Commit Graph

3308 Commits

Author SHA1 Message Date
Zhichao Cao
6d75319d95 Add tracing function of Seek() and SeekForPrev() to trace_replay (#4228)
Summary:
In the current trace_and replay, Get an WriteBatch are traced. This pull request track down the Seek() and SeekForPrev() to the trace file. <target_key, timestamp, column_family_id> are write to the file.

Replay of Iterator is not supported in the current implementation.

Tested with trace_analyzer.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4228

Differential Revision: D9201381

Pulled By: zhichao-cao

fbshipit-source-id: 6f9cc9cb3c20260af741bee065ec35c5c96354ab
2018-08-10 17:57:40 -07:00
Zhichao Cao
76d77205da Remove the redundant condition inclusion to avoid confusion (#4254)
Summary:
The pair of ROCKSDB_LITE condition inclusion is redundant, it is already inside the #ifndef ROCKSDB_LITE. Remove them to void confusion.

Tested by make asan_check.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4254

Differential Revision: D9281652

Pulled By: zhichao-cao

fbshipit-source-id: 06bf7641ede71391f21f6a3fe37fbd13f0e2a43a
2018-08-10 17:43:33 -07:00
Maysam Yabandeh
caf0f53a74 Index value delta encoding (#3983)
Summary:
Given that index value is a BlockHandle, which is basically an <offset, size> pair we can apply delta encoding on the values. The first value at each index restart interval encoded the full BlockHandle but the rest encode only the size. Refer to IndexBlockIter::DecodeCurrentValue for the detail of the encoding. This reduces the index size which helps using the  block cache more efficiently. The feature is enabled with using format_version 4.

The feature comes with a bit of cpu overhead which should be paid back by the higher cache hits due to smaller index block size.
Results with sysbench read-only using 4k blocks and using 16 index restart interval:
Format 2:
19585   rocksdb read-only range=100
Format 3:
19569   rocksdb read-only range=100
Format 4:
19352   rocksdb read-only range=100
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3983

Differential Revision: D8361343

Pulled By: maysamyabandeh

fbshipit-source-id: f882ee082322acac32b0072e2bdbb0b5f854e651
2018-08-09 16:58:40 -07:00
Yanqin Jin
de7f423a82 Add SST ingestion to ldb (#4205)
Summary:
We add two subcommands `write_extern_sst` and `ingest_extern_sst` to ldb. This PR avoids changing existing code because we hope to cherry-pick to earlier releases to support compatibility check for external SST file ingestion.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4205

Differential Revision: D9112711

Pulled By: riversand963

fbshipit-source-id: 7cae88380d4de86da8440230e87eca66755648e4
2018-08-09 14:29:11 -07:00
Zhongyi Xie
b15379dcea fix use-after-free error involving a temporary string (#4240)
Summary:
In the current code, `error_msg` is pointing to the inner buffer of a temporary std::string object. When `error_msg` is used to construct the error message, that array is already released. This PR will fix this bug by copying the string to a local variable.
Fixes https://github.com/facebook/rocksdb/issues/4239
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4240

Differential Revision: D9204334

Pulled By: miasantreble

fbshipit-source-id: 0ac599e166ae0a4ec413e32d8b8853d7c5fba878
2018-08-09 11:13:10 -07:00
Maysam Yabandeh
d8d66c937e Simplify DBWithMaxSpaceAllowedRandomized (#4235)
Summary:
The test has become complicated over the years and hard to reason about the corner cases that makes the test flaky. The patch simplifies the test and also fixes some probable synchronization issues.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4235

Differential Revision: D9187995

Pulled By: maysamyabandeh

fbshipit-source-id: 53c7b060f14367e5a9e361014578c26debfe3d27
2018-08-08 07:27:46 -07:00
Huachao Huang
badfd70a3e types: add kEntryBlobIndex for TablePropertiesCollector (#4233)
Summary:
So that we can act accordingly on blob index entries
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4233

Differential Revision: D9190205

Pulled By: yiwu-arbug

fbshipit-source-id: e5b84d5b41e44fa7a76762f1f7b0305369bb3a0c
2018-08-06 18:27:44 -07:00
Yi Wu
4cb7068c1e BlobDB: Fix VisibleToActiveSnapshot() (#4236)
Summary:
There are two issues with `VisibleToActiveSnapshot`:
1. If there are no snapshots, `oldest_snapshot` will be 0 and `VisibleToActiveSnapshot` will always return true. Since the method is used to decide whether it is safe to delete obsolete files, obsolete file won't be able to delete in this case.
2. The `auto` keyword of `auto snapshots = db_impl_->snapshots()` translate to a copy of `const SnapshotList` instead of a reference. Since copy constructor of `SnapshotList` is not defined, using the copy may yield unexpected result.

Issue 2 actually hide issue 1 from being catch by tests. During test `snapshots.empty()` can return false while it should actually be empty, and `snapshots.oldest()` return an invalid address, making `oldest_snapshot` being some random large number.

The issue was originally reported by BlobDB early adopter at Kuaishou.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4236

Differential Revision: D9188706

Pulled By: yiwu-arbug

fbshipit-source-id: a0f2624b927cf9bf28c1bb534784fee5d106f5ea
2018-08-06 16:57:42 -07:00
Jingguo Yao
ceb5fea1e3 Improve FullFilterBitsReader::HashMayMatch's doc (#4202)
Summary:
HashMayMatch is related to AddKey() instead of CreateFilter().
Also applies some minor Fixes #4191 #4200 #3910
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4202

Differential Revision: D9180945

Pulled By: maysamyabandeh

fbshipit-source-id: 6f07b81c5bb9bda5c0273475b486ba8a030471e6
2018-08-06 11:13:18 -07:00
Yanqin Jin
1f802773bc Update JobContext. (#3949)
Summary:
In the past, we assume that a job modifies a single column family. Therefore, a job can create at most one superversion since each superversion corresponds to one column family. This assumption leads to the fact that a `JobContext` has only one member variable called `superversion_context`.
Now we want to support group flush of column families, indicating that each job can create multiple superversions. Therefore, we need to make the following change to accommodate this new feature.

Add a vector of `SuperVersionContext` to `JobContext` to support installing
superversions for multiple column families in one job context.

This PR is a subset of [PR 3752](https://github.com/facebook/rocksdb/pull/3752).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3949

Differential Revision: D8864895

Pulled By: riversand963

fbshipit-source-id: 5937a48817276370d3c8172db9c8aafc826d97ca
2018-08-03 17:42:34 -07:00
Yanqin Jin
22368965a0 Modify verification logic of ObsoleteOptionsFileTest (#4218)
Summary:
The current verification logic does not consider the case in which multiple
threads (foreground and background) may execute `PurgeObsoleteFiles` function
simultaneously. Each invocation will trigger the callback adding elements to
a vector. Then we verify the elements in the vector, which can fail sometimes.

The solution is to give up checking the elements. Instead, we check the number
of OPTIONS file in the database dir.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4218

Differential Revision: D9128727

Pulled By: riversand963

fbshipit-source-id: 2b13b705fb21bc0ddd41940c4ec9b6b0c8d88224
2018-08-03 13:57:40 -07:00
DorianZheng
f9373e2d5c Make sure to call ReleaseFileNumberFromPendingOutputs
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/4219

Differential Revision: D9144294

Pulled By: riversand963

fbshipit-source-id: e46b72e5f8a149dc7a0512e38edcd0ddb0150f30
2018-08-02 18:57:34 -07:00
Andrew Kryczka
f8f6983f89 Skip range deletions at seqno zero when collapsing (#4216)
Summary:
`CollapsedRangeDelMap` internally uses seqno zero as a sentinel value to
denote a gap between range tombstones or the end of range tombstones. It
therefore expects to never have consecutive sentinel tombstones.

However, since `DeleteRange` is now supported in `SstFileWriter`, an
ingested file may contain range tombstones, and that ingested file may
be assigned global seqno zero. When such tombstones are added to the
collapsed map, they resemble sentinel tombstones due to having seqno
zero. Then, the invariant mentioned above about never having consecutive
sentinel tombstones can be violated.

The symptom of this violation was dereferencing the `end()` iterator
(#4204). The fix in this PR is to not add range tombstones with seqno
zero to the collapsed map. They're not needed anyways since they can't
possibly cover anything (in case of a key and a range tombstone with the
same seqno, the key is visible).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4216

Differential Revision: D9121716

Pulled By: ajkr

fbshipit-source-id: f5b78a70bea9527354603ea7ac8542a7e2b6a210
2018-08-01 12:12:02 -07:00
Sagar Vemuri
12b6cdeed3 Trace and Replay for RocksDB (#3837)
Summary:
A framework for tracing and replaying RocksDB operations.

A binary trace file is created by capturing the DB operations, and it can be replayed back at the same rate using db_bench.

- Column-families are supported
- Multi-threaded tracing is supported.
- TraceReader and TraceWriter are exposed to the user, so that tracing to various destinations can be enabled (say, to other messaging/logging services). By default, a FileTraceReader and FileTraceWriter are implemented to capture to a file and replay from it.
- This is not yet ideal to be enabled in production due to large performance overhead, but it can be safely tried out in a shadow setup, say, for analyzing RocksDB operations.

