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127 Commits (be04a3b6cdaab4641e86f4af6832a33b08bcf7b0)
| Author | SHA1 | Message | Date |
|---|---|---|---|
Changyu Bi
|
30bc495c03 |
Skip swaths of range tombstone covered keys in merging iterator (2022 edition) (#10449)
Summary: Delete range logic is moved from `DBIter` to `MergingIterator`, and `MergingIterator` will seek to the end of a range deletion if possible instead of scanning through each key and check with `RangeDelAggregator`. With the invariant that a key in level L (consider memtable as the first level, each immutable and L0 as a separate level) has a larger sequence number than all keys in any level >L, a range tombstone `[start, end)` from level L covers all keys in its range in any level >L. This property motivates optimizations in iterator: - in `Seek(target)`, if level L has a range tombstone `[start, end)` that covers `target.UserKey`, then for all levels > L, we can do Seek() on `end` instead of `target` to skip some range tombstone covered keys. - in `Next()/Prev()`, if the current key is covered by a range tombstone `[start, end)` from level L, we can do `Seek` to `end` for all levels > L. This PR implements the above optimizations in `MergingIterator`. As all range tombstone covered keys are now skipped in `MergingIterator`, the range tombstone logic is removed from `DBIter`. The idea in this PR is similar to https://github.com/facebook/rocksdb/issues/7317, but this PR leaves `InternalIterator` interface mostly unchanged. **Credit**: the cascading seek optimization and the sentinel key (discussed below) are inspired by [Pebble](https://github.com/cockroachdb/pebble/blob/master/merging_iter.go) and suggested by ajkr in https://github.com/facebook/rocksdb/issues/7317. The two optimizations are mostly implemented in `SeekImpl()/SeekForPrevImpl()` and `IsNextDeleted()/IsPrevDeleted()` in `merging_iterator.cc`. See comments for each method for more detail. One notable change is that the minHeap/maxHeap used by `MergingIterator` now contains range tombstone end keys besides point key iterators. This helps to reduce the number of key comparisons. For example, for a range tombstone `[start, end)`, a `start` and an `end` `HeapItem` are inserted into the heap. When a `HeapItem` for range tombstone start key is popped from the minHeap, we know this range tombstone becomes "active" in the sense that, before the range tombstone's end key is popped from the minHeap, all the keys popped from this heap is covered by the range tombstone's internal key range `[start, end)`. Another major change, *delete range sentinel key*, is made to `LevelIterator`. Before this PR, when all point keys in an SST file are iterated through in `MergingIterator`, a level iterator would advance to the next SST file in its level. In the case when an SST file has a range tombstone that covers keys beyond the SST file's last point key, advancing to the next SST file would lose this range tombstone. Consequently, `MergingIterator` could return keys that should have been deleted by some range tombstone. We prevent this by pretending that file boundaries in each SST file are sentinel keys. A `LevelIterator` now only advance the file iterator once the sentinel key is processed. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10449 Test Plan: - Added many unit tests in db_range_del_test - Stress test: `./db_stress --readpercent=5 --prefixpercent=19 --writepercent=20 -delpercent=10 --iterpercent=44 --delrangepercent=2` - Additional iterator stress test is added to verify against iterators against expected state: https://github.com/facebook/rocksdb/issues/10538. This is based on ajkr's previous attempt https://github.com/facebook/rocksdb/pull/5506#issuecomment-506021913. ``` python3 ./tools/db_crashtest.py blackbox --simple --write_buffer_size=524288 --target_file_size_base=524288 --max_bytes_for_level_base=2097152 --compression_type=none --max_background_compactions=8 --value_size_mult=33 --max_key=5000000 --interval=10 --duration=7200 --delrangepercent=3 --delpercent=9 --iterpercent=25 --writepercent=60 --readpercent=3 --prefixpercent=0 --num_iterations=1000 --range_deletion_width=100 --verify_iterator_with_expected_state_one_in=1 ``` - Performance benchmark: I used a similar setup as in the blog [post](http://rocksdb.org/blog/2018/11/21/delete-range.html) that introduced DeleteRange, "a database with 5 million data keys, and 10000 range tombstones (ignoring those dropped during compaction) that were written in regular intervals after 4.5 million data keys were written". As expected, the performance with this PR depends on the range tombstone width. ``` # Setup: TEST_TMPDIR=/dev/shm ./db_bench_main --benchmarks=fillrandom --writes=4500000 --num=5000000 TEST_TMPDIR=/dev/shm ./db_bench_main --benchmarks=overwrite --writes=500000 --num=5000000 --use_existing_db=true --writes_per_range_tombstone=50 # Scan entire DB TEST_TMPDIR=/dev/shm ./db_bench_main --benchmarks=readseq[-X5] --use_existing_db=true --num=5000000 --disable_auto_compactions=true # Short range scan (10 Next()) TEST_TMPDIR=/dev/shm/width-100/ ./db_bench_main --benchmarks=seekrandom[-X5] --use_existing_db=true --num=500000 --reads=100000 --seek_nexts=10 --disable_auto_compactions=true # Long range scan(1000 Next()) TEST_TMPDIR=/dev/shm/width-100/ ./db_bench_main --benchmarks=seekrandom[-X5] --use_existing_db=true --num=500000 --reads=2500 --seek_nexts=1000 --disable_auto_compactions=true ``` Avg over of 10 runs (some slower tests had fews runs): For the first column (tombstone), 0 means no range tombstone, 100-10000 means width of the 10k range tombstones, and 1 means there is a single range tombstone in the entire DB (width is 1000). The 1 tombstone case is to test regression when there's very few range tombstones in the DB, as no range tombstone is likely to take a different code path than with range tombstones. - Scan entire DB | tombstone width | Pre-PR ops/sec | Post-PR ops/sec | ±% | | ------------- | ------------- | ------------- | ------------- | | 0 range tombstone |2525600 (± 43564) |2486917 (± 33698) |-1.53% | | 100 |1853835 (± 24736) |2073884 (± 32176) |+11.87% | | 1000 |422415 (± 7466) |1115801 (± 22781) |+164.15% | | 10000 |22384 (± 227) |227919 (± 6647) |+918.22% | | 1 range tombstone |2176540 (± 39050) |2434954 (± 24563) |+11.87% | - Short range scan | tombstone width | Pre-PR ops/sec | Post-PR ops/sec | ±% | | ------------- | ------------- | ------------- | ------------- | | 0 range tombstone |35398 (± 533) |35338 (± 569) |-0.17% | | 100 |28276 (± 664) |31684 (± 331) |+12.05% | | 1000 |7637 (± 77) |25422 (± 277) |+232.88% | | 10000 |1367 |28667 |+1997.07% | | 1 range tombstone |32618 (± 581) |32748 (± 506) |+0.4% | - Long range scan | tombstone width | Pre-PR ops/sec | Post-PR ops/sec | ±% | | ------------- | ------------- | ------------- | ------------- | | 0 range tombstone |2262 (± 33) |2353 (± 20) |+4.02% | | 100 |1696 (± 26) |1926 (± 18) |+13.56% | | 1000 |410 (± 6) |1255 (± 29) |+206.1% | | 10000 |25 |414 |+1556.0% | | 1 range tombstone |1957 (± 30) |2185 (± 44) |+11.65% | - Microbench does not show significant regression: https://gist.github.com/cbi42/59f280f85a59b678e7e5d8561e693b61 Reviewed By: ajkr Differential Revision: D38450331 Pulled By: cbi42 fbshipit-source-id: b5ef12e8d8c289ed2e163ccdf277f5039b511fca |
2 years ago |
|
Levi Tamasi
|
81388b36e0 |
Add support for wide-column point lookups (#10540)
