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25 Commits (097f9f4425d78cd11ff1912a6ac5f8a2edd3f4e0)
| Author | SHA1 | Message | Date |
|---|---|---|---|
Akanksha Mahajan
|
1562524e63 |
Fix db_stress failure in async_io in FilePrefetchBuffer (#10949)
Summary: Fix db_stress failure in async_io in FilePrefetchBuffer. From the logs, assertion was caused when - prev_offset_ = offset but somehow prev_len != 0 and explicit_prefetch_submitted_ = true. That scenario is when we send async request to prefetch buffer during seek but in second seek that data is found in cache. prev_offset_ and prev_len_ get updated but we were not setting explicit_prefetch_submitted_ = false because of which buffers were getting out of sync. It's possible a read by another thread might have loaded the block into the cache in the meantime. Particular assertion example: ``` prev_offset: 0, prev_len_: 8097 , offset: 0, length: 8097, actual_length: 8097 , actual_offset: 0 , curr_: 0, bufs_[curr_].offset_: 4096 ,bufs_[curr_].CurrentSize(): 48541 , async_len_to_read: 278528, bufs_[curr_].async_in_progress_: false second: 1, bufs_[second].offset_: 282624 ,bufs_[second].CurrentSize(): 0, async_len_to_read: 262144 ,bufs_[second].async_in_progress_: true , explicit_prefetch_submitted_: true , copy_to_third_buffer: false ``` As we can see curr_ was expected to read 278528 but it read 48541. Also buffers are out of sync. Also `explicit_prefetch_submitted_` is set true but prev_len not 0. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10949 Test Plan: - Ran db_bench for regression to make sure there is no regression; - Ran db_stress failing without this fix, - Ran build-linux-mini-crashtest 7- 8 times locally + CircleCI Reviewed By: anand1976 Differential Revision: D41257786 Pulled By: akankshamahajan15 fbshipit-source-id: 1d100f94f8c06bbbe4cc76ca27f1bbc820c2494f |
2 years ago |
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akankshamahajan
|
ff9ad2c39b |
Fix async_io failures in case there is error in reading data (#10890)
Summary: Fix memory corruption error in scans if async_io is enabled. Memory corruption happened if data is overlapping between two buffers. If there is IOError while reading the data, it leads to empty buffer and other buffer already in progress of async read goes again for reading causing the error. Fix: Added check to abort IO in second buffer if curr_ got empty. This PR also fixes db_stress failures which happened when buffers are not aligned. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10890 Test Plan: - Ran make crash_test -j32 with async_io enabled. - Ran benchmarks to make sure there is no regression. Reviewed By: anand1976 Differential Revision: D40881731 Pulled By: akankshamahajan15 fbshipit-source-id: 39fcf2134c7b1bbb08415ede3e1ef261ac2dbc58 |
2 years ago |
|
Akanksha Mahajan
|
03fc43976d |
Async optimization in scan path (#10602)
Summary: Optimizations 1. In FilePrefetchBuffer, when data is overlapping between two buffers, it copies the data from first to third buffer, then from second to third buffer to return continuous buffer. This optimization will call ReadAsync on first buffer as soon as buffer is empty instead of getting blocked by second buffer to copy the data. 2. For fixed size readahead_size, FilePrefetchBuffer will issues two async read calls. One with length + readahead_size_/2 on first buffer(if buffer is empty) and readahead_size_/2 on second buffer during seek. - Add readahead_size to db_stress for stress testing these changes in https://github.com/facebook/rocksdb/pull/10632 Pull Request resolved: https://github.com/facebook/rocksdb/pull/10602 Test Plan: - CircleCI tests - stress_test completed successfully export CRASH_TEST_EXT_ARGS="--async_io=1" make crash_test -j32 - db_bench showed no regression With this PR: ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main1 -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=50000000 -use_direct_reads=false -seek_nexts=327680 -duration=30 -ops_between_duration_checks=1 -async_io=1 Set seed to 1661876074584472 because --seed was 0 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags Integrated BlobDB: blob cache disabled RocksDB: version 7.7.0 Date: Tue Aug 30 09:14:34 2022 CPU: 32 * Intel Xeon Processor (Skylake) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 50000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 25939.9 MB (estimated) FileSize: 13732.9 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main1] seekrandom : 270878.018 micros/op 3 ops/sec 30.068 seconds 111 operations; 618.7 MB/s (111 of 111 found) ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main1 -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=50000000 -use_direct_reads=true -seek_nexts=327680 -duration=30 -ops_between_duration_checks=1 -async_io=1 Set seed to 1661875332862922 because --seed was 0 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags Integrated BlobDB: blob cache disabled RocksDB: version 7.7.0 Date: Tue Aug 30 09:02:12 2022 CPU: 32 * Intel Xeon Processor (Skylake) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 50000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 25939.9 MB (estimated) FileSize: 13732.9 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 WARNING: Assertions are enabled; benchmarks unnecessarily slow ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main1] seekrandom : 358352.488 micros/op 2 ops/sec 30.102 seconds 84 operations; 474.4 MB/s (84 of 84 found) ``` Without PR in main: ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main1 -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=50000000 -use_direct_reads=false -seek_nexts=327680 -duration=30 -ops_between_duration_checks=1 -async_io=1 Set seed to 1661876425983045 because --seed was 0 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags Integrated BlobDB: blob cache disabled RocksDB: version 7.7.0 Date: Tue Aug 30 09:20:26 2022 CPU: 32 * Intel Xeon Processor (Skylake) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 50000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 25939.9 MB (estimated) FileSize: 13732.9 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main1] seekrandom : 280881.953 micros/op 3 ops/sec 30.054 seconds 107 operations; 605.2 MB/s (107 of 107 found) ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main1 -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=50000000 -use_direct_reads=false -seek_nexts=327680 -duration=30 -ops_between_duration_checks=1 -async_io=0 Set seed to 1661876475267771 because --seed was 0 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags Integrated BlobDB: blob cache disabled RocksDB: version 7.7.0 Date: Tue Aug 30 09:21:15 2022 CPU: 32 * Intel Xeon Processor (Skylake) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 50000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 25939.9 MB (estimated) FileSize: 13732.9 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main1] seekrandom : 363155.084 micros/op 2 ops/sec 30.142 seconds 83 operations; 468.1 MB/s (83 of 83 found) ``` Reviewed By: anand1976 Differential Revision: D39141328 Pulled By: akankshamahajan15 fbshipit-source-id: 560655922c1a437a8569c228abb31b8c0b413120 |
2 years ago |
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Akanksha Mahajan
|
4cd16d65ae |
Add new option num_file_reads_for_auto_readahead in BlockBasedTableOptions (#10556)
Summary: RocksDB does auto-readahead for iterators on noticing more than two reads for a table file if user doesn't provide readahead_size and reads are sequential. A new option num_file_reads_for_auto_readahead is added which can be configured and indicates after how many sequential reads prefetching should be start. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10556 Test Plan: Existing and new unit test Reviewed By: anand1976 Differential Revision: D38947147 Pulled By: akankshamahajan15 fbshipit-source-id: c9eeab495f84a8df7f701c42f04894e46440ad97 |
2 years ago |
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anand76
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72a3fb3424 |
Update statistics for async scan readaheads (#10585)
Summary: Imported a fix to "rocksdb.prefetched.bytes.discarded" stat from https://github.com/facebook/rocksdb/issues/10561, and added a new stat "rocksdb.async.prefetch.abort.micros" to measure time spent waiting for async reads to abort. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10585 Reviewed By: akankshamahajan15 Differential Revision: D39067000 Pulled By: anand1976 fbshipit-source-id: d7cda71abb48017239bd5fd832345a16c7024faf |
2 years ago |
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Akanksha Mahajan
|
2acbf386a3 |
Provide support for direct_reads with async_io (#10197)
Summary: Provide support for use_direct_reads with async_io. TestPlan: - Updated unit tests - db_bench: Results in https://github.com/facebook/rocksdb/pull/10197#issuecomment-1159239420 - db_stress ``` export CRASH_TEST_EXT_ARGS=" --async_io=1 --use_direct_reads=1" make crash_test -j ``` - Ran db_bench on previous RocksDB version before any async_io implementation (as there have many changes in different PRs in this area) https://github.com/facebook/rocksdb/pull/10197#issuecomment-1160781563. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10197 Reviewed By: anand1976 Differential Revision: D37255646 Pulled By: akankshamahajan15 fbshipit-source-id: fec61ae15bf4d625f79dea56e4f86e0e307ba920 |
3 years ago |
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Akanksha Mahajan
