Summary:
**Context:**
Sorting L0 files by `largest_seqno` has at least two inconvenience:
- File ingestion and compaction involving ingested files can create files of overlapping seqno range with the existing files. `force_consistency_check=true` will catch such overlap seqno range even those harmless overlap.
- For example, consider the following sequence of events ("key@n" indicates key at seqno "n")
- insert k1@1 to memtable m1
- ingest file s1 with k2@2, ingest file s2 with k3@3
- insert k4@4 to m1
- compact files s1, s2 and result in new file s3 of seqno range [2, 3]
- flush m1 and result in new file s4 of seqno range [1, 4]. And `force_consistency_check=true` will think s4 and s3 has file reordering corruption that might cause retuning an old value of k1
- However such caught corruption is a false positive since s1, s2 will not have overlapped keys with k1 or whatever inserted into m1 before ingest file s1 by the requirement of file ingestion (otherwise the m1 will be flushed first before any of the file ingestion completes). Therefore there in fact isn't any file reordering corruption.
- Single delete can decrease a file's largest seqno and ordering by `largest_seqno` can introduce a wrong ordering hence file reordering corruption
- For example, consider the following sequence of events ("key@n" indicates key at seqno "n", Credit to ajkr for this example)
- an existing SST s1 contains only k1@1
- insert k1@2 to memtable m1
- ingest file s2 with k3@3, ingest file s3 with k4@4
- insert single delete k5@5 in m1
- flush m1 and result in new file s4 of seqno range [2, 5]
- compact s1, s2, s3 and result in new file s5 of seqno range [1, 4]
- compact s4 and result in new file s6 of seqno range [2] due to single delete
- By the last step, we have file ordering by largest seqno (">" means "newer") : s5 > s6 while s6 contains a newer version of the k1's value (i.e, k1@2) than s5, which is a real reordering corruption. While this can be caught by `force_consistency_check=true`, there isn't a good way to prevent this from happening if ordering by `largest_seqno`
Therefore, we are redesigning the sorting criteria of L0 files and avoid above inconvenience. Credit to ajkr , we now introduce `epoch_num` which describes the order of a file being flushed or ingested/imported (compaction output file will has the minimum `epoch_num` among input files'). This will avoid the above inconvenience in the following ways:
- In the first case above, there will no longer be overlap seqno range check in `force_consistency_check=true` but `epoch_number` ordering check. This will result in file ordering s1 < s2 < s4 (pre-compaction) and s3 < s4 (post-compaction) which won't trigger false positive corruption. See test class `DBCompactionTestL0FilesMisorderCorruption*` for more.
- In the second case above, this will result in file ordering s1 < s2 < s3 < s4 (pre-compacting s1, s2, s3), s5 < s4 (post-compacting s1, s2, s3), s5 < s6 (post-compacting s4), which are correct file ordering without causing any corruption.
**Summary:**
- Introduce `epoch_number` stored per `ColumnFamilyData` and sort CF's L0 files by their assigned `epoch_number` instead of `largest_seqno`.
- `epoch_number` is increased and assigned upon `VersionEdit::AddFile()` for flush (or similarly for WriteLevel0TableForRecovery) and file ingestion (except for allow_behind_true, which will always get assigned as the `kReservedEpochNumberForFileIngestedBehind`)
- Compaction output file is assigned with the minimum `epoch_number` among input files'
- Refit level: reuse refitted file's epoch_number
- Other paths needing `epoch_number` treatment:
- Import column families: reuse file's epoch_number if exists. If not, assign one based on `NewestFirstBySeqNo`
- Repair: reuse file's epoch_number if exists. If not, assign one based on `NewestFirstBySeqNo`.
- Assigning new epoch_number to a file and adding this file to LSM tree should be atomic. This is guaranteed by us assigning epoch_number right upon `VersionEdit::AddFile()` where this version edit will be apply to LSM tree shape right after by holding the db mutex (e.g, flush, file ingestion, import column family) or by there is only 1 ongoing edit per CF (e.g, WriteLevel0TableForRecovery, Repair).
- Assigning the minimum input epoch number to compaction output file won't misorder L0 files (even through later `Refit(target_level=0)`). It's due to for every key "k" in the input range, a legit compaction will cover a continuous epoch number range of that key. As long as we assign the key "k" the minimum input epoch number, it won't become newer or older than the versions of this key that aren't included in this compaction hence no misorder.
- Persist `epoch_number` of each file in manifest and recover `epoch_number` on db recovery
- Backward compatibility with old db without `epoch_number` support is guaranteed by assigning `epoch_number` to recovered files by `NewestFirstBySeqno` order. See `VersionStorageInfo::RecoverEpochNumbers()` for more
- Forward compatibility with manifest is guaranteed by flexibility of `NewFileCustomTag`
- Replace `force_consistent_check` on L0 with `epoch_number` and remove false positive check like case 1 with `largest_seqno` above
- Due to backward compatibility issue, we might encounter files with missing epoch number at the beginning of db recovery. We will still use old L0 sorting mechanism (`NewestFirstBySeqno`) to check/sort them till we infer their epoch number. See usages of `EpochNumberRequirement`.
- Remove fix https://github.com/facebook/rocksdb/pull/5958#issue-511150930 and their outdated tests to file reordering corruption because such fix can be replaced by this PR.
