Summary:
This is an implementation of non-exclusive locks for pessimistic transactions. It is relatively simple and does not prevent starvation (ie. it's possible that request for exclusive access will never be granted if there are always threads holding shared access). It is done by changing `KeyLockInfo` to hold an set a transaction ids, instead of just one, and adding a flag specifying whether this lock is currently held with exclusive access or not.
Some implementation notes:
- Some lock diagnostic functions had to be updated to return a set of transaction ids for a given lock, eg. `GetWaitingTxn` and `GetLockStatusData`.
- Deadlock detection is a bit more complicated since a transaction can now wait on multiple other transactions. A BFS is done in this case, and deadlock detection depth is now just a limit on the number of transactions we visit.
- Expirable transactions do not work efficiently with shared locks at the moment, but that's okay for now.
Closes https://github.com/facebook/rocksdb/pull/1573
Differential Revision: D4239097
Pulled By: lth
fbshipit-source-id: da7c074
Summary:
Made delete_obsolete_files_period_micros option dynamic. It can be updating using DB::SetDBOptions().
Closes https://github.com/facebook/rocksdb/pull/1595
Differential Revision: D4246569
Pulled By: tonek
fbshipit-source-id: d23f560
Summary:
Reduce number of comparisons in heap by caching which child node in the first level is smallest (left_child or right_child)
So next time we can compare directly against the smallest child
I see that the total number of calls to comparator drops significantly when using this optimization
Before caching (~2mil key comparison for iterating the DB)
```
$ DEBUG_LEVEL=0 make db_bench -j64 && ./db_bench --benchmarks="readseq" --db="/dev/shm/heap_opt" --use_existing_db --disable_auto_compactions --cache_size=1000000000 --perf_level=2
readseq : 0.338 micros/op 2959201 ops/sec; 327.4 MB/s user_key_comparison_count = 2000008
```
After caching (~1mil key comparison for iterating the DB)
```
$ DEBUG_LEVEL=0 make db_bench -j64 && ./db_bench --benchmarks="readseq" --db="/dev/shm/heap_opt" --use_existing_db --disable_auto_compactions --cache_size=1000000000 --perf_level=2
readseq : 0.309 micros/op 3236801 ops/sec; 358.1 MB/s user_key_comparison_count = 1000011
```
It also improves
Closes https://github.com/facebook/rocksdb/pull/1600
Differential Revision: D4256027
Pulled By: IslamAbdelRahman
fbshipit-source-id: 76fcc66
Summary:
disable UBSAN for functions with intentional left shift on -ve number / overflow
These functions are
rocksdb:: Hash
FixedLengthColBufEncoder::Append
FaultInjectionTest:: Key
Closes https://github.com/facebook/rocksdb/pull/1577
Differential Revision: D4240801
Pulled By: IslamAbdelRahman
fbshipit-source-id: 3e1caf6
Summary:
Having -ve value for max_write_buffer_number does not make sense and cause us to do a left shift on a -ve value number
Closes https://github.com/facebook/rocksdb/pull/1579
Differential Revision: D4240798
Pulled By: IslamAbdelRahman
fbshipit-source-id: bd6267e
Summary:
In one deployment we saw high latencies (presumably from slow iterator operations) and a lot of CPU time reported by perf with this stack:
```
rocksdb::MergingIterator::Next
rocksdb::DBIter::FindNextUserEntryInternal
rocksdb::DBIter::Seek
```
I think what's happening is:
1. we create a snapshot iterator,
2. we do lots of Put()s for the same key x; this creates lots of entries in memtable,
3. we seek the iterator to a key slightly smaller than x,
4. the seek walks over lots of entries in memtable for key x, skipping them because of high sequence numbers.
CC IslamAbdelRahman
Closes https://github.com/facebook/rocksdb/pull/1413
Differential Revision: D4083879
Pulled By: IslamAbdelRahman
fbshipit-source-id: a83ddae
Summary:
Current write stalling system has the problem of lacking of positive feedback if the restricted rate is already too low. Users sometimes stack in very low slowdown value. With the diff, we add a positive feedback (increasing the slowdown value) if we recover from slowdown state back to normal. To avoid the positive feedback to keep the slowdown value to be to high, we add issue a negative feedback every time we are close to the stop condition. Experiments show it is easier to reach a relative balance than before.
Also increase level0_stop_writes_trigger default from 24 to 32. Since level0_slowdown_writes_trigger default is 20, stop trigger 24 only gives four files as the buffer time to slowdown writes. In order to avoid stop in four files while 20 files have been accumulated, the slowdown value must be very low, which is amost the same as stop. It also doesn't give enough time for the slowdown value to converge. Increase it to 32 will smooth out the system.
