Summary:
Changes the API of the MemPurge process: the `bool experimental_allow_mempurge` and `experimental_mempurge_policy` flags have been replaced by a `double experimental_mempurge_threshold` option.
This change of API reflects another major change introduced in this PR: the MemPurgeDecider() function now works by sampling the memtables being flushed to estimate the overall amount of useful payload (payload minus the garbage), and then compare this useful payload estimate with the `double experimental_mempurge_threshold` value.
Therefore, when the value of this flag is `0.0` (default value), mempurge is simply deactivated. On the other hand, a value of `DBL_MAX` would be equivalent to always going through a mempurge regardless of the garbage ratio estimate.
At the moment, a `double experimental_mempurge_threshold` value else than 0.0 or `DBL_MAX` is opnly supported`with the `SkipList` memtable representation.
Regarding the sampling, this PR includes the introduction of a `MemTable::UniqueRandomSample` function that collects (approximately) random entries from the memtable by using the new `SkipList::Iterator::RandomSeek()` under the hood, or by iterating through each memtable entry, depending on the target sample size and the total number of entries.
The unit tests have been readapted to support this new API.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8628
Reviewed By: pdillinger
Differential Revision: D30149315
Pulled By: bjlemaire
fbshipit-source-id: 1feef5390c95db6f4480ab4434716533d3947f27
Summary:
`CompareKeyContext::operator()` on the trunk has a bug: when comparing
column family IDs, `lhs` is used for both sides of the comparison. This
results in the `KeyContext`s getting sorted solely based on key, which
in turn means that keys with the same column family do not necessarily
form a single range in the sorted list. This violates an assumption of the
batched `MultiGet` logic, leading to the same column family
showing up multiple times in the list of `MultiGetColumnFamilyData`.
The end result is the code attempting to check out the thread-local
`SuperVersion` for the same CF multiple times, causing an
assertion violation in debug builds and memory corruption/crash in
release builds.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8633
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D30169182
Pulled By: ltamasi
fbshipit-source-id: a47710652df7e95b14b40fb710924c11a8478023
Summary:
We've been seeing occasional crashes on CI while inserting into the
vectors in `ObsoleteFilesTest.DeleteObsoleteOptionsFile`. The crashes
don't reproduce locally (could be either a race or an object lifecycle
issue) but the good news is that the vectors in question are not really
used for anything meaningful by the test. (The assertion about the sizes
of the two vectors being equal is guaranteed to hold, since the two sync
points where they are populated are right after each other.) The patch
simply removes the vectors from the test, alongside the associated
callbacks and sync points.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8624
Test Plan: `make check`
Reviewed By: akankshamahajan15
Differential Revision: D30118485
Pulled By: ltamasi
fbshipit-source-id: 0a4c3d06584e84cd2b1dcc212d274fa1b89cb647
Summary:
PR https://github.com/facebook/rocksdb/issues/5908 added `flush_jobs_info_` to `FlushJob` to make sure
`OnFlushCompleted()` is called after committing flush results to
MANIFEST. However, `flush_jobs_info_` is not updated in atomic
flush, causing `NotifyOnFlushCompleted()` to skip `OnFlushCompleted()`.
This PR fixes this, in a similar way to https://github.com/facebook/rocksdb/issues/5908 that handles regular flush.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8585
Test Plan: make check
Reviewed By: jay-zhuang
Differential Revision: D29913720
Pulled By: riversand963
fbshipit-source-id: 4ff023c98372fa2c93188d4a5c8a4e9ffa0f4dda
Summary:
The `ColumnFamilyData::UnrefAndTryDelete` code currently on the trunk
unlocks the DB mutex before destroying the `ThreadLocalPtr` holding
the per-thread `SuperVersion` pointers when the only remaining reference
is the back reference from `super_version_`. The idea behind this was to
break the circular dependency between `ColumnFamilyData` and `SuperVersion`:
when the penultimate reference goes away, `ColumnFamilyData` can clean up
the `SuperVersion`, which can in turn clean up `ColumnFamilyData`. (Assuming there
is a `SuperVersion` and it is not referenced by anything else.) However,
unlocking the mutex throws a wrench in this plan by making it possible for another thread
to jump in and take another reference to the `ColumnFamilyData`, keeping the
object alive in a zombie `ThreadLocalPtr`-less state. This can cause issues like
https://github.com/facebook/rocksdb/issues/8440 ,
https://github.com/facebook/rocksdb/issues/8382 ,
and might also explain the `was_last_ref` assertion failures from the `ColumnFamilySet`
destructor we sometimes observe during close in our stress tests.
Digging through the archives, this unlocking goes way back to 2014 (or earlier). The original
rationale was that `SuperVersionUnrefHandle` used to lock the mutex so it can call
`SuperVersion::Cleanup`; however, this logic turned out to be deadlock-prone.
https://github.com/facebook/rocksdb/pull/3510 fixed the deadlock but left the
unlocking in place. https://github.com/facebook/rocksdb/pull/6147 then introduced
the circular dependency and associated cleanup logic described above (in order
to enable iterators to keep the `ColumnFamilyData` for dropped column families alive),
and moved the unlocking-relocking snippet to its present location in `UnrefAndTryDelete`.