- Misc:
- update existing tests with `epoch_number` so make check will pass
- update https://github.com/facebook/rocksdb/pull/5958#issue-511150930 tests to verify corruption is fixed using `epoch_number` and cover universal/fifo compaction/CompactRange/CompactFile cases
- assert db_mutex is held for a few places before calling ColumnFamilyData::NewEpochNumber()
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10922
Test Plan:
- `make check`
- New unit tests under `db/db_compaction_test.cc`, `db/db_test2.cc`, `db/version_builder_test.cc`, `db/repair_test.cc`
- Updated tests (i.e, `DBCompactionTestL0FilesMisorderCorruption*`) under https://github.com/facebook/rocksdb/pull/5958#issue-511150930
- [Ongoing] Compatibility test: manually run 36a5686ec0 (with file ingestion off for running the `.orig` binary to prevent this bug affecting upgrade/downgrade formality checking) for 1 hour on `simple black/white box`, `cf_consistency/txn/enable_ts with whitebox + test_best_efforts_recovery with blackbox`
- [Ongoing] normal db stress test
- [Ongoing] db stress test with aggressive value https://github.com/facebook/rocksdb/pull/10761
Reviewed By: ajkr
Differential Revision: D41063187
Pulled By: hx235
fbshipit-source-id: 826cb23455de7beaabe2d16c57682a82733a32a9
Summary:
**Context/Summary:**
This reverts commit fc74abb436 and related HISTORY record.
The issue with PR 10777 or general approach using earliest_mem_seqno like https://github.com/facebook/rocksdb/pull/5958#issue-511150930 is that the earliest seqno of memtable of each CFs does not get persisted and will always start with 0 upon Recover(). Later when creating a new memtable in certain CF, we use the last seqno of the whole DB (but not of that CF from previous DB session) for this CF. This will lead to false positive overlapping seqno and PR 10777 will throw something like https://github.com/facebook/rocksdb/blob/main/db/compaction/compaction_picker.cc#L1002-L1004
Luckily a more elegant and complete solution to the overlapping seqno problem these PR aim to solve does not have above problem, see https://github.com/facebook/rocksdb/pull/10922. It is already being pursued and in the process of review. So we can just revert this PR and focus on getting PR10922 to land.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10999
Test Plan: make check
Reviewed By: anand1976
Differential Revision: D41572604
Pulled By: hx235
fbshipit-source-id: 9d9bdf594abd235e2137045cef513ca0b14e0a3a
Summary:
**Context:**
Same as https://github.com/facebook/rocksdb/pull/5958#issue-511150930 but apply the fix to FIFO Compaction case
Repro:
```
COERCE_CONTEXT_SWICH=1 make -j56 db_stress
./db_stress --acquire_snapshot_one_in=0 --adaptive_readahead=0 --allow_data_in_errors=True --async_io=1 --avoid_flush_during_recovery=0 --avoid_unnecessary_blocking_io=0 --backup_max_size=104857600 --backup_one_in=0 --batch_protection_bytes_per_key=0 --block_size=16384 --bloom_bits=18 --bottommost_compression_type=disable --bytes_per_sync=262144 --cache_index_and_filter_blocks=0 --cache_size=8388608 --cache_type=lru_cache --charge_compression_dictionary_building_buffer=0 --charge_file_metadata=1 --charge_filter_construction=1 --charge_table_reader=1 --checkpoint_one_in=0 --checksum_type=kCRC32c --clear_column_family_one_in=0 --column_families=1 --compact_files_one_in=0 --compact_range_one_in=1000 --compaction_pri=3 --open_files=-1 --compaction_style=2 --fifo_allow_compaction=1 --compaction_ttl=0 --compression_max_dict_buffer_bytes=8388607 --compression_max_dict_bytes=16384 --compression_parallel_threads=1 --compression_type=zlib --compression_use_zstd_dict_trainer=1 --compression_zstd_max_train_bytes=0 --continuous_verification_interval=0 --data_block_index_type=0 --db=/dev/shm/rocksdb_test0/rocksdb_crashtest_whitebox --db_write_buffer_size=8388608 --delpercent=4 --delrangepercent=1 --destroy_db_initially=1 --detect_filter_construct_corruption=0 --disable_wal=0 --enable_compaction_filter=0 --enable_pipelined_write=1 --fail_if_options_file_error=1 --file_checksum_impl=none --flush_one_in=1000 --format_version=5 --get_current_wal_file_one_in=0 --get_live_files_one_in=0 --get_property_one_in=0 --get_sorted_wal_files_one_in=0 --index_block_restart_interval=15 --index_type=3 --ingest_external_file_one_in=100 --initial_auto_readahead_size=0 --iterpercent=10 --key_len_percent_dist=1,30,69 --level_compaction_dynamic_level_bytes=True --log2_keys_per_lock=10 --long_running_snapshots=0 --mark_for_compaction_one_file_in=10 --max_auto_readahead_size=16384 --max_background_compactions=20 --max_bytes_for_level_base=10485760 --max_key=100000 --max_key_len=3 --max_manifest_file_size=1073741824 --max_write_batch_group_size_bytes=1048576 --max_write_buffer_number=3 --max_write_buffer_size_to_maintain=4194304 --memtable_prefix_bloom_size_ratio=0.5 --memtable_protection_bytes_per_key=1 --memtable_whole_key_filtering=1 --memtablerep=skip_list --mmap_read=1 --mock_direct_io=False --nooverwritepercent=1 --num_file_reads_for_auto_readahead=0 --num_levels=1 --open_metadata_write_fault_one_in=0 --open_read_fault_one_in=32 --open_write_fault_one_in=0 --ops_per_thread=200000 --optimize_filters_for_memory=0 --paranoid_file_checks=1 --partition_filters=0 --partition_pinning=1 --pause_background_one_in=0 --periodic_compaction_seconds=0 --prefix_size=8 --prefixpercent=5 --prepopulate_block_cache=0 --progress_reports=0 --read_fault_one_in=0 --readahead_size=16384 --readpercent=45 --recycle_log_file_num=1 --reopen=20 --ribbon_starting_level=999 --snapshot_hold_ops=1000 --sst_file_manager_bytes_per_sec=0 --sst_file_manager_bytes_per_truncate=0 --subcompactions=2 --sync=0 --sync_fault_injection=0 --target_file_size_base=524288 --target_file_size_multiplier=2 --test_batches_snapshots=0 --top_level_index_pinning=3 --unpartitioned_pinning=0 --use_direct_io_for_flush_and_compaction=0 --use_direct_reads=0 --use_full_merge_v1=1 --use_merge=0 --use_multiget=1 --user_timestamp_size=0 --value_size_mult=32 --verify_checksum=1 --verify_checksum_one_in=0 --verify_db_one_in=1000 --verify_sst_unique_id_in_manifest=1 --wal_bytes_per_sync=0 --wal_compression=zstd --write_buffer_size=524288 --write_dbid_to_manifest=0 --writepercent=35
put or merge error: Corruption: force_consistency_checks(DEBUG): VersionBuilder: L0 file https://github.com/facebook/rocksdb/issues/479 with seqno 23711 29070 vs. file https://github.com/facebook/rocksdb/issues/482 with seqno 27138 29049
```
**Summary:**
FIFO only does intra-L0 compaction in the following four cases. For other cases, FIFO drops data instead of compacting on data, which is irrelevant to the overlapping seqno issue we are solving.
- [FIFOCompactionPicker::PickSizeCompaction](https://github.com/facebook/rocksdb/blob/7.6.fb/db/compaction/compaction_picker_fifo.cc#L155) when `total size < compaction_options_fifo.max_table_files_size` and `compaction_options_fifo.allow_compaction == true`
- For this path, we simply reuse the fix in `FindIntraL0Compaction` https://github.com/facebook/rocksdb/pull/5958/files#diff-c261f77d6dd2134333c4a955c311cf4a196a08d3c2bb6ce24fd6801407877c89R56
- This path was not stress-tested at all. Therefore we covered `fifo.allow_compaction` in stress test to surface the overlapping seqno issue we are fixing here.
- [FIFOCompactionPicker::PickCompactionToWarm](https://github.com/facebook/rocksdb/blob/7.6.fb/db/compaction/compaction_picker_fifo.cc#L313) when `compaction_options_fifo.age_for_warm > 0`
- For this path, we simply replicate the idea in https://github.com/facebook/rocksdb/pull/5958#issue-511150930 and skip files of largest seqno greater than `earliest_mem_seqno`
- This path was not stress-tested at all. However covering `age_for_warm` option worths a separate PR to deal with db stress compatibility. Therefore we manually tested this path for this PR
- [FIFOCompactionPicker::CompactRange](https://github.com/facebook/rocksdb/blob/7.6.fb/db/compaction/compaction_picker_fifo.cc#L365) that ends up picking one of the above two compactions
- [CompactionPicker::CompactFiles](https://github.com/facebook/rocksdb/blob/7.6.fb/db/compaction/compaction_picker.cc#L378)
- Since `SanitizeCompactionInputFiles()` will be called [before](https://github.com/facebook/rocksdb/blob/7.6.fb/db/compaction/compaction_picker.h#L111-L113) `CompactionPicker::CompactFiles` , we simply replicate the idea in https://github.com/facebook/rocksdb/pull/5958#issue-511150930 in `SanitizeCompactionInputFiles()`. To simplify implementation, we return `Stats::Abort()` on encountering seqno-overlapped file when doing compaction to L0 instead of skipping the file and proceed with the compaction.
Some additional clean-up included in this PR:
- Renamed `earliest_memtable_seqno` to `earliest_mem_seqno` for consistent naming
- Added comment about `earliest_memtable_seqno` in related APIs
- Made parameter `earliest_memtable_seqno` constant and required
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10777
Test Plan:
- make check
- New unit test `TEST_P(DBCompactionTestFIFOCheckConsistencyWithParam, FlushAfterIntraL0CompactionWithIngestedFile)`corresponding to the above 4 cases, which will fail accordingly without the fix
- Regular CI stress run on this PR + stress test with aggressive value https://github.com/facebook/rocksdb/pull/10761 and on FIFO compaction only
Reviewed By: ajkr
Differential Revision: D40090485
Pulled By: hx235
fbshipit-source-id: 52624186952ee7109117788741aeeac86b624a4f
Summary:
Allow the last level only compaction able to output result to penultimate level if the penultimate level is empty. Which will also block the other compaction output to the penultimate level.