|
8353ae8b27 |
Add few optimizations in async_io for short scans (#10140)
Summary: This PR adds few optimizations for async_io for shorter scans. 1. If async_io is enabled, seek would create FilePrefetchBuffer object to fetch the data asynchronously. However `FilePrefetchbuffer::num_file_reads_` wasn't taken into consideration if it calls Next after Seek and would go for Prefetching. This PR fixes that and Next will go for prefetching only if `FilePrefetchbuffer::num_file_reads_` is greater than 2 along with if blocks are sequential. This scenario is only for implicit auto readahead. 2. For seek, when it calls TryReadFromCacheAsync to poll it makes async call as well because TryReadFromCacheAsync flow wasn't changed. So I updated to return after poll instead of further prefetching any data. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10140 Test Plan: 1. Added a unit test 2. Ran crash_test with async_io = 1 to make sure nothing crashes. Reviewed By: anand1976 Differential Revision: D37042242 Pulled By: akankshamahajan15 fbshipit-source-id: b8e6b7cb2ee0886f37a8f53951948b9084e8ffda |
3 years ago |
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Akanksha Mahajan
|
a479c2c2b2 |
Fix stress test failure "Corruption: checksum mismatch" or "Iterator Diverged" with async_io enabled (#10032)
Summary: In case of non sequential reads with `async_io`, `FilePRefetchBuffer::TryReadFromCacheAsync` can be called for previous blocks with `offset < bufs_[curr_].offset_` which wasn't handled correctly resulting wrong data being returned from buffer. Since `FilePRefetchBuffer::PrefetchAsync` can be called for any data block, it sets `prev_len_` to 0 indicating `FilePRefetchBuffer::TryReadFromCacheAsync` to go for the prefetching even though offset < bufs_[curr_].offset_ This is because async prefetching is always done in second buffer (to avoid mutex) even though curr_ is empty leading to offset < bufs_[curr_].offset_ in some cases. If prev_len_ is non zero then `TryReadFromCacheAsync` returns false if `offset < bufs_[curr_].offset_ && prev_len != 0` indicating reads are not sequential and previous call wasn't PrefetchAsync. - This PR also simplifies `FilePRefetchBuffer::TryReadFromCacheAsync` as it was getting complicated covering different scenarios based on `async_io` enabled/disabled. If `for_compaction` is set true, it now calls `FilePRefetchBufferTryReadFromCache` following synchronous flow as before. Its decided in BlockFetcher.cc Pull Request resolved: https://github.com/facebook/rocksdb/pull/10032 Test Plan: 1. export CRASH_TEST_EXT_ARGS=" --async_io=1" make crash_test -j completed successfully locally 2. make crash_test -j completed successfully locally 3. Reran CircleCi mini crashtest job 4 - 5 times. 4. Updated prefetch_test for more coverage. Reviewed By: anand1976 Differential Revision: D36579858 Pulled By: akankshamahajan15 fbshipit-source-id: 0c428d62b45e12e082a83acf533a5e37a584bedf |
3 years ago |
|
Akanksha Mahajan
|
2db6a4a1d6 |
Seek parallelization (#9994)
Summary: The RocksDB iterator is a hierarchy of iterators. MergingIterator maintains a heap of LevelIterators, one for each L0 file and for each non-zero level. The Seek() operation naturally lends itself to parallelization, as it involves positioning every LevelIterator on the correct data block in the correct SST file. It lookups a level for a target key, to find the first key that's >= the target key. This typically involves reading one data block that is likely to contain the target key, and scan forward to find the first valid key. The forward scan may read more data blocks. In order to find the right data block, the iterator may read some metadata blocks (required for opening a file and searching the index). This flow can be parallelized. Design: Seek will be called two times under async_io option. First seek will send asynchronous request to prefetch the data blocks at each level and second seek will follow the normal flow and in FilePrefetchBuffer::TryReadFromCacheAsync it will wait for the Poll() to get the results and add the iterator to min_heap. - Status::TryAgain is passed down from FilePrefetchBuffer::PrefetchAsync to block_iter_.Status indicating asynchronous request has been submitted. - If for some reason asynchronous request returns error in submitting the request, it will fallback to sequential reading of blocks in one pass. - If the data already exists in prefetch_buffer, it will return the data without prefetching further and it will be treated as single pass of seek. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9994 Test Plan: - **Run Regressions.