Summary:
Add some comments in db_impl.h. Also reordered function order a little bit so that I can add a comment to flag the area of functions implementing DB interface.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5338
Differential Revision: D15498284
Pulled By: siying
fbshipit-source-id: 3d7c59c8303577fe44d13c74ae84c7ce05164f77
Summary:
RocksDB always tries to perform a hard link operation on the external SST file to ingest. This operation can fail if the external SST resides on a different device/FS, or the underlying FS does not support hard link. Currently RocksDB assumes that if the link fails, the user is willing to perform file copy, which is not true according to the post. This commit provides an option named 'failed_move_fall_back_to_copy' for users to choose which behavior they want.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5333
Differential Revision: D15457597
Pulled By: HaoyuHuang
fbshipit-source-id: f3626e13f845db4f7ed970a53ec8a2b1f0d62214
Summary:
Add file comment in db/db_iter.h and minor changes in other parts.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5340
Differential Revision: D15484605
Pulled By: siying
fbshipit-source-id: 173771f9d5bd51303de5410ee5afd0a4af9d6572
Summary:
Modified FindIntraL0Compaction to stop picking more files if total
amount of compensated bytes would be larger than max_compaction_bytes
option.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5329
Differential Revision: D15435728
Pulled By: ThomasFersch
fbshipit-source-id: d118a6da88d5df8ee20944422ade37cf6b15d60c
Summary:
In version_set.cc, there is a function GetCurrentManifestPath. The goal of this task is to refactor ListColumnFamilies function so that ListColumnFamilies calls GetCurrentManifestPath to search for MANIFEST.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5331
Differential Revision: D15444524
Pulled By: HaoyuHuang
fbshipit-source-id: 1dcbd030bc0f2e835695741f450bba150f2f2903
Summary:
Remove PATENTS related wording from a few stragglers which still reference the old PATENTS file.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5326
Differential Revision: D15423297
Pulled By: sagar0
fbshipit-source-id: 4babcddfc120b7d2fed6eb3898287cf8012bf8ea
Summary:
Right now, in log writer, we call flush after writing each physical record. I don't see the necessarity of it. Right now, the underlying writer has a buffer, so there isn't a concern that the write request is too large either. On the other hand, in an Env where every flush is expensive, the current approach is significantly slower than only flushing after a whole record finishes, when the record is very large.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5328
Differential Revision: D15425032
Pulled By: siying
fbshipit-source-id: 440ebef002dfbb60c59d8388c9ddfc83d79700aa
Summary:
WritePrepared transactions when configured with two_write_queues=true offers higher throughput with unordered_write feature without however compromising the rocksdb guarantees. This is because it performs ordering among writes in a 2nd step that is not tied to memtable write speed. The 2nd step is naturally provided by 2PC when the commit phase does the ordering as well. Without 2PC, the 2nd step would only be provided when we use two_write_queues=true, where WritePrepared after performing the writes, in a 2nd step uses the 2nd queue to assign order to the writes.
The patch clarifies the need for two_write_queues=true in the HISTORY and inline comments of unordered_writes. Moreover it extends the stress tests of WritePrepared to unordred_write.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5313
Differential Revision: D15379977
Pulled By: maysamyabandeh
fbshipit-source-id: 5b6f05b9b59285dcbf3b0532215ba9fe7d926e00
Summary:
RocksDB secondary can replay both MANIFEST and WAL now.
On the one hand, the memory usage by memtables will grow after replaying WAL for sometime. On the other hand, replaying the MANIFEST can bring the database persistent data to a more recent point in time, giving us the opportunity to discard some memtables containing out-dated data.
