Summary:
This has been running in production on some key workloads, so
we believe it to be safe and extremely low cost. Nevertheless, I've
added code to ensure that "force_consistency_checks" is mentioned in
any corruption reports so that people know how to disable in case of
false positive corruption reports.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7446
Test Plan:
make check, CI, temporary debug print new message with
./version_builder_test
Reviewed By: ajkr
Differential Revision: D23972101
Pulled By: pdillinger
fbshipit-source-id: 9623e400f3752577c0ecf977e6d0915562cf9968
Summary:
Add a new Option "allow_data_in_errors". When it's set by users, it allows them to opt-in to get error messages containing corrupted keys/values. Corrupt keys, values will be logged in the messages, logs, status etc. that will help users with the useful information regarding affected data.
By default value is set false to prevent users data to be exposed in the messages.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7420
Test Plan:
1. make check -j64
2. Add a new test case
Reviewed By: ajkr
Differential Revision: D23835028
Pulled By: akankshamahajan15
fbshipit-source-id: 8d2eba8fb898e79fcf1fccc07295065a75eb59b1
Summary:
After unclean crash, the tail of the log could look as follows due to block buffering, even when the call to `ROCKSDB_LOG_ERROR()` finished.
```
2020/09/29-13:54:39.596710 7f67025fe700 [ERROR] [/db_impl/db_impl_compaction_flush.cc:2500] Waiting after background compaction err
```
This PR forces the flush while logging warning severity or higher to prevent that case.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7462
Reviewed By: riversand963
Differential Revision: D24000154
Pulled By: ajkr
fbshipit-source-id: 3bf5f1e69a62ee10e84095cebc88937a8f81b4ad
Summary:
The assertion checks that there is no overlap in sequence numbers across levels in universal compaction. However, this assumption doesn't hold when there is a delete triggered compaction or a trivial move, as they operate on a subset of a level.
Tests -
make check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7421
Reviewed By: ajkr
Differential Revision: D23872672
Pulled By: anand1976
fbshipit-source-id: c386deab8e01a5746ca996ff1f4ebcae3b15b7d2
Summary:
Add db_basic_test status check list. Some of the warnings are suppressed. It is possible that some of them are due to real bugs.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7452
Test Plan: See CI tests pass.
Reviewed By: zhichao-cao
Differential Revision: D23979764
fbshipit-source-id: 6151570c2a9b931b0fbb3fe939a94b2bd1583cbe
Summary:
The patch adds support for injecting errors when reading from `RandomAccessFile`
using `FaultInjectionTestEnv`. (This functionality was curiously missing
w/r/t `RandomAccessFile`, even though it was implemented for `RandomRWFile`.)
The patch also fixes up a test case in `blob_db_test` which uses `FaultInjectionTestEnv`
but has so far relied on reads from `RandomAccessFile`s succeeding even after
deactivating the filesystem.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7447
Test Plan: `make check`
Reviewed By: zhichao-cao
Differential Revision: D23971740
Pulled By: ltamasi
fbshipit-source-id: 8492736cb64b1ee138c658822535f3ff4fe560c6
Summary:
A generic algorithm in progress depends on a templatized
version of fastrange, so this change generalizes it and renames
it to fit our style guidelines, FastRange32, FastRange64, and now
FastRangeGeneric.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7436
Test Plan: added a few more test cases
Reviewed By: jay-zhuang
Differential Revision: D23958153
Pulled By: pdillinger
fbshipit-source-id: 8c3b76101653417804997e5f076623a25586f3e8
Summary:
Re-add extra_compiler_flags when building unit tests for fbcode.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7437
Test Plan: Integrate with buck and run internal tests.
Reviewed By: pdillinger
Differential Revision: D23943924
Pulled By: riversand963
fbshipit-source-id: b92b7ad003e06e0860c45efc5f7f9684233d0c55
Summary:
Possible fix for a TSAN issue reported in EnableFileDeletions.
disable_delete_obsolete_files_ should only be accessed holding the db
mutex, but for logging it was being accessed outside holding the mutex,
now fixed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7435
Test Plan: existing tests, watch for recurrence
Reviewed By: ltamasi
Differential Revision: D23917578
Pulled By: pdillinger
fbshipit-source-id: 8573025bca3f6fe169b24b87bbfc4ce9667b0482
Summary:
Add a method `CheckWals` in `WalSet` to check the logs on disk. See `CheckWals`'s comments.
