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1504 Commits (6cac4c79d457f199271e05caca07539fc588e7d0)
Author | SHA1 | Message | Date |
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Yanqin Jin | b6cfda1283 |
Support `iter_start_ts` for backward iteration (#10200)
Summary: Resolves https://github.com/facebook/rocksdb/issues/9761 With this PR, applications can create an iterator with the following ```cpp ReadOptions read_opts; read_opts.timestamp = &ts_ub; read_opts.iter_start_ts = &ts_lb; auto* it = db->NewIterator(read_opts); it->SeekToLast(); // or it->SeekForPrev("foo"); it->Prev(); ... ``` The application can access different versions of the same user key via `key()`, `value()`, and `timestamp()`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10200 Test Plan: make check Reviewed By: ltamasi Differential Revision: D37258074 Pulled By: riversand963 fbshipit-source-id: 3f0b866ade50dcff7ef60d506397a9dd6ec91565 |
3 years ago |
Gang Liao | d7ebb58cb5 |
Add blob cache tickers, perf context statistics, and DB properties (#10203)
Summary: In order to be able to monitor the performance of the new blob cache, we made the follow changes: - Add blob cache hit/miss/insertion tickers (see https://github.com/facebook/rocksdb/wiki/Statistics) - Extend the perf context similarly (see https://github.com/facebook/rocksdb/wiki/Perf-Context-and-IO-Stats-Context) - Implement new DB properties (see e.g. https://github.com/facebook/rocksdb/blob/main/include/rocksdb/db.h#L1042-L1051) that expose the capacity and current usage of the blob cache. This PR is a part of https://github.com/facebook/rocksdb/issues/10156 Pull Request resolved: https://github.com/facebook/rocksdb/pull/10203 Reviewed By: ltamasi Differential Revision: D37478658 Pulled By: gangliao fbshipit-source-id: d8ee3f41d47315ef725e4551226330b4b6832e40 |
3 years ago |
sdong | 246d469750 |
Reduce overhead of SortFileByOverlappingRatio() (#10161)
Summary: Currently SortFileByOverlappingRatio() is O(nlogn). It is usually OK but When there are a lot of files in an LSM-tree, SortFileByOverlappingRatio() can take non-trivial amount of time. The problem is severe when the user is loading keys in sorted order, where compaction is only trivial move and this operation becomes the bottleneck and limit the total throughput. This commit makes SortFileByOverlappingRatio() only find the top 50 files based on score. 50 files are usually enough for the parallel compactions needed for the level, and in case it is not enough, we would fall back to random, which should be acceptable. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10161 Test Plan: Run a fillseq that generates a lot of files, and observe throughput improved (although stall is not yet eliminated). The command ran: TEST_TMPDIR=/dev/shm/ ./db_bench_sort --benchmarks=fillseq --compression_type=lz4 --write_buffer_size=5000000 --num=100000000 --value_size=1000 The throughput improved by 11%. Reviewed By: jay-zhuang Differential Revision: D37129469 fbshipit-source-id: 492da2ef5bfc7cdd6daa3986b50d2ff91f88542d |
3 years ago |
Yanqin Jin | 725df120e9 |
Fix race condition between file purge and backup/checkpoint (#10187)
Summary: Resolves https://github.com/facebook/rocksdb/issues/10129 I extracted this fix from https://github.com/facebook/rocksdb/issues/7516 since it's also already a bug in main branch, and we want to separate it from the main part of the PR. There can be a race condition between two threads. Thread 1 executes `DBImpl::FindObsoleteFiles()` while thread 2 executes `GetSortedWals()`. ``` Time thread 1 thread 2 | mutex_.lock | read disable_delete_obsolete_files_ | ... | wait on log_sync_cv and release mutex_ | mutex_.lock | ++disable_delete_obsolete_files_ | mutex_.unlock | mutex_.lock | while (pending_purge_obsolete_files > 0) { bg_cv.wait;} | wake up with mutex_ locked | compute WALs tracked by MANIFEST | mutex_.unlock | wake up with mutex_ locked | ++pending_purge_obsolete_files_ | mutex_.unlock | | delete obsolete WAL | WAL missing but tracked in MANIFEST. V ``` The fix proposed eliminates the possibility of the above by increasing `pending_purge_obsolete_files_` before `FindObsoleteFiles()` can possibly release the mutex. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10187 Test Plan: make check Reviewed By: ltamasi Differential Revision: D37214235 Pulled By: riversand963 fbshipit-source-id: 556ab1b58ae6d19150169dfac4db08195c797184 |
3 years ago |
Yueh-Hsuan Chiang | 2a3792edfc |
Add suggest_compact_range() and suggest_compact_range_cf() to C API. (#10175)
Summary: Add suggest_compact_range() and suggest_compact_range_cf() to C API. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10175 Test Plan: As verifying the result requires SyncPoint, which is not available in the c_test.c, the test is currently done by invoking the functions and making sure it does not crash. Reviewed By: jay-zhuang Differential Revision: D37305191 Pulled By: ajkr fbshipit-source-id: 0fe257b45914f6c9aeb985d8b1820dafc57a20db |
3 years ago |
Baptiste Lemaire | 5879053fd0 |
Dynamically changeable `MemPurge` option (#10011)
Summary: **Summary** Make the mempurge option flag a Mutable Column Family option flag. Therefore, the mempurge feature can be dynamically toggled. **Motivation** RocksDB users prefer having the ability to switch features on and off without having to close and reopen the DB. This is particularly important if the feature causes issues and needs to be turned off. Dynamically changing a DB option flag does not seem currently possible. Moreover, with this new change, the MemPurge feature can be toggled on or off independently between column families, which we see as a major improvement. **Content of this PR** This PR includes removal of the `experimental_mempurge_threshold` flag as a DB option flag, and its re-introduction as a `MutableCFOption` flag. I updated the code to handle dynamic changes of the flag (in particular inside the `FlushJob` file). Additionally, this PR includes a new test to demonstrate the capacity of the code to toggle the MemPurge feature on and off, as well as the addition in the `db_stress` module of 2 different mempurge threshold values (0.0 and 1.0) that can be randomly changed with the `set_option_one_in` flag. This is useful to stress test the dynamic changes. **Benchmarking** I will add numbers to prove that there is no performance impact within the next 12 hours. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10011 Reviewed By: pdillinger Differential Revision: D36462357 Pulled By: bjlemaire fbshipit-source-id: 5e3d63bdadf085c0572ecc2349e7dd9729ce1802 |
3 years ago |
Yueh-Hsuan Chiang | e103b87296 |
Add get_column_family_metadata() and related functions to C API (#10207)