(it includes the PR https://github.com/facebook/rocksdb/issues/10829)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10822
Reviewed By: siying
Differential Revision: D40389180
Pulled By: jay-zhuang
fbshipit-source-id: 4e5dcdce307795b5e07b5dd1fa29dd75bb093bad
Summary:
Earlier implementation of round-robin priority can only pick one file at a time and disallows parallel compactions within the same level. In this PR, round-robin compaction policy will expand towards more input files with respecting some additional constraints, which are summarized as follows:
* Constraint 1: We can only pick consecutive files
- Constraint 1a: When a file is being compacted (or some input files are being compacted after expanding), we cannot choose it and have to stop choosing more files
- Constraint 1b: When we reach the last file (with the largest keys), we cannot choose more files (the next file will be the first one with small keys)
* Constraint 2: We should ensure the total compaction bytes (including the overlapped files from the next level) is no more than `mutable_cf_options_.max_compaction_bytes`
* Constraint 3: We try our best to pick as many files as possible so that the post-compaction level size can be just less than `MaxBytesForLevel(start_level_)`
* Constraint 4: If trivial move is allowed, we reuse the logic of `TryNonL0TrivialMove()` instead of expanding files with Constraint 3
More details can be found in `LevelCompactionBuilder::SetupOtherFilesWithRoundRobinExpansion()`.
The above optimization accelerates the process of moving the compaction cursor, in which the write-amp can be further reduced. While a large compaction may lead to high write stall, we break this large compaction into several subcompactions **regardless of** the `max_subcompactions` limit. The number of subcompactions for round-robin compaction priority is determined through the following steps:
* Step 1: Initialized against `max_output_file_limit`, the number of input files in the start level, and also the range size limit `ranges.size()`
* Step 2: Call `AcquireSubcompactionResources()`when max subcompactions is not sufficient, but we may or may not obtain desired resources, additional number of resources is stored in `extra_num_subcompaction_threads_reserved_`). Subcompaction limit is changed and update `num_planned_subcompactions` with `GetSubcompactionLimit()`
* Step 3: Call `ShrinkSubcompactionResources()` to ensure extra resources can be released (extra resources may exist for round-robin compaction when the number of actual number of subcompactions is less than the number of planned subcompactions)
More details can be found in `CompactionJob::AcquireSubcompactionResources()`,`CompactionJob::ShrinkSubcompactionResources()`, and `CompactionJob::ReleaseSubcompactionResources()`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10341
Test Plan: Add `CompactionPriMultipleFilesRoundRobin[1-3]` unit test in `compaction_picker_test.cc` and `RoundRobinSubcompactionsAgainstResources.SubcompactionsUsingResources/[0-4]`, `RoundRobinSubcompactionsAgainstPressureToken.PressureTokenTest/[0-1]` in `db_compaction_test.cc`
Reviewed By: ajkr, hx235
Differential Revision: D37792644
Pulled By: littlepig2013
fbshipit-source-id: 7fecb7c4ffd97b34bbf6e3b760b2c35a772a0657
Summary:
Support per_key_placement for last level compaction, which will
be used for tiered compaction.
* compaction iterator reports which level a key should output to;
* compaction get the output level information and check if it's safe to
output the data to penultimate level;
* all compaction output files will be installed.
* extra internal compaction stats added for penultimate level.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9964
Test Plan:
* Unittest
* db_bench, no significate difference: https://gist.github.com/jay-zhuang/3645f8fb97ec0ab47c10704bb39fd6e4
* microbench manual compaction no significate difference: https://gist.github.com/jay-zhuang/ba679b3e89e24992615ee9eef310e6dd
* run the db_stress multiple times (not covering the new feature) looks good (internal: https://fburl.com/sandcastle/9w84pp2m)
Reviewed By: ajkr
Differential Revision: D36249494
Pulled By: jay-zhuang
fbshipit-source-id: a96da57c8031c1df83e4a7a8567b657a112b80a3
Summary:
In leveled compaction, L0->L1 trivial move will allow more than one file to be moved in one compaction. This would allow L0 files to be moved down faster when data is loaded in sequential order, making slowdown or stop condition harder to hit. Also seek L0->L1 trivial move when only some files qualify.
1. We always try to find L0->L1 trivial move from the oldest files. Keep including newer files, until adding a new file won't trigger a trivial move
2. Modify the trivial move condition so that this compaction would be tagged as trivial move.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10188
Test Plan:
See throughput improvements with db_bench with fast fillseq benchmark and small L0 files:
./db_bench_l0_move --benchmarks=fillseq --compression_type=lz4 --write_buffer_size=5000000 --num=100000000 --value_size=1000 -level_compaction_dynamic_level_bytes
The throughput improved by about 50%. Stalling still happens though.
Reviewed By: jay-zhuang
Differential Revision: D37224743
fbshipit-source-id: 8958d97f22e12bdfc14d2e85930f6fa0070e9659
Summary:
As disscussed in (https://github.com/facebook/rocksdb/issues/9223), Here added a new API named DB::OpenAndTrimHistory, this API will open DB and trim data to the timestamp specofied by **trim_ts** (The data with newer timestamp than specified trim bound will be removed). This API should only be used at a timestamp-enabled db instance recovery.
And this PR implemented a new iterator named HistoryTrimmingIterator to support trimming history with a new API named DB::OpenAndTrimHistory. HistoryTrimmingIterator wrapped around the underlying InternalITerator such that keys whose timestamps newer than **trim_ts** should not be returned to the compaction iterator while **trim_ts** is not null.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9410
Reviewed By: ltamasi
Differential Revision: D34410207
Pulled By: riversand963
fbshipit-source-id: e54049dc234eccd673244c566b15df58df5a6236
Summary:
- Make `compression_per_level` dynamical changeable with `SetOptions`;
- Fix a bug that `compression_per_level` is not used for flush;
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9658
Test Plan: CI
Reviewed By: ajkr
Differential Revision: D34700749
Pulled By: jay-zhuang
fbshipit-source-id: a23b9dfa7ad03d393c1d71781d19e91de796f49c
Summary:
The ImmutableCFOptions contained a bunch of fields that belonged to the ImmutableDBOptions. This change cleans that up by introducing an ImmutableOptions struct. Following the pattern of Options struct, this class inherits from the DB and CFOption structs (of the Immutable form).