This method will be used to check consistency of WALs during DB recovery.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7236
Test Plan: a set of tests are added to wal_edit_test.cc.
Reviewed By: riversand963
Differential Revision: D23036505
Pulled By: cheng-chang
fbshipit-source-id: 5b1d6857ac173429b00f950c32c4a5b8d063a732
Summary:
The patch introduces a helper method in `util/compression.h` called `UncompressData`
that dispatches calls to the correct uncompression method based on type, and changes
`UncompressBlockContentsForCompressionType` and `Benchmark::Uncompress` in
`db_bench` so they are implemented in terms of the new method. This eliminates
some code duplication. (`Benchmark::Compress` is also updated to use the previously
introduced `CompressData` helper.)
In addition, the patch brings the implementation of `Snappy_Uncompress` into sync with
the other uncompression methods by making the method compute the buffer size and allocate
the buffer itself. Finally, the patch eliminates some potentially risky back-and-forth conversions
between various unsigned and signed integer types by exposing the size of the allocated buffer
as a `size_t` instead of an `int`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7434
Test Plan:
`make check`
`./db_bench -benchmarks=compress,uncompress --compression_type ...`
Reviewed By: riversand963
Differential Revision: D23900011
Pulled By: ltamasi
fbshipit-source-id: b25df63ceec4639889be94acb22eb53e530c54e0
Summary:
Fix few test cases and add them in ASSERT_STATUS_CHECKED build.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7427
Test Plan:
1. ASSERT_STATUS_CHECKED=1 make -j48 check,
2. travis build for ASSERT_STATUS_CHECKED,
3. Without ASSERT_STATUS_CHECKED: make check -j64, CircleCI build and travis build
Reviewed By: pdillinger
Differential Revision: D23909983
Pulled By: akankshamahajan15
fbshipit-source-id: 42d7e4aea972acb9fcddb7ca73fcb82f93272434
Summary:
Add new AppendWithVerify and PositionedAppendWithVerify APIs to Env and FileSystem to bring the data verification information (data checksum information) from upper layer (e.g., WritableFileWriter) to the storage layer. This PR only include the API definition, no functional codes are added to unblock other developers which depend on these APIs.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7419
Test Plan: make -j32
Reviewed By: pdillinger
Differential Revision: D23883196
Pulled By: zhichao-cao
fbshipit-source-id: 94676c26bc56144cc32e3661f84f21eccd790411
Summary:
Implement a parsing tool io_tracer_parser that takes IO trace file (binary file) with command line argument --io_trace_file and output file with --output_file and dumps the IO trace records in outputfile in human readable form.
Also added unit test cases that generates IO trace records and calls io_tracer_parse to parse those records.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7333
Test Plan:
make check -j64,
Add unit test cases.
Reviewed By: anand1976
Differential Revision: D23772360
Pulled By: akankshamahajan15
fbshipit-source-id: 9c20519c189362e6663352d08863326f3e496271
Summary:
This option is apparently used by some teams within Facebook
(internal ref T75998621)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7431
Test Plan: USE_CLANG=1 make check before (fails) and after
Reviewed By: jay-zhuang
Differential Revision: D23876584
Pulled By: pdillinger
fbshipit-source-id: abb8b67a1f1aac75327944d266e284b2b6727191
Summary:
a4a4a2dabd changed the contract of `TableReader::NewIterator()` to require
`ReadOptions` outlive the returned iterator. But I didn't notice that
`SstFileReader` violates the new contract and needs to be adapted. The unit test
provided here exposes the problem when run under ASAN.