Summary: * Add metadata related structs and functions in C API, including - `rocksdb_get_column_family_metadata()` and `rocksdb_get_column_family_metadata_cf()` that returns `rocksdb_column_family_metadata_t`. - `rocksdb_column_family_metadata_t` and its get functions & destroy function. - `rocksdb_level_metadata_t` and its and its get functions & destroy function. - `rocksdb_file_metadata_t` and its and get functions & destroy functions. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10207 Test Plan: Extend the existing c_test.c to include additional checks for column_family_metadata inside CheckCompaction. Reviewed By: riversand963 Differential Revision: D37305209 Pulled By: ajkr fbshipit-source-id: 0a5183206353acde145f5f9b632c3bace670aa6e |
3 years ago |
Peter Dillinger | 84210c9489 |
Add data block hash index to crash test, fix MultiGet issue (#10220)
Summary: There was a bug in the MultiGet enhancement in https://github.com/facebook/rocksdb/issues/9899 with data block hash index, which was not caught because data block hash index was never added to stress tests. This change fixes both issues. Fixes https://github.com/facebook/rocksdb/issues/10186 I intend to pick this into the 7.4.0 release candidate Pull Request resolved: https://github.com/facebook/rocksdb/pull/10220 Test Plan: Failure quickly reproduces in crash test with kDataBlockBinaryAndHash, and does not seem to with the fix. Reproducing the failure with a unit test I believe would be too tricky and fragile to be worthwhile. Reviewed By: anand1976 Differential Revision: D37315647 Pulled By: pdillinger fbshipit-source-id: 9f648265bba867275edc752f7a56611a59401cba |
3 years ago |
Peter Dillinger | 6358e1b967 |
Start release 7.5 development (#10204)
Summary: Update HISTORY.md and version.h Pull Request resolved: https://github.com/facebook/rocksdb/pull/10204 Test Plan: version bump only Reviewed By: ajkr Differential Revision: D37271866 Pulled By: pdillinger fbshipit-source-id: 0ccaa2af36648a5b6017c172a7826a244e1aec93 |
3 years ago |
Peter Dillinger | fac7a23685 |
Update HISTORY for 7.4.0 release freeze (#10196)
Summary: Planned for Sunday 6/19 Pull Request resolved: https://github.com/facebook/rocksdb/pull/10196 Test Plan: no code Reviewed By: akankshamahajan15 Differential Revision: D37244857 Pulled By: pdillinger fbshipit-source-id: afbf4aa201983b3c01c16b5f55c68f2325d17421 |
3 years ago |
Changyu Bi | 0e0a19832e |
Fix a bug in WriteBatchInternal::Append when write batch KV protection is turned on (#10201)
Summary:
This bug was discovered after write batch checksum verification before WAL is added (https://github.com/facebook/rocksdb/issues/10114) and stress test with write batch checksum protection is turned on (https://github.com/facebook/rocksdb/issues/10037). In this [line](
|
3 years ago |
Andrew Kryczka | d5d8920f2c |
Fix race condition with WAL tracking and `FlushWAL(true /* sync */)` (#10185)
Summary: `FlushWAL(true /* sync */)` is used internally and for manual WAL sync. It had a bug when used together with `track_and_verify_wals_in_manifest` where the synced size tracked in MANIFEST was larger than the number of bytes actually synced. The bug could be repro'd almost immediately with the following crash test command: `python3 tools/db_crashtest.py blackbox --simple --write_buffer_size=524288 --max_bytes_for_level_base=2097152 --target_file_size_base=524288 --duration=3600 --interval=10 --sync_fault_injection=1 --disable_wal=0 --checkpoint_one_in=1000 --max_key=10000 --value_size_mult=33`. An example error message produced by the above command is shown below. The error sometimes arose from the checkpoint and other times arose from the main stress test DB. ``` Corruption: Size mismatch: WAL (log number: 119) in MANIFEST is 27938 bytes , but actually is 27859 bytes on disk. ``` Pull Request resolved: https://github.com/facebook/rocksdb/pull/10185 Test Plan: - repro unit test - the above crash test command no longer finds the error. It does find a different error after a while longer such as "Corruption: WAL file 481 required by manifest but not in directory list" Reviewed By: riversand963 Differential Revision: D37200993 Pulled By: ajkr fbshipit-source-id: 98e0071c1a89f4d009888512ed89f9219779ae5f |
3 years ago |
Hui Xiao | a5d773e077 |
Add rate-limiting support to batched MultiGet() (#10159)
Summary: **Context/Summary:** https://github.com/facebook/rocksdb/pull/9424 added rate-limiting support for user reads, which does not include batched `MultiGet()`s that call `RandomAccessFileReader::MultiRead()`. The reason is that it's harder (compared with RandomAccessFileReader::Read()) to implement the ideal rate-limiting where we first call `RateLimiter::RequestToken()` for allowed bytes to multi-read and then consume those bytes by satisfying as many requests in `MultiRead()` as possible. For example, it can be tricky to decide whether we want partially fulfilled requests within one `MultiRead()` or not. However, due to a recent urgent user request, we decide to pursue an elementary (but a conditionally ineffective) solution where we accumulate enough rate limiter requests toward the total bytes needed by one `MultiRead()` before doing that `MultiRead()`. This is not ideal when the total bytes are huge as we will actually consume a huge bandwidth from rate-limiter causing a burst on disk. This is not what we ultimately want with rate limiter. Therefore a follow-up work is noted through TODO comments. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10159 Test Plan: - Modified existing unit test `DBRateLimiterOnReadTest/DBRateLimiterOnReadTest.NewMultiGet` - Traced the underlying system calls `io_uring_enter` and verified they are 10 seconds apart from each other correctly under the setting of `strace -ftt -e trace=io_uring_enter ./db_bench -benchmarks=multireadrandom -db=/dev/shm/testdb2 -readonly -num=50 -threads=1 -multiread_batched=1 -batch_size=100 -duration=10 -rate_limiter_bytes_per_sec=200 -rate_limiter_refill_period_us=1000000 -rate_limit_bg_reads=1 -disable_auto_compactions=1 -rate_limit_user_ops=1` where each `MultiRead()` read about 2000 bytes (inspected by debugger) and the rate limiter grants 200 bytes per seconds. - Stress test: - Verified `./db_stress (-test_cf_consistency=1/test_batches_snapshots=1) -use_multiget=1 -cache_size=1048576 -rate_limiter_bytes_per_sec=10241024 -rate_limit_bg_reads=1 -rate_limit_user_ops=1` work Reviewed By: ajkr, anand1976 Differential Revision: D37135172 Pulled By: hx235 fbshipit-source-id: 73b8e8f14761e5d4b77235dfe5d41f4eea968bcd |
3 years ago |
Peter Dillinger | 1aac814578 |
Use optimized folly DistributedMutex in LRUCache when available (#10179)