Finally, https://github.com/facebook/rocksdb/pull/7749 fixed a memory leak but
apparently exacerbated the race by (otherwise correctly) switching to `UnrefAndTryDelete`
in `SuperVersion::Cleanup`.
The patch simply eliminates the unlocking and relocking, which has been unnecessary
ever since https://github.com/facebook/rocksdb/issues/3510 made `SuperVersionUnrefHandle` lock-free.
This closes the window during which another thread could increase the reference count,
and hopefully fixes the issues above.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8605
Test Plan: Ran `make check` and stress tests locally.
Reviewed By: pdillinger
Differential Revision: D30051035
Pulled By: ltamasi
fbshipit-source-id: 8fe559e4b4ad69fc142579f8bc393ef525918528
Summary:
Prior to this change, the "wal_dir" DBOption would always be set (defaults to dbname) when the DBOptions were sanitized. Because of this setitng in the options file, it was not possible to rename/relocate a database directory after it had been created and use the existing options file.
After this change, the "wal_dir" option is only set under specific circumstances. Methods were added to the ImmutableDBOptions class to see if it is set and if it is set to something other than the dbname. Additionally, a method was added to retrieve the effective value of the WAL dir (either the option or the dbname/path).
Tests were added to the core and ldb to test that a database could be created and renamed without issue. Additional tests for various permutations of wal_dir were also added.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8582
Reviewed By: pdillinger, autopear
Differential Revision: D29881122
Pulled By: mrambacher
fbshipit-source-id: 67d3d033dc8813d59917b0a3fba2550c0efd6dfb
Summary:
This PR tries to remove some unnecessary checks as well as unreachable code blocks to
improve readability. An obvious non-public API method naming typo is also corrected.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8565
Test Plan: make check
Reviewed By: lth
Differential Revision: D29963984
Pulled By: riversand963
fbshipit-source-id: cc96e8f09890e5cfe9b20eadb63bdca5484c150a
Summary:
Calling the GetImpl function could leave reference to a local
callback function in a field of a parameter struct. As this is
performance-critical code, I'm not going to attempt to sanitize this
code too much, but make the existing hack a bit cleaner by reverting
what it overwrites in the input struct.
Added SaveAndRestore utility class to make that easier.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8590
Test Plan:
added unit test for SaveAndRestore; existing tests for
GetImpl
Reviewed By: riversand963
Differential Revision: D29947983
Pulled By: pdillinger
fbshipit-source-id: 2f608853f970bc06724e834cc84dcc4b8599ddeb
Summary:
If DB::GetSortedWalFiles() runs without file deletion disbled, file might get deleted in the middle and error is returned to users. It makes the function hard to use. Fix it by disabling file deletion if it is not done.
Fix another minor issue of logging within DB mutex, which should not be done unless a major failure happens.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8591
Test Plan: Run all existing tests
Reviewed By: pdillinger
Differential Revision: D29969412
fbshipit-source-id: d5f42b5271608a35b9b07687ce18157d7447b0de
Summary:
The main challenge to make the memtable garbage collection prototype (nicknamed `mempurge`) was to not get rid of WAL files that contain unflushed (but mempurged) data. That was successfully guaranteed by not writing the VersionEdit to the MANIFEST file after a successful mempurge.
By not writing VersionEdits to the `MANIFEST` file after a succesful mempurge operation, we do not change the earliest log file number that contains unflushed data: `cfd->GetLogNumber()` (`cfd->SetLogNumber()` is only called in `VersionSet::ProcessManifestWrites`). As a result, a number of functions introduced earlier just for the mempurge operation are not obscolete/redundant. (e.g.: `FlushJob::ExtractEarliestLogFileNumber`), and this PR aims at cleaning up all these now-unnecessary functions. In particular, we no longer need to store the earliest log file number in the `MemTable` struct itself. This PR therefore also reverts the `MemTable` struct to its original form.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8558
Test Plan: Already included in `db_flush_test.cc`.
Reviewed By: anand1976
Differential Revision: D29764351
Pulled By: bjlemaire
fbshipit-source-id: 0f43b260fa270251862512f397d3f24ee62e8437
Summary:
If the primary's CURRENT file is missing or inaccessible, the secondary should not hang
trying repeatedly to switch to the next MANIFEST.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8200
Test Plan: make check
Reviewed By: jay-zhuang
Differential Revision: D27840627
Pulled By: riversand963
fbshipit-source-id: 071fed97cbab1bc5cdefd1dc235e5cd406c174e1
Summary:
Rare TSAN and valgrind failures are caused by unnecessary
reading of a field on the TaskLimiterToken::limiter_ for an assertion
after the token has been released and the limiter destroyed. To simplify
we can simply destroy the token before triggering DB shutdown
(potentially destroying the limiter). This makes the ReleaseOnce logic
unnecessary.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8567
Test Plan: watch for more failures in CI
Reviewed By: ajkr
Differential Revision: D29811795
Pulled By: pdillinger
fbshipit-source-id: 135549ebb98fe4f176d1542ed85d5bd6350a40b3
Summary:
Try avoid expensive updating options operation if
`SetDBOptions()` does not change any option value.