Only one structural change (the ImmutableCFOptions::fs was changed to a shared_ptr from a raw one) is in this PR. All of the other changes involve moving the member variables from the ImmutableCFOptions into the ImmutableOptions and changing member variables or function parameters as required for compilation purposes.
Follow-on PRs may do a further clean-up of the code, such as renaming variables (such as "ImmutableOptions cf_options") and potentially eliminating un-needed function parameters (there is no longer a need to pass both an ImmutableDBOptions and an ImmutableOptions to a function).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8262
Reviewed By: pdillinger
Differential Revision: D28226540
Pulled By: mrambacher
fbshipit-source-id: 18ae71eadc879dedbe38b1eb8e6f9ff5c7147dbf
Summary:
These three options should be made dynamically changeable. Simply add them to MutableCFOptions and made the change.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6615
Test Plan: Add a unit test to make sure that SetOptions() can change the options.
Reviewed By: riversand963
Differential Revision: D20755951
fbshipit-source-id: 8165f4fd7a7a665cc7fb049698935022a5d2e7ff
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
Summary:
## Problem Description
Our process was abort when it call `CheckConsistency`. And the information in `stderr` show that "`L0 files seqno 3001491972 3004797440 vs. 3002875611 3004524421` ". Here are the causes of the accident I investigated.
* RocksDB will call `CheckConsistency` whenever `MANIFEST` file is update. It will check sequence number interval of every file, except files which were ingested.
* When one file is ingested into RocksDB, it will be assigned the value of global sequence number, and the minimum and maximum seqno of this file are equal, which are both equal to global sequence number.
* `CheckConsistency` determines whether the file is ingested by whether the smallest and largest seqno of an sstable file are equal.
* If IntraL0Compaction picks one sst which was ingested just now and compacted it into another sst, the `smallest_seqno` of this new file will be smaller than his `largest_seqno`.
* If more than one ingested file was ingested before memtable schedule flush, and they all compact into one new sstable file by `IntraL0Compaction`. The sequence interval of this new file will be included in the interval of the memtable. So `CheckConsistency` will return a `Corruption`.
* If a sstable was ingested after the memtable was schedule to flush, which would assign a larger seqno to it than memtable. Then the file was compacted with other files (these files were all flushed before the memtable) in L0 into one file. This compaction start before the flush job of memtable start, but completed after the flush job finish. So this new file produced by the compaction (we call it s1) would have a larger interval of sequence number than the file produced by flush (we call it s2). **But there was still some data in s1 written into RocksDB before the s2, so it's possible that some data in s2 was cover by old data in s1.** Of course, it would also make a `Corruption` because of overlap of seqno. There is the relationship of the files:
> s1.smallest_seqno < s2.smallest_seqno < s2.largest_seqno < s1.largest_seqno
So I skip pick sst file which was ingested in function `FindIntraL0Compaction `
## Reason
Here is my bug report: https://github.com/facebook/rocksdb/issues/5913
There are two situations that can cause the check to fail.
### First situation：
- First we ingest five external sst into Rocksdb, and they happened to be ingested in L0. and there had been some data in memtable, which make the smallest sequence number of memtable is less than which of sst that we ingest.
- If there had been one compaction job which compacted sst from L0 to L1, `LevelCompactionPicker` would trigger a `IntraL0Compaction` which would compact this five sst from L0 to L0. We call this sst A, which was merged from five ingested sst.
- Then some data was put into memtable, and memtable was flushed to L0. We called this sst B.
- RocksDB check consistency , and find the `smallest_seqno` of B is less than that of A and crash. Because A was merged from five sst, the smallest sequence number of it was less than the biggest sequece number of itself, so RocksDB could not tell if A was produce by ingested.
### Secondary situaion
- First we have flushed many sst in L0, we call them [s1, s2, s3].
- There is an immutable memtable request to be flushed, but because flush thread is busy, so it has not been picked. we call it m1. And at the moment, one sst is ingested into L0. We call it s4. Because s4 is ingested after m1 became immutable memtable, so it has a larger log sequence number than m1.
- m1 is flushed in L0. because it is small, this flush job finish quickly. we call it s5.
- [s1, s2, s3, s4] are compacted into one sst to L0, by IntraL0Compaction. We call it s6.
- compacted 4@0 files to L0
- When s6 is added into manifest, the corruption happened. because the largest sequence number of s6 is equal to s4, and they are both larger than that of s5. But because s1 is older than m1, so the smallest sequence number of s6 is smaller than that of s5.
- s6.smallest_seqno < s5.smallest_seqno < s5.largest_seqno < s6.largest_seqno
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5958
Differential Revision: D18601316
fbshipit-source-id: 5fe54b3c9af52a2e1400728f565e895cde1c7267
Summary:
In order to improve code readability, this PR moves LevelCompactionBuilder and LevelCompactionPicker to compaction_picker_level.h and .cc
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5369
Differential Revision: D15540172
Pulled By: miasantreble
fbshipit-source-id: c1a578b93f127cd63661b53f32b356e6edd349af
Summary:
Modified FindIntraL0Compaction to stop picking more files if total
amount of compensated bytes would be larger than max_compaction_bytes
option.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5329
Differential Revision: D15435728
Pulled By: ThomasFersch
fbshipit-source-id: d118a6da88d5df8ee20944422ade37cf6b15d60c
Summary:
Depending on the config, manual compaction (leveled compaction style) does following compactions:
L0->L1
L1->L2
...