Currently supported DB operations:
- Writes:
-- Put
-- Merge
-- Delete
-- SingleDelete
-- DeleteRange
-- Write
- Reads:
-- Get (point lookups)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3837

Differential Revision: D7974837

Pulled By: sagar0

fbshipit-source-id: 8ec65aaf336504bc1f6ed0feae67f6ed5ef97a72
2018-08-01 00:27:08 -07:00
Yanqin Jin
54de56844d Remove random writes from SST file ingestion (#4172)
Summary:
RocksDB used to store global_seqno in external SST files written by
SstFileWriter. During file ingestion, RocksDB uses `pwrite` to update the
`global_seqno`. Since random write is not supported in some non-POSIX compliant
file systems, external SST file ingestion is not supported on these file
systems. To address this limitation, we no longer update `global_seqno` during
file ingestion. Later RocksDB uses the MANIFEST and other information in table
properties to deduce global seqno for externally-ingested SST files.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4172

Differential Revision: D8961465

Pulled By: riversand963

fbshipit-source-id: 4382ec85270a96be5bc0cf33758ca2b167b05071
2018-07-27 16:12:23 -07:00
DorianZheng
f5e46354d2 Protect external file when ingesting (#4099)
Summary:
If crash happen after a hard link established, Recover function may reuse the file number that has already assigned to the internal file, and this will overwrite the external file. To protect the external file, we have to make sure the file number will never being reused.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/4099

Differential Revision: D9034092

Pulled By: riversand963

fbshipit-source-id: 3f1a737440b86aa2ef01673e5013aacbb7c33e28
2018-07-27 14:13:12 -07:00
Siying Dong
fd45495cf5 DBImpl::IngestExternalFile() should grab mutex when releasing file number in failure case (#4189)
Summary:
995fcf7573 has a bug: ReleaseFileNumberFromPendingOutputs() added is not protected by the DB mutex. Fix it by grabbing the lock for this operation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4189

Differential Revision: D9015447

Pulled By: siying

fbshipit-source-id: b8506e09a96c3f95a6fe32b5ca5fcdb9bee88937
2018-07-26 11:12:29 -07:00
Siying Dong
2a81633da2 Fix bug when seeking backward against an out-of-bound iterator (#4187)
Summary:
92ee3350e0 introduces an out-of-bound check in BlockBasedTableIterator::Valid(). However, this flag is not reset when re-seeking in backward direction. This caused the iterator to be invalide by mistake. Fix it by always resetting the out-of-bound flag in every seek.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4187

Differential Revision: D8996600

Pulled By: siying

fbshipit-source-id: b6235ea614f71381e50e7904c4fb036300604ac1
2018-07-25 17:14:01 -07:00
Manuel Ung
ea212e5316 WriteUnPrepared: Implement unprepared batches for transactions (#4104)
Summary:
This adds support for writing unprepared batches based on size defined in `TransactionOptions::max_write_batch_size`. This is done by overriding methods that modify data (Put/Delete/SingleDelete/Merge) and checking first if write batch size has exceeded threshold. If so, the write batch is written to DB as an unprepared batch.

Support for Commit/Rollback for unprepared batch is added as well. This has been done by simply extending the WritePrepared Commit/Rollback logic to take care of all unprep_seq numbers either when updating prepare heap, or adding to commit map. For updating the commit map, this logic exists inside `WriteUnpreparedCommitEntryPreReleaseCallback`.

A test change was also made to have transactions unregister themselves when committing without prepare. This is because with write unprepared, there may be unprepared entries (which act similarly to prepared entries) already when a commit is done without prepare.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4104

Differential Revision: D8785717

Pulled By: lth

fbshipit-source-id: c02006e281ec1ce00f628e2a7beec0ee73096a91
2018-07-24 00:13:18 -07:00
Zhongyi Xie
f95a5b2464 Avoid unnecessary big for-loop when reporting ticker stats stored in GetContext (#3490)
Summary:
Currently in `Version::Get` when reporting ticker stats stored in `GetContext`, there is a big for-loop through all `Ticker` which adds unnecessary cost to overall CPU usage. We can optimize by storing only ticker values that are used in `Get()` calls in a new struct `GetContextStats` since only a small fraction of all tickers are used in `Get()` calls. For comparison, with the new approach we only need to visit 17 values while old approach will require visiting 100+ `Ticker`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3490

Differential Revision: D6969154

Pulled By: miasantreble

fbshipit-source-id: fc27072965a3a94125a3e6883d20dafcf5b84029
2018-07-20 16:58:13 -07:00
Siying Dong
a5e851e113 Reformatting some recent changes (#4161)
Summary:
Lint is not happy with some new code recently committed. Format them.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4161

Differential Revision: D8940582

Pulled By: siying

fbshipit-source-id: c9b43b1ef8c88b5e923911058b44eb77234b36b7
2018-07-20 14:43:38 -07:00
Siying Dong
8425c8bd4d BlockBasedTableReader: automatically adjust tail prefetch size (#4156)
Summary:
Right now we use one hard-coded prefetch size to prefetch data from the tail of the SST files. However, this may introduce a waste for some use cases, while not efficient for others.
Introduce a way to adjust this prefetch size by tracking 32 recent times, and pick a value with which the wasted read is less than 10%
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4156

Differential Revision: D8916847

Pulled By: siying

fbshipit-source-id: 8413f9eb3987e0033ed0bd910f83fc2eeaaf5758
2018-07-20 14:43:37 -07:00
Yanqin Jin
2736752b33 Fix a bug in MANIFEST group commit (#4157)
Summary:
PR #3944 introduces group commit of `VersionEdit` in MANIFEST. The
implementation has a bug. When updating the log file number of each column
family, we must consider only `VersionEdit`s that operate on the same column
family. Otherwise, a column family may accidentally set its log file number
higher than actual value, indicating that log files with smaller file number
will be ignored, thus causing some updates to be lost.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4157

Differential Revision: D8916650

Pulled By: riversand963

fbshipit-source-id: 8f456cf688f17bf35ad87b38e30e899aa162f201
2018-07-19 17:27:56 -07:00
Dmitri Smirnov
78ab11cd71 Return new operator for Status allocations for Windows (#4128)
Summary: Windows requires new/delete for memory allocations to be overriden. Refactor to be less intrusive.

Differential Revision: D8878047

Pulled By: siying

fbshipit-source-id: 35f2b5fec2f88ea48c9be926539c6469060aab36
2018-07-19 15:09:06 -07:00
Sagar Vemuri
f3801528c1 Disable DBFlushTest.SyncFail and DBTest.GroupCommitTest on Travis (#4154)
Summary:
I am temporarily disabling DBFlushTest.SyncFail and DBTest.GroupCommitTest tests on Travis until we figure out the root-cause. These tests will still continue to run locally though.
I haven't been able to reproduce these failures locally so far (even on a [local Travis environment](https://docs.travis-ci.com/user/common-build-problems/#Troubleshooting-Locally-in-a-Docker-Image) ).

These tests  are failing way too frequently causing everyone to wonder why their PR failed on travis, and waste time in debugging.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4154

Differential Revision: D8907258

Pulled By: sagar0

fbshipit-source-id: f40068b16e9245fb3791b6a4796435d1ce1ed205
2018-07-18 18:43:11 -07:00
Siying Dong
37e0fdc824 DBSSTTest.DeleteSchedulerMultipleDBPaths data race (#4146)
Summary:
Fix a minor data race in DBSSTTest.DeleteSchedulerMultipleDBPaths reported by TSAN
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4146

Differential Revision: D8880945

Pulled By: siying

fbshipit-source-id: 25c632f685757735c59ad4ff26b2f346a443a446
2018-07-17 17:57:46 -07:00
Yi Wu
d538ebdff0 Fix write get stuck when pipelined write is enabled (#4143)
Summary:
Fix the issue when pipelined write is enabled, writers can get stuck indefinitely and not able to finish the write. It can show with the following example: Assume there are 4 writers W1, W2, W3, W4 (W1 is the first, W4 is the last).

T1: all writers pending in WAL writer queue:
WAL writer queue: W1, W2, W3, W4
memtable writer queue: empty

T2. W1 finish WAL writer and move to memtable writer queue:
WAL writer queue: W2, W3, W4,
memtable writer queue: W1

T3. W2 and W3 finish WAL write as a batch group. W2 enter ExitAsBatchGroupLeader and move the group to memtable writer queue, but before wake up next leader.
WAL writer queue: W4
memtable writer queue: W1, W2, W3

T4. W1, W2, W3 finish memtable write as a batch group. Note that W2 still in the previous ExitAsBatchGroupLeader, although W1 have done memtable write for W2.
WAL writer queue: W4
memtable writer queue: empty

T5. The thread corresponding to W3 create another writer W3' with the same address as W3.
WAL writer queue: W4, W3'
memtable writer queue: empty

T6. W2 continue with ExitAsBatchGroupLeader. Because the address of W3' is the same as W3, the last writer in its group, it thinks there are no pending writers, so it reset newest_writer_ to null, emptying the queue. W4 and W3' are deleted from the queue and will never be wake up.

The issue exists since pipelined write was introduced in 5.5.0.