Closes https://github.com/facebook/rocksdb/pull/1562
Differential Revision: D4218519
Pulled By: siying
fbshipit-source-id: 95e4088
Summary:
LZ4 1.7.3 emits warnings when calling the deprecated function `LZ4_compress_limitedOutput_continue()`. Starting in r129, LZ4 introduces `LZ4_compress_fast_continue()` as a replacement, and the two functions calls are [exactly equivalent](https://github.com/lz4/lz4/blob/dev/lib/lz4.c#L1408).
Closes https://github.com/facebook/rocksdb/pull/1532
Differential Revision: D4199240
Pulled By: siying
fbshipit-source-id: 138c2bc
Summary:
We should close the fd, before overriding it. This bug was
introduced by f89caa127b
Closes https://github.com/facebook/rocksdb/pull/1553
Differential Revision: D4214101
Pulled By: siying
fbshipit-source-id: 0d65de0
Summary:
- Made RangeDelAggregator's InternalKeyComparator member a reference-to-const so we don't need to copy-construct it. Also added InternalKeyComparator to ImmutableCFOptions so we don't need to construct one for each DBIter.
- Made MemTable::NewRangeTombstoneIterator and the table readers' NewRangeTombstoneIterator() functions return nullptr instead of NewEmptyInternalIterator to avoid the allocation. Updated callers accordingly.
Closes https://github.com/facebook/rocksdb/pull/1548
Differential Revision: D4208169
Pulled By: ajkr
fbshipit-source-id: 2fd65cf
Summary:
When calling StatisticsImpl::HistogramInfo::getMergedHistogram(), if
there is a dying thread, which is calling
ThreadLocalPtr::StaticMeta::OnThreadExit() to merge its thread values to
HistogramInfo, deadlock will occur. Because the former try to hold
merge_lock then ThreadMeta::mutex_, but the later try to hold
ThreadMeta::mutex_ then merge_lock. In short, the locking order isn't
the same.
This patch addressed this issue by releasing merge_lock before folding
thread values.
Closes https://github.com/facebook/rocksdb/pull/1552
Differential Revision: D4211942
Pulled By: ajkr
fbshipit-source-id: ef89bcb
Summary:
Currently, deadlock cycles are held in std::unordered_map. The problem with it is that it allocates/deallocates memory on every insertion/deletion. This limits throughput since we're doing this expensive operation while holding a global mutex. Fix this by using a vector which caches memory instead.
Running the deadlock stress test, this change increased throughput from 39k txns/s -> 49k txns/s. The effect is more noticeable in MyRocks.
Closes https://github.com/facebook/rocksdb/pull/1545
Differential Revision: D4205662
Pulled By: lth
fbshipit-source-id: ff990e4
Summary:
Currently, in the Direct I/O read mode, the last sector of the file, if not full, is not handled correctly. If the return value of pread is not multiplier of kSectorSize, we still go ahead and continue reading, even if the buffer is not aligned. With the commit, if the return value is not multiplier of kSectorSize, and all but the last sector has been read, we simply return.
Closes https://github.com/facebook/rocksdb/pull/1550
Differential Revision: D4209609
Pulled By: lightmark
fbshipit-source-id: cb0b439
Summary:
This patch clarifies the contract of PositionedAppend with some unit
tests and also implements it for PosixWritableFile. (Tasks: 14524071)
Closes https://github.com/facebook/rocksdb/pull/1514
Differential Revision: D4204907
Pulled By: maysamyabandeh
fbshipit-source-id: 06eabd2
Summary:
It is hard to measure acutal memory usage by std containers. Even
providing a custom allocator will miss count some of the usage. Here we
only do a wild guess on its memory usage.
Closes https://github.com/facebook/rocksdb/pull/1511
Differential Revision: D4179945
Pulled By: yiwu-arbug
fbshipit-source-id: 32ab929
Summary:
Currently our skip-list have an optimization to speedup sequential
inserts from a single stream, by remembering the last insert position.
We extend the idea to support sequential inserts from multiple streams,
and even tolerate small reordering wihtin each stream.
This PR is the interface part adding the following:
- Add `memtable_insert_prefix_extractor` to allow specifying prefix for each key.
- Add `InsertWithHint()` interface to memtable, to allow underlying
implementation to return a hint of insert position, which can be later
pass back to optimize inserts.
- Memtable will maintain a map from prefix to hints and pass the hint
via `InsertWithHint()` if `memtable_insert_prefix_extractor` is non-null.
Closes https://github.com/facebook/rocksdb/pull/1419
Differential Revision: D4079367
Pulled By: yiwu-arbug
fbshipit-source-id: 3555326
Summary:
This fixes a correctness issue where ranges with same begin key would overwrite each other.
This diff uses InternalKey as TombstoneMap's key such that all tombstones have unique keys even when their start keys overlap. We also update TombstoneMap to use an internal key comparator.