```
$ ./sst_file_reader_test --gtest_filter=SstFileReaderTest.ReadOptionsOutOfScope
Note: Google Test filter = SstFileReaderTest.ReadOptionsOutOfScope
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from SstFileReaderTest
[ RUN ] SstFileReaderTest.ReadOptionsOutOfScope
=================================================================
==3238048==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7ffd6189e158 at pc 0x000001298350 bp 0x7ffd6189c280 sp 0x7ffd6189c278
READ of size 8 at 0x7ffd6189e158 thread T0
#0 0x129834f in rocksdb::BlockBasedTableIterator::InitDataBlock() table/block_based/block_based_table_iterator.cc:236
https://github.com/facebook/rocksdb/issues/1 0x12b01f7 in rocksdb::BlockBasedTableIterator::SeekImpl(rocksdb::Slice const*) table/block_based/block_based_table_iterator.cc:77
https://github.com/facebook/rocksdb/issues/2 0x844d28 in rocksdb::IteratorWrapperBase<rocksdb::Slice>::SeekToFirst() table/iterator_wrapper.h:116
https://github.com/facebook/rocksdb/issues/3 0x844d28 in rocksdb::DBIter::SeekToFirst() db/db_iter.cc:1352
https://github.com/facebook/rocksdb/issues/4 0x52482b in rocksdb::SstFileReaderTest_ReadOptionsOutOfScope_Test::TestBody() table/sst_file_reader_test.cc:150
https://github.com/facebook/rocksdb/issues/5 0x5f433c in void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3899
https://github.com/facebook/rocksdb/issues/6 0x5f433c in void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3935
https://github.com/facebook/rocksdb/issues/7 0x5cc2de in testing::Test::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3973
https://github.com/facebook/rocksdb/issues/8 0x5cc988 in testing::Test::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3965
https://github.com/facebook/rocksdb/issues/9 0x5cc988 in testing::TestInfo::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4149
https://github.com/facebook/rocksdb/issues/10 0x5cce9a in testing::TestInfo::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4124
https://github.com/facebook/rocksdb/issues/11 0x5cce9a in testing::TestCase::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4267
https://github.com/facebook/rocksdb/issues/12 0x5ce696 in testing::TestCase::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4253
https://github.com/facebook/rocksdb/issues/13 0x5ce696 in testing::internal::UnitTestImpl::RunAllTests() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:6633
https://github.com/facebook/rocksdb/issues/14 0x5f541c in bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3899
https://github.com/facebook/rocksdb/issues/15 0x5f541c in bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3935
https://github.com/facebook/rocksdb/issues/16 0x5cee74 in testing::UnitTest::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:6242
https://github.com/facebook/rocksdb/issues/17 0x4c0332 in RUN_ALL_TESTS() third-party/gtest-1.8.1/fused-src/gtest/gtest.h:22104
https://github.com/facebook/rocksdb/issues/18 0x4c0332 in main table/sst_file_reader_test.cc:213
https://github.com/facebook/rocksdb/issues/19 0x7fb0263281a5 in __libc_start_main (/usr/local/fbcode/platform007/lib/libc.so.6+0x211a5)
https://github.com/facebook/rocksdb/issues/20 0x523e56 (/data/users/andrewkr/rocksdb/sst_file_reader_test+0x523e56)
Address 0x7ffd6189e158 is located in stack of thread T0 at offset 568 in frame
#0 0x52428f in rocksdb::SstFileReaderTest_ReadOptionsOutOfScope_Test::TestBody() table/sst_file_reader_test.cc:131
This frame has 9 object(s):
[32, 40) 'reader'
[96, 104) '<unknown>'
[160, 168) '<unknown>'
[224, 232) 'iter'
[288, 304) 'gtest_ar'
[352, 368) '<unknown>'
[416, 440) 'keys'
[480, 512) '<unknown>'
[544, 680) 'ropts' <== Memory access at offset 568 is inside this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext
(longjmp and C++ exceptions *are* supported)
AddressSanitizer: stack-use-after-scope table/block_based/block_based_table_iterator.cc:236 in rocksdb::BlockBasedTableIterator::InitDataBlock()
...
```
The fix is to use `ArenaWrappedDBIter` which has support for holding a
`ReadOptions` in an `Arena` whose lifetime is tied to the iterator.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7432
Test Plan: verified the provided unit test no longer fails
Reviewed By: pdillinger
Differential Revision: D23880043
Pulled By: ajkr
fbshipit-source-id: 9464c37408f7bd7c9c4a90ceffb04d9f0ca7a494
Summary:
While rocksdb can compile on both macOS and Linux with Buck, it couldn't be
compiled on Windows. The only way to compile it on Windows was with the CMake
build.
To keep the multi-platform complexity low, I've simply included all the Windows
bits in the TARGETS file, and added large #if blocks when not on Windows, the
same was done on the posix specific files.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7406
Test Plan:
On my devserver:
buck test //rocksdb/...
