Summary:
**Context:**
Some existing internal calls of `GenericRateLimiter::Request()` in backupable_db.cc and newly added internal calls in https://github.com/facebook/rocksdb/pull/8722/ do not make sure `bytes <= GetSingleBurstBytes()` as required by rate_limiter https://github.com/facebook/rocksdb/blob/master/include/rocksdb/rate_limiter.h#L47.
**Impacts of this bug include:**
(1) In debug build, when `GenericRateLimiter::Request()` requests bytes greater than `GenericRateLimiter:: kMinRefillBytesPerPeriod = 100` byte, process will crash due to assertion failure. See https://github.com/facebook/rocksdb/pull/9063#discussion_r737034133 and for possible scenario
(2) In production build, although there will not be the above crash due to disabled assertion, the bug can lead to a request of small bytes being blocked for a long time by a request of same priority with insanely large bytes from a different thread. See updated https://github.com/facebook/rocksdb/wiki/Rate-Limiter ("Notice that although....the maximum bytes that can be granted in a single request have to be bounded...") for more info.
There is an on-going effort to move rate-limiting to file wrapper level so rate limiting in `BackupEngine` and this PR might be made obsolete in the future.
**Summary:**
- Implemented loop-calling `GenericRateLimiter::Request()` with `bytes <= GetSingleBurstBytes()` as a static private helper function `BackupEngineImpl::LoopRateLimitRequestHelper`
-- Considering make this a util function in `RateLimiter` later or do something with `RateLimiter::RequestToken()`
- Replaced buggy internal callers with this helper function wherever requested byte is not pre-limited by `GetSingleBurstBytes()`
- Removed the minimum refill bytes per period enforced by `GenericRateLimiter` since it is useless and prevents testing `GenericRateLimiter` for extreme case with small refill bytes per period.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9063
Test Plan:
- Added a new test that failed the assertion before this change and now passes
- It exposed bugs in [the write during creation in `CopyOrCreateFile()`](df7cc66e17/utilities/backupable/backupable_db.cc (L2034-L2043)), [the read of table properties in `GetFileDbIdentities()`](df7cc66e17/utilities/backupable/backupable_db.cc (L2372-L2378)), [some read of metadata in `BackupMeta::LoadFromFile()`](df7cc66e17/utilities/backupable/backupable_db.cc (L2726))
- Passing Existing tests
Reviewed By: ajkr
Differential Revision: D31824535
Pulled By: hx235
fbshipit-source-id: d2b3dea7a64e2a4b1e6a59fca322f0800a4fcbcc
Summary:
New classes FileStorageInfo and LiveFileStorageInfo and
'experimental' function DB::GetLiveFilesStorageInfo, which is intended
to largely replace several fragmented DB functions needed to create
checkpoints and backups.
This function is now used to create checkpoints and backups, because
it fixes many (probably not all) of the prior complexities of checkpoint
not having atomic access to DB metadata. This also ensures strong
functional test coverage of the new API. Specifically, much of the old
CheckpointImpl::CreateCustomCheckpoint has been migrated to and
updated in DBImpl::GetLiveFilesStorageInfo, with the former now
calling the latter.
Also, the class FileStorageInfo in metadata.h compatibly replaces
BackupFileInfo and serves as a new base class for SstFileMetaData.
Some old fields of SstFileMetaData are still provided (for now) but
deprecated.
Although FileStorageInfo::directory is accurate when using db_paths
and/or cf_paths, these have never been supported by Checkpoint
nor BackupEngine and still are not. This change does now detect
these cases and return NotSupported when appropriate. (More work
needed for support.)
Somehow this change broke ProgressCallbackDuringBackup, but
the progress_callback logic was dubious to begin with because it
would call the callback based on copy buffer size, not size actually
copied. Logic and test updated to track size actually copied
per-thread.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8968
Test Plan:
tests updated.
DB::GetLiveFilesStorageInfo mostly tested by use in CheckpointImpl.
DBTest.SnapshotFiles updated to also test GetLiveFilesStorageInfo,
including reading the data after DB close.
Added CheckpointTest.CheckpointWithDbPath (NotSupported).
Reviewed By: siying
Differential Revision: D31242045
Pulled By: pdillinger
fbshipit-source-id: b183d1ce9799e220daaefd6b3b5365d98de676c0
Summary:
Context:
While all the non-trivial write operations in BackupEngine go through the RateLimiter, reads currently do not. In general, this is not a huge issue because (especially since some I/O efficiency fixes) reads in BackupEngine are mostly limited by corresponding writes, for both backup and restore. But in principle we should charge the RateLimiter for reads as well.
- Charged read operations in `BackupEngineImpl::CopyOrCreateFile`, `BackupEngineImpl::ReadFileAndComputeChecksum`, `BackupEngineImpl::BackupMeta::LoadFromFile` and `BackupEngineImpl::GetFileDbIdentities`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8722
Test Plan:
- Passed existing tests
- Passed added unit tests
Reviewed By: pdillinger
Differential Revision: D30610464
Pulled By: hx235
fbshipit-source-id: 9b08c9387159a5385c8d390d6666377a0d0117e5
Summary:
A "LATEST_BACKUP" file was left in the backup directory by
"BackupEngineTest.NoDeleteWithReadOnly" test, affecting future test
runs. In particular, it caused "BackupEngineTest.IOStats" to fail since
it relies on backup directory containing only data written by its
`BackupEngine`.