Closes #3704
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4143

Differential Revision: D8871599

Pulled By: yiwu-arbug

fbshipit-source-id: 3502674e51066a954a0660257e24ac588f815e2a
2018-07-17 17:27:51 -07:00
Siying Dong
ddc07b40fc Remove managed iterator
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/4124

Differential Revision: D8829910

Pulled By: siying

fbshipit-source-id: f3e952ccf3a631071a5d77c48e327046f8abb560
2018-07-17 14:43:18 -07:00
Siying Dong
995fcf7573 Pending output file number should be released after bulkload failure (#4145)
Summary:
If bulkload fails for an input error, the pending output file number wasn't released. This bug can cause all future files with larger number than the current number won't be deleted, even they are compacted. This commit fixes the bug.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4145

Differential Revision: D8877900

Pulled By: siying

fbshipit-source-id: 080be92a23d43305ca1e13fe1c06eb4cd0b01466
2018-07-17 14:13:16 -07:00
Maysam Yabandeh
b55da012f6 Refactor IndexBlockIter (#4141)
Summary:
Refactor IndexBlockIter to reduce conditional branches on key_includes_seq_. IndexBlockIter::Prev is also separated from DataBlockIter::Prev, not to cache the prev entries as they are of less importance when iterating over the index block.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4141

Differential Revision: D8866437

Pulled By: maysamyabandeh

fbshipit-source-id: fdac76880426fc2be7d3c6354c09ab98f6657d4b
2018-07-16 17:13:10 -07:00
Sagar Vemuri
991120fa10 Allow ttl to be changed dynamically (#4133)
Summary:
Allow ttl to be changed dynamically.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4133

Differential Revision: D8845440

Pulled By: sagar0

fbshipit-source-id: c8c87ae643b3a8c4123e4c037c4645efc094a2d3
2018-07-16 14:27:53 -07:00
Nathan VanBenschoten
ef7815b803 Support range deletion tombstones in IngestExternalFile SSTs (#3778)
Summary:
Fixes #3391.

This change adds a `DeleteRange` method to `SstFileWriter` and adds
support for ingesting SSTs with range deletion tombstones. This is
important for applications that need to atomically ingest SSTs while
clearing out any existing keys in a given key range.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3778

Differential Revision: D8821836

Pulled By: anand1976

fbshipit-source-id: ca7786c1947ff129afa703dab011d524c7883844
2018-07-13 22:43:09 -07:00
Peter Mattis
90fc40690a Relax VersionStorageInfo::GetOverlappingInputs check (#4050)
Summary:
Do not consider the range tombstone sentinel key as causing 2 adjacent
sstables in a level to overlap. When a range tombstone's end key is the
largest key in an sstable, the sstable's end key is so to a "sentinel"
value that is the smallest key in the next sstable with a sequence
number of kMaxSequenceNumber. This "sentinel" is guaranteed to not
overlap in internal-key space with the next sstable. Unfortunately,
GetOverlappingFiles uses user-keys to determine overlap and was thus
considering 2 adjacent sstables in a level to overlap if they were
separated by this sentinel key. This in turn would cause compactions to
be larger than necessary.

Note that this conflicts with
https://github.com/facebook/rocksdb/pull/2769 and cases
`DBRangeDelTest.CompactionTreatsSplitInputLevelDeletionAtomically` to
fail.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4050

Differential Revision: D8844423

Pulled By: ajkr

fbshipit-source-id: df3f9f1db8f4cff2bff77376b98b83c2ae1d155b
2018-07-13 17:42:38 -07:00
Yanqin Jin
21171615c1 Reduce execution time of IngestFileWithGlobalSeqnoRandomized (#4131)
Summary:
Make `ExternalSSTFileTest.IngestFileWithGlobalSeqnoRandomized` run faster.

`make format`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4131

Differential Revision: D8839952

Pulled By: riversand963

fbshipit-source-id: 4a7e842fde1cde4dc902e928a1cf511322578521
2018-07-13 17:27:39 -07:00
Maysam Yabandeh
8581a93a6b Per-thread unique test db names (#4135)
Summary:
The patch makes sure that two parallel test threads will operate on different db paths. This enables using open source tools such as gtest-parallel to run the tests of a file in parallel.
Example: ``` ~/gtest-parallel/gtest-parallel ./table_test```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4135

Differential Revision: D8846653

Pulled By: maysamyabandeh

fbshipit-source-id: 799bad1abb260e3d346bcb680d2ae207a852ba84
2018-07-13 17:27:39 -07:00
Fosco Marotto
8527012bb6 Converted db/merge_test.cc to use gtest (#4114)
Summary:
Picked up a task to convert this to use the gtest framework.  It can't be this simple, can it?