Summary: folly DistributedMutex is faster than standard mutexes though imposes some static obligations on usage. See https://github.com/facebook/folly/blob/main/folly/synchronization/DistributedMutex.h for details. Here we use this alternative for our Cache implementations (especially LRUCache) for better locking performance, when RocksDB is compiled with folly. Also added information about which distributed mutex implementation is being used to cache_bench output and to DB LOG. Intended follow-up: * Use DMutex in more places, perhaps improving API to support non-scoped locking * Fix linking with fbcode compiler (needs ROCKSDB_NO_FBCODE=1 currently) Credit: Thanks Siying for reminding me about this line of work that was previously left unfinished. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10179 Test Plan: for correctness, existing tests. CircleCI config updated. Also Meta-internal buck build updated. For performance, ran simultaneous before & after cache_bench. Out of three comparison runs, the middle improvement to ops/sec was +21%: Baseline: USE_CLANG=1 DEBUG_LEVEL=0 make -j24 cache_bench (fbcode compiler) ``` Complete in 20.201 s; Rough parallel ops/sec = 1584062 Thread ops/sec = 107176 Operation latency (ns): Count: 32000000 Average: 9257.9421 StdDev: 122412.04 Min: 134 Median: 3623.0493 Max: 56918500 Percentiles: P50: 3623.05 P75: 10288.02 P99: 30219.35 P99.9: 683522.04 P99.99: 7302791.63 ``` New: (add USE_FOLLY=1) ``` Complete in 16.674 s; Rough parallel ops/sec = 1919135 (+21%) Thread ops/sec = 135487 Operation latency (ns): Count: 32000000 Average: 7304.9294 StdDev: 108530.28 Min: 132 Median: 3777.6012 Max: 91030902 Percentiles: P50: 3777.60 P75: 10169.89 P99: 24504.51 P99.9: 59721.59 P99.99: 1861151.83 ``` Reviewed By: anand1976 Differential Revision: D37182983 Pulled By: pdillinger fbshipit-source-id: a17eb05f25b832b6a2c1356f5c657e831a5af8d1 |
3 years ago |
Andrew Kryczka | 5d6005c780 |
Add WriteOptions::protection_bytes_per_key (#10037)
Summary: Added an option, `WriteOptions::protection_bytes_per_key`, that controls how many bytes per key we use for integrity protection in `WriteBatch`. It takes effect when `WriteBatch::GetProtectionBytesPerKey() == 0`. Currently the only supported value is eight. Invoking a user API with it set to any other nonzero value will result in `Status::NotSupported` returned to the user. There is also a bug fix for integrity protection with `inplace_callback`, where we forgot to take into account the possible change in varint length when calculating KV checksum for the final encoded buffer. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10037 Test Plan: - Manual - Set default value of `WriteOptions::protection_bytes_per_key` to eight and ran `make check -j24` - Enabled in MyShadow for 1+ week - Automated - Unit tests have a `WriteMode` that enables the integrity protection via `WriteOptions` - Crash test - in most cases, use `WriteOptions::protection_bytes_per_key` to enable integrity protection Reviewed By: cbi42 Differential Revision: D36614569 Pulled By: ajkr fbshipit-source-id: 8650087ceac9b61b560f1e5fafe5e1baf9c725fb |
3 years ago |
Changyu Bi | 8cf86258b8 |
Update HISTORY.md for #10114 (#10189)
Summary: Update HISTORY.md for https://github.com/facebook/rocksdb/issues/10114: write batch checksum verification before writing to WAL. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10189 Reviewed By: ajkr Differential Revision: D37226366 Pulled By: cbi42 fbshipit-source-id: cd2f076961abc35f35783e0f2cc3beda68cdb446 |
3 years ago |
Peter Dillinger | 126c223714 |
Remove deprecated block-based filter (#10184)
Summary: In https://github.com/facebook/rocksdb/issues/9535, release 7.0, we hid the old block-based filter from being created using the public API, because of its inefficiency. Although we normally maintain read compatibility on old DBs forever, filters are not required for reading a DB, only for optimizing read performance. Thus, it should be acceptable to remove this code and the substantial maintenance burden it carries as useful features are developed and validated (such as user timestamp). This change completely removes the code for reading and writing the old block-based filters, net removing about 1370 lines of code no longer needed. Options removed from testing / benchmarking tools. The prior existence is only evident in a couple of places: * `CacheEntryRole::kDeprecatedFilterBlock` - We can update this public API enum in a major release to minimize source code incompatibilities. * A warning is logged when an old table file is opened that used the old block-based filter. This is provided as a courtesy, and would be a pain to unit test, so manual testing should suffice. Unfortunately, sst_dump does not tell you whether a file uses block-based filter, and the structure of the code makes it very difficult to fix. * To detect that case, `kObsoleteFilterBlockPrefix` (renamed from `kFilterBlockPrefix`) for metaindex is maintained (for now). Other notes: * In some cases where numbers are associated with filter configurations, we have had to update the assigned numbers so that they all correspond to something that exists. * Fixed potential stat counting bug by assuming `filter_checked = false` for cases like `filter == nullptr` rather than assuming `filter_checked = true` * Removed obsolete `block_offset` and `prefix_extractor` parameters from several functions. * Removed some unnecessary checks `if (!table_prefix_extractor() && !prefix_extractor)` because the caller guarantees the prefix extractor exists and is compatible Pull Request resolved: https://github.com/facebook/rocksdb/pull/10184 Test Plan: tests updated, manually test new warning in LOG using base version to generate a DB Reviewed By: riversand963 Differential Revision: D37212647 Pulled By: pdillinger fbshipit-source-id: 06ee020d8de3b81260ffc36ad0c1202cbf463a80 |
3 years ago |
anand76 | a6691d0f65 |
Update stats to help users estimate MultiGet async IO impact (#10182)
Summary: Add a couple of stats to help users estimate the impact of potential MultiGet perf improvements - 1. NUM_LEVEL_READ_PER_MULTIGET - A histogram stat for number of levels that required MultiGet to read from a file 2. MULTIGET_COROUTINE_COUNT - A ticker stat to count the number of times the coroutine version of MultiGetFromSST was used The NUM_DATA_BLOCKS_READ_PER_LEVEL stat is obsoleted as it doesn't provide useful information for MultiGet optimization. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10182 Reviewed By: akankshamahajan15 Differential Revision: D37213296 Pulled By: anand1976 fbshipit-source-id: 5d2b7708017c0e278578ae4bffac3926f6530efb |
3 years ago |
Peter Dillinger | 3d358a7e25 |