** ``` ./db_bench -db=/tmp/prefix_scan_prefetch_main -benchmarks="fillseq" -key_size=32 -value_size=512 -num=5000000 -use_direct_io_for_flush_and_compaction=true -target_file_size_base=16777216 ``` i) Previous release 7.0 run for normal prefetching with async_io disabled: ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.0 Date: Thu Mar 17 13:11:34 2022 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main] seekrandom : 483618.390 micros/op 2 ops/sec; 338.9 MB/s (249 of 249 found) ``` ii) normal prefetching after changes with async_io disable: ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Set seed to 1652922591315307 because --seed was 0 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.3 Date: Wed May 18 18:09:51 2022 CPU: 32 * Intel Xeon Processor (Skylake) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main] seekrandom : 483080.466 micros/op 2 ops/sec 120.287 seconds 249 operations; 340.8 MB/s (249 of 249 found) ``` iii) db_bench with async_io enabled completed succesfully ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 -async_io=1 -adaptive_readahead=1 Set seed to 1652924062021732 because --seed was 0 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.3 Date: Wed May 18 18:34:22 2022 CPU: 32 * Intel Xeon Processor (Skylake) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main] seekrandom : 553913.576 micros/op 1 ops/sec 120.199 seconds 217 operations; 293.6 MB/s (217 of 217 found) ``` - db_stress with async_io disabled completed succesfully ``` export CRASH_TEST_EXT_ARGS=" --async_io=0" make crash_test -j ``` I**n Progress**: db_stress with async_io is failing and working on debugging/fixing it. Reviewed By: anand1976 Differential Revision: D36459323 Pulled By: akankshamahajan15 fbshipit-source-id: abb1cd944abe712bae3986ae5b16704b3338917c |
3 years ago |
|
sdong
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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 |
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Akanksha Mahajan
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3653029dda |
Add stats related to async prefetching (#9845)
Summary: Add stats PREFETCHED_BYTES_DISCARDED and POLL_WAIT_MICROS. PREFETCHED_BYTES_DISCARDED records number of prefetched bytes discarded by FilePrefetchBuffer. POLL_WAIT_MICROS records the time taken by underling file_system Poll API. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9845 Test Plan: Update existing tests Reviewed By: anand1976 Differential Revision: D35909694 Pulled By: akankshamahajan15 fbshipit-source-id: e009ef940bb9ed72c9446f5529095caabb8a1e36 |
3 years ago |
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Akanksha Mahajan
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5bd374b392 |
Add experimental new FS API AbortIO to cancel read request (#9901)
Summary: Add experimental new API AbortIO in FileSystem to abort the read requests submitted asynchronously through ReadAsync API. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9901 Test Plan: Existing tests Reviewed By: anand1976 Differential Revision: D35885591 Pulled By: akankshamahajan15 fbshipit-source-id: df3944e6e9e6e487af1fa688376b4abb6837fb02 |
3 years ago |
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Akanksha Mahajan
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0c7f455f85 |
Make initial auto readahead_size configurable (#9836)
Summary: Make initial auto readahead_size configurable Pull Request resolved: https://github.com/facebook/rocksdb/pull/9836 Test Plan: Added new unit test Ran regression: Without change: ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.0 Date: Thu Mar 17 13:11:34 2022 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main] seekrandom : 483618.390 micros/op 2 ops/sec; 338.9 MB/s (249 of 249 found) ``` With this change: ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Set seed to 1649895440554504 because --seed was 0 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.2 Date: Wed Apr 13 17:17:20 2022 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main] ... finished 100 ops seekrandom : 476892.488 micros/op 2 ops/sec; 344.6 MB/s (252 of 252 found) ``` Reviewed By: anand1976 Differential Revision: D35632815 Pulled By: akankshamahajan15 fbshipit-source-id: c8057a88f9294c9d03b1d434b03affe02f74d796 |
3 years ago |
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Akanksha Mahajan
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36bc3da97f |
Fix segfault in FilePrefetchBuffer with async_io enabled (#9777)
Summary: If FilePrefetchBuffer object is destroyed and then later Poll() calls callback on object which has been destroyed, it gives segfault on accessing destroyed object. It was caught after adding unit tests that tests Posix implementation of ReadAsync and Poll APIs. This PR also updates and fixes existing IOURing tests which were not running locally because RocksDbIOUringEnable function wasn't defined and IOUring was disabled for those tests Pull Request resolved: https://github.com/facebook/rocksdb/pull/9777 Test Plan: Added new unit test Reviewed By: anand1976 Differential Revision: D35254002 Pulled By: akankshamahajan15 fbshipit-source-id: 68e80054ffb14ae25c255920ebc6548ca5f130a1 |