It works, but should all the std::cout be removed?

```
[$] ~/git/rocksdb [gft !]: ./merge_test
[==========] Running 2 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 2 tests from MergeTest
[ RUN      ] MergeTest.MergeDbTest
Test read-modify-write counters...
a: 3
1
2
a: 3
b: 1225
3
Compaction started ...
Compaction ended
a: 3
b: 1225
Test merge-based counters...
a: 3
1
2
a: 3
b: 1225
3
Test merge in memtable...
a: 3
1
2
a: 3
b: 1225
3
Test Partial-Merge
Test merge-operator not set after reopen
[       OK ] MergeTest.MergeDbTest (93 ms)
[ RUN      ] MergeTest.MergeDbTtlTest
Opening database with TTL
Test read-modify-write counters...
a: 3
1
2
a: 3
b: 1225
3
Compaction started ...
Compaction ended
a: 3
b: 1225
Test merge-based counters...
a: 3
1
2
a: 3
b: 1225
3
Test merge in memtable...
Opening database with TTL
a: 3
1
2
a: 3
b: 1225
3
Test Partial-Merge
Opening database with TTL
Opening database with TTL
Opening database with TTL
Opening database with TTL
Test merge-operator not set after reopen
[       OK ] MergeTest.MergeDbTtlTest (97 ms)
[----------] 2 tests from MergeTest (190 ms total)

[----------] Global test environment tear-down
[==========] 2 tests from 1 test case ran. (190 ms total)
[  PASSED  ] 2 tests.
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4114

Differential Revision: D8822886

Pulled By: gfosco

fbshipit-source-id: c299d008e883c3bb911d2b357a2e9e4423f8e91a
2018-07-13 14:13:07 -07:00
Anand Ananthabhotla
e3eba52a5d Re-enable kUniversalSubcompactions option_config (#4125)
Summary:
1. Move kUniversalSubcompactions up before kEnd in db_test_util.h, so
tests that cycle through all the option_configs include this
2. Skip kUniversalSubcompactions wherever kUniversalCompaction and
kUniversalCompactionMultilevel are skipped

Related to #3935
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4125

Differential Revision: D8828637

Pulled By: anand1976

fbshipit-source-id: 650dee15fd27d85281cf9bb4ca8ab460e04cac6f
2018-07-13 11:13:01 -07:00
Tamir Duberstein
7bee48bdbd Add GCC 8 to Travis (#3433)
Summary:
- Avoid `strdup` to use jemalloc on Windows
- Use `size_t` for consistency
- Add GCC 8 to Travis
- Add CMAKE_BUILD_TYPE=Release to Travis
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3433

Differential Revision: D6837948

Pulled By: sagar0

fbshipit-source-id: b8543c3a4da9cd07ee9a33f9f4623188e233261f
2018-07-13 10:58:06 -07:00
Yanqin Jin
90ebf1a257 Reduce execution time of a test. (#4127)
Summary:
Reduce the number of key ranges in `ExternalSSTFileTest.OverlappingRanges` so
that the test completes in shorter time to avoid timeouts.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4127

Differential Revision: D8827851

Pulled By: riversand963

fbshipit-source-id: a16387b0cc92a7c872b1c50f0cfbadc463afc9db
2018-07-12 17:42:03 -07:00
Yanqin Jin
dbeaa0d397 Reduce #iterations to shorten execution time. (#4123)
Summary:
Reduce #iterations from 5000 to 1000 so that
`ExternalSSTFileTest.CompactDuringAddFileRandom` can finish faster.
On the one hand, 5000 iterations does not seem to improve the quality of unit
test in comparison with 1000. On the other hand, long running tests should belong to stress tests.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4123

Differential Revision: D8822514

Pulled By: riversand963

fbshipit-source-id: 0f439b8d5ccd9a4aed84638f8bac16382de17245
2018-07-12 14:42:39 -07:00
Nikhil Benesch
5f3088d565 Range deletion performance improvements + cleanup (#4014)
Summary:
This fixes the same performance issue that #3992 fixes but with much more invasive cleanup.

I'm more excited about this PR because it paves the way for fixing another problem we uncovered at Cockroach where range deletion tombstones can cause massive compactions. For example, suppose L4 contains deletions from [a, c) and [x, z) and no other keys, and L5 is entirely empty. L6, however, is full of data. When compacting L4 -> L5, we'll end up with one file that spans, massively, from [a, z). When we go to compact L5 -> L6, we'll have to rewrite all of L6! If, instead of range deletions in L4, we had keys a, b, x, y, and z, RocksDB would have been smart enough to create two files in L5: one for a and b and another for x, y, and z.

With the changes in this PR, it will be possible to adjust the compaction logic to split tombstones/start new output files when they would span too many files in the grandparent level.

ajkr please take a look when you have a minute!
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4014

Differential Revision: D8773253

Pulled By: ajkr

fbshipit-source-id: ec62fa85f648fdebe1380b83ed997f9baec35677
2018-07-12 14:42:39 -07:00
Nikhil Benesch
5cd8240b86 Test range deletions with more configurations (#4021)
Summary:
Run the basic range deletion tests against the standard set of
configurations. This testing exposed that files with hash indexes and
partitioned indexes were not handling the case where the file contained
only range deletions--i.e., where the index was empty.

Additionally file a TODO about the fact that range deletions are broken
when allow_mmap_reads = true is set.

/cc ajkr nvanbenschoten

Best viewed with ?w=1: https://github.com/facebook/rocksdb/pull/4021/files?w=1
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4021

Differential Revision: D8811860

Pulled By: ajkr

fbshipit-source-id: 3cc07e6d6210a2a00b932866481b3d5c59775343
2018-07-11 15:57:49 -07:00
Yanqin Jin
331cb63641 SetOptions Backup Race Condition (#4108)
Summary:
Prior to this PR, there was a race condition between `DBImpl::SetOptions` and `BackupEngine::CreateNewBackup`, as illustrated below.
```
Time                  thread 1                           thread 2
  |   CreateNewBackup -> GetLiveFiles
  |                                         SetOptions -> RenameTempFileToOptionsFile
  |                                         SetOptions -> RenameTempFileToOptionsFile
  |                                         SetOptions -> RenameTempFileToOptionsFile // unlink oldest OPTIONS file
  |   copy the oldest OPTIONS // IO error!
  V
```
Proposed fix is to check the value of `DBImpl::disable_obsolete_files_deletion_` before calling `DeleteObsoleteOptionsFiles`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4108

Differential Revision: D8796360

Pulled By: riversand963

fbshipit-source-id: 02045317f793ea4c7d4400a5bf333b8502fa3e82
2018-07-11 14:57:46 -07:00
Manuel Ung
b9846370e9 WriteUnPrepared: Add support for recovering WriteUnprepared transactions (#4078)
Summary:
This adds support for recovering WriteUnprepared transactions through the following changes:
- The information in `RecoveredTransaction` is extended so that it can reference multiple batches.
- `MarkBeginPrepare` is extended with a bool indicating whether it is an unprepared begin, and this is passed down to `InsertRecoveredTransaction` to indicate whether the current transaction is prepared or not.
- `WriteUnpreparedTxnDB::Initialize` is overridden so that it will rollback unprepared transactions from the recovered transactions. This can be done without updating the prepare heap/commit map, because this is before the DB has finished initializing, and after writing the rollback batch, those data structures should not contain information about the rolled back transaction anyway.

Commit/Rollback of live transactions is still unimplemented and will come later.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4078

Differential Revision: D8703382

Pulled By: lth

fbshipit-source-id: 7e0aada6c23bd39299f1f20d6c060492e0e6b60a
2018-07-06 17:59:13 -07:00
Yanqin Jin
db7ae0a485 Fix a map lookup that may throw exception. (#4098)
Summary:
`std::map::at(key)` throws std::out_of_range if key does not exist. Current
code does not handle this. Although this case is unlikely, I feel it's safe to
use `std::map::find`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4098

Differential Revision: D8753865

Pulled By: riversand963

fbshipit-source-id: 9a9ba43badb0fb5e0d24cd87903931fd12f3f8ec
2018-07-06 16:12:49 -07:00
Huachao Huang
35b83327a7 compaction: fix max_subcompactions option for CompactRange (#4082)
Summary:
The max_subcompactions option was introduced in https://github.com/facebook/rocksdb/pull/3775.
Closes https://github.com/facebook/rocksdb/pull/4082

Differential Revision: D8743258

Pulled By: ajkr

fbshipit-source-id: d60ee75769dfc19ab6f8754e4ff3a267848f1ed9
2018-07-05 20:12:56 -07:00
Zhongyi Xie
b3efb1cbe0 fix clang analyzer warnings (#4072)
Summary:
clang analyze is giving the following warnings:
> db/compaction_job.cc:1178:16: warning: Called C++ object pointer is null
    } else if (meta->smallest.size() > 0) {
               ^~~~~~~~~~~~~~~~~~~~~