Skip updating is not guaranteed, for example, changing `bytes_per_sync`
to `0` may still trigger updating, as the value could be sanitized.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8518
Test Plan: added unittest
Reviewed By: riversand963
Differential Revision: D29672639
Pulled By: jay-zhuang
fbshipit-source-id: b7931de62ceea6f1bdff0d1209adf1197d3ed1f4
Summary:
Currently, the code shows that we delete memtables immedately after it is trimmed from history. Although it should never happen as the super version still holds the memtable, which is only switched after it, it feels a good practice not to do it, but use clean it up in the standard way: put it to WriteContext and clean it after DB mutex.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8530
Test Plan: Run all existing tests.
Reviewed By: ajkr
Differential Revision: D29703410
fbshipit-source-id: 21d8068ac6377de4b6fa7a89697195742659fde4
Summary:
I previously didn't notice the DB mutex was being held during
block cache entry stat scans, probably because I primarily checked for
read performance regressions, because they require the block cache and
are traditionally latency-sensitive.
This change does some refactoring to avoid holding DB mutex and to
avoid triggering and waiting for a scan in GetProperty("rocksdb.cfstats").
Some tests have to be updated because now the stats collector is
populated in the Cache aggressively on DB startup rather than lazily.
(I hope to clean up some of this added complexity in the future.)
This change also ensures proper treatment of need_out_of_mutex for
non-int DB properties.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8538
Test Plan:
Added unit test logic that uses sync points to fail if the DB mutex
is held during a scan, covering the various ways that a scan might be
triggered.
Performance test - the known impact to holding the DB mutex is on
TransactionDB, and the easiest way to see the impact is to hack the
scan code to almost always miss and take an artificially long time
scanning. Here I've injected an unconditional 5s sleep at the call to
ApplyToAllEntries.
Before (hacked):
$ TEST_TMPDIR=/dev/shm ./db_bench.base_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
randomtransaction : 433.219 micros/op 2308 ops/sec; 0.1 MB/s ( transactions:78999 aborts:0)
rocksdb.db.write.micros P50 : 16.135883 P95 : 36.622503 P99 : 66.036115 P100 : 5000614.000000 COUNT : 149677 SUM : 8364856
$ TEST_TMPDIR=/dev/shm ./db_bench.base_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
randomtransaction : 448.802 micros/op 2228 ops/sec; 0.1 MB/s ( transactions:75999 aborts:0)
rocksdb.db.write.micros P50 : 16.629221 P95 : 37.320607 P99 : 72.144341 P100 : 5000871.000000 COUNT : 143995 SUM : 13472323
Notice the 5s P100 write time.
After (hacked):
$ TEST_TMPDIR=/dev/shm ./db_bench.new_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
randomtransaction : 303.645 micros/op 3293 ops/sec; 0.1 MB/s ( transactions:98999 aborts:0)
rocksdb.db.write.micros P50 : 16.061871 P95 : 33.978834 P99 : 60.018017 P100 : 616315.000000 COUNT : 187619 SUM : 4097407
$ TEST_TMPDIR=/dev/shm ./db_bench.new_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
randomtransaction : 310.383 micros/op 3221 ops/sec; 0.1 MB/s ( transactions:96999 aborts:0)
rocksdb.db.write.micros P50 : 16.270026 P95 : 35.786844 P99 : 64.302878 P100 : 603088.000000 COUNT : 183819 SUM : 4095918
P100 write is now ~0.6s. Not good, but it's the same even if I completely bypass all the scanning code:
$ TEST_TMPDIR=/dev/shm ./db_bench.new_skip -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
randomtransaction : 311.365 micros/op 3211 ops/sec; 0.1 MB/s ( transactions:96999 aborts:0)
rocksdb.db.write.micros P50 : 16.274362 P95 : 36.221184 P99 : 68.809783 P100 : 649808.000000 COUNT : 183819 SUM : 4156767
$ TEST_TMPDIR=/dev/shm ./db_bench.new_skip -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
randomtransaction : 308.395 micros/op 3242 ops/sec; 0.1 MB/s ( transactions:97999 aborts:0)
rocksdb.db.write.micros P50 : 16.106222 P95 : 37.202403 P99 : 67.081875 P100 : 598091.000000 COUNT : 185714 SUM : 4098832
No substantial difference.
Reviewed By: siying
Differential Revision: D29738847
Pulled By: pdillinger
fbshipit-source-id: 1c5c155f5a1b62e4fea0fd4eeb515a8b7474027b
Summary:
In this PR, `mempurge` is made compatible with the Write Ahead Log: in case of recovery, the DB is now capable of recovering the data that was "mempurged" and kept in the `imm()` list of immutable memtables.