The fix is to promote "LATEST_BACKUP" to an explicitly managed file so
it is deleted in `BackupEngineTest` constructor if it exists.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8887
Test Plan:
below command used to fail. Now it passes:
```
$ TEST_TMPDIR=/dev/shm ./backupable_db_test --gtest_filter='BackupEngineTest.NoDeleteWithReadOnly:BackupEngineTest.IOStats'
```
Reviewed By: pdillinger
Differential Revision: D30812336
Pulled By: ajkr
fbshipit-source-id: 32dfbe1368ebdab872e610764bfea5daf9a2af09
Summary:
Gets `Statistics` from the options associated with the `DB` undergoing backup, and populates new ticker stats with the thread-local `IOContext` read/write counters for the threads doing backup work.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8819
Reviewed By: pdillinger
Differential Revision: D30779238
Pulled By: ajkr
fbshipit-source-id: 75ccafc355f90906df5cf80367f7245b985772d8
Summary:
* Consolidate use of std::regex for testing to testharness.cc, to
minimize Facebook linters constantly flagging uses in non-production
code.
* Improve syntax and error messages for asserting some string matches a
regex in tests.
* Add a public Regex wrapper class to encapsulate existing usage in
ObjectRegistry.
* Remove unnecessary include <regex>
* Put warnings that use of Regex in production code could cause bad
performance or stack overflow.
Intended follow-up work:
* Replace std::regex with another underlying implementation like RE2
* Improve ObjectRegistry interface in terms of possibly confusing literal
string matching vs. regex and in terms of reporting invalid regex.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8740
Test Plan:
tests updated, basic unit test for public Regex, and some manual
testing of temporary changes to see example error messages:
utilities/backupable/backupable_db_test.cc:917: Failure
000010_1162373755_138626.blob (child.name)
does not match regex
[0-9]+_[0-9]+_[0-9]+[.]blobHAHAHA (pattern)
db/db_basic_test.cc:74: Failure
R3SHSBA8C4U0CIMV2ZB0 (sid3)
does not match regex [0-9A-Z]{20}HAHAHA
Reviewed By: mrambacher
Differential Revision: D30706246
Pulled By: pdillinger
fbshipit-source-id: ba845e8f563ccad39bdb58f44f04e9da8f78c3fd
Summary:
If RateLimiter burst bytes changes during concurrent Restore
operations
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8732
Test Plan: updated unit test fails with TSAN before change, passes after
Reviewed By: ajkr
Differential Revision: D30683879
Pulled By: pdillinger
fbshipit-source-id: d0ddb3587ade91ee2a4d926b475acf7781b03086
Summary:
Guarantees that if a restore is interrupted, DB::Open will fail. This works by
restoring CURRENT first to CURRENT.tmp then as a final step renaming to CURRENT.
Also makes restore respect BackupEngineOptions::sync (default true). When set,
the restore is guaranteed persisted by the time it returns OK. Also makes the above
atomicity guarantee work in case the interruption is power loss or OS crash (not just
process interruption or crash).
Fixes https://github.com/facebook/rocksdb/issues/8500
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8568
Test Plan:
added to backup mini-stress unit test. Passes with
gtest_repeat=100 (whereas fails 7 times without the CURRENT.tmp)
Reviewed By: akankshamahajan15
Differential Revision: D29812605
Pulled By: pdillinger
fbshipit-source-id: 24e9a993b305b1835ca95558fa7a7152e54cda8e
Summary:
Various tests had disabled valgrind due to it slowing down and timing
out (as is the case right now) the CI runs. Where a test was disabled with no comment,
I assumed slowness was the cause. For these tests that were slow under
valgrind, as well as the ones identified in https://github.com/facebook/rocksdb/issues/8352, this PR moves them
behind the compiler flag `-DROCKSDB_FULL_VALGRIND_RUN`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8475
Test Plan: running `make full_valgrind_test`, `make valgrind_test`, `make check`; will verify they appear working correctly
Reviewed By: jay-zhuang
Differential Revision: D29504843
Pulled By: ajkr
fbshipit-source-id: 2aac90749cfbd30d5ce11cb29a07a1b9314eeea7
Summary:
An early design of BackupEngine used stackable DB, so I guess a
DB had to opt-in to being backupable. Unfortunately the naming of that
obsolete design still infects our public API and implementation.
This change fixes the public API, with a deprecated
backward-compatibility header. `BackupableDBOptions` is renamed to
`BackupEngineOptions` (copy-replace in the public header) and
backup_engine.h replaces backupable_db.h (present for backward
compatibility). The only other change in backupable_db.h ->
backup_engine.h is cleaning up headers.
Later changes will fix the internal implementation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8274
Test Plan:
The internal implementation of BackupEngine uses the name
BackupEngineOptions, while the unit tests use the old name
BackupableDBOptions. This gives me confidence that both still work.
Reviewed By: mrambacher
Differential Revision: D28259471
Pulled By: pdillinger
fbshipit-source-id: a25dbe327b9772143488e7bb0ec7139ee42d0613
Summary:
In a distributed environment, a file `rename()` operation can succeed on server (remote)
side, but the client can somehow return non-ok status to RocksDB. Possible reasons include
network partition, connection issue, etc. This happens in `rocksdb::SetCurrentFile()`, which
can be called in `LogAndApply() -> ProcessManifestWrites()` if RocksDB tries to switch to a
new MANIFEST. We currently always delete the new MANIFEST if an error occurs.
This is problematic in distributed world. If the server-side successfully updates the CURRENT
file via renaming, then a subsequent `DB::Open()` will try to look for the new MANIFEST and fail.
As a fix, we can track the execution result of IO operations on the new MANIFEST.
- If IO operations on the new MANIFEST fail, then we know the CURRENT must point to the original
MANIFEST. Therefore, it is safe to remove the new MANIFEST.
- If IO operations on the new MANIFEST all succeed, but somehow we end up in the clean up
code block, then we do not know whether CURRENT points to the new or old MANIFEST. (For local
POSIX-compliant FS, it should still point to old MANIFEST, but it does not matter if we keep the
new MANIFEST.) Therefore, we keep the new MANIFEST.
- Any future `LogAndApply()` will switch to a new MANIFEST and update CURRENT.