Summary: The patch adds a new API `GetEntity` that can be used to perform wide-column point lookups. It also extends the `Get` code path and the `MemTable` / `MemTableList` and `Version` / `GetContext` logic accordingly so that wide-column entities can be served from both memtables and SSTs. If the result of a lookup is a wide-column entity (`kTypeWideColumnEntity`), it is passed to the application in deserialized form; if it is a plain old key-value (`kTypeValue`), it is presented as a wide-column entity with a single default (anonymous) column. (In contrast, regular `Get` returns plain old key-values as-is, and returns the value of the default column for wide-column entities, see https://github.com/facebook/rocksdb/issues/10483 .) The result of `GetEntity` is a self-contained `PinnableWideColumns` object. `PinnableWideColumns` contains a `PinnableSlice`, which either stores the underlying data in its own buffer or holds on to a cache handle. It also contains a `WideColumns` instance, which indexes the contents of the `PinnableSlice`, so applications can access the values of columns efficiently. There are several pieces of functionality which are currently not supported for wide-column entities: there is currently no `MultiGetEntity` or wide-column iterator; also, `Merge` and `GetMergeOperands` are not supported, and there is no `GetEntity` implementation for read-only and secondary instances. We plan to implement these in future PRs. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10540 Test Plan: `make check` Reviewed By: akankshamahajan15 Differential Revision: D38847474 Pulled By: ltamasi fbshipit-source-id: 42311a34ccdfe88b3775e847a5e2a5296e002b5b |
2 years ago |
|
Andrew Kryczka
|
91166012c8 |
Prevent a case of WriteBufferManager flush thrashing (#6364)
Summary: Previously, the flushes triggered by `WriteBufferManager` could affect the same CF repeatedly if it happens to get consecutive writes. Such flushes are not particularly useful for reducing memory usage since they switch nearly-empty memtables to immutable while they've just begun filling their first arena block. In fact they may not even reduce the mutable memory count if they involve replacing one mutable memtable containing one arena block with a new mutable memtable containing one arena block. Further, if such switches happen even a few times before a flush finishes, the immutable memtable limit will be reached and writes will stall. This PR adds a heuristic to not switch memtables to immutable for CFs that already have one or more immutable memtables awaiting flush. There is a memory usage regression if the user continues writing to the same CF, that DB does not have any CFs eligible for switching, flushes are not finishing, and the `WriteBufferManager` was constructed with `allow_stall=false`. Before, it would grow by switching nearly empty memtables until writes stall. Now, it would grow by filling memtables until writes stall. This feels like an acceptable behavior change because users who prefer to stall over violate the memory limit should be using `allow_stall=true`, which is unaffected by this PR. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6364 Test Plan: - Command: `rm -rf /dev/shm/dbbench/ && TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillrandom -num_multi_db=8 -num_column_families=2 -write_buffer_size=4194304 -db_write_buffer_size=16777216 -compression_type=none -statistics=true -target_file_size_base=4194304 -max_bytes_for_level_base=16777216` - `rocksdb.db.write.stall` count before this PR: 175 - `rocksdb.db.write.stall` count after this PR: 0 Reviewed By: jay-zhuang Differential Revision: D20167197 Pulled By: ajkr fbshipit-source-id: 4a64064e9bc33d57c0a35f15547542d0191d0cb7 |
2 years ago |
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Changyu Bi
|
9d77bf8f7b |
Fragment memtable range tombstone in the write path (#10380)
Summary: - Right now each read fragments the memtable range tombstones https://github.com/facebook/rocksdb/issues/4808. This PR explores the idea of fragmenting memtable range tombstones in the write path and reads can just read this cached fragmented tombstone without any fragmenting cost. This PR only does the caching for immutable memtable, and does so right before a memtable is added to an immutable memtable list. The fragmentation is done without holding mutex to minimize its performance impact. - db_bench is updated to print out the number of range deletions executed if there is any. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10380 Test Plan: - CI, added asserts in various places to check whether a fragmented range tombstone list should have been constructed. - Benchmark: as this PR only optimizes immutable memtable path, the number of writes in the benchmark is chosen such an immutable memtable is created and range tombstones are in that memtable. ``` single thread: ./db_bench --benchmarks=fillrandom,readrandom --writes_per_range_tombstone=1 --max_write_buffer_number=100 --min_write_buffer_number_to_merge=100 --writes=500000 --reads=100000 --max_num_range_tombstones=100 multi_thread ./db_bench --benchmarks=fillrandom,readrandom --writes_per_range_tombstone=1 --max_write_buffer_number=100 --min_write_buffer_number_to_merge=100 --writes=15000 --reads=20000 --threads=32 --max_num_range_tombstones=100 ``` Commit 99cdf16464a057ca44de2f747541dedf651bae9e is included in benchmark result. It was an earlier attempt where tombstones are fragmented for each write operation. Reader threads share it using a shared_ptr which would slow down multi-thread read performance as seen in benchmark results. Results are averaged over 5 runs. Single thread result: | Max # tombstones | main fillrandom micros/op | 99cdf16464a057ca44de2f747541dedf651bae9e | Post PR | main readrandom micros/op | 99cdf16464a057ca44de2f747541dedf651bae9e | Post PR | | ------------- | ------------- |------------- |------------- |------------- |------------- |------------- | | 0 |6.68 |6.57 |6.72 |4.72 |4.79 |4.54 | | 1 |6.67 |6.58 |6.62 |5.41 |4.74 |4.72 | | 10 |6.59 |6.5 |6.56 |7.83 |4.69 |4.59 | | 100 |6.62 |6.75 |6.58 |29.57 |5.04 |5.09 | | 1000 |6.54 |6.82 |6.61 |320.33 |5.22 |5.21 | 32-thread result: note that "Max # tombstones" is per thread. | Max # tombstones | main fillrandom micros/op | 99cdf16464a057ca44de2f747541dedf651bae9e | Post PR | main readrandom micros/op | 99cdf16464a057ca44de2f747541dedf651bae9e | Post PR | | ------------- | ------------- |------------- |------------- |------------- |------------- |------------- | | 0 |234.52 |260.25 |239.42 |5.06 |5.38 |5.09 | | 1 |236.46 |262.0 |231.1 |19.57 |22.14 |5.45 | | 10 |236.95 |263.84 |251.49 |151.73 |21.61 |5.73 | | 100 |268.16 |296.8 |280.13 |2308.52 |22.27 |6.57 | Reviewed By: ajkr Differential Revision: D37916564 Pulled By: cbi42 fbshipit-source-id: 05d6d2e16df26c374c57ddcca13a5bfe9d5b731e |
2 years ago |
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Jay Zhuang
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a3acf2ef87 |
Add seqno to time mapping (#10338)
Summary: Which will be used for tiered storage to preclude hot data from compacting to the cold tier (the last level). Internally, adding seqno to time mapping. A periodic_task is scheduled to record the current_seqno -> current_time in certain cadence. When memtable flush, the mapping informaiton is stored in sstable property. During compaction, the mapping information are merged and get the approximate time of sequence number, which is used to determine if a key is recently inserted or not and preclude it from the last level if it's recently inserted (within the `preclude_last_level_data_seconds`). Pull Request resolved: https://github.com/facebook/rocksdb/pull/10338 Test Plan: CI Reviewed By: siying Differential Revision: D37810187 Pulled By: jay-zhuang fbshipit-source-id: 6953be7a18a99de8b1cb3b162d712f79c2b4899f |
2 years ago |
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Yanqin Jin
|
6eafdf135a |
Encode min_log_number_to_keep and delete_wals_before in one version edit (#9766)
Summary: min_log_number_to_keep denotes that the WALs whose numbers are below this value **will** be deleted by RocksDB. delete_wals_before will be used by RocksDB if track_and_verify_wals_in_manifest is set to true. During recovery, RocksDB uses the info encoded in delete_wals_before to reconstruct its knowledge about what WALs to expect existing. If these two tags are not encoded in the same VersionEdit, then it's possible for min_log_number_to_keep=100 to exist, but delete_wals_before=100 to be lost due to power failure. Subsequent recovery will delete 99.log. If the db crashes again, the following recovery will expect to see 99.log since there is no delete_wals_before=100 in the MANIFEST, but the WAL is already deleted. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9766 Test Plan: First of all, make check. Second, format compatibility. SHORT_TEST=1 ./tools/check_format_compatible.sh Reviewed By: ltamasi Differential Revision: D35203623 Pulled By: riversand963 fbshipit-source-id: 45623fc4b4b50d299d5e0f9559a3a4c5e9522c8f |