db/compaction_job.cc:1201:33: warning: Access to field 'marked_for_compaction' results in a dereference of a null pointer (loaded from variable 'meta')
    meta->marked_for_compaction = sub_compact->builder->NeedCompact();
    ~~~~
db/version_set.cc:2770:26: warning: Called C++ object pointer is null
        uint32_t cf_id = last_writer->cfd->GetID();
                         ^~~~~~~~~~~~~~~~~~~~~~~~~
Closes https://github.com/facebook/rocksdb/pull/4072

Differential Revision: D8685852

Pulled By: miasantreble

fbshipit-source-id: b0e2fd9dfc1cbba2317723e09886384b9b1c9085
2018-06-28 19:12:35 -07:00
Manuel Ung
8ad63a4b86 WriteUnPrepared: Add new WAL marker kTypeBeginUnprepareXID (#4069)
Summary:
This adds a new WAL marker of type kTypeBeginUnprepareXID.

Also, DBImpl now contains a field called batch_per_txn (meaning one WriteBatch per transaction, or possibly multiple WriteBatches). This would also indicate that this DB is using WriteUnprepared policy.

Recovery code would be able to make use of this extra field on DBImpl in a separate diff. For now, it is just used to determine whether the WAL is compatible or not.
Closes https://github.com/facebook/rocksdb/pull/4069

Differential Revision: D8675099

Pulled By: lth

fbshipit-source-id: ca27cae1738e46d65f2bb92860fc759deb874749
2018-06-28 18:58:29 -07:00
Anand Ananthabhotla
52d4c9b7f6 Allow DB resume after background errors (#3997)
Summary:
Currently, if RocksDB encounters errors during a write operation (user requested or BG operations), it sets DBImpl::bg_error_ and fails subsequent writes. This PR allows the DB to be resumed for certain classes of errors. It consists of 3 parts -
1. Introduce Status::Severity in rocksdb::Status to indicate whether a given error can be recovered from or not
2. Refactor the error handling code so that setting bg_error_ and deciding on severity is in one place
3. Provide an API for the user to clear the error and resume the DB instance

This whole change is broken up into multiple PRs. Initially, we only allow clearing the error for Status::NoSpace() errors during background flush/compaction. Subsequent PRs will expand this to include more errors and foreground operations such as Put(), and implement a polling mechanism for out-of-space errors.
Closes https://github.com/facebook/rocksdb/pull/3997

Differential Revision: D8653831

Pulled By: anand1976

fbshipit-source-id: 6dc835c76122443a7668497c0226b4f072bc6afd
2018-06-28 12:34:40 -07:00
Yanqin Jin
26d67e357e Support group commits of version edits (#3944)
Summary:
This PR supports the group commit of multiple version edit entries corresponding to different column families. Column family drop/creation still cannot be grouped. This PR is a subset of [PR 3752](https://github.com/facebook/rocksdb/pull/3752).
Closes https://github.com/facebook/rocksdb/pull/3944

Differential Revision: D8432536

Pulled By: riversand963

fbshipit-source-id: 8f11bd05193b6c0d9272d82e44b676abfac113cb
2018-06-28 12:34:39 -07:00
Maysam Yabandeh
0a5b5d88b2 Remove ReadOnly part of PinnableSliceAndMmapReads from Lite (#4070)
Summary:
Lite does not support readonly DBs.
Closes https://github.com/facebook/rocksdb/pull/4070

Differential Revision: D8677858

Pulled By: maysamyabandeh

fbshipit-source-id: 536887d2363ee2f5d8e1ea9f1a511e643a1707fa
2018-06-28 08:42:17 -07:00
Zhongyi Xie
14f409c0f1 PrefixMayMatch: remove unnecessary check for prefix_extractor_ (#4067)
Summary:
with https://github.com/facebook/rocksdb/pull/3601 and https://github.com/facebook/rocksdb/pull/3899, `prefix_extractor_` is not really being used in block based filter and full filter's version of `PrefixMayMatch` because now `prefix_extractor` is passed as an argument. Also it is now possible that prefix_extractor_ may be initialized to nullptr when a non-standard prefix_extractor is used and also for ROCKSDB_LITE. Removing these checks should not break any existing tests.
Closes https://github.com/facebook/rocksdb/pull/4067

Differential Revision: D8669002

Pulled By: miasantreble

fbshipit-source-id: 0e701ba912b8a26734fadb72d15bb1b266b6176a
2018-06-27 20:42:43 -07:00
Zhichao Cao
1f6efabe23 Add bottommost_compression_opts to for bottommost_compression (#3985)
Summary:
…ression

 For `CompressionType` we have options `compression` and `bottommost_compression`. Thus, to make the compression options consitent with the compression type when bottommost_compression is enabled, we add the bottommost_compression_opts
Closes https://github.com/facebook/rocksdb/pull/3985

Reviewed By: riversand963

Differential Revision: D8385911

Pulled By: zhichao-cao

fbshipit-source-id: 07bc533dd61bcf1cef5927d8d62901c13d38d5fc
2018-06-27 17:42:38 -07:00
Maysam Yabandeh
235ab9dd32 Pin mmap files in ReadOnlyDB (#4053)
Summary:
https://github.com/facebook/rocksdb/pull/3881 fixed a bug where PinnableSlice pin mmap files which could be deleted with background compaction. This is however a non-issue for ReadOnlyDB when there is no compaction running and max_open_files is -1. This patch reenables the pinning feature for that case.
Closes https://github.com/facebook/rocksdb/pull/4053

Differential Revision: D8662546

Pulled By: maysamyabandeh

fbshipit-source-id: 402962602eb0f644e17822748332999c3af029fd
2018-06-27 17:13:34 -07:00
Manuel Ung
a16e00b7b9 WriteUnPrepared Txn: Disable seek to snapshot optimization (#3955)
Summary:
This is implemented by extending ReadCallback with another function `MaxUnpreparedSequenceNumber` which returns the largest visible sequence number for the current transaction, if there is uncommitted data written to DB. Otherwise, it returns zero, indicating no uncommitted data.

There are the places where reads had to be modified.
- Get and Seek/Next was just updated to seek to max(snapshot_seq, MaxUnpreparedSequenceNumber()) instead, and iterate until a key was visible.
- Prev did not need need updates since it did not use the Seek to sequence number optimization. Assuming that locks were held when writing unprepared keys, and ValidateSnapshot runs, there should only be committed keys and unprepared keys of the current transaction, all of which are visible. Prev will simply iterate to get the last visible key.
- Reseeking to skip keys optimization was also disabled for write unprepared, since it's possible to hit the max_skip condition even while reseeking. There needs to be some way to resolve infinite looping in this case.
Closes https://github.com/facebook/rocksdb/pull/3955

Differential Revision: D8286688

Pulled By: lth

fbshipit-source-id: 25e42f47fdeb5f7accea0f4fd350ef35198caafe
2018-06-27 12:23:07 -07:00
Nikhil Benesch
17339dc2f3 Add table property tracking number of range deletions (#4016)
Summary:
Add a new table property, rocksdb.num.range-deletions, which tracks the
number of range deletions in a block-based table. Range deletions are no
longer counted in rocksdb.num.entries; as discovered in PR #3778, there
are various code paths that implicitly assume that rocksdb.num.entries
counts only true keys, not range deletions.

/cc ajkr nvanbenschoten
Closes https://github.com/facebook/rocksdb/pull/4016

Differential Revision: D8527575

Pulled By: ajkr

fbshipit-source-id: 92e7edbe78fda53756a558013c9fb496e7764fd7
2018-06-26 20:27:35 -07:00
Zhongyi Xie
408205a36b use user_key and iterate_upper_bound to determine compatibility of bloom filters (#3899)
Summary:
Previously in https://github.com/facebook/rocksdb/pull/3601 bloom filter will only be checked if `prefix_extractor` in the mutable_cf_options matches the one found in the SST file.
This PR relaxes the requirement by checking if all keys in the range [user_key, iterate_upper_bound) all share the same prefix after transforming using the BF in the SST file. If so, the bloom filter is considered compatible and will continue to be looked at.
Closes https://github.com/facebook/rocksdb/pull/3899

Differential Revision: D8157459

Pulled By: miasantreble

fbshipit-source-id: 18d17cba56a1005162f8d5db7a27aba277089c41
2018-06-26 15:57:26 -07:00
Andrew Kryczka
a8e503e545 Fix universal compaction scheduling conflict with CompactFiles (#4055)
Summary:
Universal size-amp-triggered compaction was pulling the final sorted run into the compaction without checking whether any of its files are already being compacted. When all compactions are automatic, it is safe since it verifies the second-last sorted run is not already being compacted, which implies the last sorted run is also not being compacted (in automatic compaction multiple sorted runs are always compacted together). But with manual compaction, files in the last sorted run can be compacted independently, so the last sorted run also must be checked.

We were seeing the below assertion failure in `db_stress`. Also the test case included in this PR repros the failure.