This PR coordinates the MANIFEST and WAL replay, using the updates from MANIFEST replay to update the active memtable and immutable memtable list of each column family.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5305
Differential Revision: D15386512
Pulled By: riversand963
fbshipit-source-id: a3ea6fc415f8382d8cf624f52a71ebdcffa3e355
Summary:
Previously if iterator upper/lower bound presents, `DBIter` will check the bound for every key. This patch turns the check into per-file or per-data block check when applicable, by checking against either file largest/smallest key or block index key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5111
Differential Revision: D15330061
Pulled By: siying
fbshipit-source-id: 8a653fe3cd50d94d81eb2d13b087326c58ee2024
Summary:
In the current db_bench trace replay, the replay process strictly follows the timestamp to issue the queries. In some cases, user does not care about the time. Therefore, fast forward is needed for users to speed up the replay process.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5273
Differential Revision: D15389232
Pulled By: zhichao-cao
fbshipit-source-id: 735d629b9d2a167b05af3e4fa0ddf9d5d0be1806
Summary:
They are kind of flaky at the moment. Will re-enable it when flakiness is fixed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5315
Differential Revision: D15382744
Pulled By: maysamyabandeh
fbshipit-source-id: 8b2f9d81a4bb34bfd51481727a682d5cd063c5e3
Summary:
RangeDelAggregator::StripeRep::Invalidate() clears up several vectors. If we know there isn't anything to there, we can safe these small CPUs. Profiling shows that it sometimes take non-negligible amount of CPU. Worth a small optimization.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5312
Differential Revision: D15380511
Pulled By: siying
fbshipit-source-id: 53c5f34c33b4cb1e743643c6086ac56d0b84ec2e
Summary:
If DB is opened with `avoid_unnecessary_blocking_io` being true, then `~ColumnFamilyHandleImpl` enqueues a purge request and schedules a background thread to perform the deletion. Without test sync point, whether the SST file is purged or not at a later point in time is not deterministic. If the SST does not exist, it will cause an assertion failure.
How to reproduce:
```
$git checkout 6492430eaf
$make -j20 deletefile_test
$gtest-parallel --repeat 1000 --worker 16 ./deletefile_test --gtest_filter=DeleteFileTest.BackgroundPurgeCFDropTest
```
The test may fail a few times.
With changes made in this PR, repeat the above commands, and the test should not fail.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5310
Differential Revision: D15361136
Pulled By: riversand963
fbshipit-source-id: c4308d5f8da83472c893bf7f8ceed347fbfa850f
Summary:
In options_helper.cc various functions take a const unordered_map of
string -> TypeInfo for options handling. These functions pass by-value
the (const) maps, resulting in unnecessary copies.
Change to pass by reference.
This results in a noticable reduction in the amount of time spent
parsing options - in my case a set of unit tests using RocksDB which
call SetOptions() to modify options see a ~25% runtime reduction.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5295
Differential Revision: D15296334
Pulled By: riversand963
fbshipit-source-id: 4d4be3db635264943607911b296dda27fd7ce1a7
Summary:
This is a workaround for the issue described in #5169.
It has been tested on a database with very large values, but not dedicated test has been added to the code base.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5213
Differential Revision: D15243116
Pulled By: siying
fbshipit-source-id: e0c226a6cd71a60924dcd7ce7af74abcb4054484
Summary:
The recent improvement in https://github.com/facebook/rocksdb/pull/3661 could cause a deadlock: When writing recoverable state, we also commit its sequence number to commit table, which could result into evicting existing commit entry, which could result into advancing max_evicted_seq_, which would need to get snapshots from database, which requires obtaining db mutex. The patch releases db_mutex before calling the callback in WriteRecoverableState to avoid the potential deadlock. It also improves the stress tests to let the issue be manifested in the tests.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5306