3 years ago |
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Yanqin Jin
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e0c84aa0dc |
Fix a race condition in WAL tracking causing DB open failure (#9715)
Summary: There is a race condition if WAL tracking in the MANIFEST is enabled in a database that disables 2PC. The race condition is between two background flush threads trying to install flush results to the MANIFEST. Consider an example database with two column families: "default" (cfd0) and "cf1" (cfd1). Initially, both column families have one mutable (active) memtable whose data backed by 6.log. 1. Trigger a manual flush for "cf1", creating a 7.log 2. Insert another key to "default", and trigger flush for "default", creating 8.log 3. BgFlushThread1 finishes writing 9.sst 4. BgFlushThread2 finishes writing 10.sst ``` Time BgFlushThread1 BgFlushThread2 | mutex_.Lock() | precompute min_wal_to_keep as 6 | mutex_.Unlock() | mutex_.Lock() | precompute min_wal_to_keep as 6 | join MANIFEST write queue and mutex_.Unlock() | write to MANIFEST | mutex_.Lock() | cfd1->log_number = 7 | Signal bg_flush_2 and mutex_.Unlock() | wake up and mutex_.Lock() | cfd0->log_number = 8 | FindObsoleteFiles() with job_context->log_number == 7 | mutex_.Unlock() | PurgeObsoleteFiles() deletes 6.log V ``` As shown in the above, BgFlushThread2 thinks that the min wal to keep is 6.log because "cf1" has unflushed data in 6.log (cf1.log_number=6). Similarly, BgThread1 thinks that min wal to keep is also 6.log because "default" has unflushed data (default.log_number=6). No WAL deletion will be written to MANIFEST because 6 is equal to `versions_->wals_.min_wal_number_to_keep`, due to https://github.com/facebook/rocksdb/blob/7.1.fb/db/memtable_list.cc#L513:L514. The bg flush thread that finishes last will perform file purging. `job_context.log_number` will be evaluated as 7, i.e. the min wal that contains unflushed data, causing 6.log to be deleted. However, MANIFEST thinks 6.log should still exist. If you close the db at this point, you won't be able to re-open it if `track_and_verify_wal_in_manifest` is true. We must handle the case of multiple bg flush threads, and it is difficult for one bg flush thread to know the correct min wal number until the other bg flush threads have finished committing to the manifest and updated the `cfd::log_number`. To fix this issue, we rename an existing variable `min_log_number_to_keep_2pc` to `min_log_number_to_keep`, and use it to track WAL file deletion in non-2pc mode as well. This variable is updated only 1) during recovery with mutex held, or 2) in the MANIFEST write thread. `min_log_number_to_keep` means RocksDB will delete WALs below it, although there may be WALs above it which are also obsolete. Formally, we will have [min_wal_to_keep, max_obsolete_wal]. During recovery, we make sure that only WALs above max_obsolete_wal are checked and added back to `alive_log_files_`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9715 Test Plan: ``` make check ``` Also ran stress test below (with asan) to make sure it completes successfully. ``` TEST_TMPDIR=/dev/shm/rocksdb OPT=-g ASAN_OPTIONS=disable_coredump=0 \ CRASH_TEST_EXT_ARGS=--compression_type=zstd SKIP_FORMAT_BUCK_CHECKS=1 \ make J=52 -j52 blackbox_asan_crash_test ``` Reviewed By: ltamasi Differential Revision: D34984412 Pulled By: riversand963 fbshipit-source-id: c7b21a8d84751bb55ea79c9f387103d21b231005 |
3 years ago |
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anand76
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a88d8795ec |
Expand auto recovery to background read errors (#9679)
Summary: Fix and enhance the background error recovery logic to handle the following situations - 1. Background read errors during flush/compaction (previously was resulting in unrecoverable state) 2. Fix auto recovery failure on read/write errors during atomic flush. It was failing due to a bug in setting the resuming_from_bg_err variable in AtomicFlushMemTablesToOutputFiles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9679 Test Plan: Add new unit tests in error_handler_fs_test Reviewed By: riversand963 Differential Revision: D34770097 Pulled By: anand1976 fbshipit-source-id: 136da973a28d684b9c74bdf668519b0cbbbe1742 |
3 years ago |
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Baptiste Lemaire
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7bed6595f3 |
Fix mempurge crash reported in #8958 (#9671)
Summary: Change the `MemPurge` code to address a failure during a crash test reported in https://github.com/facebook/rocksdb/issues/8958. ### Details and results of the crash investigation: These failures happened in a specific scenario where the list of immutable tables was composed of 2 or more memtables, and the last memtable was the output of a previous `Mempurge` operation. Because the `PickMemtablesToFlush` function included a sorting of the memtables (previous PR related to the Mempurge project), and because the `VersionEdit` of the flush class is piggybacked onto a single one of these memtables, the `VersionEdit` was not properly selected and applied to the `VersionSet` of the DB. Since the `VersionSet` was not edited properly, the database was losing track of the SST file created during the flush process, which was subsequently deleted (and as you can expect, caused the tests to crash). The following command consistently failed, which was quite convenient to investigate the issue: `$ while rm -rf /dev/shm/single_stress && ./db_stress --clear_column_family_one_in=0 --column_families=1 --db=/dev/shm/single_stress --experimental_mempurge_threshold=5.493146827397074 --flush_one_in=10000 --reopen=0 --write_buffer_size=262144 --value_size_mult=33 --max_write_buffer_number=3 -ops_per_thread=10000; do : ; done` ### Solution proposed The memtables are no longer sorted based on their `memtableID` in the `PickMemtablesToFlush` function. Additionally, the `next_log_number` of the memtable created as an output of the `Mempurge` function now takes in the correct value (the log number of the first memtable being mempurged). Finally, the VersionEdit object of the flush class now takes the maximum `next_log_number` of the stack of memtables being flushed, which doesnt change anything when Mempurge is `off` but becomes necessary when Mempurge is `on`. ### Testing of the solution The following command no longer fails: ``$ while rm -rf /dev/shm/single_stress && ./db_stress --clear_column_family_one_in=0 --column_families=1 --db=/dev/shm/single_stress --experimental_mempurge_threshold=5.493146827397074 --flush_one_in=10000 --reopen=0 --write_buffer_size=262144 --value_size_mult=33 --max_write_buffer_number=3 -ops_per_thread=10000; do : ; done`` Additionally, I ran `db_crashtest` (`whitebox` and `blackbox`) for 2.5 hours with MemPurge on and did not observe any crash. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9671 Reviewed By: pdillinger Differential Revision: D34697424 Pulled By: bjlemaire fbshipit-source-id: d1ab675b361904351ac81a35c184030e52222874 |
3 years ago |
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mrambacher
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423538a816 |
Make MemoryAllocator into a Customizable class (#8980)