- If process reopens the db immediately after the failure, then the CURRENT file can point
to either the new MANIFEST or the old one, both of which exist. Therefore, recovery can
succeed and ignore the other.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8192
Test Plan: make check
Reviewed By: zhichao-cao
Differential Revision: D27804648
Pulled By: riversand963
fbshipit-source-id: 9c16f2a5ce41bc6aadf085e48449b19ede8423e4
Summary:
Test was flaky because for kUseDbSessionId naming, blob files use
naming scheme kLegacyCrc32cAndFileSize. So expected number of files
because of collision can vary. So disabling blobdb for this test case.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8197
Reviewed By: pdillinger
Differential Revision: D27836997
Pulled By: akankshamahajan15
fbshipit-source-id: 5eb21a5f4acae3d6b730a9e1b207264fbc18cb80
Summary:
* CreateNewBackup(WithMetadata) returning the BackupID of new backup
through optional new output param. This is especially useful with the
new mutithreading support, so that you can transactionally determine the
ID of a backup you create.
* GetBackupInfo / GetLatestBackupInfo for individual backups, so that
you don't have to comb through a vector of backups if you don't want to.
Updated HISTORY.md (including re: BlobDB support as new feature)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8170
Test Plan:
Added test logic to existing tests, to minimize increase in
cost of running tests
Reviewed By: zhichao-cao
Differential Revision: D27680410
Pulled By: pdillinger
fbshipit-source-id: 1fc45b73d81aae293ccd4a43d9583d7fd915d3eb
Summary:
Add support for blob files for backup/restore like table files.
Since DB session ID is currently not supported for blob files (there is no place to store it in
the header), so for blob files uses the
kLegacyCrc32cAndFileSize naming scheme even if
share_files_with_checksum_naming is set to kUseDbSessionId.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8129
Test Plan: Add new test units
Reviewed By: ltamasi
Differential Revision: D27408510
Pulled By: akankshamahajan15
fbshipit-source-id: b27434d189a639ef3e6ad165c61a143a2daaf06e
Summary:
Fixing another crash test failure in the case of
write_dbid_to_manifest=true and reading a backup as read-only DB.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8164
Test Plan:
enhanced unit test for backup as read-only DB, ran
blackbox_crash_test more with elevated backup_one_in
Reviewed By: zhichao-cao
Differential Revision: D27622237
Pulled By: pdillinger
fbshipit-source-id: 680d0f99ddb465a601737f2e3f2c80efd47384fb
Summary:
Forgot to re-test crash test after adding read-only filesystem
enforcement to https://github.com/facebook/rocksdb/issues/8142. The problem is ReadOnlyFileSystem would reject
CreateDirIfMissing whenever DBOptions::create_if_missing=true. The fix
that is better for users is to allow CreateDirIfMissing in
ReadOnlyFileSystem if the directory exists, so that they don't cause a
failure on using create_if_missing with opening backups as read-only
DBs. Added this option test to the unit test (in addition to being in the
crash test).
Also fixed a couple of lints.
And some better messaging from 'make format' so that when you run it
with uncommitted changes, it's clear that it's only checking the
uncommitted changes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8161
Test Plan: local blackbox_crash_test with amplified backup_one_in
Reviewed By: ajkr
Differential Revision: D27614409
Pulled By: pdillinger
fbshipit-source-id: 63ccb626c7e34c200d61c6bca2a8f60da9015179
Summary:
A current limitation of backups is that you don't know the
exact database state of when the backup was taken. With this new
feature, you can at least inspect the backup's DB state without
restoring it by opening it as a read-only DB.
Rather than add something like OpenAsReadOnlyDB to the BackupEngine API,
which would inhibit opening stackable DB implementations read-only
(if/when their APIs support it), we instead provide a DB name and Env
that can be used to open as a read-only DB.
Possible follow-up work:
* Add a version of GetBackupInfo for a single backup.
* Let CreateNewBackup return the BackupID of the newly-created backup.
Implementation details:
Refactored ChrootFileSystem to split off new base class RemapFileSystem,
which allows more general remapping of files. We use this base class to
implement BackupEngineImpl::RemapSharedFileSystem.
To minimize API impact, I decided to just add these fields `name_for_open`
and `env_for_open` to those set by GetBackupInfo when
include_file_details=true. Creating the RemapSharedFileSystem adds a bit
to the memory consumption, perhaps unnecessarily in some cases, but this
has been mitigated by (a) only initialize the RemapSharedFileSystem
lazily when GetBackupInfo with include_file_details=true is called, and
(b) using the existing `shared_ptr<FileInfo>` objects to hold most of the
mapping data.
To enhance API safety, RemapSharedFileSystem is wrapped by new
ReadOnlyFileSystem which rejects any attempts to write. This uncovered a
couple of places in which DB::OpenForReadOnly would write to the
filesystem, so I fixed these. Added a release note because this affects
logging.
Additional minor refactoring in backupable_db.cc to support the new
functionality.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8142
Test Plan:
new test (run with ASAN and UBSAN), added to stress test and
ran it for a while with amplified backup_one_in
Reviewed By: ajkr
Differential Revision: D27535408
Pulled By: pdillinger
fbshipit-source-id: 04666d310aa0261ef6b2385c43ca793ce1dfd148
Summary:
Before corrupting a file in the DB and expecting corruption to
be detected, open DB read-only to ensure file is not made obsolete by
compaction. Also, to avoid obsolete files not yet deleted, only select
live files to corrupt.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8151
Test Plan: watch CI
Reviewed By: akankshamahajan15
Differential Revision: D27568849
Pulled By: pdillinger
fbshipit-source-id: 39a69a2eafde0482b20a197949d24abe21952f27
Summary:
BackupEngine previously had unclear but strict concurrency
requirements that the API user must follow for safe use. Now we make
that clear, by separating operations into "Read," "Append," and "Write"
operations, and specifying which combinations are safe across threads on
the same BackupEngine object (previously none; now all, using a
read-write lock), and which are safe across different BackupEngine
instances open on the same backup_dir.