The twist was to add a uint64_t to the `memtable` struct to store the number of the earliest log file containing entries from the `memtable`. When a `Flush` operation is replaced with a `MemPurge`, the `VersionEdit` (which usually contains the new min log file number to pick up for recovery and the level 0 file path of the newly created SST file) is no longer appended to the manifest log, and every time the `deleteWal` method is called, a check is made on the list of immutable memtables.
This PR also includes a unit test that verifies that no data is lost upon Reopening of the database when the mempurge feature is activated. This extensive unit test includes two column families, with valid data contained in the imm() at time of "crash"/reopening (recovery).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8528
Reviewed By: pdillinger
Differential Revision: D29701097
Pulled By: bjlemaire
fbshipit-source-id: 072a900fb6ccc1edcf5eef6caf88f3060238edf9
Summary:
The removed function in this PR, just only have declared and dose not have any reference used.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8508
Reviewed By: mrambacher
Differential Revision: D29649033
Pulled By: jay-zhuang
fbshipit-source-id: df98143b73d6c184a2a60c9f7ea2548a065ee35d
Summary:
When db is open as secondary, there are basically 2 step process:
1) Collect column families from wal log
2) Apply changes to Memtable
In case primary db is TransactionDB instance, wal log will contain some additional data, like noop, etc. ColumnFamilyCollector doesn't implement methods to handle these, so it fails to open a wal log written by TransactionDB. (Everything works fine with standard DB::Open).
Memtable recovery process knows how to handle such wal logs, so only missing piece seems to be ColumnFamilyCollector.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8456
Reviewed By: ajkr
Differential Revision: D29455945
Pulled By: mrambacher
fbshipit-source-id: 5b29560fcbc008e17e95d0dc4b07558f3d63e26f
Summary:
In ```DBImpl::WriteImpl()```, we call ```PreprocessWrite()``` which, among other things, checks the BG error and returns it set. This return status is later on passed to ```WriteStatusCheck()```, which calls ```SetBGError()```. This results in a spurious call, and info logs, on every user write request. We should avoid passing the ```PreprocessWrite()``` return status to ```WriteStatusCheck()```, as the former would have called ```SetBGError()``` already if it encountered any new errors, such as error when creating a new WAL file.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8511
Test Plan: Run existing tests
Reviewed By: zhichao-cao
Differential Revision: D29639917
Pulled By: anand1976
fbshipit-source-id: 19234163969e1645dbeb273712aaf5cd9ea2b182
Summary:
In https://github.com/facebook/rocksdb/issues/8454, I introduced a new process baptized `MemPurge` (memtable garbage collection). This new PR is built upon this past mempurge prototype.
In this PR, I made the `mempurge` process a background task, which provides superior performance since the mempurge process does not cling on the db_mutex anymore, and addresses severe restrictions from the past iteration (including a scenario where the past mempurge was failling, when a memtable was mempurged but was still referred to by an iterator/snapshot/...).
Now the mempurge process ressembles an in-memory compaction process: the stack of immutable memtables is filtered out, and the useful payload is used to populate an output memtable. If the output memtable is filled at more than 60% capacity (arbitrary heuristic) the mempurge process is aborted and a regular flush process takes place, else the output memtable is kept in the immutable memtable stack. Note that adding this output memtable to the `imm()` memtable stack does not trigger another flush process, so that the flush thread can go to sleep at the end of a successful mempurge.
MemPurge is activated by making the `experimental_allow_mempurge` flag `true`. When activated, the `MemPurge` process will always happen when the flush reason is `kWriteBufferFull`.
The 3 unit tests confirm that this process supports `Put`, `Get`, `Delete`, `DeleteRange` operators and is compatible with `Iterators` and `CompactionFilters`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8505
Reviewed By: pdillinger
Differential Revision: D29619283
Pulled By: bjlemaire
fbshipit-source-id: 8a99bee76b63a8211bff1a00e0ae32360aaece95
Summary:
Previously, the following command:
```USE_CLANG=1 TEST_TMPDIR=/dev/shm/rocksdb OPT=-g make -j$(nproc) analyze```
was raising an error/warning the new_mem could potentially be a `nullptr`. This error appeared due to code changes from https://github.com/facebook/rocksdb/issues/8454, including an if-statement containing "`... && new_mem != nullptr && ...`", which made the analyzer believe that past this `if`-statement, a `new_mem==nullptr` was a possible scenario.
This code patch simply introduces `assert`s and removes this condition in the `if`-statement.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8492
Reviewed By: jay-zhuang
Differential Revision: D29571275
Pulled By: bjlemaire
fbshipit-source-id: 75d72246b70ebbbae7dea11ccb5778686d8bcbea
Summary:
Implement an experimental feature called "MemPurge", which consists in purging "garbage" bytes out of a memtable and reuse the memtable struct instead of making it immutable and eventually flushing its content to storage.
