TMPDIR=/dev/shm ./db_bench -readonly -use_existing_db -bloom_bits=10 -benchmarks=readrandom -num=3000000 -duration=30 -cache_index_and_filter_blocks -cache_size=250000 -threads=4` using DEBUG_LEVEL=0 and simultaneous before & after runs. Before ops/sec, avg over 100 runs: 121924 After ops/sec, avg over 100 runs: 125385 (+2.8%) ### Collision probability I have built a tool, ./cache_bench -stress_cache_key to broadly simulate host-wide cache activity over many months, by making some pessimistic simplifying assumptions: * Every generated file has a cache entry for every byte offset in the file (contiguous range of cache keys) * All of every file is cached for its entire lifetime We use a simple table with skewed address assignment and replacement on address collision to simulate files coming & going, with quite a variance (super-Poisson) in ages. Some output with `./cache_bench -stress_cache_key -sck_keep_bits=40`: ``` Total cache or DBs size: 32TiB Writing 925.926 MiB/s or 76.2939TiB/day Multiply by 9.22337e+18 to correct for simulation losses (but still assume whole file cached) ``` These come from default settings of 2.5M files per day of 32 MB each, and `-sck_keep_bits=40` means that to represent a single file, we are only keeping 40 bits of the 128-bit cache key. With file size of 2\*\*25 contiguous keys (pessimistic), our simulation is about 2\*\*(128-40-25) or about 9 billion billion times more prone to collision than reality. More default assumptions, relatively pessimistic: * 100 DBs in same process (doesn't matter much) * Re-open DB in same process (new session ID related to old session ID) on average every 100 files generated * Restart process (all new session IDs unrelated to old) 24 times per day After enough data, we get a result at the end: ``` (keep 40 bits) 17 collisions after 2 x 90 days, est 10.5882 days between (9.76592e+19 corrected) ``` If we believe the (pessimistic) simulation and the mathematical generalization, we would need to run a billion machines all for 97 billion days to expect a cache key collision. To help verify that our generalization ("corrected") is robust, we can make our simulation more precise with `-sck_keep_bits=41` and `42`, which takes more running time to get enough data: ``` (keep 41 bits) 16 collisions after 4 x 90 days, est 22.5 days between (1.03763e+20 corrected) (keep 42 bits) 19 collisions after 10 x 90 days, est 47.3684 days between (1.09224e+20 corrected) ``` The generalized prediction still holds. With the `-sck_randomize` option, we can see that we are beating "random" cache keys (except offsets still non-randomized) by a modest amount (roughly 20x less collision prone than random), which should make us reasonably comfortable even in "degenerate" cases: ``` 197 collisions after 1 x 90 days, est 0.456853 days between (4.21372e+18 corrected) ``` I've run other tests to validate other conditions behave as expected, never behaving "worse than random" unless we start chopping off structured data. Reviewed By: zhichao-cao Differential Revision: D33171746 Pulled By: pdillinger fbshipit-source-id: f16a57e369ed37be5e7e33525ace848d0537c88f |
3 years ago |