The changes to backupable_db.h should be backward compatible. It is
mostly about eliminating copies of what should be the same function and
(unsurprisingly) useful documentation comments were often placed on
only one of the two copies. With the re-organization, we are also
grouping different categories of operations. In the future we might add
BackupEngineReadAppendOnly, but that didn't seem necessary.
To mark API Read operations 'const', I had to mark some implementation
functions 'const' and some fields mutable.
Functional changes:
* Added RWMutex locking around public API functions to implement thread
safety on a single object. To avoid future bugs, this is another
internal class layered on top (removing many "override" in
BackupEngineImpl). It would be possible to allow more concurrency
between operations, rather than mutual exclusion, but IMHO not worth the
work.
* Fixed a race between Open() (Initialize()) and CreateNewBackup() for
different objects on the same backup_dir, where Initialize() could
delete the temporary meta file created during CreateNewBackup().
(This was found by the new test.)
Also cleaned up a couple of "status checked" TODOs, and improved a
checksum mismatch error message to include involved files.
Potential follow-up work:
* CreateNewBackup has an API wart because it doesn't tell you the
BackupID it just created, which makes it of limited use in a multithreaded
setting.
* We could also consider a Refresh() function to catch up to
changes made from another BackupEngine object to the same dir.
* Use a lock file to prevent multiple writer BackupEngines, but this
won't work on remote filesystems not supporting lock files.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8115
Test Plan:
new mini-stress test in backup unit tests, run with gcc,
clang, ASC, TSAN, and UBSAN, 100 iterations each.
Reviewed By: ajkr
Differential Revision: D27347589
Pulled By: pdillinger
fbshipit-source-id: 28d82ed2ac672e44085a739ddb19d297dad14b15
Summary:
This does not add any new public APIs or published
functionality, but adds the ability to read and use (and in tests,
write) backups with a new meta file schema, based on the old schema
but not forward-compatible (before this change). The new schema enables
some capabilities not in the old:
* Explicit versioning, so that users get clean error messages the next
time we want to break forward compatibility.
* Ignoring unrecognized fields (with warning), so that new non-critical
features can be added without breaking forward compatibility.
* Rejecting future "non-ignorable" fields, so that new features critical
to some use-cases could potentially be added outside of linear schema
versions, with broken forward compatibility.
* Fields at the end of the meta file, such as for checksum of the meta
file's contents (up to that point)
* New optional 'size' field for each file, which is checked when present
* Optionally omitting 'crc32' field, so that we aren't required to have
a crc32c checksum for files to take a backup. (E.g. to support backup
via hard links and to better support file custom checksums.)
Because we do not have a JSON parser and to share code, the new schema
is simply derived from the old schema.
BackupEngine code is updated to allow missing checksums in some places,
and to make that easier, `has_checksum` and `verify_checksum_after_work`
are eliminated. Empty `checksum_hex` indicates checksum is unknown. I'm
not too afraid of regressing on data integrity, because
(a) we have pretty good test coverage of corruption detection in backups, and
(b) we are increasingly relying on the DB itself for data integrity rather than
it being an exclusive feature of backups.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8069
Test Plan:
new unit tests, added to crash test (some local run with
boosted backup probability)
Reviewed By: ajkr
Differential Revision: D27139824
Pulled By: pdillinger
fbshipit-source-id: 9e0e4decfb42bb84783d64d2d246456d97e8e8c5
Summary:
This API can be used for things like determining how much space
can be freed up by deleting a particular backup, etc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8042
Test Plan:
validation of the API added to many existing backup unit
tests
Reviewed By: mrambacher
Differential Revision: D26936577
Pulled By: pdillinger
fbshipit-source-id: f0bbd90f0917b9781a6837652fb4616d9247816a
Summary:
New comment for share_files_with_checksum:
// Only used if share_table_files is set to true. Setting to false is
// DEPRECATED and potentially dangerous because in that case BackupEngine
// can lose data if backing up databases with distinct or divergent
// history, for example if restoring from a backup other than the latest,
// writing to the DB, and creating another backup. Setting to true (default)
// prevents these issues by ensuring that different table files (SSTs) with
// the same number are treated as distinct. See
// share_files_with_checksum_naming and ShareFilesNaming.
I have also removed interim option kFlagMatchInterimNaming, which is no
longer needed and was never needed for correct+compatible operation
(just performance).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8020
Test Plan:
tests updated. Backward+forward compatibility verified with
SHORT_TEST=1 check_format_compatible.sh. ldb uses default backup
options, and I manually verified shared_checksum in
/tmp/rocksdb_format_compatible_peterd/bak/current/ after run.
Reviewed By: ajkr
Differential Revision: D26786331
Pulled By: pdillinger
fbshipit-source-id: 36f968dfef1f5cacbd65154abe1d846151a55130
Summary:
The checkpointing logic supports passing file level checksums
to the copy_file_cb callback function which is used by the backup code
for detecting corruption during file copies.
However, this is currently implemented only for table files.
This PR extends the checksum retrieval to blob files as well.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8003
Test Plan: Add new test units
Reviewed By: ltamasi
Differential Revision: D26680701
Pulled By: akankshamahajan15
fbshipit-source-id: 1bd1e2464df6e9aa31091d35b8c72786d94cd1c5
Summary:
The main improvement here is to not include `.` or `..` in the results of `Env::GetChildren`. The occurrence of `.` or `..`; it is non-portable, dependent on the Operating System and the File System. See: https://www.gnu.org/software/libc/manual/html_node/Reading_002fClosing-Directory.html
There were lots of duplicate checks spread through the RocksDB codebase previously to skip `.` and `..`. This new removes the need for those at the source.