```
db_universal_compaction_test: db/compaction.cc:312: void rocksdb::Compaction::MarkFilesBeingCompacted(bool): Assertion `mark_as_compacted ? !inputs_[i][j]->being_compacted : inputs_[i][j]->being_compacted' failed.
Aborted (core dumped)
```
Closes https://github.com/facebook/rocksdb/pull/4055

Differential Revision: D8630094

Pulled By: ajkr

fbshipit-source-id: ac3b30a874678b76e113d4f6c42c1260411b08f8
2018-06-26 10:44:56 -07:00
Sagar Vemuri
189f0c27aa Make BlockBasedTableIterator compaction-aware (#4048)
Summary:
Pass in `for_compaction` to `BlockBasedTableIterator` via `BlockBasedTableReader::NewIterator`.

In 7103559f49, `for_compaction` was set in `BlockBasedTable::Rep` via `BlockBasedTable::SetupForCompaction`. In hindsight it was not the right decision; it also caused TSAN to complain.
Closes https://github.com/facebook/rocksdb/pull/4048

Differential Revision: D8601056

Pulled By: sagar0

fbshipit-source-id: 30127e898c15c38c1080d57710b8c5a6d64a0ab3
2018-06-25 13:19:27 -07:00
Maysam Yabandeh
80ade9ad83 Pin top-level index on partitioned index/filter blocks (#4037)
Summary:
Top-level index in partitioned index/filter blocks are small and could be pinned in memory. So far we use that by cache_index_and_filter_blocks to false. This however make it difficult to keep account of the total memory usage. This patch introduces pin_top_level_index_and_filter which in combination with cache_index_and_filter_blocks=true keeps the top-level index in cache and yet pinned them to avoid cache misses and also cache lookup overhead.
Closes https://github.com/facebook/rocksdb/pull/4037

Differential Revision: D8596218

Pulled By: maysamyabandeh

fbshipit-source-id: 3a5f7f9ca6b4b525b03ff6bd82354881ae974ad2
2018-06-22 15:27:46 -07:00
Zhongyi Xie
795e663df0 option for timing measurement of non-blocking ops during compaction (#4029)
Summary:
For example calling CompactionFilter is always timed and gives the user no way to disable.
This PR will disable the timer if `Statistics::stats_level_` (which is part of DBOptions) is `kExceptDetailedTimers`
Closes https://github.com/facebook/rocksdb/pull/4029

Differential Revision: D8583670

Pulled By: miasantreble

fbshipit-source-id: 913be9fe433ae0c06e88193b59d41920a532307f
2018-06-21 21:28:05 -07:00
Yanqin Jin
524c6e6b72 Add file name info to SequentialFileReader. (#4026)
Summary:
We potentially need this information for tracing, profiling and diagnosis.
Closes https://github.com/facebook/rocksdb/pull/4026

Differential Revision: D8555214

Pulled By: riversand963

fbshipit-source-id: 4263e06c00b6d5410b46aa46eb4e358ff2161dd2
2018-06-21 08:42:24 -07:00
Siying Dong
92ee3350e0 BlockBasedTableIterator to keep BlockIter after out of upper bound (#4004)
Summary:
b555ed30a4 makes the BlockBasedTableIterator to be invalidated if the current position if over the upper bound. However, this can bring performance regression to the case of multiple Seek()s hitting the same data block but all out of upper bound.

For example, if an SST file has a data block containing following keys : {a, z}

The user sets the upper bound to be "x", and it executed following queries:
Seek("b")
Seek("c")
Seek("d")

Before the upper bound optimization, these queries always come to this same current data block of the iterator, but now inside each Seek() the data block is read from the block cache but is returned again.

To prevent this regression case, we keep the current data block iterator if it is upper bound.
Closes https://github.com/facebook/rocksdb/pull/4004

Differential Revision: D8463192

Pulled By: siying

fbshipit-source-id: 8710628b30acde7063a097c3184d6c4333a8ef81
2018-06-19 09:57:11 -07:00
Tomas Kolda
c766887458 Fix ExternalSSTFileTest::OverlappingRanges test on Solaris Sparc (#4012)
Summary:
Fix of #4011
Closes https://github.com/facebook/rocksdb/pull/4012

Differential Revision: D8499173

Pulled By: sagar0

fbshipit-source-id: cbb2b90c544ed364a3640ea65835d577b2dbc5df
2018-06-18 14:57:37 -07:00
Zhongyi Xie
80bc35927c Should only decode restart points for uncompressed blocks (#3996)
Summary:
The Block object assumes contents are uncompressed. Block's constructor tries to read the number of restarts, but does not get an accurate number when its contents are compressed, which is causing issues like https://github.com/facebook/rocksdb/issues/3843.
This PR address this issue by skipping reconstruction of restart points when blocks are known to be compressed. Somehow the restart points can be read directly when Snappy is used and some tests (for example https://github.com/facebook/rocksdb/blob/master/db/db_block_cache_test.cc#L196) expects blocks to be fully constructed even when Snappy compression is used, so here we keep the restart point logic for Snappy.
Closes https://github.com/facebook/rocksdb/pull/3996

Differential Revision: D8416186

Pulled By: miasantreble

fbshipit-source-id: 002c0b62b9e5d89fb7736563d354ce0023c8cb28
2018-06-15 19:26:58 -07:00
Anand Ananthabhotla
c48764ba47 Don't generate a notification for a 0 size SST (#4003)
Summary:
Don't call the OnTableFileCreated listener callback when a 0 size SST
file gets created by Flush. Doing so causes an assertion failure in db_stress. It is also not correct behavior as we call env->DeleteFile() for such files right before the notification.
Closes https://github.com/facebook/rocksdb/pull/4003

Differential Revision: D8461385

Pulled By: anand1976

fbshipit-source-id: ae92d4f921c2e2cff981ad58f4929ed8b609f35d
2018-06-15 17:57:24 -07:00
zhichao-cao
3fbc865cd5 Add kOptionsStatistics to GetProperty() (#3966)
Summary:
Add a new DB property to DB::GetProperty(), which returns the option.statistics. Test is updated to pass.
Closes https://github.com/facebook/rocksdb/pull/3966

Differential Revision: D8311139

Pulled By: zhichao-cao

fbshipit-source-id: ea78f4727358c807b0e5a0ea62e09defb10ad9ac
2018-06-15 17:28:01 -07:00
奏之章
f23fed19a1 Delay verify compaction output table (#3979)
Summary:
Verify table will load SST into `TableCache`
it occupy memory & `TableCache`‘s capacity ...
but no logic use them
it's unnecessary ...

so , we verify them after all sub compact finished
Closes https://github.com/facebook/rocksdb/pull/3979

Differential Revision: D8389946

Pulled By: ajkr

fbshipit-source-id: 54bd4f474f9e7b3accf39c3068b1f36a27ec4c49
2018-06-15 12:42:53 -07:00
Fenggang Wu
fbe3b9e2b6 Udpate db_universal_compaction_test according to PR #3970 (#3995)
Summary:
The SST file sizes changed slightly after the improvement of PR #3970
which reduces the size of the properties block. Before PR #3970 a size
ratio compaction included all of the first four flushed files but it
only includes two files after. We increase the size_ratio universal
compaction option to make that compaction include all four files again.
Closes https://github.com/facebook/rocksdb/pull/3995

Differential Revision: D8426925

Pulled By: fgwu

fbshipit-source-id: 1429c38672e9f4fb4d4881fd4b06db45c4861d62
2018-06-15 10:42:21 -07:00
Siying Dong
d82f1421b4 Fix regression bug of Prev() with upper bound (#3989)
Summary:
A recent change pushed down the upper bound checking to child iterators. However, this causes the logic of following sequence wrong:
  Seek(key);
  if (!Valid()) SeekToLast();
Because !Valid() may be caused by upper bounds, rather than the end of the iterator. In this case SeekToLast() points to totally wrong places. This can cause wrong results, infinite loops, or segfault in some cases.
This sequence is called when changing direction from forward to backward. And this by itself also implicitly happen during reseeking optimization in Prev().

Fix this bug by using SeekForPrev() rather than this sequuence, as what is already done in prefix extrator case.
Closes https://github.com/facebook/rocksdb/pull/3989

Differential Revision: D8385422

Pulled By: siying

fbshipit-source-id: 429e869990cfd2dc389421e0836fc496bed67bb4
2018-06-12 16:57:36 -07:00
Maysam Yabandeh
b73652169e Extend format 3 to partitioned index/filters (#3958)
Summary:
format_version 3 changes the format of index blocks by storing user keys instead of the internal keys, which saves 8-bytes per key. This patch extends the format to top-level indexes in partitioned index/filters.
Closes https://github.com/facebook/rocksdb/pull/3958

Differential Revision: D8294615

Pulled By: maysamyabandeh

fbshipit-source-id: 17666cc16b8076c363972e2308e31547e835f0fe
2018-06-06 16:58:16 -07:00
Andrew Kryczka
4420df4b0e Check conflict at output level in CompactFiles (#3926)
Summary:
CompactFiles checked whether the existing files conflicted with the chosen compaction. But it missed checking whether future files would conflict, i.e., when another compaction was simultaneously writing new files to the same range at the same output level.
Closes https://github.com/facebook/rocksdb/pull/3926

Differential Revision: D8218996

Pulled By: ajkr

fbshipit-source-id: 21cb00a6fed4c8c62d3ed2ff810962e6bdc2fdfb
2018-06-05 14:14:05 -07:00
Zhongyi Xie
f1592a06c2 run make format for PR 3838 (#3954)
Summary:
PR https://github.com/facebook/rocksdb/pull/3838 made some changes that triggers lint warnings.
Run `make format` to fix formatting as suggested by siying .
Also piggyback two changes:
1) fix singleton destruction order for windows and posix env
2) fix two clang warnings
Closes https://github.com/facebook/rocksdb/pull/3954

Differential Revision: D8272041

Pulled By: miasantreble

fbshipit-source-id: 7c4fd12bd17aac13534520de0c733328aa3c6c9f
2018-06-05 12:58:02 -07:00
Maysam Yabandeh
d0c38c0c8c Extend some tests to format_version=3 (#3942)
Summary:
format_version=3 changes the format of SST index. This is however not being tested currently since tests only work with the default format_version which is currently 2. The patch extends the most related tests to also test for format_version=3.
Closes https://github.com/facebook/rocksdb/pull/3942

Differential Revision: D8238413

Pulled By: maysamyabandeh

fbshipit-source-id: 915725f55753dd8e9188e802bf471c23645ad035
2018-06-04 20:13:00 -07:00
Zhongyi Xie
50d7ac0ea3 Fix test for rocksdb_lite: hide incompatible option kDirectIO
Summary:
Previous commit https://github.com/facebook/rocksdb/pull/3935 unhide a few test options which includes kDirectIO. However it's not supported by RocksDB lite. Need to hide this option from the lite build.
Closes https://github.com/facebook/rocksdb/pull/3943

Differential Revision: D8242757

Pulled By: miasantreble

fbshipit-source-id: 1edfad3a5d01a46bfb7eedee765981ebe02c500a
2018-06-01 20:42:36 -07:00
Andrew Kryczka
fea2b1dfb2 Copy Get() result when file reads use mmap