On Windows:
buck build mode/win //rocksdb/src:rocksdb_lib
Reviewed By: pdillinger
Differential Revision: D23874358
Pulled By: xavierd
fbshipit-source-id: 8768b5d16d7e8f44b5ca1e2483881ca4b24bffbe
Summary:
Valgrind was reporting a problem with the configurable_test in some GTEST code. This problem was caused by using a std::function as a GTEST parameter. This change changes the test to use a string as a function parameter (backed by a map) and fixes the valgrind issue.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7424
Reviewed By: ajkr
Differential Revision: D23855540
Pulled By: pdillinger
fbshipit-source-id: 2f2be03f7f92d96644aa9fa6481e4f37f2cfa5f5
Summary:
There are some tricky behaviors related to WAL sync:
- When creating a WAL, the WAL might not be synced, if the WAL directory is not synced, the WAL file's metadata may not even be synced to disk, so during recovery, when listing the WAL directory, the WAL may not even show up.
- During each DB::Write, the WriteOption can control whether the WAL should be synced, so a WAL previously not synced on creation can be synced during Write.
For each `SyncWAL`, we'll track the synced status and the current WAL size. Previously, we only track the WAL size on closing.
During recovery, we check that the on-disk WAL size is >= the last synced size.
So this PR introduces `synced_size` and `closed` to `WalMetadata` for the above design update.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7414
Test Plan:
- updated wal_edit_test
- updated version_edit_test
Reviewed By: riversand963
Differential Revision: D23796127
Pulled By: cheng-chang
fbshipit-source-id: 5498ab80f537c48a10157e71a4745716aef5cf30
Summary:
Current implementation holds db mutex while calling
`GetAggregatedIntProperty()`. For property kEstimateTableReadersMem,
this can be expensive, especially if the number of table readers is
high.
We can release and re-acquire db mutex if
property_info.need_out_of_mutex is true.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7412
Test Plan:
make check
COMPILE_WITH_ASAN=1 make check
COMPILE_WITH_TSAN=1 make check
Also test internally on a shadow host. Used bpf to verify the
excessively long db mutex holding no longer exists when applications
call GetApproximateMemoryUsageByType().
Reviewed By: jay-zhuang
Differential Revision: D23794824
Pulled By: riversand963
fbshipit-source-id: 6bc02a59fd25613d343a62cf817467c7122c9721
Summary:
Issue：https://github.com/facebook/rocksdb/issues/7042
No PMULL runtime check will lead to SIGILL on a Raspberry pi 4.
Leverage 'getauxval' to get Hardware-Cap to detect whether target
platform does support PMULL or not in runtime.
Consider the condition that the target platform does support crc32 but not support PMULL.
In this condition, the code should leverage the crc32 instruction
rather than skip all hardware crc32 instruction.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7233
Reviewed By: jay-zhuang
Differential Revision: D23790116
fbshipit-source-id: a3ebd821fbd4a38dd2f59064adbb7c3013ee8140
Summary:
Make the test robust to spurious wakeups on condition variable,
and clear sync points to ensure no use-after-free.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7418
Test Plan: repeated runs on updated test, watch CircleCI for recurrence
Reviewed By: jay-zhuang
Differential Revision: D23828823
Pulled By: pdillinger
fbshipit-source-id: af85117d9c02602541a90252840e0e5a6996de5b
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:
Fix the flaky test failure in error_handler_fs_test. Add the sync point, solve the dependency.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7415
Test Plan: make asan_check, ~/gtest-parallel/gtest-parallel -r 100 ./error_handler_fs_test
Reviewed By: siying
Differential Revision: D23804330
Pulled By: zhichao-cao
fbshipit-source-id: 5175108651f7652e47e15978f2a9c1669ef59d80
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:
In the current implementation, any retryable IO error happens during Flush is mapped to a hard error. In this case, DB is stopped and write is stalled unless the background error is cleaned. In this PR, if WAL is DISABLED, the retryable IO error during FLush is mapped to a soft error. Such that, the memtable can continue receive the writes. At the same time, if auto resume is triggered, SwtichMemtable will not be called during Flush when resuming the DB to avoid to many small memtables. Testing cases are added.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7310
Test Plan: adding new unit test, pass make check.
Reviewed By: anand1976
Differential Revision: D23710892
Pulled By: zhichao-cao
fbshipit-source-id: bc4ca50d11c6b23b60d2c0cb171d86d542b038e9
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
Akanksha Mahajan