Also some minor fixes to `Env::GetChildren`:
* Improve error handling in POSIX implementation
* Remove unnecessary array allocation on Windows
* Fix struct name for Windows Non-UTF-8 API
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7819
Reviewed By: ajkr
Differential Revision: D25837394
Pulled By: jay-zhuang
fbshipit-source-id: 1e137e7218d38b450af9c083f73d5357abcbba2e
Summary:
In a stress test failure, we observe that a WAL is skipped when creating checkpoint, although its log number >= MinLogNumberToKeep(). This might happen in the following case:
1. when creating the checkpoint, there are 2 column families: CF0 and CF1, and there are 2 WALs: 1, 2;
2. CF0's log number is 1, CF0's active memtable is empty, CF1's log number is 2, CF1's active memtable is not empty, WAL 2 is not empty, the sequence number points to WAL 2;
2. the checkpoint process flushes CF0, since CF0' active memtable is empty, there is no need to SwitchMemtable, thus no new WAL will be created, so CF0's log number is now 2, concurrently, some data is written to CF0 and WAL 2;
3. the checkpoint process flushes CF1, WAL 3 is created and CF1's log number is now 3, CF0's log number is still 2 because CF0 is not empty and WAL 2 contains its unflushed data concurrently written in step 2;
4. the checkpoint process determines that WAL 1 and 2 are no longer needed according to [live_wal_files[i]->StartSequence() >= *sequence_number](https://github.com/facebook/rocksdb/blob/master/utilities/checkpoint/checkpoint_impl.cc#L388), so it skips linking them to the checkpoint directory;
5. but according to `MinLogNumberToKeep()`, WAL 2 still needs to be kept because CF0's log number is 2.
If the checkpoint is reopened in read-only mode, and only read from the snapshot with the initial sequence number, then there will be no data loss or data inconsistency.
But if the checkpoint is reopened and read from the most recent sequence number, suppose in step 3, there are also data concurrently written to CF1 and WAL 3, then the most recent sequence number refers to the latest entry in WAL 3, so the data written in step 2 should also be visible, but since WAL 2 is discarded, those data are lost.
When tracking WAL in MANIFEST is enabled, when reopening the checkpoint, since WAL 2 is still tracked in MANIFEST as alive, but it's missing from the checkpoint directory, a corruption will be reported.
This PR makes the checkpoint process to only skip a WAL if its log number < `MinLogNumberToKeep`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7789
Test Plan: watch existing tests to pass.
Reviewed By: ajkr
Differential Revision: D25662346
Pulled By: cheng-chang
fbshipit-source-id: 136471095baa01886cf44809455cf855f24857a0
Summary:
Consider the following sequence of events:
1. Db flushed an SST with file number N, appended to MANIFEST, and tried to sync the MANIFEST.
2. Syncing MANIFEST failed and db crashed.
3. Db tried to recover with this MANIFEST. In the meantime, no entry about the newly-flushed SST was found in the MANIFEST. Therefore, RocksDB replayed WAL and tried to flush to an SST file reusing the same file number N. This failed because file system does not support overwrite. Then Db deleted this file.
4. Db crashed again.
5. Db tried to recover. When db read the MANIFEST, there was an entry referencing N.sst. This could happen probably because the append in step 1 finally reached the MANIFEST and became visible. Since N.sst had been deleted in step 3, recovery failed.
It is possible that N.sst created in step 1 is valid. Although step 3 would still fail since the MANIFEST was not synced properly in step 1 and 2, deleting N.sst would make it impossible for the db to recover even if the remaining part of MANIFEST was appended and visible after step 5.
After this PR, in step 3, immediately after recovering from MANIFEST, a new MANIFEST is created, then we find that N.sst is not referenced in the MANIFEST, so we delete it, and we'll not reuse N as file number. Then in step 5, since the new MANIFEST does not contain N.sst, the recovery failure situation in step 5 won't happen.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7621
Test Plan:
1. some tests are updated, because these tests assume that new MANIFEST is created after WAL recovery.
2. a new unit test is added in db_basic_test to simulate step 3.
Reviewed By: riversand963
Differential Revision: D24668144
Pulled By: cheng-chang
fbshipit-source-id: 90d7487fbad2bc3714f5ede46ea949895b15ae3b
Summary:
As suggested by pdillinger ,The name of kLogFile is misleading, in some tests, kLogFile is defined as info log. Replace it with kWalFile and move it to public, which will be used in https://github.com/facebook/rocksdb/issues/7523
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7580
Test Plan: make check
Reviewed By: riversand963
Differential Revision: D24485420
Pulled By: zhichao-cao
fbshipit-source-id: 955e3dacc1021bb590fde93b0a568ffe9ad80799
Summary:
Two relatively simple functional changes to incremental backup
behavior, integrated with a minor refactoring to reduce code redundancy and
improve error/log message. There are nuances to the impact of these changes,
but I believe they are fundamentally good and generally safe. Those functional
changes:
* Incremental backups no longer read DB table files that are already saved to a
shared part of the backup directory, unless `share_files_with_checksum` is used
with `kLegacyCrc32cAndFileSize` naming (discouraged) where crc32c full file
checksums are needed to determine file naming.
* Justification: incremental backups should not need to read the whole DB,
especially without rate limiting. (Although other BackupEngine reads are not
rate limited either, other non-trivial reads are generally limited by a
corresponding write, as in copying files.) Also, the fact that this is not
already fixed was arguably a bug/oversight in the implementation of https://github.com/facebook/rocksdb/issues/7110.
* When considering whether a table file is already backed up in a shared part
of backup directory, BackupEngine would already query the sizes of source (DB)
and pre-existing destination (backup) files. BackupEngine now uses these file
sizes to detect corruption, as at least one of (a) old backup, (b) backup in
progress, or (c) current DB is corrupt if there's a size mismatch.