End-to-end tests pass and are here (https://gist.github.com/ajkr/851ffe4c1b8a15a68d33025be190a7d9) but cannot be included yet since the DeleteRange() API is yet to be checked in. Note both tests failed before this fix.
Closes https://github.com/facebook/rocksdb/pull/1484
Differential Revision: D4155248
Pulled By: ajkr
fbshipit-source-id: 304b4b9
Summary:
During Get()/MultiGet(), build up a RangeDelAggregator with range
tombstones as we search through live memtable, immutable memtables, and
SST files. This aggregator is then used by memtable.cc's SaveValue() and
GetContext::SaveValue() to check whether keys are covered.
added tests for Get on memtables/files; end-to-end tests mainly in https://reviews.facebook.net/D64761
Closes https://github.com/facebook/rocksdb/pull/1456
Differential Revision: D4111271
Pulled By: ajkr
fbshipit-source-id: 6e388d4
Summary:
DB Stats now are truncated if there are too many CFs. Extend the buffer size to allow more to be printed out. Also, separate out malloc to another log line.
Closes https://github.com/facebook/rocksdb/pull/1439
Differential Revision: D4100943
Pulled By: yiwu-arbug
fbshipit-source-id: 79f7218
Summary:
Rocksdb currently has many references to std::map.emplace_back()
which is not implemented in gcc 4.7, but valid in gcc 4.8. Confirmed that
it did not build with gcc 4.7, but builds fine with gcc 4.8
Closes https://github.com/facebook/rocksdb/pull/1272
Differential Revision: D4101385
Pulled By: IslamAbdelRahman
fbshipit-source-id: f6af453
* util/build_verion.cc.in: add this file, so cmake and make can share the
template file for generating util/build_version.cc.
* CMakeLists.txt: also, cmake v2.8.11 does not support file(GENERATE ...),
so we are using configure_file() for creating build_version.cc.
* Makefile: use util/build_verion.cc.in for creating build_version.cc.
Signed-off-by: Kefu Chai <tchaikov@gmail.com>
Summary: Using real clock causes failures of DBSSTTest.RateLimitedDelete in some cases. Turn away from the real time. Use fake time instead.
Test Plan: Run the tests and all existing tests.
Reviewers: yiwu, IslamAbdelRahman
Reviewed By: IslamAbdelRahman
Subscribers: leveldb, andrewkr, dhruba
Differential Revision: https://reviews.facebook.net/D65145
Summary:
change ioptions.comparator to user_comparator instread of internal_comparator.
Also change Comparator* to InternalKeyComparator* to make its type explicitly.
Test Plan: make all check -j64
Reviewers: andrewkr, sdong, yiwu
Reviewed By: yiwu
Subscribers: andrewkr, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D65121
Summary:
reland https://reviews.facebook.net/D62523
- Update SstFileWriter to include a property for a global sequence number in the SST file `rocksdb.external_sst_file.global_seqno`
- Update TableProperties to be aware of the offset of each property in the file
- Update BlockBasedTableReader and Block to be able to honor the sequence number in `rocksdb.external_sst_file.global_seqno` property and use it to overwrite all sequence number in the file
Something worth mentioning is that we don't update the seqno in the index block since and when doing a binary search, the reason for that is that it's guaranteed that SST files with global seqno will have only one user_key and each key will have seqno=0 encoded in it, This mean that this key is greater than any other key with seqno> 0. That mean that we can actually keep the current logic for these blocks
Test Plan: unit tests
Reviewers: sdong, yhchiang
Subscribers: andrewkr, dhruba
Differential Revision: https://reviews.facebook.net/D65211
Summary:
In the current implementation of RateLimiter, the difference
between the configured rate and the actual rate might be more
than 20%, while our test only allows 15% difference. This diff
relaxes the acceptable bias RateLimiterTest::Rate test be 25%
to make the test less flaky.
Test Plan: rate_limiter_test
Reviewers: IslamAbdelRahman, andrewkr, yiwu, lightmark, sdong
Reviewed By: sdong
Subscribers: andrewkr, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D64941
Summary: A convience method to atomically get and reset ticker count. I'm wanting to use it to have a thin wrapper to the statistics object to export ticker counts to ODS for LogDevice (since they don't even use fb303).