Fix handling of accidental truncation of IDENTITY file (#10173)
Summary: A consequence of https://github.com/facebook/rocksdb/issues/9990 was requiring a non-empty DB ID to generate new SST files. But if the DB ID is not tracked in the manifest and the IDENTITY file is somehow truncated to 0 bytes, then an empty DB ID would be assigned, leading to crash. This change ensures a non-empty DB ID is assigned and set in the IDENTITY file. Also, * Some light refactoring to clean up the logic * (I/O efficiency) If the ID is tracked in the manifest and already matches the IDENTITY file, don't needlessly overwrite the file. * (Debugging) Log the DB ID to info log on open, because sometimes IDENTITY can change if DB is moved around (though it would be unusual for info log to be copied/moved without IDENTITY file) Pull Request resolved: https://github.com/facebook/rocksdb/pull/10173 Test Plan: unit tests expanded/updated Reviewed By: ajkr Differential Revision: D37176545 Pulled By: pdillinger fbshipit-source-id: a9b414cd35bfa33de48af322a36c24538d50bef1 |
3 years ago |
Hui Xiao | d665afdbf3 |
Account memory of FileMetaData in global memory limit (#9924)
Summary: **Context/Summary:** As revealed by heap profiling, allocation of `FileMetaData` for [newly created file added to a Version](https://github.com/facebook/rocksdb/pull/9924/files#diff-a6aa385940793f95a2c5b39cc670bd440c4547fa54fd44622f756382d5e47e43R774) can consume significant heap memory. This PR is to account that toward our global memory limit based on block cache capacity. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9924 Test Plan: - Previous `make check` verified there are only 2 places where the memory of the allocated `FileMetaData` can be released - New unit test `TEST_P(ChargeFileMetadataTestWithParam, Basic)` - db bench (CPU cost of `charge_file_metadata` in write and compact) - **write micros/op: -0.24%** : `TEST_TMPDIR=/dev/shm/testdb ./db_bench -benchmarks=fillseq -db=$TEST_TMPDIR -charge_file_metadata=1 (remove this option for pre-PR) -disable_auto_compactions=1 -write_buffer_size=100000 -num=4000000 | egrep 'fillseq'` - **compact micros/op -0.87%** : `TEST_TMPDIR=/dev/shm/testdb ./db_bench -benchmarks=fillseq -db=$TEST_TMPDIR -charge_file_metadata=1 -disable_auto_compactions=1 -write_buffer_size=100000 -num=4000000 -numdistinct=1000 && ./db_bench -benchmarks=compact -db=$TEST_TMPDIR -use_existing_db=1 -charge_file_metadata=1 -disable_auto_compactions=1 | egrep 'compact'` table 1 - write #-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 80 | 3.87828 | 0.119007 | 3.86791 | 0.115674 | **-0.2673865734** 160 | 3.87677 | 0.162231 | 3.86739 | 0.16663 | **-0.2419539978** table 2 - compact #-run | (pre-PR) avg micros/op | std micros/op | (post-PR) micros/op | std micros/op | change (%) -- | -- | -- | -- | -- | -- 10 | 2,399,650.00 | 96,375.80 | 2,359,537.00 | 53,243.60 | -1.67 20 | 2,410,480.00 | 89,988.00 | 2,433,580.00 | 91,121.20 | 0.96 40 | 2.41E+06 | 121811 | 2.39E+06 | 131525 | **-0.96** 80 | 2.40E+06 | 134503 | 2.39E+06 | 108799 | **-0.78** - stress test: `python3 tools/db_crashtest.py blackbox --charge_file_metadata=1 --cache_size=1` killed as normal Reviewed By: ajkr Differential Revision: D36055583 Pulled By: hx235 fbshipit-source-id: b60eab94707103cb1322cf815f05810ef0232625 |
3 years ago |
Akanksha Mahajan | c0e0f30667 |
Implement AbortIO using io_uring (#10125)
Summary: Implement AbortIO in posix using io_uring to cancel any pending read requests submitted. Its cancelled using io_uring_prep_cancel which sets the IORING_OP_ASYNC_CANCEL flag. To cancel a request, the sqe must have ->addr set to the user_data of the request it wishes to cancel. If the request is cancelled successfully, the original request is completed with -ECANCELED and the cancel request is completed with a result of 0. If the request was already running, the original may or may not complete in error. The cancel request will complete with -EALREADY for that case. And finally, if the request to cancel wasn't found, the cancel request is completed with -ENOENT. Reference: https://kernel.dk/io_uring-whatsnew.pdf, https://lore.kernel.org/io-uring/d9a8d76d23690842f666c326631ecc2d85b6c1bc.1615566409.git.asml.silence@gmail.com/ Pull Request resolved: https://github.com/facebook/rocksdb/pull/10125 Test Plan: Existing Posix tests. Reviewed By: anand1976 Differential Revision: D36946970 Pulled By: akankshamahajan15 fbshipit-source-id: 3bc1f1521b3151d01a348fc6431eb3fc85db3a14 |
3 years ago |
Peter Dillinger | ad135f3ffd |
Document design/specification bugs with auto_prefix_mode (#10144)
Summary: auto_prefix_mode is designed to use prefix filtering in a particular "safe" set of cases where the upper bound and the seek key have different prefixes: where the upper bound is the "same length immediate successor". These conditions are not sufficient to guarantee the same iteration results as total_order_seek if the DB contains "short" keys, less than the "full" (maximum) prefix length. We are not simply disabling the optimization in these successor cases because it is likely that users are essentially getting what they want out of existing usage. Especially if users are constructing successor bounds with the intention of doing a prefix-bounded seek, the existing behavior is more expected than the total_order_seek behavior. Consequently, for now we reconcile the bad specification of behavior by documenting the existing mismatch with total_order_seek. A closely related issue affects hypothetical comparators like ReverseBytewiseComparator: if they "correctly" implement IsSameLengthImmediateSuccessor, auto_prefix_mode could omit more entries (other than "short" keys noted above). Luckily, the built-in ReverseBytewiseComparator has an "incorrect" implementation of IsSameLengthImmediateSuccessor that effectively prevents prefix optimization and, thus, the bug. This is now documented as a new constraint on IsSameLengthImmediateSuccessor, and the implementation tweaked to be simply "safe" rather than "incorrect". This change also includes unit test updates to demonstrate the above issues. (Test was cleaned up for readability and simplicity.) Intended follow-up: * Tweak documented axioms for prefix_extractor (more details then) * Consider some sort of fix for this case. I don't know what that would look like without breaking the performance of existing code. Perhaps if all keys in an SST file have prefixes that are "full length," we can track that fact and use it to allow optimization with the "same length immediate successor", but that would only apply to new files. * Consider a better system of specifying prefix bounds Pull Request resolved: https://github.com/facebook/rocksdb/pull/10144 Test Plan: test updates included Reviewed By: siying Differential Revision: D37052710 Pulled By: pdillinger fbshipit-source-id: 5f63b7d65f3f214e4b143e0f9aa1749527c587db |