The prototype is by default deactivated and is not intended for use. It is intended for correctness and validation testing. At the moment, the "MemPurge" feature can be switched on by using the `options.experimental_allow_mempurge` flag. For this early stage, when the allow_mempurge flag is set to `true`, all the flush operations will be rerouted to perform a MemPurge. This is a temporary design decision that will give us the time to explore meaningful heuristics to use MemPurge at the right time for relevant workloads . Moreover, the current MemPurge operation only supports `Puts`, `Deletes`, `DeleteRange` operations, and handles `Iterators` as well as `CompactionFilter`s that are invoked at flush time .
Three unit tests are added to `db_flush_test.cc` to test if MemPurge works correctly (and checks that the previously mentioned operations are fully supported thoroughly tested).
One noticeable design decision is the timing of the MemPurge operation in the memtable workflow: for this prototype, the mempurge happens when the memtable is switched (and usually made immutable). This is an inefficient process because it implies that the entirety of the MemPurge operation happens while holding the db_mutex. Future commits will make the MemPurge operation a background task (akin to the regular flush operation) and aim at drastically enhancing the performance of this operation. The MemPurge is also not fully "WAL-compatible" yet, but when the WAL is full, or when the regular MemPurge operation fails (or when the purged memtable still needs to be flushed), a regular flush operation takes place. Later commits will also correct these behaviors.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8454
Reviewed By: anand1976
Differential Revision: D29433971
Pulled By: bjlemaire
fbshipit-source-id: 6af48213554e35048a7e03816955100a80a26dc5
Summary:
Added BlobMetaData to ColumnFamilyMetaData and LiveBlobMetaData and DB API GetLiveBlobMetaData to retrieve it.
First pass at struct. More tests and maybe fields to come...
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8273
Reviewed By: ltamasi
Differential Revision: D29102400
Pulled By: mrambacher
fbshipit-source-id: 8a2383a4446328be6b91dced9841fdd3dfc80b73
Summary:
In PR https://github.com/facebook/rocksdb/issues/7523 , checksum handoff is introduced in RocksDB for WAL, Manifest, and SST files. When user enable checksum handoff for a certain type of file, before the data is written to the lower layer storage system, we calculate the checksum (crc32c) of each piece of data and pass the checksum down with the data, such that data verification can be down by the lower layer storage system if it has the capability. However, it cannot cover the whole lifetime of the data in the memory and also it potentially introduces extra checksum calculation overhead.
In this PR, we introduce a new interface in WritableFileWriter::Append, which allows the caller be able to pass the data and the checksum (crc32c) together. In this way, WritableFileWriter can directly use the pass-in checksum (crc32c) to generate the checksum of data being passed down to the storage system. It saves the calculation overhead and achieves higher protection coverage. When a new checksum is added with the data, we use Crc32cCombine https://github.com/facebook/rocksdb/issues/8305 to combine the existing checksum and the new checksum. To avoid the segmenting of data by rate-limiter before it is stored, rate-limiter is called enough times to accumulate enough credits for a certain write. This design only support Manifest and WAL which use log_writer in the current stage.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8412
Test Plan: make check, add new testing cases.
Reviewed By: anand1976
Differential Revision: D29151545
Pulled By: zhichao-cao
fbshipit-source-id: 75e2278c5126cfd58393c67b1efd18dcc7a30772
Summary:
`DeleteFilesInRange()` marks deleting files to `being_compacted`
before deleting, which may cause ongoing compactions report corruption
exception or ASSERT for debug build.
Adding the missing `ComputeCompactionScore()` when `being_compacted` is set.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8434
Test Plan: Unittest
Reviewed By: ajkr
Differential Revision: D29276127
Pulled By: jay-zhuang
fbshipit-source-id: f5b223e3c1fc6d821e100e3f3442bc70c1d50cf7
Summary:
Tracing the MultiGet information including timestamp, keys, and CF_IDs to the trace file for analyzing and replay.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8421
Test Plan: make check, add test to trace_analyzer_test
Reviewed By: anand1976
Differential Revision: D29221195
Pulled By: zhichao-cao
fbshipit-source-id: 30c677d6c39ab31ef4bbdf7e0d1fa1fd79f295ff
Summary:
RocksDB logs a warning if WAL truncation on DB open fails. Its possible that on some file systems, truncation is not required and they would return ```Status::NotSupported()``` for ```ReopenWritableFile```. Don't log a warning in such cases.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8414
Reviewed By: akankshamahajan15
Differential Revision: D29181738
Pulled By: anand1976
fbshipit-source-id: 6e01e9117e1e4c1d67daa4dcee7fa59d06e057a7
Summary:
This is the next part of the ImmutableOptions cleanup. After changing the use of ImmutableCFOptions to ImmutableOptions, there were places in the code that had did something like "ImmutableOptions* immutable_cf_options", where "cf" referred to the "old" type.
This change simply renames the variables to match the current type. No new functionality is introduced.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8409
Reviewed By: pdillinger
Differential Revision: D29166248
Pulled By: mrambacher
fbshipit-source-id: 96de97f8e743f5c5160f02246e3ed8269556dc6f
Summary:
DBImpl::DumpStats is supposed to do this:
Dump DB stats to LOG
For each CF, dump CFStatsNoFileHistogram to LOG
For each CF, dump CFFileHistogram to LOG
Instead, due to a longstanding bug from 2017 (https://github.com/facebook/rocksdb/issues/2126), it would dump
CFStats, which includes both CFStatsNoFileHistogram and CFFileHistogram,
in both loops, resulting in near-duplicate output.