Summary: - Make MemoryAllocator and its implementations into a Customizable class. - Added a "DefaultMemoryAllocator" which uses new and delete - Added a "CountedMemoryAllocator" that counts the number of allocs and free - Updated the existing tests to use these new allocators - Changed the memkind allocator test into a generic test that can test the various allocators. - Added tests for creating all of the allocators - Added tests to verify/create the JemallocNodumpAllocator using its options. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8980 Reviewed By: zhichao-cao Differential Revision: D32990403 Pulled By: mrambacher fbshipit-source-id: 6fdfe8218c10dd8dfef34344a08201be1fa95c76 |
3 years ago |
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lgqss
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77c7085594 |
MemTableList::TrimHistory now use allocated bytes (#9020)
Summary: Fix a bug when both max_write_buffer_size_to_maintain and max_write_buffer_number_to_maintain are 0. The bug was introduced in 6.5.0 and https://github.com/facebook/rocksdb/issues/5022. Fix https://github.com/facebook/rocksdb/issues/8371 Pull Request resolved: https://github.com/facebook/rocksdb/pull/9020 Reviewed By: pdillinger Differential Revision: D32767084 Pulled By: ajkr fbshipit-source-id: c401ee6e2557230e892d0fe8abb4966cbd18e85f |
3 years ago |
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mrambacher
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13ae16c315 |
Cleanup includes in dbformat.h (#8930)
Summary: This header file was including everything and the kitchen sink when it did not need to. This resulted in many places including this header when they needed other pieces instead. Cleaned up this header to only include what was needed and fixed up the remaining code to include what was now missing. Hopefully, this sort of code hygiene cleanup will speed up the builds... Pull Request resolved: https://github.com/facebook/rocksdb/pull/8930 Reviewed By: pdillinger Differential Revision: D31142788 Pulled By: mrambacher fbshipit-source-id: 6b45de3f300750c79f751f6227dece9cfd44085d |
3 years ago |
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Baptiste Lemaire
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e51be2c5a1 |
Improve MemPurge sampling (#8656)
Summary: Previously, the `MemPurge` sampling function was assessing whether a random entry from a memtable was garbage or not by simply querying the given memtable (see https://github.com/facebook/rocksdb/issues/8628 for more details). In this diff, I am updating the sampling function by querying not only the memtable the entry was drawn from, but also all subsequent memtables that have a greater memtable ID. I also added the size of the value for KV entries in the payload/useful payload estimates (which was also one of the reasons why sampling was not as good as mempurging all the time in terms of L0 SST files reduction). Once these changes were made, I was able to clean obsolete objects and functions from the `MemtableList` struct, and did a bit of cleanup everywhere. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8656 Reviewed By: pdillinger Differential Revision: D30288583 Pulled By: bjlemaire fbshipit-source-id: 7646a545ec56f4715949daa59ab5eee74540feb3 |
3 years ago |
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Yanqin Jin
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0879c24040 |
Fix NotifyOnFlushCompleted() for atomic flush (#8585)
Summary: PR https://github.com/facebook/rocksdb/issues/5908 added `flush_jobs_info_` to `FlushJob` to make sure `OnFlushCompleted()` is called after committing flush results to MANIFEST. However, `flush_jobs_info_` is not updated in atomic flush, causing `NotifyOnFlushCompleted()` to skip `OnFlushCompleted()`. This PR fixes this, in a similar way to https://github.com/facebook/rocksdb/issues/5908 that handles regular flush. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8585 Test Plan: make check Reviewed By: jay-zhuang Differential Revision: D29913720 Pulled By: riversand963 fbshipit-source-id: 4ff023c98372fa2c93188d4a5c8a4e9ffa0f4dda |
3 years ago |
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Baptiste Lemaire
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b278152261 |
Fix db stress crash mempurge (#8604)
Summary: The db_stress crash was caused by a call to `IsFlushPending()` made by a stats function which triggered an `assert([false])`, which I didn't plan when I created the `trigger_flush` bool. It turns out that this bool variable is not useful: I created it because I thought the `imm_flush_needed` atomic bool would actually trigger a flush. It turns out that this bool is only checked in `IsFlushPending` - this is its only use - and a flush is triggered by either a background thread checking on the imm array, or by an explicit call to `SchedulePendingFlush` which creates a flush request, that is then added to a flush request queue. In this PR, I reverted the MemtableList::Add function to what it was before my changes. I tested the fix by running the exact command line that deterministically triggered the assert error (see below), which confirmed that this is where the error was coming from. I also run `db_crashtest.py whitebox` and `blackbox` for a couple hours locally before committing this PR. Experiment run: ```./db_stress --acquire_snapshot_one_in=0 --allow_concurrent_memtable_write=1 --avoid_flush_during_recovery=0 --avoid_unnecessary_blocking_io=1 --backup_max_size=104857600 --backup_one_in=100000 --batch_protection_bytes_per_key=0 --block_size=16384 --bloom_bits=76.90653425292307 --bottommost_compression_type=disable --cache_index_and_filter_blocks=1 --cache_size=1048576 --checkpoint_one_in=1000000 --checksum_type=kCRC32c --clear_column_family_one_in=0 --column_families=1 --compact_files_one_in=1000000 --compact_range_one_in=0 --compaction_ttl=2 --compression_max_dict_buffer_bytes=0 --compression_max_dict_bytes=0 --compression_parallel_threads=1 --compression_type=zstd --compression_zstd_max_train_bytes=0 --continuous_verification_interval=0 --db=/dev/shm/rocksdb/rocksdb_crashtest_blackbox --db_write_buffer_size=0 --delpercent=4 --delrangepercent=1 --destroy_db_initially=0 --enable_compaction_filter=1 --enable_pipelined_write=0 --expected_values_path=/dev/shm/rocksdb/rocksdb_crashtest_expected --experimental_allow_mempurge=1 --experimental_mempurge_policy=kAlternate --fail_if_options_file_error=1 --file_checksum_impl=none --flush_one_in=1000000 --format_version=2 --get_current_wal_file_one_in=0 --get_live_files_one_in=1000000 --get_property_one_in=1000000 --get_sorted_wal_files_one_in=0 --index_block_restart_interval=14 --index_type=0 --iterpercent=0 --key_len_percent_dist=1,30,69 --level_compaction_dynamic_level_bytes=False --long_running_snapshots=1 --mark_for_compaction_one_file_in=10 --max_background_compactions=1 --max_bytes_for_level_base=67108864 --max_key=100000000 --max_key_len=3 --max_manifest_file_size=1073741824 --max_write_batch_group_size_bytes=64 --max_write_buffer_number=3 --max_write_buffer_size_to_maintain=0 --memtablerep=skip_list --mmap_read=0 --mock_direct_io=True --nooverwritepercent=1 --open_files=-1 --open_metadata_write_fault_one_in=8 --open_read_fault_one_in=32 --open_write_fault_one_in=16 --ops_per_thread=100000000 --optimize_filters_for_memory=1 --paranoid_file_checks=0 --partition_filters=0 --partition_pinning=0 --pause_background_one_in=1000000 --periodic_compaction_seconds=1000 --prefix_size=-1 --prefixpercent=0 --progress_reports=0 --read_fault_one_in=0 --readpercent=60 --recycle_log_file_num=1 --reopen=20 --set_options_one_in=0 --snapshot_hold_ops=100000 --sst_file_manager_bytes_per_sec=104857600 --sst_file_manager_bytes_per_truncate=0 --subcompactions=3 --sync=1 --sync_fault_injection=False --target_file_size_base=16777216 --target_file_size_multiplier=1 --test_batches_snapshots=0 --top_level_index_pinning=1 --unpartitioned_pinning=3 --use_clock_cache=0 --use_direct_io_for_flush_and_compaction=1 --use_direct_reads=0 --use_full_merge_v1=1 --use_merge=0 --use_multiget=0 --use_ribbon_filter=1 --user_timestamp_size=0 --verify_checksum=1 --verify_checksum_one_in=1000000 --verify_db_one_in=100000 --write_buffer_size=33554432 --write_dbid_to_manifest=1 --writepercent=35``` Pull Request resolved: https://github.com/facebook/rocksdb/pull/8604 Reviewed By: pdillinger Differential Revision: D30047295 Pulled By: bjlemaire fbshipit-source-id: b9e379bfa3d6b9bd2b275725fb0bca4bd81a3dbe |