3 years ago |
Yanqin Jin | 1777e5f7e9 |
Snapshots with user-specified timestamps (#9879)
Summary: In RocksDB, keys are associated with (internal) sequence numbers which denote when the keys are written to the database. Sequence numbers in different RocksDB instances are unrelated, thus not comparable. It is nice if we can associate sequence numbers with their corresponding actual timestamps. One thing we can do is to support user-defined timestamp, which allows the applications to specify the format of custom timestamps and encode a timestamp with each key. More details can be found at https://github.com/facebook/rocksdb/wiki/User-defined-Timestamp-%28Experimental%29. This PR provides a different but complementary approach. We can associate rocksdb snapshots (defined in https://github.com/facebook/rocksdb/blob/7.2.fb/include/rocksdb/snapshot.h#L20) with **user-specified** timestamps. Since a snapshot is essentially an object representing a sequence number, this PR establishes a bi-directional mapping between sequence numbers and timestamps. In the past, snapshots are usually taken by readers. The current super-version is grabbed, and a `rocksdb::Snapshot` object is created with the last published sequence number of the super-version. You can see that the reader actually has no good idea of what timestamp to assign to this snapshot, because by the time the `GetSnapshot()` is called, an arbitrarily long period of time may have already elapsed since the last write, which is when the last published sequence number is written. This observation motivates the creation of "timestamped" snapshots on the write path. Currently, this functionality is exposed only to the layer of `TransactionDB`. Application can tell RocksDB to create a snapshot when a transaction commits, effectively associating the last sequence number with a timestamp. It is also assumed that application will ensure any two snapshots with timestamps should satisfy the following: ``` snapshot1.seq < snapshot2.seq iff. snapshot1.ts < snapshot2.ts ``` If the application can guarantee that when a reader takes a timestamped snapshot, there is no active writes going on in the database, then we also allow the user to use a new API `TransactionDB::CreateTimestampedSnapshot()` to create a snapshot with associated timestamp. Code example ```cpp // Create a timestamped snapshot when committing transaction. txn->SetCommitTimestamp(100); txn->SetSnapshotOnNextOperation(); txn->Commit(); // A wrapper API for convenience Status Transaction::CommitAndTryCreateSnapshot( std::shared_ptr<TransactionNotifier> notifier, TxnTimestamp ts, std::shared_ptr<const Snapshot>* ret); // Create a timestamped snapshot if caller guarantees no concurrent writes std::pair<Status, std::shared_ptr<const Snapshot>> snapshot = txn_db->CreateTimestampedSnapshot(100); ``` The snapshots created in this way will be managed by RocksDB with ref-counting and potentially shared with other readers. We provide the following APIs for readers to retrieve a snapshot given a timestamp. ```cpp // Return the timestamped snapshot correponding to given timestamp. If ts is // kMaxTxnTimestamp, then we return the latest timestamped snapshot if present. // Othersise, we return the snapshot whose timestamp is equal to `ts`. If no // such snapshot exists, then we return null. std::shared_ptr<const Snapshot> TransactionDB::GetTimestampedSnapshot(TxnTimestamp ts) const; // Return the latest timestamped snapshot if present. std::shared_ptr<const Snapshot> TransactionDB::GetLatestTimestampedSnapshot() const; ``` We also provide two additional APIs for stats collection and reporting purposes. ```cpp Status TransactionDB::GetAllTimestampedSnapshots( std::vector<std::shared_ptr<const Snapshot>>& snapshots) const; // Return timestamped snapshots whose timestamps fall in [ts_lb, ts_ub) and store them in `snapshots`. Status TransactionDB::GetTimestampedSnapshots( TxnTimestamp ts_lb, TxnTimestamp ts_ub, std::vector<std::shared_ptr<const Snapshot>>& snapshots) const; ``` To prevent the number of timestamped snapshots from growing infinitely, we provide the following API to release timestamped snapshots whose timestamps are older than or equal to a given threshold. ```cpp void TransactionDB::ReleaseTimestampedSnapshotsOlderThan(TxnTimestamp ts); ``` Before shutdown, RocksDB will release all timestamped snapshots. Comparison with user-defined timestamp and how they can be combined: User-defined timestamp persists every key with a timestamp, while timestamped snapshots maintain a volatile mapping between snapshots (sequence numbers) and timestamps. Different internal keys with the same user key but different timestamps will be treated as different by compaction, thus a newer version will not hide older versions (with smaller timestamps) unless they are eligible for garbage collection. In contrast, taking a timestamped snapshot at a certain sequence number and timestamp prevents all the keys visible in this snapshot from been dropped by compaction. Here, visible means (seq < snapshot and most recent). The timestamped snapshot supports the semantics of reading at an exact point in time. Timestamped snapshots can also be used with user-defined timestamp. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9879 Test Plan: ``` make check TEST_TMPDIR=/dev/shm make crash_test_with_txn ``` Reviewed By: siying Differential Revision: D35783919 Pulled By: riversand963 fbshipit-source-id: 586ad905e169189e19d3bfc0cb0177a7239d1bd4 |
3 years ago |
Peter Dillinger | d3a3b02134 |
Fix bug with kHashSearch and changing prefix_extractor with SetOptions (#10128)
Summary: When opening an SST file created using index_type=kHashSearch, the *current* prefix_extractor would be saved, and used with hash index if the *new current* prefix_extractor at query time is compatible with the SST file. This is a problem if the prefix_extractor at SST open time is not compatible but SetOptions later changes (back) to one that is compatible. This change fixes that by using the known compatible (or missing) prefix extractor we save for use with prefix filtering. Detail: I have moved the InternalKeySliceTransform wrapper to avoid some indirection and remove unnecessary fields. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10128 Test Plan: expanded unit test (using some logic from https://github.com/facebook/rocksdb/issues/10122) that fails before fix and probably covers some other previously uncovered cases. Reviewed By: siying Differential Revision: D36955738 Pulled By: pdillinger fbshipit-source-id: 0c78a6b0d24054ef2f3cb237bf010c1c5589fb10 |
