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11 Commits (50e9b3f9c7e9198257d0398bf14c8ddad70527cb)
| Author | SHA1 | Message | Date |
|---|---|---|---|
Hui Xiao
|
98d5db5c2e |
Sort L0 files by newly introduced epoch_num (#10922)
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 s6 while s6 contains a newer version of the k1's value (i.e, k1@2) than s5, which is a real reordering corruption.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
|
2 years ago |
|
Yanqin Jin
|
3d0d6b8140 |
Make best-efforts recovery verify SST unique ID before Version construction (#10962)
Summary: The check for SST unique IDs added to best-efforts recovery (`Options::best_efforts_recovery` is true). With best_efforts_recovery being true, RocksDB will recover to the latest point in MANIFEST such that all valid SST files included up to this point pass unique ID checks as well. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10962 Test Plan: make check Reviewed By: pdillinger Differential Revision: D41378241 Pulled By: riversand963 fbshipit-source-id: a036064e2c17dec13d080a24ef2a9f85d607b16c |
2 years ago |
|
Baptiste Lemaire
|
d61a449364 |
Fixed manifest_dump issues when printing keys and values containing null characters (#8378)
Summary: Changed fprintf function to fputc in ApplyVersionEdit, and replaced null characters with whitespaces. Added unit test in ldb_test.py - verifies that manifest_dump --verbose output is correct when keys and values containing null characters are inserted. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8378 Reviewed By: pdillinger Differential Revision: D29034584 Pulled By: bjlemaire fbshipit-source-id: 50833687a8a5f726e247c38457eadc3e6dbab862 |
4 years ago |
|
Yanqin Jin
|
314352761f |
Ignore comparator name mismatch in ldb manifest dump (#8216)
Summary: RocksDB allows user-specified custom comparators which may not be known to `ldb`, a built-in tool for checking/mutating the database. Therefore, column family comparator names mismatch encountered during manifest dump should not prevent the dumping from proceeding. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8216 Test Plan: ``` make check ``` Also manually do the following ``` KEEP_DB=1 ./db_with_timestamp_basic_test ./ldb --db=<db> manifest_dump --verbose ``` The ldb should succeed and print something like: ``` ... --------------- Column family "default" (ID 0) -------------- log number: 6 comparator: <TestComparator>, but the comparator object is not available. ... ``` Reviewed By: ltamasi Differential Revision: D27927581 Pulled By: riversand963 fbshipit-source-id: f610b2c842187d17f575362070209ee6b74ec6d4 |
4 years ago |
|
Yanqin Jin
|
b0e20194ea |
Handle blob files when options.best_efforts_recovery is true (#8180)
Summary: If `options.best_efforts_recovery == true`, RocksDB currently tolerates missing table files and recovers to the latest version without missing table files (not considering WAL). It is necessary to handle blob files as well to make the feature more complete. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8180 Test Plan: make check Reviewed By: ltamasi Differential Revision: D27840556 Pulled By: riversand963 fbshipit-source-id: 041685d0dc2e7779ac4f0374c07a8a327704aa5e |
4 years ago |
|
Yanqin Jin
|
64517d184a |
Make secondary instance use ManifestTailer (#7998)
Summary: This PR - adds a class `ManifestTailer` that inherits from `VersionEditHandlerPointInTime`. `ManifestTailer::Iterate()` can be called multiple times to tail the primary instance's MANIFEST and apply the changes to the secondary, - updates the implementation of `ReactiveVersionSet::ReadAndApply` to use this class, - removes unused code in version_set.cc, - updates existing tests, e.g. removing deleted sync points from unit tests, - adds a new test to address the bug in https://github.com/facebook/rocksdb/issues/7815. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7998 Test Plan: make check Existing and newly-added tests in version_set_test.cc and db_secondary_test.cc Reviewed By: jay-zhuang Differential Revision: D26926641 Pulled By: riversand963 fbshipit-source-id: 8d4dd15db0ba863c213f743e33b5a207e948c980 |
4 years ago |
|
Yanqin Jin
|
8b6b6aeb1a |
Refactor with VersionEditHandler (#6581)
Summary: Added a few classes in the same class hierarchy to remove code duplication and refactor the logic of reading and processing MANIFEST files. New classes are as follows. ``` class VersionEditHandlerBase; class ListColumnFamiliesHandler : VersionEditHandlerBase; class FileChecksumRetriever : VersionEditHandlerBase; class DumpManifestHandler : VersionEditHandler; ``` Classes that already existed before this PR are as follows. ``` class VersionEditHandler : VersionEditHandlerBase; ``` With these classes, refactored functions: `VersionSet::Recover()`, `VersionSet::ListColumnFamilies()`, `VersionSet::DumpManifest()`, `GetFileChecksumFromManifest()`. Test Plan (devserver): ``` make check COMPILE_WITH_ASAN=1 make check ``` These refactored code, especially recovery-related logic, will be tested intensively by all existing unit tests and stress tests. For example, run ``` make crash_test ``` Verified 3 successful runs on devserver. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6581 Reviewed By: ajkr Differential Revision: D20616217 Pulled By: riversand963 fbshipit-source-id: 048c7743aa4be2623ccd0cc3e61c0027e604e78b |
4 years ago |
|
Cheng Chang
|
1b224324b5 |
Track WAL in MANIFEST: persist WALs to and recover WALs from MANIFEST (#7256)
Summary: This PR makes it able to `LogAndApply` `VersionEdit`s related to WALs, and also be able to `Recover` from MANIFEST with WAL related `VersionEdit`s. The `VersionEdit`s related to WAL are treated similarly as those related to column family operations, they are not applied to versions, but can be in a commit group. Mixing WAL related `VersionEdit`s with other types of edits will make logic in `ProcessManifestWrite` more complicated, so `VersionEdit`s related to WAL can either be WAL additions or deletions, like column family add and drop. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7256 Test Plan: a set of unit tests are added in `version_set_test.cc` Reviewed By: riversand963 Differential Revision: D23123238 Pulled By: cheng-chang fbshipit-source-id: 246be2ed4744fd03fa2738aba408aaa611d0379c |
4 years ago |
|
Akanksha Mahajan
|
b175eceb09 |
Store FSWritableFilePtr object in WritableFileWriter (#7193)
Summary:
Replace FSWritableFile pointer with FSWritableFilePtr
object in WritableFileWriter.