Test Plan:
test in LogDevice shadow cluster.
https://fburl.com/461868822
Reviewers: andrewkr, yhchiang, IslamAbdelRahman
Reviewed By: IslamAbdelRahman
Subscribers: andrewkr, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D64869
Summary:
We always run consistency checks when compiling in debug mode
allow users to set Options::force_consistency_checks to true to be able to run such checks even when compiling in release mode
Test Plan:
make check -j64
make release
Reviewers: lightmark, sdong, yiwu
Reviewed By: yiwu
Subscribers: hermanlee4, andrewkr, yoshinorim, jkedgar, dhruba
Differential Revision: https://reviews.facebook.net/D64701
Summary:
I saw this exception thrown because sometimes we may resize with -ve value
if we have empty max_bytes_for_level_multiplier_additional vector
Test Plan: run the tests
Reviewers: yiwu
Reviewed By: yiwu
Subscribers: andrewkr, dhruba
Differential Revision: https://reviews.facebook.net/D64791
Hello and thank you for RocksDB,
I noticed when using log_write_bench that writes were always 88 bytes:
> strace -e trace=write ./log_write_bench -num_records 2 2>&1 | head -n 2
write(3, "\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371"..., 88) = 88
write(3, "\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371\371"..., 88) = 88
> strace -e trace=write ./log_write_bench -record_size 4096 -num_records 2 2>&1 | head -n 2
write(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 88) = 88
write(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 88) = 88
I think this should be:
<< record.assign('X', FLAGS_record_size);
>> record.assign(FLAGS_record_size, 'X');
So fill and not buffer. Otherwise I always see writes of size 88 (the decimal value for chr "X").
string& assign (const char* s, size_t n);
buffer - Copies the first n characters from the array of characters pointed by s.
string& assign (size_t n, char c);
fill - Replaces the current value by n consecutive copies of character c.
perl -le 'print ord "X"'
88
With the change:
> strace -e trace=write ./log_write_bench -record_size 4096 -num_records 2 2>&1 | head -n 2
write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 4096) = 4096
write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 4096) = 4096
> strace -e trace=write ./log_write_bench -num_records 2 2>&1 | head -n 2
write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 249) = 249
write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 249) = 249
Thanks.
01c27be5fbhttps://reviews.facebook.net/D16239
Summary:
- Update SstFileWriter to include a property for a global sequence number in the SST file `rocksdb.external_sst_file.global_seqno`
- Update TableProperties to be aware of the offset of each property in the file
- Update BlockBasedTableReader and Block to be able to honor the sequence number in `rocksdb.external_sst_file.global_seqno` property and use it to overwrite all sequence number in the file
Something worth mentioning is that we don't update the seqno in the index block since and when doing a binary search, the reason for that is that it's guaranteed that SST files with global seqno will have only one user_key and each key will have seqno=0 encoded in it, This mean that this key is greater than any other key with seqno> 0. That mean that we can actually keep the current logic for these blocks
Test Plan: unit tests
Reviewers: andrewkr, yhchiang, yiwu, sdong
Reviewed By: sdong
Subscribers: hcz, andrewkr, dhruba
Differential Revision: https://reviews.facebook.net/D62523
Summary:
Add new Iterator API, `SeekForPrev`: find the last key that <= target key
support prefix_extractor
support prefix_same_as_start
support upper_bound
not supported in iterators without Prev()
Also add tests in db_iter_test and db_iterator_test
Pass all tests
Cheers!
Test Plan: make all check -j64
Reviewers: andrewkr, yiwu, IslamAbdelRahman, sdong
Reviewed By: sdong
Subscribers: andrewkr, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D64149
Summary: Use ImmutableDBOptions/MutableDBOptions internally and DBOptions only for user-facing APIs. MutableDBOptions is barely a placeholder for now. I'll start to move options to MutableDBOptions in following diffs.
Test Plan:
make all check
Reviewers: yhchiang, IslamAbdelRahman, sdong
Reviewed By: sdong
Subscribers: andrewkr, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D64065
Summary:
MyRocks build is broken because they are using "-Werror=missing-field-initializers"
We should fix that by explicitly passing these arguments
Test Plan: Build MyRocks
Reviewers: sdong, yiwu
Reviewed By: yiwu
Subscribers: andrewkr, dhruba
Differential Revision: https://reviews.facebook.net/D64161
Summary: 0.9 can make the test flaky since just found one test fail with 0.88
Test Plan: make all check
Reviewers: sdong, andrewkr
Reviewed By: andrewkr
Subscribers: andrewkr, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D63939
Summary: EnvPosixTestWithParam.TwoPools relies on explicit sleeping, so it sometimes fail. Fix it.
Test Plan: Run tests with high parallelism many times and make sure the test passes.
Reviewers: yiwu, andrewkr
Reviewed By: andrewkr
Subscribers: leveldb, andrewkr, dhruba
Differential Revision: https://reviews.facebook.net/D63417
Summary: Add mutable options info into `OptionsTypeInfo` and use it to parse mutable options map. Also support `max_bytes_for_level_multiplier_additional` in option file.
Test Plan: unit test
Reviewers: yhchiang, IslamAbdelRahman, sdong
Reviewed By: sdong
Subscribers: andrewkr, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D63843