3 years ago |
|
Baptiste Lemaire
|
c521a9ab2b |
Retire superfluous functions introduced in earlier mempurge PRs. (#8558)
Summary: The main challenge to make the memtable garbage collection prototype (nicknamed `mempurge`) was to not get rid of WAL files that contain unflushed (but mempurged) data. That was successfully guaranteed by not writing the VersionEdit to the MANIFEST file after a successful mempurge. By not writing VersionEdits to the `MANIFEST` file after a succesful mempurge operation, we do not change the earliest log file number that contains unflushed data: `cfd->GetLogNumber()` (`cfd->SetLogNumber()` is only called in `VersionSet::ProcessManifestWrites`). As a result, a number of functions introduced earlier just for the mempurge operation are not obscolete/redundant. (e.g.: `FlushJob::ExtractEarliestLogFileNumber`), and this PR aims at cleaning up all these now-unnecessary functions. In particular, we no longer need to store the earliest log file number in the `MemTable` struct itself. This PR therefore also reverts the `MemTable` struct to its original form. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8558 Test Plan: Already included in `db_flush_test.cc`. Reviewed By: anand1976 Differential Revision: D29764351 Pulled By: bjlemaire fbshipit-source-id: 0f43b260fa270251862512f397d3f24ee62e8437 |
3 years ago |
|
Baptiste Lemaire
|
206845c057 |
Mempurge support for wal (#8528)
Summary: In this PR, `mempurge` is made compatible with the Write Ahead Log: in case of recovery, the DB is now capable of recovering the data that was "mempurged" and kept in the `imm()` list of immutable memtables. The twist was to add a uint64_t to the `memtable` struct to store the number of the earliest log file containing entries from the `memtable`. When a `Flush` operation is replaced with a `MemPurge`, the `VersionEdit` (which usually contains the new min log file number to pick up for recovery and the level 0 file path of the newly created SST file) is no longer appended to the manifest log, and every time the `deleteWal` method is called, a check is made on the list of immutable memtables. This PR also includes a unit test that verifies that no data is lost upon Reopening of the database when the mempurge feature is activated. This extensive unit test includes two column families, with valid data contained in the imm() at time of "crash"/reopening (recovery). Pull Request resolved: https://github.com/facebook/rocksdb/pull/8528 Reviewed By: pdillinger Differential Revision: D29701097 Pulled By: bjlemaire fbshipit-source-id: 072a900fb6ccc1edcf5eef6caf88f3060238edf9 |
3 years ago |
|
Baptiste Lemaire
|
837705ad80 |
Make mempurge a background process (equivalent to in-memory compaction). (#8505)
Summary: In https://github.com/facebook/rocksdb/issues/8454, I introduced a new process baptized `MemPurge` (memtable garbage collection). This new PR is built upon this past mempurge prototype. In this PR, I made the `mempurge` process a background task, which provides superior performance since the mempurge process does not cling on the db_mutex anymore, and addresses severe restrictions from the past iteration (including a scenario where the past mempurge was failling, when a memtable was mempurged but was still referred to by an iterator/snapshot/...). Now the mempurge process ressembles an in-memory compaction process: the stack of immutable memtables is filtered out, and the useful payload is used to populate an output memtable. If the output memtable is filled at more than 60% capacity (arbitrary heuristic) the mempurge process is aborted and a regular flush process takes place, else the output memtable is kept in the immutable memtable stack. Note that adding this output memtable to the `imm()` memtable stack does not trigger another flush process, so that the flush thread can go to sleep at the end of a successful mempurge. MemPurge is activated by making the `experimental_allow_mempurge` flag `true`. When activated, the `MemPurge` process will always happen when the flush reason is `kWriteBufferFull`. The 3 unit tests confirm that this process supports `Put`, `Get`, `Delete`, `DeleteRange` operators and is compatible with `Iterators` and `CompactionFilters`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8505 Reviewed By: pdillinger Differential Revision: D29619283 Pulled By: bjlemaire fbshipit-source-id: 8a99bee76b63a8211bff1a00e0ae32360aaece95 |
3 years ago |
|
storagezhang
|
711881bc25 |
Fix some typos in comments (#8066)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8066 Reviewed By: jay-zhuang Differential Revision: D27280799 Pulled By: mrambacher fbshipit-source-id: 68f91f5af4ffe0a84be581961bf9366887f47702 |
4 years ago |
|
Levi Tamasi
|
1afbd1948c |
Add initial blob support to batched MultiGet (#7766)
Summary: The patch adds initial support for reading blobs to the batched `MultiGet` API. The current implementation simply retrieves the blob values as the blob indexes are encountered; that is, reads from blob files are currently not batched. (This will be optimized in a separate phase.) In addition, the patch removes some dead code related to BlobDB from the batched `MultiGet` implementation, namely the `is_blob` / `is_blob_index` flags that are passed around in `DBImpl` and `MemTable` / `MemTableListVersion`. These were never hooked up to anything and wouldn't work anyways, since a single flag is not sufficient to communicate the "blobness" of multiple key-values. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7766 Test Plan: `make check` Reviewed By: jay-zhuang Differential Revision: D25479290 Pulled By: ltamasi fbshipit-source-id: 7aba2d290e31876ee592bcf1adfd1018713a8000 |
4 years ago |
|
Cheng Chang
|
fd7d8dc56e |
Do not log unnecessary WAL obsoletion events (#7765)
Summary: min_wal_number_to_keep should not be decreasing, if it does not increase, then there is no need to log the WAL obsoletions in MANIFEST since a previous one has been logged. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7765 Test Plan: watch existing tests and stress tests to pass Reviewed By: pdillinger Differential Revision: D25462542 Pulled By: cheng-chang fbshipit-source-id: 0085fcb6edf5cf2b0fc32f9932a7566f508768ff |
4 years ago |
|
Cheng Chang
|
efe827baf0 |
Always track WAL obsoletion (#7759)
Summary: Currently, when a WAL becomes obsolete after flushing, if VersionSet::WalSet does not contain the WAL, we do not track the WAL obsoletion event in MANIFEST. But consider this case: * WAL 10 is synced, a VersionEdit is LogAndApplied to MANIFEST to log this WAL addition event, but the VersionEdit is not applied to WalSet yet since its corresponding ManifestWriter is still pending in the write queue; * Since the above ManifestWriter is blocking, the LogAndApply will block on a conditional variable and release the db mutex, so another LogAndApply can proceed to enqueue other VersionEdits concurrently; * Now flush happens, and WAL 10 becomes obsolete, although WalSet does not contain WAL 10 yet, we should call LogAndApply to enqueue a VersionEdit to indicate the obsoletion of WAL 10; * otherwise, when the queued edit indicating WAL 10 addition is logged to MANIFEST, and DB crashes and reopens, the WAL 10 might have been removed from disk, but it still exists in MANIFEST. This PR changes the behavior to: always `LogAndApply` any WAL addition or obsoletion event, without considering the order issues caused by concurrency, but when applying the edits to `WalSet`, do not add the WALs if they are already obsolete. In this approach, the logical events of WAL addition and obsoletion are always tracked in MANIFEST, so we can inspect the MANIFEST and know all the previous WAL events, but we choose to ignore certain events due to the concurrency issues such as the case above, or the case in https://github.com/facebook/rocksdb/pull/7725. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7759 Test Plan: make check Reviewed By: pdillinger Differential Revision: D25423089 Pulled By: cheng-chang fbshipit-source-id: 9cb9a7fbc1875bf954f2a42f9b6cfd6d49a7b21c |