This fixes the bug.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8380
Test Plan: Manual inspection of LOG after db_bench
Reviewed By: jay-zhuang
Differential Revision: D29017535
Pulled By: pdillinger
fbshipit-source-id: 3010604c4a629a80347f129cd746ce9b0d0cbda6
Summary:
Currently, we either use the file system inode or a monotonically incrementing runtime ID as the block cache key prefix. However, if we use a monotonically incrementing runtime ID (in the case that the file system does not support inode id generation), in some cases, it cannot ensure uniqueness (e.g., we have secondary cache migrated from host to host). We use DbSessionID (20 bytes) + current file number (at most 10 bytes) as the new cache block key prefix when the secondary cache is enabled. So can accommodate scenarios such as transfer of cache state across hosts.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8360
Test Plan: add the test to lru_cache_test
Reviewed By: pdillinger
Differential Revision: D29006215
Pulled By: zhichao-cao
fbshipit-source-id: 6cff686b38d83904667a2bd39923cd030df16814
Summary:
Added the ability to cancel an in-progress range compaction by storing to an atomic "canceled" variable pointed to within the CompactRangeOptions structure.
Tested via two tests added to db_tests2.cc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8351
Reviewed By: ajkr
Differential Revision: D28808894
Pulled By: ddevec
fbshipit-source-id: cb321361c9e23b084b188bb203f11c375a22c2dd
Summary:
I noticed ```openat``` system call with ```O_WRONLY``` flag and ```sync_file_range``` and ```truncate``` on WAL file when using ```rocksdb::DB::OpenForReadOnly``` by way of ```db_bench --readonly=true --benchmarks=readseq --use_existing_db=1 --num=1 ...```
Noticed in ```strace``` after seeing the last modification time of the WAL file change after each run (with ```--readonly=true```).
I think introduced by 7d7f14480e from https://github.com/facebook/rocksdb/pull/8122
I added a test to catch the WAL file being truncated and the modification time on it changing.
I am not sure if a mock filesystem with mock clock could be used to avoid having to sleep 1.1s.
The test could also check the set of files is the same and that the sizes are also unchanged.
Before:
```
[ RUN ] DBBasicTest.ReadOnlyReopenMtimeUnchanged
db/db_basic_test.cc:182: Failure
Expected equality of these values:
file_mtime_after_readonly_reopen
Which is: 1621611136
file_mtime_before_readonly_reopen
Which is: 1621611135
file is: 000010.log
[ FAILED ] DBBasicTest.ReadOnlyReopenMtimeUnchanged (1108 ms)
```
After:
```
[ RUN ] DBBasicTest.ReadOnlyReopenMtimeUnchanged
[ OK ] DBBasicTest.ReadOnlyReopenMtimeUnchanged (1108 ms)
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8313
Reviewed By: pdillinger
Differential Revision: D28656925
Pulled By: jay-zhuang
fbshipit-source-id: ea9e215cb53e7c830e76bc5fc75c45e21f12a1d6
Summary:
The ImmutableCFOptions contained a bunch of fields that belonged to the ImmutableDBOptions. This change cleans that up by introducing an ImmutableOptions struct. Following the pattern of Options struct, this class inherits from the DB and CFOption structs (of the Immutable form).
Only one structural change (the ImmutableCFOptions::fs was changed to a shared_ptr from a raw one) is in this PR. All of the other changes involve moving the member variables from the ImmutableCFOptions into the ImmutableOptions and changing member variables or function parameters as required for compilation purposes.
Follow-on PRs may do a further clean-up of the code, such as renaming variables (such as "ImmutableOptions cf_options") and potentially eliminating un-needed function parameters (there is no longer a need to pass both an ImmutableDBOptions and an ImmutableOptions to a function).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8262
Reviewed By: pdillinger
Differential Revision: D28226540
Pulled By: mrambacher
fbshipit-source-id: 18ae71eadc879dedbe38b1eb8e6f9ff5c7147dbf
Summary:
Previously the shutdown process did not properly wait for all
`compaction_thread_limiter` tokens to be released before proceeding to
delete the DB's C++ objects. When this happened, we saw tests like
"DBCompactionTest.CompactionLimiter" flake with the following error:
```
virtual
rocksdb::ConcurrentTaskLimiterImpl::~ConcurrentTaskLimiterImpl():
Assertion `outstanding_tasks_ == 0' failed.
```
There is a case where a token can still be alive even after the shutdown
process has waited for BG work to complete. In particular, this happens
because the shutdown process only waits for flush/compaction scheduled/unscheduled counters to all
reach zero. These counters are decremented in `BackgroundCallCompaction()`
functions. However, tokens are released in `BGWork*Compaction()` functions, which
actually wrap the `BackgroundCallCompaction()` function.