This new object wraps FSWritableFile pointer.
Objective: If tracing is enabled, FSWritableFile Ptr returns
FSWritableFileTracingWrapper pointer that includes all necessary
information in IORecord and calls underlying FileSystem and invokes
IOTracer to dump that record in a binary file. If tracing is disabled
then, underlying FileSystem pointer is returned directly.
FSWritableFilePtr wrapper class is added to bypass the
FSWritableFileWrapper when
tracing is disabled.
Test Plan: make check -j64
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7193
Reviewed By: anand1976
Differential Revision: D23355915
Pulled By: akankshamahajan15
fbshipit-source-id: e62a27a13c1fd77e36a6dbafc7006d969bed25cf
|
4 years ago |
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Yanqin Jin
|
569b87e8c7 |
Fail recovery when MANIFEST record checksum mismatch (#6996)
Summary: https://github.com/facebook/rocksdb/issues/5411 refactored `VersionSet::Recover` but introduced a bug, explained as follows. Before, once a checksum mismatch happens, `reporter` will set `s` to be non-ok. Therefore, Recover will stop processing the MANIFEST any further. ``` // Correct // Inside Recover LogReporter reporter; reporter.status = &s; log::Reader reader(..., reporter); while (reader.ReadRecord() && s.ok()) { ... } ``` The bug is that, the local variable `s` in `ReadAndRecover` won't be updated by `reporter` while reading the MANIFEST. It is possible that the reader sees a checksum mismatch in a record, but `ReadRecord` retries internally read and finds the next valid record. The mismatched record will be ignored and no error is reported. ``` // Incorrect // Inside Recover LogReporter reporter; reporter.status = &s; log::Reader reader(..., reporter); s = ReadAndRecover(reader, ...); // Inside ReadAndRecover Status s; // Shadows the s in Recover. while (reader.ReadRecord() && s.ok()) { ... } ``` `LogReporter` can use a separate `log_read_status` to track the errors while reading the MANIFEST. RocksDB can process more MANIFEST entries only if `log_read_status.ok()`. Test plan (devserver): make check Pull Request resolved: https://github.com/facebook/rocksdb/pull/6996 Reviewed By: ajkr Differential Revision: D22105746 Pulled By: riversand963 fbshipit-source-id: b22f717a423457a41ca152a242abbb64cf91fc38 |
5 years ago |
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Yanqin Jin
|
fb09ef05dc |
Attempt to recover from db with missing table files (#6334)
Summary: There are situations when RocksDB tries to recover, but the db is in an inconsistent state due to SST files referenced in the MANIFEST being missing. In this case, previous RocksDB will just fail the recovery and return a non-ok status. This PR enables another possibility. During recovery, RocksDB checks possible MANIFEST files, and try to recover to the most recent state without missing table file. `VersionSet::Recover()` applies version edits incrementally and "materializes" a version only when this version does not reference any missing table file. After processing the entire MANIFEST, the version created last will be the latest version. `DBImpl::Recover()` calls `VersionSet::Recover()`. Afterwards, WAL replay will *not* be performed. To use this capability, set `options.best_efforts_recovery = true` when opening the db. Best-efforts recovery is currently incompatible with atomic flush. Test plan (on devserver): ``` $make check $COMPILE_WITH_ASAN=1 make all && make check ``` Pull Request resolved: https://github.com/facebook/rocksdb/pull/6334 Reviewed By: anand1976 Differential Revision: D19778960 Pulled By: riversand963 fbshipit-source-id: c27ea80f29bc952e7d3311ecf5ee9c54393b40a8 |
5 years ago |