4 years ago |
|
Cheng Chang
|
07030c6f4a |
Do not track obsolete WALs in MANIFEST even if they are synced (#7725)
Summary: Consider the case: 1. All column families are flushed, so all WALs become obsolete, but no WAL is removed from disk yet because the removal is asynchronous, a VersionEdit is written to MANIFEST indicating that WALs before a certain WAL number are obsolete, let's say this number is 3; 2. `SyncWAL` is called, so all the on-disk WALs are synced, and if track_and_verify_wal_in_manifest=true, the WALs will be tracked in MANIFEST, let's say the WAL numbers are 1 and 2; 3. DB crashes; 4. During DB recovery, when replaying MANIFEST, we first see that WAL with number < 3 are obsolete, then we see that WAL 1 and 2 are synced, so according to current implementation of `WalSet`, the `WalSet` will be recovered to include WAL 1 and 2; 5. WAL 1 and 2 are asynchronously deleted from disk, then the WAL verification algorithm fails with `Corruption: missing WAL`. The above case is reproduced in a new unit test `DBBasicTestTrackWal::DoNotTrackObsoleteWal`. The fix is to maintain the upper bound of the obsolete WAL numbers, any WAL with number less than the maintained number is considered to be obsolete, so shouldn't be tracked even if they are later synced. The number is maintained in `WalSet`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7725 Test Plan: 1. a new unit test `DBBasicTestTrackWal::DoNotTrackObsoleteWal` is added. 2. run `make crash_test` on devserver. Reviewed By: riversand963 Differential Revision: D25238914 Pulled By: cheng-chang fbshipit-source-id: f5dccd57c3d89f19565ec5731f2d42f06d272b72 |
4 years ago |
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Cheng Chang
|
70f2e0916a |
Write min_log_number_to_keep to MANIFEST during atomic flush under 2 phase commit (#7570)
Summary: When 2 phase commit is enabled, if there are prepared data in a WAL, the WAL should be kept, the minimum log number for such a WAL is written to MANIFEST during flush. In atomic flush, such information is not written to MANIFEST. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7570 Test Plan: Added a new unit test `DBAtomicFlushTest.ManualFlushUnder2PC`, this test fails in atomic flush without this PR, after this PR, it succeeds. Reviewed By: riversand963 Differential Revision: D24394222 Pulled By: cheng-chang fbshipit-source-id: 60ce74b21b704804943be40c8de01b41269cf116 |
4 years ago |
|
Yanqin Jin
|
e062a719cc |
Fix assertion failure in bg flush (#7362)
Summary: https://github.com/facebook/rocksdb/issues/7340 reports and reproduces an assertion failure caused by a combination of the following: - atomic flush is disabled. - a column family can appear multiple times in the flush queue at the same time. This behavior was introduced in release 5.17. Consequently, it is possible that two flushes race with each other. One bg flush thread flushes all memtables. The other thread calls `FlushMemTableToOutputFile()` afterwards, and hits the assertion error below. ``` assert(cfd->imm()->NumNotFlushed() != 0); assert(cfd->imm()->IsFlushPending()); ``` Fix this by reverting the behavior. In non-atomic-flush case, a column family can appear in the flush queue at most once at the same time. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7362 Test Plan: make check Also run stress test successfully for 10 times. ``` make crash_test ``` Reviewed By: ajkr Differential Revision: D25172996 Pulled By: riversand963 fbshipit-source-id: f1559b6366cc609e961e3fc83fae548f1fad08ce |
4 years ago |
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Cheng Chang
|
8c93b16f02 |
Track WAL in MANIFEST: Update logic for computing min_log_number_to_keep in atomic flush (#7660)
Summary: The logic for computing min_log_number_to_keep in atomic flush was incorrect. For example, when all column families are flushed, the min_log_number_to_keep should be the latest new log. But the incorrect logic calls `PrecomputeMinLogNumberToKeepNon2PC` for each column family, and returns the minimum of them. However, `PrecomputeMinLogNumberToKeepNon2PC(cf)` assumes column families other than `cf` are flushed, but in case all column families are flushed, this assumption is incorrect. Without this fix, the WAL referenced by the computed min_log_number_to_keep may actually contain no unflushed data, so the WAL might have actually been deleted from disk on recovery, then an incorrect error `Corruption: missing WAL` will be reported. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7660 Test Plan: run `make crash_test_with_atomic_flush` on devserver added a unit test in `db_flush_test` Reviewed By: riversand963 Differential Revision: D24906265 Pulled By: cheng-chang fbshipit-source-id: 08deda62e71f67f59e3b7925cdd86dd09bd4f430 |
4 years ago |
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Cheng Chang
|
1e40696dd1 |
Track WAL in MANIFEST: LogAndApply WAL events to MANIFEST (#7601)
Summary: When a WAL is synced, an edit is written to MANIFEST. After flushing memtables, the obsoleted WALs are piggybacked to MANIFEST while writing the new L0 files to MANIFEST. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7601 Test Plan: `track_and_verify_wals_in_manifest` is enabled by default for all tests extending `DBBasicTest`, and in db_stress_test. Unit test `wal_edit_test`, `version_edit_test`, and `version_set_test` are also updated. Watch all tests to pass. Reviewed By: ltamasi Differential Revision: D24553957 Pulled By: cheng-chang fbshipit-source-id: 66a569ff1bdced38e22900bd240b73113906e040 |
4 years ago |
|
Yanqin Jin
|
6134ce6444 |
Perform post-flush updates of memtable list in a callback (#6069)
Summary: Currently, the following interleaving of events can lead to SuperVersion containing both immutable memtables as well as the resulting L0. This can cause Get to return incorrect result if there are merge operands. This may also affect other operations such as single deletes. ``` time main_thr bg_flush_thr bg_compact_thr compact_thr set_opts_thr 0 | WriteManifest:0 1 | issue compact 2 | wait 3 | Merge(counter) 4 | issue flush 5 | wait 6 | WriteManifest:1 7 | wake up 8 | write manifest 9 | wake up 10 | Get(counter) 11 | remove imm V ``` The reason behind is that: one bg flush thread's installing new `Version` can be batched and performed by another thread that is the "leader" MANIFEST writer. This bg thread removes the memtables from current super version only after `LogAndApply` returns. After the leader MANIFEST writer signals (releasing mutex) this bg flush thread, it is possible that another thread sees this cf with both memtables (whose data have been flushed to the newest L0) and the L0 before this bg flush thread removes the memtables. To address this issue, each bg flush thread can pass a callback function to `LogAndApply`. The callback is responsible for removing the memtables. Therefore, the leader MANIFEST writer can call this callback and remove the memtables before releasing the mutex. Test plan (devserver) ``` $make merge_test $./merge_test --gtest_filter=MergeTest.MergeWithCompactionAndFlush $make check ``` Pull Request resolved: https://github.com/facebook/rocksdb/pull/6069 Reviewed By: cheng-chang Differential Revision: D18790894 Pulled By: riversand963 fbshipit-source-id: e41bd600c0448b4f4b2deb3f7677f95e3076b4ed |
4 years ago |
|
Levi Tamasi
|
b0e7834100 |
Integrate blob file writing with the flush logic (#7345)