A simple sleep could repro the race condition:
```
$ diff --git a/db/db_impl/db_impl_compaction_flush.cc
b/db/db_impl/db_impl_compaction_flush.cc
index 806bc548a..ba59efa89 100644
--- a/db/db_impl/db_impl_compaction_flush.cc
+++ b/db/db_impl/db_impl_compaction_flush.cc
@@ -2442,6 +2442,7 @@ void DBImpl::BGWorkCompaction(void* arg) {
static_cast<PrepickedCompaction*>(ca.prepicked_compaction);
static_cast_with_check<DBImpl>(ca.db)->BackgroundCallCompaction(
prepicked_compaction, Env::Priority::LOW);
+ sleep(1);
delete prepicked_compaction;
}
$ ./db_compaction_test --gtest_filter=DBCompactionTest.CompactionLimiter
db_compaction_test: util/concurrent_task_limiter_impl.cc:24: virtual rocksdb::ConcurrentTaskLimiterImpl::~ConcurrentTaskLimiterImpl(): Assertion `outstanding_tasks_ == 0' failed.
Received signal 6 (Aborted)
#0 /usr/local/fbcode/platform007/lib/libc.so.6(gsignal+0xcf) [0x7f02673c30ff] ?? ??:0
https://github.com/facebook/rocksdb/issues/1 /usr/local/fbcode/platform007/lib/libc.so.6(abort+0x134) [0x7f02673ac934] ?? ??:0
...
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8253
Test Plan: sleeps to expose race conditions
Reviewed By: akankshamahajan15
Differential Revision: D28168064
Pulled By: ajkr
fbshipit-source-id: 9e5167c74398d323e7975980c5cc00f450631160
Summary:
Add `num_levels`, `is_bottommost`, and table file creation
`reason` to `FilterBuildingContext`, in anticipation of more powerful
Bloom-like filter support.
To support this, added `is_bottommost` and `reason` to
`TableBuilderOptions`, which allowed removing `reason` parameter from
`rocksdb::BuildTable`.
I attempted to remove `skip_filters` from `TableBuilderOptions`, because
filter construction decisions should arise from options, not one-off
parameters. I could not completely remove it because the public API for
SstFileWriter takes a `skip_filters` parameter, and translating this
into an option change would mean awkwardly replacing the table_factory
if it is BlockBasedTableFactory with new filter_policy=nullptr option.
I marked this public skip_filters option as deprecated because of this
oddity. (skip_filters on the read side probably makes sense.)
At least `skip_filters` is now largely hidden for users of
`TableBuilderOptions` and is no longer used for implementing the
optimize_filters_for_hits option. Bringing the logic for that option
closer to handling of FilterBuildingContext makes it more obvious that
hese two are using the same notion of "bottommost." (Planned:
configuration options for Bloom-like filters that generalize
`optimize_filters_for_hits`)
Recommended follow-up: Try to get away from "bottommost level" naming of
things, which is inaccurate (see
VersionStorageInfo::RangeMightExistAfterSortedRun), and move to
"bottommost run" or just "bottommost."
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8246
Test Plan:
extended an existing unit test to exercise and check various
filter building contexts. Also, existing tests for
optimize_filters_for_hits validate some of the "bottommost" handling,
which is now closely connected to FilterBuildingContext::is_bottommost
through TableBuilderOptions::is_bottommost
Reviewed By: mrambacher
Differential Revision: D28099346
Pulled By: pdillinger
fbshipit-source-id: 2c1072e29c24d4ac404c761a7b7663292372600a
Summary:
Greatly reduced the not-quite-copy-paste giant parameter lists
of rocksdb::NewTableBuilder, rocksdb::BuildTable,
BlockBasedTableBuilder::Rep ctor, and BlockBasedTableBuilder ctor.
Moved weird separate parameter `uint32_t column_family_id` of
TableFactory::NewTableBuilder into TableBuilderOptions.
Re-ordered parameters to TableBuilderOptions ctor, so that `uint64_t
target_file_size` is not randomly placed between uint64_t timestamps
(was easy to mix up).
Replaced a couple of fields of BlockBasedTableBuilder::Rep with a
FilterBuildingContext. The motivation for this change is making it
easier to pass along more data into new fields in FilterBuildingContext
(follow-up PR).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8240
Test Plan: ASAN make check
Reviewed By: mrambacher
Differential Revision: D28075891
Pulled By: pdillinger
fbshipit-source-id: fddb3dbb8260a0e8bdcbb51b877ebabf9a690d4f
Summary:
This PR is a first step at attempting to clean up some of the Mutable/Immutable Options code. With this change, a DBOption and a ColumnFamilyOption can be reconstructed from their Mutable and Immutable equivalents, respectively.
readrandom tests do not show any performance degradation versus master (though both are slightly slower than the current 6.19 release).
There are still fields in the ImmutableCFOptions that are not CF options but DB options. Eventually, I would like to move those into an ImmutableOptions (= ImmutableDBOptions+ImmutableCFOptions). But that will be part of a future PR to minimize changes and disruptions.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8176
Reviewed By: pdillinger
Differential Revision: D27954339
Pulled By: mrambacher
fbshipit-source-id: ec6b805ba9afe6e094bffdbd76246c2d99aa9fad
Summary:
Add compaction API for secondary instance, which compact the files to a secondary DB path without installing to the LSM tree.