3 years ago |
Akanksha Mahajan | f85b31a2e9 |
Fix bug for WalManager with compressed WAL (#10130)
Summary: RocksDB uses WalManager to manage WAL files. In WalManager::ReadFirstLine(), the assumption is that reading the first record of a valid WAL file will return OK status and set the output sequence to non-zero value. This assumption has been broken by WAL compression which writes a `kSetCompressionType` record which is not associated with any sequence number. Consequently, WalManager::GetSortedWalsOfType() will skip these WALs and not return them to caller, e.g. Checkpoint, Backup, causing the operations to fail. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10130 Test Plan: - Newly Added test Reviewed By: riversand963 Differential Revision: D36985744 Pulled By: akankshamahajan15 fbshipit-source-id: dfde7b3be68b6a30b75b49479779748eedf29f7f |
3 years ago |
Yanqin Jin | d739de63e5 |
Fix a bug in WAL tracking (#10087)
Summary: Closing https://github.com/facebook/rocksdb/issues/10080 When `SyncWAL()` calls `MarkLogsSynced()`, even if there is only one active WAL file, this event should still be added to the MANIFEST. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10087 Test Plan: make check Reviewed By: ajkr Differential Revision: D36797580 Pulled By: riversand963 fbshipit-source-id: 24184c9dd606b3939a454ed41de6e868d1519999 |
3 years ago |
Gang Liao | e6432dfd4c |
Make it possible to enable blob files starting from a certain LSM tree level (#10077)
Summary: Currently, if blob files are enabled (i.e. `enable_blob_files` is true), large values are extracted both during flush/recovery (when SST files are written into level 0 of the LSM tree) and during compaction into any LSM tree level. For certain use cases that have a mix of short-lived and long-lived values, it might make sense to support extracting large values only during compactions whose output level is greater than or equal to a specified LSM tree level (e.g. compactions into L1/L2/... or above). This could reduce the space amplification caused by large values that are turned into garbage shortly after being written at the price of some write amplification incurred by long-lived values whose extraction to blob files is delayed. In order to achieve this, we would like to do the following: - Add a new configuration option `blob_file_starting_level` (default: 0) to `AdvancedColumnFamilyOptions` (and `MutableCFOptions` and extend the related logic) - Instantiate `BlobFileBuilder` in `BuildTable` (used during flush and recovery, where the LSM tree level is L0) and `CompactionJob` iff `enable_blob_files` is set and the LSM tree level is `>= blob_file_starting_level` - Add unit tests for the new functionality, and add the new option to our stress tests (`db_stress` and `db_crashtest.py` ) - Add the new option to our benchmarking tool `db_bench` and the BlobDB benchmark script `run_blob_bench.sh` - Add the new option to the `ldb` tool (see https://github.com/facebook/rocksdb/wiki/Administration-and-Data-Access-Tool) - Ideally extend the C and Java bindings with the new option - Update the BlobDB wiki to document the new option. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10077 Reviewed By: ltamasi Differential Revision: D36884156 Pulled By: gangliao fbshipit-source-id: 942bab025f04633edca8564ed64791cb5e31627d |
3 years ago |
Gang Liao | 3dc6ebaf74 |
Support specifying blob garbage collection parameters when CompactRange() (#10073)
Summary: Garbage collection is generally controlled by the BlobDB configuration options `enable_blob_garbage_collection` and `blob_garbage_collection_age_cutoff`. However, there might be use cases where we would want to temporarily override these options while performing a manual compaction. (One use case would be doing a full key-space manual compaction with full=100% garbage collection age cutoff in order to minimize the space occupied by the database.) Our goal here is to make it possible to override the configured GC parameters when using the `CompactRange` API to perform manual compactions. This PR would involve: - Extending the `CompactRangeOptions` structure so clients can both force-enable and force-disable GC, as well as use a different cutoff than what's currently configured - Storing whether blob GC should actually be enabled during a certain manual compaction and the cutoff to use in the `Compaction` object (considering the above overrides) and passing it to `CompactionIterator` via `CompactionProxy` - Updating the BlobDB wiki to document the new options. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10073 Test Plan: Adding unit tests and adding the new options to the stress test tool. Reviewed By: ltamasi Differential Revision: D36848700 Pulled By: gangliao fbshipit-source-id: c878ef101d1c612429999f513453c319f75d78e9 |
3 years ago |
Akanksha Mahajan | 45b1c788c4 |
Update History.md for #9922 (#10092)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10092 Reviewed By: riversand963 Differential Revision: D36832311 Pulled By: akankshamahajan15 fbshipit-source-id: 8fb1cf90b1d4dddebbfbeebeddb15f6905968e9b |
3 years ago |
Jay Zhuang | 5864900cf4 |
Get current LogFileNumberSize the same as log_writer (#10086)
Summary: `db_impl.alive_log_files_` is used to track the WAL size in `db_impl.logs_`. Get the `LogFileNumberSize` obj in `alive_log_files_` the same time as `log_writer` to keep them consistent. For this issue, it's not safe to do `deque::reverse_iterator::operator*` and `deque::pop_front()` concurrently, so remove the tail cache. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10086 Test Plan: ``` # on Windows gtest-parallel ./db_test --gtest_filter=DBTest.FileCreationRandomFailure -r 1000 -w 100 ``` Reviewed By: riversand963 Differential Revision: D36822373 Pulled By: jay-zhuang fbshipit-source-id: 5e738051dfc7bcf6a15d85ba25e6365df6b6a6af |
3 years ago |
Changyu Bi | 463873f1bb |
Add bug fix to HISTORY.md (#10091)
Summary: Add to HISTORY.md the bug fixed in https://github.com/facebook/rocksdb/issues/10051 Pull Request resolved: https://github.com/facebook/rocksdb/pull/10091 Reviewed By: ajkr Differential Revision: D36821861 Pulled By: cbi42 fbshipit-source-id: 598812fab88f65c0147ece53cff55cf4ea73aac6 |
3 years ago |
Peter Dillinger | a00cffaf69 |
Reduce risk of backup or checkpoint missing a WAL file (#10083)