* Justification: a random related fix that also helps to cover a small hole
in corruption checking uncovered by the other functional change:
* For `share_table_files` without "checksum" (not recommended), the other
change regresses in detecting fundamentally unsafe use of this option
combination: when you might generate different versions of same SST file
number. As demonstrated by `BackupableDBTest.FailOverwritingBackups,` this
regression is greatly mitigated by the new file size checking. Nevertheless,
almost no reason to use `share_files_with_checksum=false` should remain, and
comments are updated appropriately.
Also, this change renames internal function `CalculateChecksum` to
`ReadFileAndComputeChecksum` to make the performance impact of this function
clear in code reviews.
It is not clear what 'same_path' is for in backupable_db.cc, and I suspect it
cannot be true for a DB with unique file names (like DBImpl). Nevertheless,
I've tried to keep its functionality intact when `true` to minimize risk for
now, despite having no unit tests for which it is true.
Select impact details (much more in unit tests): For
`share_files_with_checksum`, I am confident there is no regression (vs.
pre-6.12) in detecting DB or backup corruption at backup creation time, mostly
because the old design did not leverage this extra checksum computation for
detecting inconsistencies at backup creation time. (With computed checksums in
names, a recently corrupted file just looked like a different file vs. what was
already backed up.)
Even in the hypothetical case of DB session id collision (~100 bits entropy
collision), file size in name and/or our file size check add an extra layer of
protection against false success in creating an accurate new backup. (Unit test
included.)
`DB::VerifyChecksum` and `BackupEngine::VerifyBackup` with checksum checking
are still able to catch corruptions that `CreateNewBackup` does not. Note that
when custom file checksum support is added to BackupEngine, that will
essentially give the same power as `DB::VerifyChecksum` into `CreateNewBackup`.
We could add options for `CreateNewBackup` to cover some of what would be
caught by `VerifyBackup` with checksum checking.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7413
Test Plan:
Two new unit tests included, both of which fail without these
changes. Although we don't test the I/O improvement directly, we test it
indirectly in DB corruption detection power that was inadvertently unlocked
with new backup file naming PLUS computing current content checksums (now
removed). (I don't think that case of DB corruption detection justifies reading
the whole DB on incremental backup.)
Reviewed By: zhichao-cao
Differential Revision: D23818480
Pulled By: pdillinger
fbshipit-source-id: 148aff16f001af5b9fd4b22f155311c2461f1bac
Summary:
This change reverts BackupEngine to 6.12 state to accommodate a
higher-priority fix that does not easily merge with this custom checksum
support. We intend to reinstate this support soon, by merging a revert
of this change.
For backupable_db_test, I've removed the tests depending on this
feature.
I've also removed relevant HISTORY.md entry.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7411
Test Plan: unit tests
Reviewed By: ajkr
Differential Revision: D23793835
Pulled By: pdillinger
fbshipit-source-id: 7e861436539584799b13d1a8ae559b81b6d08052
Summary:
Prior to 6.12, backup files using share_files_with_checksum had
the file size encoded in the file name, after the last '\_' and before
the last '.'. We considered this an implementation detail subject to
change, and indeed removed this information from the file name (with an
option to use old behavior) because it was considered
ineffective/inefficient for file name uniqueness. However, some
downstream RocksDB users were relying on this information since the file
size is not explicitly in the backup manifest file.
This primary purpose of this change is "retrofitting" the 6.12 release
(not yet a public release) to simultaneously support the benefits of the
new naming scheme (I/O performance and data correctness at scale) and
preserve the file size information, both as default behaviors. With this
change, we are essentially making the file size information encoded in
the file name an official, though obscure, extension of the backup meta
file format.
We preserve an option (kLegacyCrc32cAndFileSize) to use the original
"legacy" naming scheme, with its caveats, and make it easy to omit the
file size information (no kFlagIncludeFileSize), for more compact file
names. But note that changing the naming scheme used on an existing db
and backup directory can lead to transient space amplification, as some
files will be stored under two names in the shared_checksum directory.
Because some backups were saved using the original 6.12 naming scheme,
we offer two ways of dealing with those files: SST files generated by
older 6.12 versions can either use the default naming scheme in effect
when the SST files were generated (kFlagMatchInterimNaming, default, no
transient space amplification) or can use a new naming scheme (no
kFlagMatchInterimNaming, potential space amplification because some
already stored files getting a new name).
We don't have a natural way to detect which files were generated by
previous 6.12 versions, but this change hacks one in by changing DB
session ids to now use a more concise encoding, reducing file name
length, saving ~dozen bytes from SST files, and making them visually
distinct from DB ids so that they are less likely to be mixed up.
Two final auxiliary notes:
Recognizing that the backup file names have become a de facto part of
the backup meta schema, this change makes them easier to parse and
extend by putting a distinct marker, 's', before DB session ids embedded
in the name. When we extend this to allow custom checksums in the name,
they can get their own marker to ensure safe parsing. For backward
compatibility, file size does not get a marker but is assumed for
`_[0-9]+[.]`
Another change from initial 6.12 default behavior is never including
file custom checksum in the file name. Looking ahead to 6.13, we do not
want the default behavior to cause backup space amplification for
someone turning on file custom checksum checking in BackupEngine; we
want that to be an easy decision. When implemented, including file
custom checksums in backup file names will be a non-default option.
Actual file name patterns and priorities, as regexes:
kLegacyCrc32cAndFileSize OR pre-6.12 SST file ->
[0-9]+_[0-9]+_[0-9]+[.]sst
kFlagMatchInterimNaming set (default) AND early 6.12 SST file ->
[0-9]+_[0-9a-fA-F-]+[.]sst
kUseDbSessionId AND NOT kFlagIncludeFileSize ->
[0-9]+_s[0-9A-Z]{20}[.]sst
kUseDbSessionId AND kFlagIncludeFileSize (default) ->
[0-9]+_s[0-9A-Z]{20}_[0-9]+[.]sst
We might add opt-in options for more '\_' separated data in the name,
but embedded file size, if present, will always be after last '\_' and
before '.sst'.