Differential Revision: D15341458
Pulled By: maysamyabandeh
fbshipit-source-id: 05dcbed7e21b789fd1e5fd5ee8eea08077162323
Summary:
After cherry-pick a bug fix to 6.2.fb branch, update the HISTORY.md file to reflect this change.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5309
Differential Revision: D15358002
Pulled By: riversand963
fbshipit-source-id: 5a60510ec6dd444ce5ffaefc69b2e4c38914a921
Summary:
The test was not using separate MemTablePostProcessInfo per memetable insert thread and thus tsan was complaining about data race.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5308
Differential Revision: D15356420
Pulled By: maysamyabandeh
fbshipit-source-id: 46c2f2d19fb02c3c775b587aa09ca9c0dae6ed04
Summary:
This PR has two fixes for crash test failures -
1. Fix a bug in TestMultiGet() in db_stress that was passing list of key to MultiGet() in the wrong order, thus ensuring that actual values don't match expected values
2. Remove an incorrect assertion in FilePickerMultiGet::GetNextFileInLevelWithKeys() that checks that files in a level are in sorted order. This is not true with MultiGet(), especially if there are duplicate keys and we may have to go back one file for the next key. Furthermore, this assertion makes more sense when a new version is created, rather than at lookup time
Test -
asan_crash and ubsan_crash tests
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5301
Differential Revision: D15337383
Pulled By: anand1976
fbshipit-source-id: 35092cb15bbc1700e5e823cbe07bfa62f1e9e6c6
Summary:
Performing unordered writes in rocksdb when unordered_write option is set to true. When enabled the writes to memtable are done without joining any write thread. This offers much higher write throughput since the upcoming writes would not have to wait for the slowest memtable write to finish. The tradeoff is that the writes visible to a snapshot might change over time. If the application cannot tolerate that, it should implement its own mechanisms to work around that. Using TransactionDB with WRITE_PREPARED write policy is one way to achieve that. Doing so increases the max throughput by 2.2x without however compromising the snapshot guarantees.
The patch is prepared based on an original by siying
Existing unit tests are extended to include unordered_write option.
Benchmark Results:
```
TEST_TMPDIR=/dev/shm/ ./db_bench_unordered --benchmarks=fillrandom --threads=32 --num=10000000 -max_write_buffer_number=16 --max_background_jobs=64 --batch_size=8 --writes=3000000 -level0_file_num_compaction_trigger=99999 --level0_slowdown_writes_trigger=99999 --level0_stop_writes_trigger=99999 -enable_pipelined_write=false -disable_auto_compactions --unordered_write=1
```
With WAL
- Vanilla RocksDB: 78.6 MB/s
- WRITER_PREPARED with unordered_write: 177.8 MB/s (2.2x)
- unordered_write: 368.9 MB/s (4.7x with relaxed snapshot guarantees)
Without WAL
- Vanilla RocksDB: 111.3 MB/s
- WRITER_PREPARED with unordered_write: 259.3 MB/s MB/s (2.3x)
- unordered_write: 645.6 MB/s (5.8x with relaxed snapshot guarantees)
- WRITER_PREPARED with unordered_write disable concurrency control: 185.3 MB/s MB/s (2.35x)
Limitations:
- The feature is not yet extended to `max_successive_merges` > 0. The feature is also incompatible with `enable_pipelined_write` = true as well as with `allow_concurrent_memtable_write` = false.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5218
Differential Revision: D15219029
Pulled By: maysamyabandeh
fbshipit-source-id: 38f2abc4af8780148c6128acdba2b3227bc81759
Summary:
Previous code may call `~ColumnFamilyData` in `DBImpl::AtomicFlushMemTablesToOutputFiles` if the column family is dropped or `cfd->IsFlushPending() == false`. In `~ColumnFamilyData`, the db mutex is released briefly and re-acquired. This can cause correctness issue. The reason is as follows.
Assume there are more bg flush threads. After bg_flush_thr1 releases the db mutex, bg_flush_thr2 can grab it and pop an element from the flush queue. This will cause bg_flush_thr2 to accidentally pick some memtables which should have been picked by bg_flush_thr1. To make the matter worse, bg_flush_thr2 can clear `flush_requested_` flag for the memtable list, causing a subsequent call to `MemTableList::IsFlushPending()` by bg_flush_thr1 to return false, which is wrong.