Summary: We recently saw a case in crash test in which a WAL file in the middle of the list of live WALs was not included in the backup, so the DB was not openable due to missing WAL. We are not sure why, but this change should at least turn that into a backup-time failure by ensuring all the WAL files expected by the manifest (according to VersionSet) are included in `GetSortedWalFiles()` (used by `GetLiveFilesStorageInfo()`, `BackupEngine`, and `Checkpoint`) Related: to maximize the effectiveness of track_and_verify_wals_in_manifest with GetSortedWalFiles() during checkpoint/backup, we will now sync WAL in GetLiveFilesStorageInfo() when track_and_verify_wals_in_manifest=true. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10083 Test Plan: added new unit test for the check in GetSortedWalFiles() Reviewed By: ajkr Differential Revision: D36791608 Pulled By: pdillinger fbshipit-source-id: a27bcf0213fc7ab177760fede50d4375d579afa6 |
3 years ago |
Yanqin Jin | 514f0b0937 |
Fail DB::Open() if logger cannot be created (#9984)
Summary: For regular db instance and secondary instance, we return error and refuse to open DB if Logger creation fails. Our current code allows it, but it is really difficult to debug because there will be no LOG files. The same for OPTIONS file, which will be explored in another PR. Furthermore, Arena::AllocateAligned(size_t bytes, size_t huge_page_size, Logger* logger) has an assertion as the following: ```cpp #ifdef MAP_HUGETLB if (huge_page_size > 0 && bytes > 0) { assert(logger != nullptr); } #endif ``` It can be removed. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9984 Test Plan: make check Reviewed By: jay-zhuang Differential Revision: D36347754 Pulled By: riversand963 fbshipit-source-id: 529798c0511d2eaa2f0fd40cf7e61c4cbc6bc57e |
3 years ago |
Muthu Krishnan | c9c58a320f |
Add C API for User Defined Timestamp (#9914)
Summary: Fixes https://github.com/facebook/rocksdb/issues/9889 Pull Request resolved: https://github.com/facebook/rocksdb/pull/9914 Reviewed By: akankshamahajan15 Differential Revision: D36599983 Pulled By: riversand963 fbshipit-source-id: 39000fb473f850d88359e90b287035257854af0d |
3 years ago |
Akanksha Mahajan | 28ea1fb44a |
Provide support for IOTracing for ReadAsync API (#9833)
Summary: Same as title Pull Request resolved: https://github.com/facebook/rocksdb/pull/9833 Test Plan: Add unit test and manually check the output of tracing logs For fixed readahead_size it logs as: ``` Access Time : 193352113447923 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 15075 , IO Status: OK, Length: 12288, Offset: 659456 Access Time : 193352113465232 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 14425 , IO Status: OK, Length: 12288, Offset: 671744 Access Time : 193352113481539 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 13062 , IO Status: OK, Length: 12288, Offset: 684032 Access Time : 193352113497692 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 13649 , IO Status: OK, Length: 12288, Offset: 696320 Access Time : 193352113520043 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 19384 , IO Status: OK, Length: 12288, Offset: 708608 Access Time : 193352113538401 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 15406 , IO Status: OK, Length: 12288, Offset: 720896 Access Time : 193352113554855 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 13670 , IO Status: OK, Length: 12288, Offset: 733184 Access Time : 193352113571624 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 13855 , IO Status: OK, Length: 12288, Offset: 745472 Access Time : 193352113587924 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 13953 , IO Status: OK, Length: 12288, Offset: 757760 Access Time : 193352113603285 , File Name: 000026.sst , File Operation: Prefetch , Latency: 59 , IO Status: Not implemented: Prefetch not supported, Length: 8868, Offset: 898349 ``` For implicit readahead: ``` Access Time : 193351865156587 , File Name: 000026.sst , File Operation: Prefetch , Latency: 48 , IO Status: Not implemented: Prefetch not supported, Length: 12266, Offset: 391174 Access Time : 193351865160354 , File Name: 000026.sst , File Operation: Prefetch , Latency: 51 , IO Status: Not implemented: Prefetch not supported, Length: 12266, Offset: 395248 Access Time : 193351865164253 , File Name: 000026.sst , File Operation: Prefetch , Latency: 49 , IO Status: Not implemented: Prefetch not supported, Length: 12266, Offset: 399322 Access Time : 193351865165461 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 222871 , IO Status: OK, Length: 135168, Offset: 401408 ``` Reviewed By: anand1976 Differential Revision: D35601634 Pulled By: akankshamahajan15 fbshipit-source-id: 5a4f32a850af878efa0767bd5706380152a1f26e |
3 years ago |
sdong | 356f8c5d81 |
FindObsoleteFiles() to directly check whether candidate files are live (#10040)
Summary: Right now, in FindObsoleteFiles() we build a list of all live SST files from all existing Versions. This is all done in DB mutex, and is O(m*n) where m is number of versions and n is number of files. In some extereme cases, it can take very long. The list is used to see whether a candidate file still shows up in a version. With this commit, every candidate file is directly check against all the versions for file existance. This operation would be O(m*k) where k is number of candidate files. Since is usually small (except perhaps full compaction in universal compaction), this is usually much faster than the previous solution. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10040 Test Plan: TBD Reviewed By: riversand963 Differential Revision: D36613391 fbshipit-source-id: 3f13b090f755d9b3ae417faec62cd6e798bac1eb |
3 years ago |
Yiyuan Liu | b71466e982 |
Improve transaction C-API (#9252)
Summary: This PR wants to improve support for transaction in C-API: * Support two-phase commit. * Support `get_pinned` and `multi_get` in transaction. * Add `rocksdb_transactiondb_flush` * Support get writebatch from transaction and rebuild transaction from writebatch. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9252 Reviewed By: jay-zhuang Differential Revision: D36459007 Pulled By: riversand963 fbshipit-source-id: 47371d527be821c496353a7fe2fd18d628069a98 |
3 years ago |
sdong | c78a87cd71 |
Avoid malloc_usable_size() call inside LRU Cache mutex (#10026)
Summary: In LRU Cache mutex, we sometimes call malloc_usable_size() to calculate memory used by the metadata object. We prevent it by saving the charge + metadata size, rather than charge, inside the metadata itself. Within the mutex, usually only total charge is needed so we don't need to repeat. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10026 Test Plan: Run existing tests. Reviewed By: pdillinger Differential Revision: D36556253 fbshipit-source-id: f60c96d13cde3af77732e5548e4eac4182fa9801 |
3 years ago |
Yu Zhang | d4081bf0be |
Add timestamp support to CompactedDBImpl (#10030)