Summary: The patch adds support for writing blob files during flush by integrating `BlobFileBuilder` with the flush logic, most importantly, `BuildTable` and `CompactionIterator`. If `enable_blob_files` is set, large values are extracted to blob files and replaced with references. The resulting blob files are then logged to the MANIFEST as part of the flush job's `VersionEdit` and added to the `Version`, similarly to table files. Errors related to writing blob files fail the flush, and any blob files written by such jobs are immediately deleted (again, similarly to how SST files are handled). In addition, the patch extends the logging and statistics around flushes to account for the presence of blob files (e.g. `InternalStats::CompactionStats::bytes_written`, which is used for calculating write amplification, now considers the blob files as well). Pull Request resolved: https://github.com/facebook/rocksdb/pull/7345 Test Plan: Tested using `make check` and `db_bench`. Reviewed By: riversand963 Differential Revision: D23506369 Pulled By: ltamasi fbshipit-source-id: 646885f22dfbe063f650d38a1fedc132f499a159 |
4 years ago |
|
Akanksha Mahajan
|
3844612625 |
Bug Fix for memtables not trimmed down. (#7296)
Summary: When a memtable is trimmed in MemTableListVersion, the memtable is only added to delete list if it is the last reference. However it is not the last reference as it is held by the super version. But the super version would not be switched if the delete list is empty. So the memtable is never destroyed and memory usage increases beyond write_buffer_size + max_write_buffer_size_to_maintain. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7296 Test Plan: 1. ./db_bench -benchmarks=randomtransaction -optimistic_transaction_db=1 -statistics -stats_interval_seconds=1 -duration=90 -num=500000 --max_write_buffer_size_to_maintain=16000000 --transaction_set_snapshot Reviewed By: ltamasi Differential Revision: D23267395 Pulled By: akankshamahajan15 fbshipit-source-id: 3a8d437fe9f4015f851ff84c0e29528aa946b650 |
4 years ago |
|
Yanqin Jin
|
d47c871190 |
Fix data race to VersionSet::io_status_ (#7034)
Summary: After https://github.com/facebook/rocksdb/issues/6949 , VersionSet::io_status_ can be concurrently accessed by multiple threads without lock, causing tsan test to fail. For example, a bg flush thread resets io_status_ before calling LogAndApply(), while another thread already in the process of LogAndApply() reads io_status_. This is a bug. We do not have to reset io_status_ each time we call LogAndApply(). io_status_ is part of the state of VersionSet, and it indicates the outcome of preceding MANIFEST/CURRENT files IO operations. Its value should be updated only when: 1. MANIFEST/CURRENT files IO fail for the first time. 2. MANIFEST/CURRENT files IO succeed as part of recovering from a prior failure without process restart, e.g. calling Resume(). Test Plan (devserver): COMPILE_WITH_TSAN=1 make check COMPILE_WITH_TSAN=1 make db_test2 ./db_test2 --gtest_filter=DBTest2.CompactionStall Pull Request resolved: https://github.com/facebook/rocksdb/pull/7034 Reviewed By: zhichao-cao Differential Revision: D22247137 Pulled By: riversand963 fbshipit-source-id: 77b83e05390f3ee3cd2d96d3fdd6fe4f225e3216 |
4 years ago |
|
Yanqin Jin
|
e66199d848 |
First step towards handling MANIFEST write error (#6949)
Summary: This PR provides preliminary support for handling IO error during MANIFEST write. File write/sync is not guaranteed to be atomic. If we encounter an IOError while writing/syncing to the MANIFEST file, we cannot be sure about the state of the MANIFEST file. The version edits may or may not have reached the file. During cleanup, if we delete the newly-generated SST files referenced by the pending version edit(s), but the version edit(s) actually are persistent in the MANIFEST, then next recovery attempt will process the version edits(s) and then fail since the SST files have already been deleted. One approach is to truncate the MANIFEST after write/sync error, so that it is safe to delete the SST files. However, file truncation may not be supported on certain file systems. Therefore, we take the following approach. If an IOError is detected during MANIFEST write/sync, we disable file deletions for the faulty database. Depending on whether the IOError is retryable (set by underlying file system), either RocksDB or application can call `DB::Resume()`, or simply shutdown and restart. During `Resume()`, RocksDB will try to switch to a new MANIFEST and write all existing in-memory version storage in the new file. If this succeeds, then RocksDB may proceed. If all recovery is completed, then file deletions will be re-enabled. Note that multiple threads can call `LogAndApply()` at the same time, though only one of them will be going through the process MANIFEST write, possibly batching the version edits of other threads. When the leading MANIFEST writer finishes, all of the MANIFEST writing threads in this batch will have the same IOError. They will all call `ErrorHandler::SetBGError()` in which file deletion will be disabled. Possible future directions: - Add an `ErrorContext` structure so that it is easier to pass more info to `ErrorHandler`. Currently, as in this example, a new `BackgroundErrorReason` has to be added. Test plan (dev server): make check Pull Request resolved: https://github.com/facebook/rocksdb/pull/6949 Reviewed By: anand1976 Differential Revision: D22026020 Pulled By: riversand963 fbshipit-source-id: f3c68a2ef45d9b505d0d625c7c5e0c88495b91c8 |
4 years ago |
|
Peter Dillinger
|
aaece2a98d |
Fix some defects reported by Coverity Scan (#6933)
Summary: Confusing checks for null that are never null Pull Request resolved: https://github.com/facebook/rocksdb/pull/6933 Test Plan: make check Reviewed By: cheng-chang Differential Revision: D21885466 Pulled By: pdillinger fbshipit-source-id: 4b48e03c2a33727f2702b0d12292f9fda5a3c475 |
5 years ago |
|
Zhichao Cao
|
4246888101 |
Pass IOStatus to write path and set retryable IO Error as hard error in BG jobs (#6487)
Summary: In the current code base, we use Status to get and store the returned status from the call. Specifically, for IO related functions, the current Status cannot reflect the IO Error details such as error scope, error retryable attribute, and others. With the implementation of https://github.com/facebook/rocksdb/issues/5761, we have the new Wrapper for IO, which returns IOStatus instead of Status. However, the IOStatus is purged at the lower level of write path and transferred to Status. The first job of this PR is to pass the IOStatus to the write path (flush, WAL write, and Compaction). The second job is to identify the Retryable IO Error as HardError, and set the bg_error_ as HardError. In this case, the DB Instance becomes read only. User is informed of the Status and need to take actions to deal with it (e.g., call db->Resume()). Pull Request resolved: https://github.com/facebook/rocksdb/pull/6487 Test Plan: Added the testing case to error_handler_fs_test. Pass make asan_check Reviewed By: anand1976 Differential Revision: D20685017 Pulled By: zhichao-cao fbshipit-source-id: ff85f042896243abcd6ef37877834e26f36b6eb0 |
5 years ago |
|
Zhichao Cao
|
8d73137ae8 |
Replace Directory with FSDirectory in DB (#6468)
Summary: In the current code base, we can use Directory from Env to manage directory (e.g, Fsync()). The PR https://github.com/facebook/rocksdb/issues/5761 introduce the File System as a new Env API. So we further replace the Directory class in DB with FSDirectory such that we can have more IO information from IOStatus returned by FSDirectory. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6468 Test Plan: pass make asan_check Differential Revision: D20195261 Pulled By: zhichao-cao fbshipit-source-id: 93962cb9436852bfcfb76e086d9e7babd461cbe1 |
5 years ago |
|
Huisheng Liu
|
904a60ff63 |
return timestamp from get (#6409)
Summary:
Added new Get() methods that return timestamp. Dummy implementation is given so that classes derived from DB don't need to be touched to provide their implementation. MultiGet is not included.
ReadRandom perf test (10 minutes) on the same development machine ram drive with the same DB data shows no regression (within marge of error). The test is adapted from https://github.com/facebook/rocksdb/wiki/RocksDB-In-Memory-Workload-Performance-Benchmarks.