Ln-1 -> Ln
Ln -> Ln
The final Ln -> Ln compaction is partly unnecessary as it recompacts all the files that were just generated by the Ln-1 -> Ln. We should avoid recompacting such files. This rule should be applied to Lmax only.
Resolves issue https://github.com/facebook/rocksdb/issues/4995
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5138
Differential Revision: D14940106
Pulled By: miasantreble
fbshipit-source-id: 8d3cf5507a17e76f3333cfd4bac5256d005636e5
Summary:
**Summary:**
Simplified the code layout by moving FIFOCompactionPicker to a separate file.
**Why?:**
While trying to add ttl functionality to universal compaction, I found that `FIFOCompactionPicker` class and its impl methods to be interspersed between `LevelCompactionPicker` methods which kind-of made the code a little hard to traverse. So I moved `FIFOCompactionPicker` to a separate compaction_picker_fifo.h/cc file, similar to `UniversalCompactionPicker`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4724
Differential Revision: D13227914
Pulled By: sagar0
fbshipit-source-id: 89471766ea67fa4d87664a41c057dd7df4b3d4e3
Summary:
When a CompactRange() call for a level is truncated before the end key
is reached, because it exceeds max_compaction_bytes, we need to properly
set the compaction_end parameter to indicate the stop key. The next
CompactRange will use that as the begin key. We set it to the smallest
key of the next file in the level after expanding inputs to get a clean
cut.
Previously, we were setting it before expanding inputs. So we could end
up recompacting some files. In a pathological case, where a single key
has many entries spanning all the files in the level (possibly due to
merge operands without a partial merge operator, thus resulting in
compaction output identical to the input), this would result in
an endless loop over the same set of files.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4496
Differential Revision: D10395026
Pulled By: anand1976
fbshipit-source-id: f0c2f89fee29b4b3be53b6467b53abba8e9146a9
Summary:
…ression
For `CompressionType` we have options `compression` and `bottommost_compression`. Thus, to make the compression options consitent with the compression type when bottommost_compression is enabled, we add the bottommost_compression_opts
Closes https://github.com/facebook/rocksdb/pull/3985
Reviewed By: riversand963
Differential Revision: D8385911
Pulled By: zhichao-cao
fbshipit-source-id: 07bc533dd61bcf1cef5927d8d62901c13d38d5fc
Summary:
This is still WIP, but I'm hoping for early feedback on the overall approach.
This patch implements deletion triggered compaction, which till now only
worked for leveled, for universal style. SST files are marked for
compaction by the CompactOnDeletionCollertor table property. This is
expected to be used when free disk space is low and the user wants to
reclaim space by deleting a bunch of keys. The deletions are expected to
be dense. In such a situation, we want to avoid a full compaction due to
its space overhead.
The strategy used in this case is similar to leveled. We pick one file
from the set of files marked for compaction. We then expand the inputs
to a clean cut on the same level, and then pick overlapping files from
the next non-mepty level. Picking files from the next level can cause
the key range to expand, and we opportunistically expand inputs in the
source level to include files wholly in this key range.
The main side effect of this is that it breaks the property of no time
range overlap between levels. This shouldn't break any functionality.
Closes https://github.com/facebook/rocksdb/pull/3860
Differential Revision: D8124397
Pulled By: anand1976
fbshipit-source-id: bfa2a9dd6817930e991b35d3a8e7e61304ed3dcf
Summary:
Sometimes we want to compact files as fast as possible, but don't want to set a large `max_subcompactions` in the `DBOptions` by default.
I add a `max_subcompactions` options to `CompactionOptions` so that we can choose a proper concurrency dynamically.
Closes https://github.com/facebook/rocksdb/pull/3775
Differential Revision: D7792357
Pulled By: ajkr
fbshipit-source-id: 94f54c3784dce69e40a229721a79a97e80cd6a6c
Summary:
Bug report: https://www.facebook.com/groups/rocksdb.dev/permalink/1389452781153232/
Non-empty `level0_compactions_in_progress_` was aborting `CompactFiles` after incrementing `bg_compaction_scheduled_`, and in that case we never decremented it. This blocked future compactions and prevented DB close as we wait for scheduled compactions to finish/abort during close.
I eliminated `CompactFiles`'s dependency on `level0_compactions_in_progress_`. Since it takes a contiguous span of L0 files -- through the last L0 file if any L1+ files are included -- it's fine to run in parallel with other compactions involving L0. We make the same assumption in intra-L0 compaction.
Closes https://github.com/facebook/rocksdb/pull/2849
Differential Revision: D5780440
Pulled By: ajkr
fbshipit-source-id: 15b15d3faf5a699aed4b82a58352d4a7bb23e027
Summary:
This reverts the previous commit 1d7048c598, which broke the build.
Did a `git revert 1d7048c`.
Closes https://github.com/facebook/rocksdb/pull/2627
Differential Revision: D5476473
Pulled By: sagar0
fbshipit-source-id: 4756ff5c0dfc88c17eceb00e02c36176de728d06
Summary: This uses `clang-tidy` to comment out unused parameters (in functions, methods and lambdas) in fbcode. Cases that the tool failed to handle are fixed manually.
Reviewed By: igorsugak
Differential Revision: D5454343
fbshipit-source-id: 5dee339b4334e25e963891b519a5aa81fbf627b2
Summary:
Introducing FIFO compactions with TTL.