3 years ago |
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Akanksha Mahajan
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49a10feb21 |
Provide implementation to prefetch data asynchronously in FilePrefetchBuffer (#9674)
Summary: In FilePrefetchBuffer if reads are sequential, after prefetching call ReadAsync API to prefetch data asynchronously so that in next prefetching data will be available. Data prefetched asynchronously will be readahead_size/2. It uses two buffers, one for synchronous prefetching and one for asynchronous. In case, the data is overlapping, the data is copied from both buffers to third buffer to make it continuous. This feature is under ReadOptions::async_io and is under experimental. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9674 Test Plan: 1. Add new unit tests 2. Run **db_stress** to make sure nothing crashes. - Normal prefetch without `async_io` ran successfully: ``` export CRASH_TEST_EXT_ARGS=" --async_io=0" make crash_test -j ``` 3. **Run Regressions**. i) Main branch without any change for normal prefetching with async_io disabled: ``` ./db_bench -db=/tmp/prefix_scan_prefetch_main -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=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.0 Date: Thu Mar 17 13:11:34 2022 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main] seekrandom : 483618.390 micros/op 2 ops/sec; 338.9 MB/s (249 of 249 found) ``` ii) normal prefetching after changes with async_io disable: ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_withchange -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.0 Date: Thu Mar 17 14:11:31 2022 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_withchange] seekrandom : 471347.227 micros/op 2 ops/sec; 348.1 MB/s (255 of 255 found) ``` Reviewed By: anand1976 Differential Revision: D34731543 Pulled By: akankshamahajan15 fbshipit-source-id: 8e23aa93453d5fe3c672b9231ad582f60207937f |
3 years ago |
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Andrew Kryczka
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babe56ddba |
Add rate limiter priority to ReadOptions (#9424)
Summary: Users can set the priority for file reads associated with their operation by setting `ReadOptions::rate_limiter_priority` to something other than `Env::IO_TOTAL`. Rate limiting `VerifyChecksum()` and `VerifyFileChecksums()` is the motivation for this PR, so it also includes benchmarks and minor bug fixes to get that working. `RandomAccessFileReader::Read()` already had support for rate limiting compaction reads. I changed that rate limiting to be non-specific to compaction, but rather performed according to the passed in `Env::IOPriority`. Now the compaction read rate limiting is supported by setting `rate_limiter_priority = Env::IO_LOW` on its `ReadOptions`. There is no default value for the new `Env::IOPriority` parameter to `RandomAccessFileReader::Read()`. That means this PR goes through all callers (in some cases multiple layers up the call stack) to find a `ReadOptions` to provide the priority. There are TODOs for cases I believe it would be good to let user control the priority some day (e.g., file footer reads), and no TODO in cases I believe it doesn't matter (e.g., trace file reads). The API doc only lists the missing cases where a file read associated with a provided `ReadOptions` cannot be rate limited. For cases like file ingestion checksum calculation, there is no API to provide `ReadOptions` or `Env::IOPriority`, so I didn't count that as missing. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9424 Test Plan: - new unit tests - new benchmarks on ~50MB database with 1MB/s read rate limit and 100ms refill interval; verified with strace reads are chunked (at 0.1MB per chunk) and spaced roughly 100ms apart. - setup command: `./db_bench -benchmarks=fillrandom,compact -db=/tmp/testdb -target_file_size_base=1048576 -disable_auto_compactions=true -file_checksum=true` - benchmarks command: `strace -ttfe pread64 ./db_bench -benchmarks=verifychecksum,verifyfilechecksums -use_existing_db=true -db=/tmp/testdb -rate_limiter_bytes_per_sec=1048576 -rate_limit_bg_reads=1 -rate_limit_user_ops=true -file_checksum=true` - crash test using IO_USER priority on non-validation reads with https://github.com/facebook/rocksdb/issues/9567 reverted: `python3 tools/db_crashtest.py blackbox --max_key=1000000 --write_buffer_size=524288 --target_file_size_base=524288 --level_compaction_dynamic_level_bytes=true --duration=3600 --rate_limit_bg_reads=true --rate_limit_user_ops=true --rate_limiter_bytes_per_sec=10485760 --interval=10` Reviewed By: hx235 Differential Revision: D33747386 Pulled By: ajkr fbshipit-source-id: a2d985e97912fba8c54763798e04f006ccc56e0c |