The fix is to delay `ColumnFamilyData::Unref` and `~ColumnFamilyData` for column families not selected for flush until `AtomicFlushMemTablesToOutputFiles` returns. Furthermore, a bg flush thread should not clear `MemTableList::flush_requested_` in `MemTableList::PickMemtablesToFlush` unless atomic flush is not used **or** the memtable list does not have unpicked memtables.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5294
Differential Revision: D15295297
Pulled By: riversand963
fbshipit-source-id: 03b101205ca22c242647cbf488bcf0ed80b2ecbd
Summary:
https://github.com/facebook/rocksdb/pull/5256 broke it: `block_iter_.user_key()` may not be valid even if `block_iter_points_to_real_block_` is true. E.g. if there was an IO error or Status::Incomplete.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5291
Differential Revision: D15273324
Pulled By: al13n321
fbshipit-source-id: 442e5b09f9884a58f92a6ac1ca93af719c219886
Summary:
CachableEntry is used in a variety of contexts: it may refer to a cached
object (i.e. an object in the block cache), an owned object, or an
unowned object; also, in some cases (most notably with iterators), the
responsibility of managing the pointed-to object gets handed off to
another object. Each of the above scenarios have different implications
for the lifecycle of the referenced object. For the most part, the patch
does not change the lifecycle of managed objects; however, it makes
these relationships explicit, and it also enables us to eliminate some
hacks and accident-prone code around releasing cache handles and
deleting/cleaning up objects. (The only places where the patch changes
how an objects are managed are the partitions of partitioned indexes and
filters.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5252
Differential Revision: D15101358
Pulled By: ltamasi
fbshipit-source-id: 9eb59e9ae5a7230e3345789762d0ba1f189485be
Summary:
There were no C bindings for lowering thread pool priority. This adds those.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5285
Differential Revision: D15290050
Pulled By: siying
fbshipit-source-id: b2ed94d0c39d27434ace2204829a242b53d0d67a
Summary:
When reseek happens in merging iterator, reseeking a child iterator can be avoided if:
(1) the iterator represents imutable data
(2) reseek() to a larger key than the current key
(3) the current key of the child iterator is larger than the seek key
because it is guaranteed that the result will fall into the same position.
This optimization will be useful for use cases where users keep seeking to keys nearby in ascending order.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5286
Differential Revision: D15283635
Pulled By: siying
fbshipit-source-id: 35f79ffd5ce3609146faa8cd55f2bfd733502f83
Summary:
This PR fixes a couple of bugs in FilePickerMultiGet that were causing db_stress test failures. The failures were caused by -
1. Improper handling of a key that matches the user key portion of an L0 file's largest key. In this case, the curr_index_in_curr_level file index in L0 for that key was getting incremented, but batch_iter_ was not advanced. By design, all keys in a batch are supposed to be checked against an L0 file before advancing to the next L0 file. Not advancing to the next key in the batch was causing a double increment of curr_index_in_curr_level due to the same key being processed again
2. Improper handling of a key that matches the user key portion of the largest key in the last file of L1 and higher. This was resulting in a premature end to the processing of the batch for that level when the next key in the batch is a duplicate. Typically, the keys in MultiGet will not be duplicates, but its good to handle that case correctly
Test -
asan_crash
make check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5292
Differential Revision: D15282530
Pulled By: anand1976
fbshipit-source-id: d1a6a86e0af273169c3632db22a44d79c66a581f
Summary:
Right now, DBIter::Next() always checks whether an entry is for the same user key as the previous entry to see whether the key should be hidden to the user. However, if previous entry's sequence number is 0, the check is not needed because 0 is the oldest possible sequence number.
We could extend it from seqnum 0 case to simply prev_seqno >= current_seqno. However, it is less robust with bug or unexpected situations, while the gain is relatively low. We can always extend it later when needed.
In a readseq benchmark with full formed LSM-tree, number of key comparisons called is reduced from 2.981 to 2.165. readseq against a fully compacted DB, no key comparison is called. Performance in this benchmark didn't show obvious improvement, which is expected because key comparisons only takes small percentage of CPU. But it may show up to be more effective if users have an expensive customized comparator.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5244
Differential Revision: D15067257
Pulled By: siying
fbshipit-source-id: b7e1ef3ec4fa928cba509683d2b3246e35d270d9