FIFO compaction is based on size only which makes it tricky to enable in production as use cases can have organic growth. A user requested an option to drop files based on the time of their creation instead of the total size.
To address that request:
- Added a new TTL option to FIFO compaction options.
- Updated FIFO compaction score to take TTL into consideration.
- Added a new table property, creation_time, to keep track of when the SST file is created.
- Creation_time is set as below:
- On Flush: Set to the time of flush.
- On Compaction: Set to the max creation_time of all the files involved in the compaction.
- On Repair and Recovery: Set to the time of repair/recovery.
- Old files created prior to this code change will have a creation_time of 0.
- FIFO compaction with TTL is enabled when ttl > 0. All files older than ttl will be deleted during compaction. i.e. `if (file.creation_time < (current_time - ttl)) then delete(file)`. This will enable cases where you might want to delete all files older than, say, 1 day.
- FIFO compaction will fall back to the prior way of deleting files based on size if:
- the creation_time of all files involved in compaction is 0.
- the total size (of all SST files combined) does not drop below `compaction_options_fifo.max_table_files_size` even if the files older than ttl are deleted.
This feature is not supported if max_open_files != -1 or with table formats other than Block-based.
**Test Plan:**
Added tests.
**Benchmark results:**
Base: FIFO with max size: 100MB ::
```
svemuri@dev15905 ~/rocksdb (fifo-compaction) $ TEST_TMPDIR=/dev/shm ./db_bench --benchmarks=readwhilewriting --num=5000000 --threads=16 --compaction_style=2 --fifo_compaction_max_table_files_size_mb=100
readwhilewriting : 1.924 micros/op 519858 ops/sec; 13.6 MB/s (1176277 of 5000000 found)
```
With TTL (a low one for testing) ::
```
svemuri@dev15905 ~/rocksdb (fifo-compaction) $ TEST_TMPDIR=/dev/shm ./db_bench --benchmarks=readwhilewriting --num=5000000 --threads=16 --compaction_style=2 --fifo_compaction_max_table_files_size_mb=100 --fifo_compaction_ttl=20
readwhilewriting : 1.902 micros/op 525817 ops/sec; 13.7 MB/s (1185057 of 5000000 found)
```
Example Log lines:
```
2017/06/26-15:17:24.609249 7fd5a45ff700 (Original Log Time 2017/06/26-15:17:24.609177) [db/compaction_picker.cc:1471] [default] FIFO compaction: picking file 40 with creation time 1498515423 for deletion
2017/06/26-15:17:24.609255 7fd5a45ff700 (Original Log Time 2017/06/26-15:17:24.609234) [db/db_impl_compaction_flush.cc:1541] [default] Deleted 1 files
...
2017/06/26-15:17:25.553185 7fd5a61a5800 [DEBUG] [db/db_impl_files.cc:309] [JOB 0] Delete /dev/shm/dbbench/000040.sst type=2 #40 -- OK
2017/06/26-15:17:25.553205 7fd5a61a5800 EVENT_LOG_v1 {"time_micros": 1498515445553199, "job": 0, "event": "table_file_deletion", "file_number": 40}
```
SST Files remaining in the dbbench dir, after db_bench execution completed:
```
svemuri@dev15905 ~/rocksdb (fifo-compaction) $ ls -l /dev/shm//dbbench/*.sst
-rw-r--r--. 1 svemuri users 30749887 Jun 26 15:17 /dev/shm//dbbench/000042.sst
-rw-r--r--. 1 svemuri users 30768779 Jun 26 15:17 /dev/shm//dbbench/000044.sst
-rw-r--r--. 1 svemuri users 30757481 Jun 26 15:17 /dev/shm//dbbench/000046.sst
```
Closes https://github.com/facebook/rocksdb/pull/2480
Differential Revision: D5305116
Pulled By: sagar0
fbshipit-source-id: 3e5cfcf5dd07ed2211b5b37492eb235b45139174
Summary:
1. Move universal compaction picker to separate files compaction_picker_universal.cc and compaction_picker_universal.h.
2. Rename some functions to make the code easier to understand.
3. Move leveled compaction picking code to a dedicated class, so that we we don't need to pass some common variable around when calling functions. It also allowed us to break down LevelCompactionPicker::PickCompaction() to smaller functions.
Closes https://github.com/facebook/rocksdb/pull/2100
Differential Revision: D4845948
Pulled By: siying
fbshipit-source-id: efa0ab4
Summary:
Move some files under util/ to new directories env/, monitoring/ options/ and cache/
Closes https://github.com/facebook/rocksdb/pull/2090
Differential Revision: D4833681
Pulled By: siying
fbshipit-source-id: 2fd8bef
Summary:
Level-based L0->L0 compaction operates on spans of files that aren't currently being compacted. It reduces the number of L0 files, thus making write stall conditions harder to reach.
- L0->L0 is triggered when base level is unavailable due to pending compactions
- L0->L0 always outputs one file of at most `max_level0_burst_file_size` bytes.
- Subcompactions are disabled for L0->L0 since we want to output one file.
- Input files are chosen as the longest span of available files that will fit within the size limit. This minimizes number of files in L0.
Closes https://github.com/facebook/rocksdb/pull/2027
Differential Revision: D4760318
Pulled By: ajkr
fbshipit-source-id: 9d07183
Summary:
IsTrivialMove returns true if no input file overlaps with output_level+1 with more than max_compaction_bytes_ bytes.