3 years ago |
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Akanksha Mahajan
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04b2c16f9b |
Fix bug in rocksdb internal automatic prefetching (#9234)
Summary: After introducing adaptive_readahead, the original flow got broken. Readahead size was set to 0 because of which rocksdb wasn't be able to do automatic prefetching which it enables after seeing sequential reads. This PR fixes it. ---------------------------------------------------------------------------------------------------- Before this patch: b_bench -use_existing_db=true -db=/tmp/prefix_scan -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 6.27 Date: Tue Nov 30 11:56:50 2021 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 WARNING: Assertions are enabled; benchmarks unnecessarily slow ------------------------------------------------ DB path: [/tmp/prefix_scan] seekrandom : 5356367.174 micros/op 0 ops/sec; 29.4 MB/s (23 of 23 found) ---------------------------------------------------------------------------------------------------- After the patch: ./db_bench -use_existing_db=true -db=/tmp/prefix_scan -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 6.27 Date: Tue Nov 30 14:38:33 2021 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 WARNING: Assertions are enabled; benchmarks unnecessarily slow ------------------------------------------------ DB path: [/tmp/prefix_scan] seekrandom : 456504.277 micros/op 2 ops/sec; 359.8 MB/s (264 of 264 found) Pull Request resolved: https://github.com/facebook/rocksdb/pull/9234 Test Plan: Ran ./db_bench -db=/data/mysql/rocksdb/prefix_scan -benchmarks="fillseq" -key_size=32 -value_size=512 -num=5000000 -use_d irect_io_for_flush_and_compaction=true -target_file_size_base=16777216 and then ./db_bench -use_existing_db=true -db=/data/mysql/rocksdb/prefix_scan -benchmarks="seekrandom" -key_size=32 -value_siz e=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 and compared the results. Reviewed By: anand1976 Differential Revision: D32743965 Pulled By: akankshamahajan15 fbshipit-source-id: b950fba68c91963b7deb5c20acdf471bc60251f5 |
3 years ago |
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Levi Tamasi
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dc5de45af8 |
Support readahead during compaction for blob files (#9187)
Summary: The patch adds a new BlobDB configuration option `blob_compaction_readahead_size` that can be used to enable prefetching data from blob files during compaction. This is important when using storage with higher latencies like HDDs or remote filesystems. If enabled, prefetching is used for all cases when blobs are read during compaction, namely garbage collection, compaction filters (when the existing value has to be read from a blob file), and `Merge` (when the value of the base `Put` is stored in a blob file). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9187 Test Plan: Ran `make check` and the stress/crash test. Reviewed By: riversand963 Differential Revision: D32565512 Pulled By: ltamasi fbshipit-source-id: 87be9cebc3aa01cc227bec6b5f64d827b8164f5d |
3 years ago |
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Akanksha Mahajan
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17ce1ca48b |
Reuse internal auto readhead_size at each Level (expect L0) for Iterations (#9056)
Summary: RocksDB does auto-readahead for iterators on noticing more than two sequential reads for a table file if user doesn't provide readahead_size. The readahead starts at 8KB and doubles on every additional read up to max_auto_readahead_size. However at each level, if iterator moves over next file, readahead_size starts again from 8KB. This PR introduces a new ReadOption "adaptive_readahead" which when set true will maintain readahead_size at each level. So when iterator moves from one file to another, new file's readahead_size will continue from previous file's readahead_size instead of scratch. However if reads are not sequential it will fall back to 8KB (default) with no prefetching for that block. 1. If block is found in cache but it was eligible for prefetch (block wasn't in Rocksdb's prefetch buffer), readahead_size will decrease by 8KB. 2. It maintains readahead_size for L1 - Ln levels. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9056 Test Plan: Added new unit tests Ran db_bench for "readseq, seekrandom, seekrandomwhilewriting, readrandom" with --adaptive_readahead=true and there was no regression if new feature is enabled. Reviewed By: anand1976 Differential Revision: D31773640 Pulled By: akankshamahajan15 fbshipit-source-id: 7332d16258b846ae5cea773009195a5af58f8f98 |