Summary: This PR is the second and last part for adding user defined timestamp support to read only DB. Specifically, the change in this PR includes: - `options.timestamp` respected by `CompactedDBImpl::Get` and `CompactedDBImpl::MultiGet` to return results visible up till that timestamp. - `CompactedDBImpl::Get(...,std::string* timestsamp)` and `CompactedDBImpl::MultiGet(std::vector<std::string>* timestamps)` return the timestamp(s) associated with the key(s). Pull Request resolved: https://github.com/facebook/rocksdb/pull/10030 Test Plan: ``` $COMPILE_WITH_ASAN=1 make -j24 all $./db_readonly_with_timestamp_test --gtest_filter="DBReadOnlyTestWithTimestamp.CompactedDB*" $./db_basic_test --gtest_filter="DBBasicTest.CompactedDB*" $make all check ``` Reviewed By: riversand963 Differential Revision: D36613926 Pulled By: jowlyzhang fbshipit-source-id: 5b7ed7fef822708c12e2caf7a8d2deb6a696f0f0 |
3 years ago |
Akanksha Mahajan | 700d597bd8 |
Expose unix time in rocksdb::Snapshot (#9923)
Summary: RocksDB snapshot already has a member unix_time_ set after snapshot is taken. It is now exposed through GetSnapshotTime() API. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9923 Test Plan: Update unit tests Reviewed By: riversand963 Differential Revision: D36048275 Pulled By: akankshamahajan15 fbshipit-source-id: 825210ec287deb0bc3aaa9b8e1f079f07ad686fa |
3 years ago |
Levi Tamasi | 253ae017fa |
Update version on main to 7.4 and add 7.3 to the format compatibility checks (#10038)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10038 Reviewed By: riversand963 Differential Revision: D36604533 Pulled By: ltamasi fbshipit-source-id: 54ccd0a4b32a320b5640a658ea6846ee897065d1 |
3 years ago |
Levi Tamasi | bed40e7266 |
Update HISTORY for 7.3 release (#10031)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10031 Reviewed By: riversand963 Differential Revision: D36567741 Pulled By: ltamasi fbshipit-source-id: 058f8cc856d276db6e1aed07a89ac0b7118c4435 |
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 |
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](
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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 |
Bo Wang | 5be1579ead |
Address comments for PR #9988 and #9996 (#10020)
Summary: 1. The latest change of DecideRateLimiterPriority in https://github.com/facebook/rocksdb/pull/9988 is reverted. 2. For https://github.com/facebook/rocksdb/blob/main/db/builder.cc#L345-L349 2.1. Remove `we will regrad this verification as user reads` from the comments. 2.2. `Do not set` the read_options.rate_limiter_priority to Env::IO_USER . Flush should be a background job. 2.3. Update db_rate_limiter_test.cc. 3. In IOOptions, mark `prio` as deprecated for future removal. 4. In `file_system.h`, mark `IOPriority` as deprecated for future removal. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10020 Test Plan: Unit tests. Reviewed By: ajkr Differential Revision: D36525317 Pulled By: gitbw95 fbshipit-source-id: 011ba421822f8a124e6d25a2661c4e242df6ad36 |
3 years ago |
Jay Zhuang | c6d326d3d7 |
Track SST unique id in MANIFEST and verify (#9990)
Summary: Start tracking SST unique id in MANIFEST, which is used to verify with SST properties to make sure the SST file is not overwritten or misplaced. A DB option `try_verify_sst_unique_id` is introduced to enable/disable the verification, if enabled, it opens all SST files during DB-open to read the unique_id from table properties (default is false), so it's recommended to use it with `max_open_files = -1` to pre-open the files. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9990 Test Plan: unittests, format-compatible test, mini-crash Reviewed By: anand1976 Differential Revision: D36381863 Pulled By: jay-zhuang fbshipit-source-id: 89ea2eb6b35ed3e80ead9c724eb096083eaba63f |
3 years ago |
gitbw95 | 4da34b97ee |
Set Read rate limiter priority dynamically and pass it to FS (#9996)
Summary: ### Context: Background compactions and flush generate large reads and writes, and can be long running, especially for universal compaction. In some cases, this can impact foreground reads and writes by users. ### Solution User, Flush, and Compaction reads share some code path. For this task, we update the rate_limiter_priority in ReadOptions for code paths (e.g. FindTable (mainly in BlockBasedTable::Open()) and various iterators), and eventually update the rate_limiter_priority in IOOptions for FSRandomAccessFile. **This PR is for the Read path.** The **Read:** dynamic priority for different state are listed as follows: | State | Normal | Delayed | Stalled | | ----- | ------ | ------- | ------- | | Flush (verification read in BuildTable()) | IO_USER | IO_USER | IO_USER | | Compaction | IO_LOW | IO_USER | IO_USER | | User | User provided | User provided | User provided | We will respect the read_options that the user provided and will not set it. The only sst read for Flush is the verification read in BuildTable(). It claims to be "regard as user read". **Details** 1. Set read_options.rate_limiter_priority dynamically: - User: Do not update the read_options. Use the read_options that the user provided. - Compaction: Update read_options in CompactionJob::ProcessKeyValueCompaction(). - Flush: Update read_options in BuildTable(). 2. Pass the rate limiter priority to FSRandomAccessFile functions: - After calling the FindTable(), read_options is passed through GetTableReader(table_cache.cc), BlockBasedTableFactory::NewTableReader(block_based_table_factory.cc), and BlockBasedTable::Open(). The Open() needs some updates for the ReadOptions variable and the updates are also needed for the called functions, including PrefetchTail(), PrepareIOOptions(), ReadFooterFromFile(), ReadMetaIndexblock(), ReadPropertiesBlock(), PrefetchIndexAndFilterBlocks(), and ReadRangeDelBlock(). - In RandomAccessFileReader, the functions to be updated include Read(), MultiRead(), ReadAsync(), and Prefetch(). - Update the downstream functions of NewIndexIterator(), NewDataBlockIterator(), and BlockBasedTableIterator(). ### Test Plans Add unit tests. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9996 Reviewed By: anand1976 Differential Revision: D36452483 Pulled By: gitbw95 fbshipit-source-id: 60978204a4f849bb9261cb78d9bc1cb56d6008cf |
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 |
Jay Zhuang | b84e3363f5 |
Add table_properties_collector_factories override (#9995)
Summary: Add table_properties_collector_factories override on the remote side. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9995 Test Plan: unittest added Reviewed By: ajkr Differential Revision: D36392623 Pulled By: jay-zhuang fbshipit-source-id: 3ba031294d90247ca063d7de7b43178d38e3f66a |
3 years ago |