This change was originally applied to version 6.12. (See https://github.com/facebook/rocksdb/issues/7390)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7400
Test Plan:
unit tests included. Sync point callbacks are used to mimic
previous version SST files.
Reviewed By: ajkr
Differential Revision: D23759587
Pulled By: pdillinger
fbshipit-source-id: f62d8af4e0978de0a34f26288cfbe66049b70025
Summary:
This is a "real" fix for the issue worked around in https://github.com/facebook/rocksdb/issues/7294.
To get DB checksum info for live files, we now read the manifest file
that will become part of the checkpoint/backup. This requires a little
extra handling in taking a custom checkpoint, including only reading the
manifest file up to the size prescribed by the checkpoint.
This moves GetFileChecksumsFromManifest from backup code to
file_checksum_helper.{h,cc} and removes apparently unnecessary checking
related to column families.
Updated HISTORY.md and warned potential future users of
DB::GetLiveFilesChecksumInfo()
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7309
Test Plan: updated unit test, before and after
Reviewed By: ajkr
Differential Revision: D23311994
Pulled By: pdillinger
fbshipit-source-id: 741e30a2dc1830e8208f7648fcc8c5f000d4e2d5
Summary:
On a read-write DB configured with
DBOptions::file_checksum_gen_factory, BackupEngine::CreateNewBackup can
fail intermittently, with non-OK status. This is due to a race between
GetLiveFiles and GetLiveFilesChecksumInfo in creating backups.
For patching 6.12 release (as this commit is intended for, except this is a
forward-merged version), we can simply treat files for which we falsely failed
to get checksum info as legacy files lacking checksum info.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7294
Test Plan: unit test reproducer included
Reviewed By: ajkr
Differential Revision: D23253489
Pulled By: pdillinger
fbshipit-source-id: 9e4945dad120b776ad3e753be10b962f61f28e14
Summary:
Some tests like BackupableDBTest.FileCollision and
ShareTableFilesWithChecksumsNewNaming are intermittently failing,
probably due to unpredictable flushing with FillDB. This change
should fix the failures seen and help to prevent similar flakiness in
future tests in the file.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7273
Test Plan: make check, and with valgrind
Reviewed By: siying
Differential Revision: D23176947
Pulled By: pdillinger
fbshipit-source-id: 654b73a64db475f2b9b065ed53a889a8b9083c59
Summary:
The param tests did not take any effect previously. This PR re-enables it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7260
Test Plan: Some manual tests and `./backupable_db_test`.
Reviewed By: siying
Differential Revision: D23140902
Pulled By: pdillinger
fbshipit-source-id: cd62b11b926affed25127d9074fa97a1c7f748c4
Summary:
The flaky test in the title is caused by two problems. First, there is a bug in the BackupEngine that results in skipping computing the default crc32 checksum when `share_table_files` is enabled and the table is already backed up. Second, when `RestoreDBFromBackup` fails and the backup was being restored to the DB directory, it is likely that `RestoreDBFromBackup` has cleaned up the DB directory before it fails, and therefore, files in old backups may collide with files to be backed up if `share_files_with_checksum` is not enabled.
New tests that cover the above problems are added.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7254
Test Plan: `./backupable_db_test`
Reviewed By: pdillinger
Differential Revision: D23118715
Pulled By: gg814
fbshipit-source-id: 7be8de912808944be59e93d602c7431a54c079eb
Summary:
A new option `std::shared_ptr<FileChecksumGenFactory> backup_checksum_gen_factory` is added to `BackupableDBOptions`. This allows custom checksum functions to be used for creating, verifying, or restoring backups.
Tests are added.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7085
Test Plan: Passed make check
Reviewed By: pdillinger
Differential Revision: D22390756
Pulled By: gg814
fbshipit-source-id: 3b7756ca444c2129844536b91c3ca09f53b6248f
Summary:
Fix the data race warning by removing an unnecessary variable that causes the warning.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7177
Test Plan:
`COMPILE_WITH_TSAN=1 make backupable_db_test`
`./backupable_db_test --gtest_filter=*TableFileWithDbChecksumCorruptedDuringBackup*`
Reviewed By: riversand963
Differential Revision: D22774430
Pulled By: gg814
fbshipit-source-id: 3b0b1ac344d0375c64da564cc97f98745c289959
Summary:
BackupableDBTest.RateLimiting test is failing due to timed out
on our test server. It might be because of nested loops run sequentially that test different type of combinations of parameters. This patch converts the test into parameterized test so that all combinations can be tested out.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7167
Test Plan: make check -j64
Reviewed By: zhichao-cao
Differential Revision: D22709531
Pulled By: akankshamahajan15
fbshipit-source-id: 95518153e87b3b5311a6c1960a191bca58898786
Summary:
BackupEngine requires computing table checksums twice when backing up table files to the `shared_checksum` directory.
The repeated computation can be avoided by utilizing the db session id stored as a part of the table properties.
Filenames of table files in the `shared_checksum` directory depend on the following conditions:
1. the naming scheme is `kOptionalChecksumAndDbSessionId`,
2. `db_session_id` is not empty,
3. checksum is available in the DB manifest.
If 1,2,3 are satisfied, then the filenames will be of the form `<file_number>_<checksum>_<db_session_id>.sst`.
If 1,2 are satisfied, then the filenames will be of the form `<file_number>_<db_session_id>.sst`.
In all other cases, the filenames are of the form `<file_number>_<checksum>_<size>.sst`.
Additionally, if `kOptionalChecksumAndDbSessionId` is used (and not falling back to `kChecksumAndFileSize`), the `<checksum>` appeared in the filenames is hexadecimally encoded, instead of being plain `uint32_t` value.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7110
Test Plan: backupable_db_test and manual tests.