Summary:
For iterator reads, a `SuperVersion` is pinned to preserve a snapshot of SST files, and `Block`s are pinned to allow `key()` and `value()` to return pointers directly into a RocksDB memory region. This works for both non-mmap reads, where the block owns the memory region, and mmap reads, where the file owns the memory region.

For point reads with `PinnableSlice`, only the `Block` object is pinned. This works for non-mmap reads because the block owns the memory region, so even if the file is deleted after compaction, the memory region survives. However, for mmap reads, file deletion causes the memory region to which the `PinnableSlice` refers to be unmapped.   The result is usually a segfault upon accessing the `PinnableSlice`, although sometimes it returned wrong results (I repro'd this a bunch of times with `db_stress`).

This PR copies the value into the `PinnableSlice` when it comes from mmap'd memory. We can tell whether the `Block` owns its memory using `Block::cachable()`, which is unset when reads do not use the provided buffer as is the case with mmap file reads. When that is false we ensure the result of `Get()` is copied.

This feels like a short-term solution as ideally we'd have the `PinnableSlice` pin the mmap'd memory so we can do zero-copy reads. It seemed hard so I chose this approach to fix correctness in the meantime.
Closes https://github.com/facebook/rocksdb/pull/3881

Differential Revision: D8076288

Pulled By: ajkr

fbshipit-source-id: 31d78ec010198723522323dbc6ea325122a46b08
2018-06-01 16:57:58 -07:00
straw
89b37081a1 add c api rocksdb_sstfilewriter_file_size
Summary: Closes https://github.com/facebook/rocksdb/pull/3922

Differential Revision: D8208528

Pulled By: ajkr

fbshipit-source-id: d384fe53cf526f2aadc7b79a423ce36dbd3ff224
2018-06-01 09:43:59 -07:00
Maysam Yabandeh
44cf84932f Fix the bug of some test scenarios being put after kEnd
Summary:
DBTestBase::OptionConfig includes the scenarios that unit tests could iterate over them by calling ChangeOptions(). Some of the options have  been mistakenly put after kEnd which makes them essentially invisible to ChangeOptions() caller. This patch fixes it except for kUniversalSubcompactions which is left as TODO since it would break some unit tests.
Closes https://github.com/facebook/rocksdb/pull/3935

Differential Revision: D8230748

Pulled By: maysamyabandeh

fbshipit-source-id: edddb8fffcd161af1809fef24798ce118f8593db
2018-05-31 19:28:00 -07:00
QingpingWang
2807678b11 c api set bottommost level compaction
Summary: Closes https://github.com/facebook/rocksdb/pull/3928

Differential Revision: D8224962

Pulled By: ajkr

fbshipit-source-id: 3caf463509a935bff46530f27232a85ae7e4e484
2018-05-31 17:30:50 -07:00
Siying Dong
82089d59c3 DBImpl::FindObsoleteFiles() not to call GetChildren() on the same path
Summary:
DBImpl::FindObsoleteFiles() may call GetChildren() multiple times if different CFs are on the same path. Fix it.
Closes https://github.com/facebook/rocksdb/pull/3885

Differential Revision: D8084634

Pulled By: siying

fbshipit-source-id: b471fbc251f6a05e9243304dc14c0831060cc0b0
2018-05-31 12:58:33 -07:00
maoyouxiang
a35451eaa4 fix deadlock with enable_pipelined_write=true and max_successive_merges > 0
Summary:
fix this https://github.com/facebook/rocksdb/issues/3916
Closes https://github.com/facebook/rocksdb/pull/3923

Differential Revision: D8215192

Pulled By: yiwu-arbug

fbshipit-source-id: a4c2f839a91d92dc70906d2b7c6de0fe014a2422
2018-05-31 11:13:14 -07:00
Siying Dong
4dd80debd0 Remove tests from ROCKSDB_VALGRIND_RUN
Summary:
In order to make valgrind check test to pass in a day, remove some tests that run prohibitively slow under valgrind.
Closes https://github.com/facebook/rocksdb/pull/3924

Differential Revision: D8210184

Pulled By: siying

fbshipit-source-id: 5b06fb08f3cf57571d422d05a0dbddc9f9376f7a
2018-05-30 16:15:16 -07:00
Anand Ananthabhotla
a736255de8 Delete triggered compaction for universal style
Summary:
This is still WIP, but I'm hoping for early feedback on the overall approach.

This patch implements deletion triggered compaction, which till now only
worked for leveled, for universal style. SST files are marked for
compaction by the CompactOnDeletionCollertor table property. This is
expected to be used when free disk space is low and the user wants to
reclaim space by deleting a bunch of keys. The deletions are expected to
be dense. In such a situation, we want to avoid a full compaction due to
its space overhead.

The strategy used in this case is similar to leveled. We pick one file
from the set of files marked for compaction. We then expand the inputs
to a clean cut on the same level, and then pick overlapping files from
the next non-mepty level. Picking files from the next level can cause
the key range to expand, and we opportunistically expand inputs in the
source level to include files wholly in this key range.

The main side effect of this is that it breaks the property of no time
range overlap between levels. This shouldn't break any functionality.
Closes https://github.com/facebook/rocksdb/pull/3860

Differential Revision: D8124397

Pulled By: anand1976

fbshipit-source-id: bfa2a9dd6817930e991b35d3a8e7e61304ed3dcf
2018-05-29 15:44:34 -07:00
Yanqin Jin
cf826de3ed Fix compilation error when OPT="-DROCKSDB_LITE".
Summary: Closes https://github.com/facebook/rocksdb/pull/3917

Differential Revision: D8187733

Pulled By: riversand963

fbshipit-source-id: e4aa179cd0791ca77167e357f99de9afd4aef910
2018-05-29 12:28:59 -07:00
奏之章
1c1bafa668 Fix VersionStorageInfo::EstimateLiveDataSize seg fault
Summary:
`HandleEstimateLiveDataSize`'s `need_out_of_mutex` is true
402b7aa07f/db/internal_stats.cc (L412-L413)
so , is will ref a `SuperVersion`
402b7aa07f/db/db_impl.cc (L1896-L1908)
so , the param `version` of `InternalStats::HandleEstimateLiveDataSize` is safe , but `cfd_->current()` is not safe !
402b7aa07f/db/internal_stats.cc (L790-L795)

the `cfd_->current()` maybe invalid ...

here's mongo-rocks crash backtrace
```
 mongod(mongo::printStackTrace(std::basic_ostream<char, std::char_traits<char> >&)+0x41) [0x7fe3a3137c51]
 mongod(+0x2152E89) [0x7fe3a3136e89]
 mongod(+0x21534F6) [0x7fe3a31374f6]
 libpthread.so.0(+0xF5E0) [0x7fe39f5e45e0]
 mongod(rocksdb::InternalKeyComparator::Compare(rocksdb::Slice const&, rocksdb::Slice const&) const+0x17) [0x7fe3a22375a7]
 mongod(rocksdb::VersionStorageInfo::EstimateLiveDataSize() const+0x3AA) [0x7fe3a228daba]
 mongod(rocksdb::InternalStats::HandleEstimateLiveDataSize(unsigned long*, rocksdb::DBImpl*, rocksdb::Version*)+0x20) [0x7fe3a2250d70]
 mongod(rocksdb::DBImpl::GetIntPropertyInternal(rocksdb::ColumnFamilyData*, rocksdb::DBPropertyInfo const&, bool, unsigned long*)+0xEF) [0x7fe3a21e3dbf]
```
Closes https://github.com/facebook/rocksdb/pull/3912

Differential Revision: D8179944

Pulled By: yiwu-arbug

fbshipit-source-id: 26f314a8f98f4c2dc4348745d759f26f0e8d95e1
2018-05-28 11:27:08 -07:00
Maysam Yabandeh
402b7aa07f Exclude seq from index keys
Summary:
Index blocks have the same format as data blocks. The keys therefore similarly to the keys in the data blocks are internal keys, which means that in addition to the user key it also has 8 bytes that encodes sequence number and value type. This extra 8 bytes however is not necessary in index blocks since the index keys act as an separator between two data blocks. The only exception is when the last key of a block and the first key of the next block share the same user key, in which the sequence number is required to act as a separator.
The patch excludes the sequence from index keys only if the above special case does not happen for any of the index keys. It then records that in the property block. The reader looks at the property block to see if it should expect sequence numbers in the keys of the index block.s
Closes https://github.com/facebook/rocksdb/pull/3894

Differential Revision: D8118775

Pulled By: maysamyabandeh

fbshipit-source-id: 915479f028b5799ca91671d67455ecdefbd873bd
2018-05-25 18:42:43 -07:00
Yanqin Jin
aa53579d6c Fix segfault caused by object premature destruction
Summary:
Please refer to earlier discussion in [issue 3609](https://github.com/facebook/rocksdb/issues/3609).
There was also an alternative fix in [PR 3888](https://github.com/facebook/rocksdb/pull/3888), but the proposed solution requires complex change.

To summarize the cause of the problem. Upon creation of a column family, a `BlockBasedTableFactory` object is `new`ed and encapsulated by a `std::shared_ptr`. Since there is no other `std::shared_ptr` pointing to this `BlockBasedTableFactory`, when the column family is dropped, the `ColumnFamilyData` is `delete`d, causing the destructor of `std::shared_ptr`. Since there is no other `std::shared_ptr`, the underlying memory is also freed.
Later when the db exits, it releases all the table readers, including the table readers that have been operating on the dropped column family. This needs to access the `table_options` owned by `BlockBasedTableFactory` that has already been deleted. Therefore, a segfault is raised.
Previous workaround is to purge all obsolete files upon `ColumnFamilyData` destruction, which leads to a force release of table readers of the dropped column family. However this does not work when the user disables file deletion.

Our solution in this PR is making a copy of `table_options` in `BlockBasedTable::Rep`. This solution increases memory copy and usage, but is much simpler.

Test plan
```
$ make -j16
$ ./column_family_test --gtest_filter=ColumnFamilyTest.CreateDropAndDestroy:ColumnFamilyTest.CreateDropAndDestroyWithoutFileDeletion
```

Expected behavior:
All tests should pass.
Closes https://github.com/facebook/rocksdb/pull/3898

Differential Revision: D8149421

Pulled By: riversand963

fbshipit-source-id: eaecc2e064057ef607fbdd4cc275874f866c3438
2018-05-25 11:57:51 -07:00
QingpingWang
070319f7bb add flush_before_backup parameter to c api rocksdb_backup_engine_create_new_backup
Summary:
Add flush_before_backup to rocksdb_backup_engine_create_new_backup. make c api able to control the flush before backup behavior.
Closes https://github.com/facebook/rocksdb/pull/3897

Differential Revision: D8157676

Pulled By: ajkr

fbshipit-source-id: 88998c62f89f087bf8672398fd7ddafabbada505
2018-05-24 22:28:52 -07:00
Yi Wu
bc7e8d472e LRUCache midpoint insertion
Summary:
Implement midpoint insertion strategy where new blocks will be insert to the middle of LRU list, then move the head on the first hit in cache.
Closes https://github.com/facebook/rocksdb/pull/3877