base line (commit
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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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Levi Tamasi
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db7c687523 |
Fix a data race related to memtable trimming (#6187)
Summary: https://github.com/facebook/rocksdb/pull/6177 introduced a data race involving `MemTableList::InstallNewVersion` and `MemTableList::NumFlushed`. The patch fixes this by caching whether the current version has any memtable history (i.e. flushed memtables that are kept around for transaction conflict checking) in an `std::atomic<bool>` member called `current_has_history_`, similarly to how `current_memory_usage_excluding_last_` is handled. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6187 Test Plan: ``` make clean COMPILE_WITH_TSAN=1 make db_test -j24 ./db_test ``` Differential Revision: D19084059 Pulled By: ltamasi fbshipit-source-id: 327a5af9700fb7102baea2cc8903c085f69543b9 |
5 years ago |
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Levi Tamasi
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bd8404feff |
Do not schedule memtable trimming if there is no history (#6177)
Summary: We have observed an increase in CPU load caused by frequent calls to `ColumnFamilyData::InstallSuperVersion` from `DBImpl::TrimMemtableHistory` when using `max_write_buffer_size_to_maintain` to limit the amount of memtable history maintained for transaction conflict checking. Part of the issue is that trimming can potentially be scheduled even if there is no memtable history. The patch adds a check that fixes this. See also https://github.com/facebook/rocksdb/pull/6169. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6177 Test Plan: Compared `perf` output for ``` ./db_bench -benchmarks=randomtransaction -optimistic_transaction_db=1 -statistics -stats_interval_seconds=1 -duration=90 -num=500000 --max_write_buffer_size_to_maintain=16000000 --transaction_set_snapshot=1 --threads=32 ``` before and after the change. There is a significant reduction for the call chain `rocksdb::DBImpl::TrimMemtableHistory` -> `rocksdb::ColumnFamilyData::InstallSuperVersion` -> `rocksdb::ThreadLocalPtr::StaticMeta::Scrape` even without https://github.com/facebook/rocksdb/pull/6169. Differential Revision: D19057445 Pulled By: ltamasi fbshipit-source-id: dff81882d7b280e17eda7d9b072a2d4882c50f79 |
5 years ago |
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奏之章
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c4ce8e637f |
Fix RangeDeletion bug (#6062)
Summary: Read keys from a snapshot that a range deletion were added after the snapshot was created and this range deletion was inside an immutable memtable, we will get wrong key set. More detail rest in codes. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6062 Differential Revision: D18966785 Pulled By: pdillinger fbshipit-source-id: 38a60bb1e2d0a1dbfc8ec641617200b6a02b86c3 |
5 years ago |
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蔡渠棠
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f29e6b3be2 |
bugfix: MemTableList::RemoveOldMemTables invalid iterator after remov… (#6013)
Summary: Fix issue https://github.com/facebook/rocksdb/issues/6012. I found that it may be caused by the following codes in function _RemoveOldMemTables()_ in **db/memtable_list.cc** : ``` for (auto it = memlist.rbegin(); it != memlist.rend(); ++it) { MemTable* mem = *it; if (mem->GetNextLogNumber() > log_number) { break; } current_->Remove(mem, to_delete); ``` The iterator **it** turns invalid after `current_->Remove(mem, to_delete);` Pull Request resolved: https://github.com/facebook/rocksdb/pull/6013 Test Plan: ``` make check ``` Differential Revision: D18401107 Pulled By: riversand963 fbshipit-source-id: bf0da3b868ed70f7aff24cf7b3e2049c0c5c7a4e |
5 years ago |
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Yi Wu
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1f9d7c0f54 |
Fix OnFlushCompleted fired before flush result write to MANIFEST (#5908)
Summary: When there are concurrent flush job on the same CF, `OnFlushCompleted` can be called before the flush result being install to LSM. Fixing the issue by passing `FlushJobInfo` through `MemTable`, and the thread who commit the flush result can fetch the `FlushJobInfo` and fire `OnFlushCompleted` on behave of the thread actually writing the SST. Fix https://github.com/facebook/rocksdb/issues/5892 Pull Request resolved: https://github.com/facebook/rocksdb/pull/5908 Test Plan: Add new test. The test will fail without the fix. Differential Revision: D17916144 Pulled By: riversand963 fbshipit-source-id: e18df67d9533b5baee52ae3605026cdeb05cbe10 |
5 years ago |
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Vijay Nadimpalli
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4c49e38f15 |
MultiGet batching in memtable (#5818)
Summary: RocksDB has a MultiGet() API that implements batched key lookup for higher performance (https://github.com/facebook/rocksdb/blob/master/include/rocksdb/db.h#L468). Currently, batching is implemented in BlockBasedTableReader::MultiGet() for SST file lookups. One of the ways it improves performance is by pipelining bloom filter lookups (by prefetching required cachelines for all the keys in the batch, and then doing the probe) and thus hiding the cache miss latency. The same concept can be extended to the memtable as well. This PR involves implementing a pipelined bloom filter lookup in DynamicBloom, and implementing MemTable::MultiGet() that can leverage it. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5818 Test Plan: Existing tests Performance Test: Ran the below command which fills up the memtable and makes sure there are no flushes and then call multiget. Ran it on master and on the new change and see atleast 1% performance improvement across all the test runs I did. Sometimes the improvement was upto 5%. TEST_TMPDIR=/data/users/$USER/benchmarks/feature/ numactl -C 10 ./db_bench -benchmarks="fillseq,multireadrandom" -num=600000 -compression_type="none" -level_compaction_dynamic_level_bytes -write_buffer_size=200000000 -target_file_size_base=200000000 -max_bytes_for_level_base=16777216 -reads=90000 -threads=1 -compression_type=none -cache_size=4194304000 -batch_size=32 -disable_auto_compactions=true -bloom_bits=10 -cache_index_and_filter_blocks=true -pin_l0_filter_and_index_blocks_in_cache=true -multiread_batched=true -multiread_stride=4 -statistics -memtable_whole_key_filtering=true -memtable_bloom_size_ratio=10 Differential Revision: D17578869 Pulled By: vjnadimpalli fbshipit-source-id: 23dc651d9bf49db11d22375bf435708875a1f192 |
5 years ago |
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Zhongyi Xie
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2f41ecfe75 |
Refactor trimming logic for immutable memtables (#5022)
Summary: MyRocks currently sets `max_write_buffer_number_to_maintain` in order to maintain enough history for transaction conflict checking. The effectiveness of this approach depends on the size of memtables. When memtables are small, it may not keep enough history; when memtables are large, this may consume too much memory. We are proposing a new way to configure memtable list history: by limiting the memory usage of immutable memtables. The new option is `max_write_buffer_size_to_maintain` and it will take precedence over the old `max_write_buffer_number_to_maintain` if they are both set to non-zero values. The new option accounts for the total memory usage of flushed immutable memtables and mutable memtable. When the total usage exceeds the limit, RocksDB may start dropping immutable memtables (which is also called trimming history), starting from the oldest one. The semantics of the old option actually works both as an upper bound and lower bound. History trimming will start if number of immutable memtables exceeds the limit, but it will never go below (limit-1) due to history trimming. In order the mimic the behavior with the new option, history trimming will stop if dropping the next immutable memtable causes the total memory usage go below the size limit. For example, assuming the size limit is set to 64MB, and there are 3 immutable memtables with sizes of 20, 30, 30. Although the total memory usage is 80MB > 64MB, dropping the oldest memtable will reduce the memory usage to 60MB < 64MB, so in this case no memtable will be dropped. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5022 Differential Revision: D14394062 Pulled By: miasantreble fbshipit-source-id: 60457a509c6af89d0993f988c9b5c2aa9e45f5c5 |
5 years ago |
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Vijay Nadimpalli
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d150e01474 |
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
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API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
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5 years ago |
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Zhongyi Xie
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d68f9f4580 |
simplify include directive involving inttypes (#5402)
Summary: When using `PRIu64` type of printf specifier, current code base does the following: ``` #ifndef __STDC_FORMAT_MACROS #define __STDC_FORMAT_MACROS #endif #include <inttypes.h> ``` However, this can be simplified to ``` #include <cinttypes> ``` as long as flag `-std=c++11` is used. This should solve issues like https://github.com/facebook/rocksdb/issues/5159 Pull Request resolved: https://github.com/facebook/rocksdb/pull/5402 Differential Revision: D15701195 Pulled By: miasantreble fbshipit-source-id: 6dac0a05f52aadb55e9728038599d3d2e4b59d03 |
6 years ago |
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Siying Dong
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000b9ec217 |
Move some logging related files to logging/ (#5387)
Summary: Many logging related source files are under util/. It will be more structured if they are together. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5387 Differential Revision: D15579036 Pulled By: siying fbshipit-source-id: 3850134ed50b8c0bb40a0c8ae1f184fa4081303f |
6 years ago |
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Vijay Nadimpalli
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49c5a12dbe |
Organizing rocksdb/db directory
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/5390 Differential Revision: D15579388 Pulled By: vjnadimpalli fbshipit-source-id: 5bfc95e31554b8ff05b97b76d6534113f527f366 |
6 years ago |
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Siying Dong
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8843129ece |
Move some memory related files from util/ to memory/ (#5382)
Summary: Move arena, allocator, and memory tools under util to a separate memory/ directory. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5382 Differential Revision: D15564655 Pulled By: siying fbshipit-source-id: 9cd6b5d0d3d52b39606e19221fa154596e5852a5 |
6 years ago |
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Siying Dong
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e9e0101ca4 |
Move test related files under util/ to test_util/ (#5377)
Summary: There are too many types of files under util/. Some test related files don't belong to there or just are just loosely related. Mo ve them to a new directory test_util/, so that util/ is cleaner. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5377 Differential Revision: D15551366 Pulled By: siying fbshipit-source-id: 0f5c8653832354ef8caa31749c0143815d719e2c |
6 years ago |