The API will be used to remote compaction.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8171
Test Plan: `make check`
Reviewed By: ajkr
Differential Revision: D27694545
Pulled By: jay-zhuang
fbshipit-source-id: 8ff3ec1bffdb2e1becee994918850c8902caf731
Summary:
In current RocksDB, in recover the information form WAL, we do the consistency check for each column family when one WAL file is corrupted and PointInTimeRecovery is set. However, it will report a false positive alert on "SST file is ahead of WALs" when one of the CF current log number is greater than the corrupted WAL number (CF contains the data beyond the corrupted WAl) due to a new column family creation during flush. In this case, a new WAL is created (it is empty) during a flush. Also, due to some reason (e.g., storage issue or crash happens before SyncCloseLog is called), the old WAL is corrupted. The new CF has no data, therefore, it does not have the consistency issue.
Fix: when checking cfd->GetLogNumber() > corrupted_wal_number also check cfd->GetLiveSstFilesSize() > 0. So the CFs with no SST file data will skip the check here.
Note potential ignored inconsistency caused due to fix: empty CF can also be caused by write+delete. In this case, after flush, there is no SST files being generated. However, this CF still have the log in the WAL. When the WAL is corrupted, the DB might be inconsistent.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8207
Test Plan: added unit test, make crash_test
Reviewed By: riversand963
Differential Revision: D27898839
Pulled By: zhichao-cao
fbshipit-source-id: 931fc2d8b92dd00b4169bf84b94e712fd688a83e
Summary:
Add comment to DisableManualCompaction() which was missing.
Also explictly return from DBImpl::CompactRange() to avoid memtable flush when manual compaction is disabled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8186
Test Plan: Run existing unit tests.
Reviewed By: jay-zhuang
Differential Revision: D27744517
fbshipit-source-id: 449548a48905903b888dc9612bd17480f6596a71
Summary:
When WriteBufferManager is shared across DBs and column families
to maintain memory usage under a limit, OOMs have been observed when flush cannot
finish but writes continuously insert to memtables.
In order to avoid OOMs, when memory usage goes beyond buffer_limit_ and DBs tries to write,
this change will stall incoming writers until flush is completed and memory_usage
drops.
Design: Stall condition: When total memory usage exceeds WriteBufferManager::buffer_size_
(memory_usage() >= buffer_size_) WriterBufferManager::ShouldStall() returns true.
DBImpl first block incoming/future writers by calling write_thread_.BeginWriteStall()
(which adds dummy stall object to the writer's queue).
Then DB is blocked on a state State::Blocked (current write doesn't go
through). WBStallInterface object maintained by every DB instance is added to the queue of
WriteBufferManager.
If multiple DBs tries to write during this stall, they will also be
blocked when check WriteBufferManager::ShouldStall() returns true.
End Stall condition: When flush is finished and memory usage goes down, stall will end only if memory
waiting to be flushed is less than buffer_size/2. This lower limit will give time for flush
to complete and avoid continous stalling if memory usage remains close to buffer_size.
WriterBufferManager::EndWriteStall() is called,
which removes all instances from its queue and signal them to continue.
Their state is changed to State::Running and they are unblocked. DBImpl
then signal all incoming writers of that DB to continue by calling
write_thread_.EndWriteStall() (which removes dummy stall object from the
queue).
DB instance creates WBMStallInterface which is an interface to block and
signal DBs during stall.
When DB needs to be blocked or signalled by WriteBufferManager,
state_for_wbm_ state is changed accordingly (RUNNING or BLOCKED).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7898
Test Plan: Added a new test db/db_write_buffer_manager_test.cc
Reviewed By: anand1976
Differential Revision: D26093227
Pulled By: akankshamahajan15
fbshipit-source-id: 2bbd982a3fb7033f6de6153aa92a221249861aae
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:
As the name of `DBImpl::WriteLevel0TableForRecovery` suggests, the resulting table file
should be placed on L0. However, the argument `level` passed to `BuildTable()` is -1.
We need to correct this since the level information will be useful to determine file placement.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8187
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D27748570
Pulled By: riversand963
fbshipit-source-id: e1cd23128a8de31f14b1edc2ea92754c154e4f10
Summary:
Current flush reason attribution is misleading or incorrect (depending on what the original intention was):
- Flush due to WAL reaching its maximum size is attributed to `kWriteBufferManager`
- Flushes due to full write buffer and write buffer manager are not distinguishable, both are attributed to `kWriteBufferFull`
This changes the first to a new flush reason `kWALFull`, and splits the second between `kWriteBufferManager` and `kWriteBufferFull`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8150
Reviewed By: zhichao-cao
Differential Revision: D27569645
Pulled By: ot
fbshipit-source-id: 7e3c8ca186a6e71976e6b8e937297eebd4b769cc
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:
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
Baptiste Lemaire