3 years ago |
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Akanksha Mahajan
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a0e0feca62 |
Improve BlockPrefetcher to prefetch only for sequential scans (#7394)
Summary: BlockPrefetcher is used by iterators to prefetch data if they anticipate more data to be used in future and this is valid for forward sequential scans. But BlockPrefetcher tracks only num_file_reads_ and not if reads are sequential. This presents problem for MultiGet with large number of keys when it reseeks index iterator and data block. FilePrefetchBuffer can end up doing large readahead for reseeks as readahead size increases exponentially once readahead is enabled. Same issue is with BlockBasedTableIterator. Add previous length and offset read as well in BlockPrefetcher (creates FilePrefetchBuffer) and FilePrefetchBuffer (does prefetching of data) to determine if reads are sequential and then prefetch. Update the last block read after cache hit to take reads from cache also in account. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7394 Test Plan: Add new unit test case Reviewed By: anand1976 Differential Revision: D23737617 Pulled By: akankshamahajan15 fbshipit-source-id: 8e6917c25ed87b285ee495d1b68dc623d71205a3 |
4 years ago |
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Ziyue Yang
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0c2d71edba |
Fix typo: replace readadhead with readahead (#7953)
Summary: This PR replaces several "readadhead" typos with "readahead". Pull Request resolved: https://github.com/facebook/rocksdb/pull/7953 Reviewed By: ajkr Differential Revision: D26518903 Pulled By: jay-zhuang fbshipit-source-id: 6f7dece0e39ec4f71c4a936399bcb2e02574f42a |
4 years ago |
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anand76
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01298c8ff7 |
Return Status from FilePrefetchBuffer::TryReadFromCache() (#7816)
Summary: Return the Status from TryReadFromCache() in an argument to make it easier to report prefetch errors to the user. Tests: make crash_test make check Pull Request resolved: https://github.com/facebook/rocksdb/pull/7816 Reviewed By: akankshamahajan15 Differential Revision: D25717222 Pulled By: anand1976 fbshipit-source-id: c320d3c12d4146bda16df78ff6927eee584c1810 |
4 years ago |
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Anand Ananthabhotla
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9a5886bd8c |
Extend Get/MultiGet deadline support to table open (#6982)
Summary: Current implementation of the ```read_options.deadline``` option only checks the deadline for random file reads during point lookups. This PR extends the checks to file opens, prefetches and preloads as part of table open. The main changes are in the ```BlockBasedTable```, partitioned index and filter readers, and ```TableCache``` to take ReadOptions as an additional parameter. In ```BlockBasedTable::Open```, in order to retain existing behavior w.r.t checksum verification and block cache usage, we filter out most of the options in ```ReadOptions``` except ```deadline```. However, having the ```ReadOptions``` gives us more flexibility to honor other options like verify_checksums, fill_cache etc. in the future. Additional changes in callsites due to function signature changes in ```NewTableReader()``` and ```FilePrefetchBuffer```. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6982 Test Plan: Add new unit tests in db_basic_test Reviewed By: riversand963 Differential Revision: D22219515 Pulled By: anand1976 fbshipit-source-id: 8a3b92f4a889808013838603aa3ca35229cd501b |
5 years ago |
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sdong
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fdf882ded2 |
Replace namespace name "rocksdb" with ROCKSDB_NAMESPACE (#6433)
Summary: When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433 Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag. Differential Revision: D19977691 fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e |
5 years ago |
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sdong
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b931f84e56 |
Divide file_reader_writer.h and .cc (#5803)
Summary: file_reader_writer.h and .cc contain several files and helper function, and it's hard to navigate. Separate it to multiple files and put them under file/ Pull Request resolved: https://github.com/facebook/rocksdb/pull/5803 Test Plan: Build whole project using make and cmake. Differential Revision: D17374550 fbshipit-source-id: 10efca907721e7a78ed25bbf74dc5410dea05987 |
5 years ago |