Closes https://github.com/facebook/rocksdb/pull/1619
Differential Revision: D4278338
Pulled By: yiwu-arbug
fbshipit-source-id: 994c001
Summary:
Issue scenario:
(1) We have 3 files in L1 and we issue a compaction that will compact them into 1 file in L2
(2) While compaction (1) is running, we flush a file into L0 and trigger another compaction that decide to move this file to L1 and then move it again to L2 (this file don't overlap with any other files)
(3) compaction (1) finishes and install the file it generated in L2, but this file overlap with the file we generated in (2) so we break the LSM consistency
Looks like this issue can be triggered by using non-exclusive manual compaction or AddFile()
Test Plan: unit tests
Reviewers: sdong
Reviewed By: sdong
Subscribers: hermanlee4, jkedgar, andrewkr, dhruba, yoshinorim
Differential Revision: https://reviews.facebook.net/D64947
Summary: There's no reference to ImmutableCFOptions elsewhere in /include/rocksdb. ImmutableCFOptions was introduced in this commit (5665e5e285) but later its reference in /include/rocksdb/table.h is removed.
Test Plan:
make all check
Reviewers: IslamAbdelRahman, sdong, yhchiang
Reviewed By: yhchiang
Subscribers: yhchiang, andrewkr, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D63177
Summary:
Add a new option that can be used to set a specific compression algorithm for bottommost level.
This option will only affect levels larger than base level.
I have also updated CompactionJobInfo to include the compression algorithm used in compaction
Test Plan:
added new unittest
existing unittests
Reviewers: andrewkr, yhchiang, sdong
Reviewed By: sdong
Subscribers: lightmark, andrewkr, dhruba, yoshinorim
Differential Revision: https://reviews.facebook.net/D57669
Summary:
ReleaseCompactionFiles must be called when DB mutex is held,
but the documentation is mission.
Test Plan: no code change
Reviewers: anthony, IslamAbdelRahman, kradhakrishnan, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D54987
Summary:
List of changes:
1) Fix the snprintf() usage in cases where wrong variable was used to determine the output buffer size.
2) Remove unnecessary checks before calling delete operator.
3) Increase code correctness by using size_t type when getting vector's size.
4) Unify the coding style by removing namespace::std usage at the top of the file to confirm to the majority usage.
5) Fix various lint errors pointed out by 'arc lint'.
Test Plan:
Code review and build:
git diff
make clean
make -j 32 commit-prereq
arc lint
Reviewers: kradhakrishnan, sdong, rven, anthony, yhchiang, igor
Reviewed By: igor
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D51849
Summary:
This diff provides a framework for doing manual
compactions in parallel with other compactions. We now have a deque of manual compactions. We also pass manual compactions as an argument from RunManualCompactions down to
BackgroundCompactions, so that RunManualCompactions can be reentrant.
Parallelism is controlled by the two routines
ConflictingManualCompaction to allow/disallow new parallel/manual
compactions based on already existing ManualCompactions. In this diff, by default manual compactions still have to run exclusive of other compactions. However, by setting the compaction option, exclusive_manual_compaction to false, it is possible to run other compactions in parallel with a manual compaction. However, we are still restricted to one manual compaction per column family at a time. All of these restrictions will be relaxed in future diffs.
I will be adding more tests later.
Test Plan: Rocksdb regression + new tests + valgrind
Reviewers: igor, anthony, IslamAbdelRahman, kradhakrishnan, yhchiang, sdong
Reviewed By: sdong
Subscribers: yoshinorim, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D47973
Summary:
Since level 0 files can overlap, two level 0 compactions cannot
run in parallel. Compact files needs to check this before running a
compaction.
Test Plan: CompactFilesTest.L0ConflictsFiles
Reviewers: igor, IslamAbdelRahman, anthony, sdong, yhchiang
Reviewed By: yhchiang
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D50079
Summary:
Although there are currently counters to keep track of the
stall caused by having too many L0 files, there is no distinction as
to whether when that stall occurs either (A) L0-L1 compaction is taking
place to try and mitigate it, or (B) no L0-L1 compaction has been scheduled
at the moment. This diff adds a counter for (A) so that the nature of L0
stalls can be better understood.
Test Plan: make all && make check
Reviewers: sdong, igor, anthony, noetzli, yhchiang
Reviewed By: yhchiang
Subscribers: MarkCallaghan, dhruba
Differential Revision: https://reviews.facebook.net/D46749
Summary:
See task #7983654. The example was triggering an assert in compaction job
because the compaction was not marked as manual. With this patch,
CompactionPicker::FormCompaction() marks compactions as manual. This patch
also fixes a couple of typos, adds optimistic_transaction_example to
.gitignore and librocksdb as a dependency for examples. Adding librocksdb as
a dependency makes sure that the examples are built with the latest changes
in librocksdb.
Test Plan: make clean && cd examples && make all && ./compact_files_example
Reviewers: rven, sdong, anthony, igor, yhchiang
Reviewed By: yhchiang
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D45117
Summary: Fix for universal compaction with trivial move, when the ouput level is 0. The tests where failing. Fixed by allowing normal compaction when output level is 0.
Test Plan: modified test cases run successfully.
Reviewers: sdong, yhchiang, IslamAbdelRahman
Reviewed By: IslamAbdelRahman
Subscribers: anthony, kradhakrishnan, leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D42933
Summary: This change enables trivial move if all the input files are non onverlapping while doing Universal Compaction.
Test Plan: ./compaction_picker_test and db_test ran successfully with the new testcases.
Reviewers: sdong
Reviewed By: sdong
Subscribers: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D40875
Hui Xiao