Differential Revision: D8100895

Pulled By: yiwu-arbug

fbshipit-source-id: f4bd83cb8be469e5d02072cfc8bd66011391f3da
2018-05-24 15:57:33 -07:00
Yanqin Jin
4011012d9d Specify the underlying type of enums.
Summary:
Explicitly specify the underlying type of enums help developers understand the physical storage.
Closes https://github.com/facebook/rocksdb/pull/3892

Differential Revision: D8107027

Pulled By: riversand963

fbshipit-source-id: a00efecbba46df4a3c8eed0994a2d4972ad1a1d3
2018-05-23 16:12:59 -07:00
Andrew Kryczka
7db721b9a6 Avoid sleep in DBTest.GroupCommitTest to fix flakiness
Summary:
DBTest.GroupCommitTest would often fail when run under valgrind because its sleeps were insufficient to guarantee a group commit had multiple entries. Instead we can use sync point to force a leader to wait until a non-leader thread has enqueued its work, thus guaranteeing a leader can do group commit work for multiple threads.
Closes https://github.com/facebook/rocksdb/pull/3883

Differential Revision: D8079429

Pulled By: ajkr

fbshipit-source-id: 61dc50fad29d2c85547842f681288de60fa29049
2018-05-22 12:16:25 -07:00
Siying Dong
3db1ada3bf PersistRocksDBOptions() to use WritableFileWriter
Summary:
By using WritableFileWriter rather than WritableFile directly, we can buffer multiple Append() calls to one write() file system call, which will be expensive to underlying Env without its own write buffering.
Closes https://github.com/facebook/rocksdb/pull/3882

Differential Revision: D8080673

Pulled By: siying

fbshipit-source-id: e0db900cb3c178166aa738f3985db65e3ae2cf1b
2018-05-21 16:42:22 -07:00
Zhongyi Xie
c3ebc75843 Move prefix_extractor to MutableCFOptions
Summary:
Currently it is not possible to change bloom filter config without restart the db, which is causing a lot of operational complexity for users.
This PR aims to make it possible to dynamically change bloom filter config.
Closes https://github.com/facebook/rocksdb/pull/3601

Differential Revision: D7253114

Pulled By: miasantreble

fbshipit-source-id: f22595437d3e0b86c95918c484502de2ceca120c
2018-05-21 14:43:11 -07:00
Yanqin Jin
263ef52b65 Update ColumnFamilyTest for multi-CF verification
Summary:
Change `keys_` from `set<string>` to `vector<set<string>>` so that each column
family's keys are stored in one set.

ajkr When you have a chance, can you PTAL? Thanks!
Closes https://github.com/facebook/rocksdb/pull/3871

Differential Revision: D8056447

Pulled By: riversand963

fbshipit-source-id: 650d0f9cad02b1bc005fc329ad76edbf053e6386
2018-05-21 11:57:42 -07:00
Andrew Kryczka
7b655214d2 Assert keys/values pinned by range deletion meta-block iterators
Summary:
`RangeDelAggregator` holds the pointers returned by `BlockIter::key()` and `BlockIter::value()` so requires the data to which they point is pinned. `BlockIter::key()` points into block memory and is guaranteed to be pinned if and only if prefix encoding is disabled (or, equivalently, restart interval is set to one). I think `BlockIter::value()` is always pinned. Added an assert for these and removed the wrong TODO about increasing restart interval, which would enable key prefix encoding and break the assertion.
Closes https://github.com/facebook/rocksdb/pull/3875

Differential Revision: D8063667

Pulled By: ajkr

fbshipit-source-id: 60b5ebcc0cdd610dd6aad9e74a23378793672c41
2018-05-21 09:57:00 -07:00
Zhongyi Xie
ed4d3393fb fix a division by zero bug
Summary:
fixes the failing clang_analyze contrun test
Closes https://github.com/facebook/rocksdb/pull/3872

Differential Revision: D8059241

Pulled By: miasantreble

fbshipit-source-id: e8fc1838004fe16a823456188386b8b39429803b
2018-05-18 21:57:24 -07:00
Siying Dong
17af09fcce Implement key shortening functions in ReverseBytewiseComparator
Summary:
Right now ReverseBytewiseComparator::FindShortestSeparator() doesn't really shorten key, and ReverseBytewiseComparator::FindShortestSuccessor() seems to return wrong results. The code is confusing too as it uses BytewiseComparatorImpl::FindShortestSeparator() but the function actually won't do anything if the the first key is larger than the second.

Implement ReverseBytewiseComparator::FindShortestSeparator() and override ReverseBytewiseComparator::FindShortestSuccessor() to be empty.
Closes https://github.com/facebook/rocksdb/pull/3836

Differential Revision: D7959762

Pulled By: siying

fbshipit-source-id: 93acb621c16ce6f23e087ae4e19f7d84d1254683
2018-05-17 18:27:16 -07:00
Zhongyi Xie
1d7ca20f29 add override to virtual functions
Summary:
this will fix the failing clang_check test
Closes https://github.com/facebook/rocksdb/pull/3868

Differential Revision: D8050880

Pulled By: miasantreble

fbshipit-source-id: 749932e2e4025f835c961c068d601e522a126da6
2018-05-17 17:57:48 -07:00
Mike Kolupaev
8bf555f487 Change and clarify the relationship between Valid(), status() and Seek*() for all iterators. Also fix some bugs
Summary:
Before this PR, Iterator/InternalIterator may simultaneously have non-ok status() and Valid() = true. That state means that the last operation failed, but the iterator is nevertheless positioned on some unspecified record. Likely intended uses of that are:
 * If some sst files are corrupted, a normal iterator can be used to read the data from files that are not corrupted.
 * When using read_tier = kBlockCacheTier, read the data that's in block cache, skipping over the data that is not.

However, this behavior wasn't documented well (and until recently the wiki on github had misleading incorrect information). In the code there's a lot of confusion about the relationship between status() and Valid(), and about whether Seek()/SeekToLast()/etc reset the status or not. There were a number of bugs caused by this confusion, both inside rocksdb and in the code that uses rocksdb (including ours).

This PR changes the convention to:
 * If status() is not ok, Valid() always returns false.
 * Any seek operation resets status. (Before the PR, it depended on iterator type and on particular error.)

This does sacrifice the two use cases listed above, but siying said it's ok.

Overview of the changes:
 * A commit that adds missing status checks in MergingIterator. This fixes a bug that actually affects us, and we need it fixed. `DBIteratorTest.NonBlockingIterationBugRepro` explains the scenario.
 * Changes to lots of iterator types to make all of them conform to the new convention. Some bug fixes along the way. By far the biggest changes are in DBIter, which is a big messy piece of code; I tried to make it less big and messy but mostly failed.
 * A stress-test for DBIter, to gain some confidence that I didn't break it. It does a few million random operations on the iterator, while occasionally modifying the underlying data (like ForwardIterator does) and occasionally returning non-ok status from internal iterator.

To find the iterator types that needed changes I searched for "public .*Iterator" in the code. Here's an overview of all 27 iterator types:

Iterators that didn't need changes:
 * status() is always ok(), or Valid() is always false: MemTableIterator, ModelIter, TestIterator, KVIter (2 classes with this name anonymous namespaces), LoggingForwardVectorIterator, VectorIterator, MockTableIterator, EmptyIterator, EmptyInternalIterator.
 * Thin wrappers that always pass through Valid() and status(): ArenaWrappedDBIter, TtlIterator, InternalIteratorFromIterator.

Iterators with changes (see inline comments for details):
 * DBIter - an overhaul:
    - It used to silently skip corrupted keys (`FindParseableKey()`), which seems dangerous. This PR makes it just stop immediately after encountering a corrupted key, just like it would for other kinds of corruption. Let me know if there was actually some deeper meaning in this behavior and I should put it back.
    - It had a few code paths silently discarding subiterator's status. The stress test caught a few.
    - The backwards iteration code path was expecting the internal iterator's set of keys to be immutable. It's probably always true in practice at the moment, since ForwardIterator doesn't support backwards iteration, but this PR fixes it anyway. See added DBIteratorTest.ReverseToForwardBug for an example.
    - Some parts of backwards iteration code path even did things like `assert(iter_->Valid())` after a seek, which is never a safe assumption.
    - It used to not reset status on seek for some types of errors.
    - Some simplifications and better comments.
    - Some things got more complicated from the added error handling. I'm open to ideas for how to make it nicer.
 * MergingIterator - check status after every operation on every subiterator, and in some places assert that valid subiterators have ok status.
 * ForwardIterator - changed to the new convention, also slightly simplified.
 * ForwardLevelIterator - fixed some bugs and simplified.
 * LevelIterator - simplified.
 * TwoLevelIterator - changed to the new convention. Also fixed a bug that would make SeekForPrev() sometimes silently ignore errors from first_level_iter_.
 * BlockBasedTableIterator - minor changes.
 * BlockIter - replaced `SetStatus()` with `Invalidate()` to make sure non-ok BlockIter is always invalid.
 * PlainTableIterator - some seeks used to not reset status.
 * CuckooTableIterator - tiny code cleanup.
 * ManagedIterator - fixed some bugs.
 * BaseDeltaIterator - changed to the new convention and fixed a bug.
 * BlobDBIterator - seeks used to not reset status.
 * KeyConvertingIterator - some small change.
Closes https://github.com/facebook/rocksdb/pull/3810

Differential Revision: D7888019

Pulled By: al13n321

fbshipit-source-id: 4aaf6d3421c545d16722a815b2fa2e7912bc851d
2018-05-17 02:56:56 -07:00
Maysam Yabandeh
46fde6b653 Fix race condition between log_.erase and log_.back
Summary:
log_ contract specifies that it should not be modified unless both mutex_ and log_write_mutex_ are held. log_.erase however does that with only holding mutex_. This causes a race condition with two_write_queues since logs_.back is read with holding only log_write_mutex_ (which is correct according to logs_ contract) but logs_.erase is called concurrently. This is probably the cause of logs_.back returning nullptr in https://github.com/facebook/rocksdb/issues/3852 although I could not reproduce it.
Fixes https://github.com/facebook/rocksdb/issues/3852
Closes https://github.com/facebook/rocksdb/pull/3859

Differential Revision: D8026103

Pulled By: maysamyabandeh

fbshipit-source-id: ee394e00fe4aa520d884c5ef87981e9d6b5ccb28
2018-05-16 13:01:33 -07:00