Reviewed By: ajkr
Differential Revision: D22508992
Pulled By: gg814
fbshipit-source-id: 5669f0ea9ad5a097f69f6d87aca4abba15032389
Summary:
Cleans up some of the dependencies on test code in the Makefile while building tools:
- Moves the test::RandomString, DBBaseTest::RandomString into Random
- Moves the test::RandomHumanReadableString into Random
- Moves the DestroyDir method into file_utils
- Moves the SetupSyncPointsToMockDirectIO into sync_point.
- Moves the FaultInjection Env and FS classes under env
These changes allow all of the tools to build without dependencies on test_util, thereby simplifying the build dependencies. By moving the FaultInjection code, the dependency in db_stress on different libraries for debug vs release was eliminated.
Tested both release and debug builds via Make and CMake for both static and shared libraries.
More work remains to clean up how the tools are built and remove some unnecessary dependencies. There is also more work that should be done to get the Makefile and CMake to align in their builds -- what is in the libraries and the sizes of the executables are different.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7097
Reviewed By: riversand963
Differential Revision: D22463160
Pulled By: pdillinger
fbshipit-source-id: e19462b53324ab3f0b7c72459dbc73165cc382b2
Summary:
Although PR https://github.com/facebook/rocksdb/issues/7032 fixes the construction of the `SstFileDumper` in `GetFileDbIdentities` by setting a proper `Env` of the `Options` passed in the constructor, the file path was not corrected accordingly. This actually disables backup engine to use db session ids in the file names since the `db_session_id` is always empty.
Now it is fixed by setting the correct path in the construction of `SstFileDumper`. Furthermore, to preserve the Direct IO property that backup engine already has, parameter `EnvOptions` is added to `GetFileDbIdentities` and `SstFileDumper`.
The `BackupUsingDirectIO` test is updated accordingly.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7104
Test Plan: backupable_db_test and some manual tests.
Reviewed By: ajkr
Differential Revision: D22443245
Pulled By: gg814
fbshipit-source-id: 056a9bb8b82947c5e73d7c3fbb62bfe23af5e562
Summary:
The fix in PR https://github.com/facebook/rocksdb/issues/7082 is not really successful because there is still a small chance that the test will fail.
In addtion to flushing, we close the DB and then reopen before corrupting a table file in the DB. Specifically, we corrupt a table file before backup takes place as follows.
* Open DB
* Fill DB
* Flush DB (optional, no flushing here also works)
* Close DB
* Reopen DB
* Corrupt a table file in the DB
This should make the test reliable.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7102
Test Plan:
`while ./backupable_db_test --gtest_filter=*TableFileCorruptedBeforeBackup*; do true; done`
(kept running for an hour or so :)
Reviewed By: pdillinger
Differential Revision: D22432417
Pulled By: gg814
fbshipit-source-id: d407eee93ff428bb662f80cde1659fbf0149d0cd
Summary:
If the corruption of a table file is done before flushing, then db manifest may record the checksum for the corrupted table, which results in "matching checksums" when backup engine tries to verfiy the checksum, and causes a flaky test.
Fix the issue by adding `Flush()` before trying to corrupt a table file in *db*.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7082
Test Plan:
`buck test`
Without the fix, failed 5 of 100 tests.
Suspected whether the pseudo randomness causes the issue: doubling `keys_iteration` resulted in 2 of 100 tests failed; deterministically corrupting tables file also caused 2 of 100 tests to fail.
With the fix, passed 200 of 200 tests.
Reviewed By: pdillinger
Differential Revision: D22375421
Pulled By: gg814
fbshipit-source-id: 7304618e7520684b6087e42d0b58329c5ad18329
Summary:
When table file checksums are enabled and stored in the DB manifest by using the RocksDB default crc32c checksum function, BackupEngine will calculate the crc32c checksum of the file to be copied and compare the calculated result with the one stored in the DB manifest before copying the file to the backup directory.
After copying to the backup directory, BackupEngine will verify the checksum of the copied file with the one calculated before copying. This helps detect some rare corruption events such as bit-flips during the copying process.
No verification with checksums in DB manifest will be performed if the table file checksum function is not the RocksDB default crc32c checksum function.
In addition, If `share_table_files` and `share_files_with_checksum` are true, BackupEngine will compare the checksums computed before and after copying of the table files.
Corresponding tests are added.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7015
Test Plan: Passed make check
Reviewed By: pdillinger
Differential Revision: D22165732
Pulled By: gg814
fbshipit-source-id: ee0e8cc397c455eba64545c29380b9d9853588ec
Summary:
`bool BackupableDBOptions::new_naming_for_backup_files` is updated to `BackupTableNameOption BackupableDBOptions::share_files_with_checksum_naming`, where `BackupTableNameOption` is an `enum` type with two enumerators `kChecksumAndFileSize` and `kChecksumAndFileSize`. This opens up possibilities of extenting the current naming scheme for backup table files. By default, `BackupTableNameOption BackupableDBOptions::share_files_with_checksum_naming` is set to `kChecksumAndDbSessionId`.
Revert `BackupEngine::VerifyBackup` to only check file sizes by default.
Also fix the construction of the `SstFileDumper` in `GetFileDbIdentities` by setting a proper `Env` of the `Options` passed in the constructor.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7032
Test Plan: make check
Reviewed By: ajkr
Differential Revision: D22237763
Pulled By: gg814
fbshipit-source-id: 466902a4e731babd64e30f0e82ca1aa82962e52e
Summary:
A parameter `verify_with_checksum` is added to `BackupEngine::VerifyBackup`, which is true by default. So now `BackupEngine::VerifyBackup` verifies backup files with checksum AND file size by default. When `verify_with_checksum` is false, `BackupEngine::VerifyBackup` only compares file sizes to verify backup files.
Also add a test for the case when corruption does not change the file size.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7014
Test Plan: Passed backupable_db_test
Reviewed By: zhichao-cao
Differential Revision: D22165590
Pulled By: gg814
fbshipit-source-id: 606a7450714e868bceb38598c89fd356c6004f4f
Hui Xiao