Commit Graph

110 Commits

Author SHA1 Message Date
sdong
d0f3894cf1 In block based table builder, make variables for estimating file size atomic (#6636)
Summary:
With https://github.com/facebook/rocksdb/issues/6262, TSAN complains about data race of some variables. Those variables are used to estimate file size and are accessed in writer and background threads. Since file size estimation doesn't have to be 100% accurate, we make some variables atomic and use relaxed memory order.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6636

Test Plan: Run all tests with TSAN.

Reviewed By: anand1976

Differential Revision: D20820635

fbshipit-source-id: 1ea45ff38be15e33674ffe06b7d42fc9fe161ea5
2020-04-02 16:16:24 -07:00
Ziyue Yang
8088482dd6 Fix a division by zero after #6262 (#6633)
Summary:
With https://github.com/facebook/rocksdb/issues/6262, UBSAN fails with "division by zero":

[ RUN      ] Timestamp/DBBasicTestWithTimestampCompressionSettings.PutAndGetWithCompaction/3
internal_repo_rocksdb/repo/table/block_based/block_based_table_builder.cc:1066:39: runtime error: division by zero
    #0 0x7ffb3117b071 in rocksdb::BlockBasedTableBuilder::WriteRawBlock(rocksdb::Slice const&, rocksdb::CompressionType, rocksdb::BlockHandle*, bool) internal_repo_rocksdb/repo/table/block_based/block_based_table_builder.cc:1066
    https://github.com/facebook/rocksdb/issues/1 0x7ffb311775e1 in rocksdb::BlockBasedTableBuilder::WriteBlock(rocksdb::Slice const&, rocksdb::BlockHandle*, bool) internal_repo_rocksdb/repo/table/block_based/block_based_table_builder.cc:848
    https://github.com/facebook/rocksdb/issues/2 0x7ffb311771a2 in rocksdb::BlockBasedTableBuilder::WriteBlock(rocksdb::BlockBuilder*, rocksdb::BlockHandle*, bool) internal_repo_rocksdb/repo/table/block_based/block_based_table_builder.cc:832

This is caused by not returning immediately after CompressAndVerifyBlock call
in WriteBlock when rep_->status == kBuffered.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6633

Test Plan: Run all existing test.

Reviewed By: anand1976

Differential Revision: D20808366

fbshipit-source-id: 09f24b7c0fbaf4c7a8fc48cac61fa6fcb9b85811
2020-04-02 11:57:05 -07:00
Ziyue Yang
03a781a90c Add pipelined & parallel compression optimization (#6262)
Summary:
This PR adds support for pipelined & parallel compression optimization for `BlockBasedTableBuilder`. This optimization makes block building, block compression and block appending a pipeline, and uses multiple threads to accelerate block compression. Users can set `CompressionOptions::parallel_threads` greater than 1 to enable compression parallelism.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6262

Reviewed By: ajkr

Differential Revision: D20651306

fbshipit-source-id: 62125590a9c15b6d9071def9dc72589c1696a4cb
2020-04-01 16:40:18 -07:00
Levi Tamasi
e6f86cfb36 Revert the recent cache deleter change (#6620)
Summary:
Revert "Use function objects as deleters in the block cache (https://github.com/facebook/rocksdb/issues/6545)"

    This reverts commit 6301dbe7a7.

    Revert "Call out the cache deleter related interface change in HISTORY.md (https://github.com/facebook/rocksdb/issues/6606)"

    This reverts commit 3a35542f86.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6620

Test Plan: `make check`

Reviewed By: zhichao-cao

Differential Revision: D20773311

Pulled By: ltamasi

fbshipit-source-id: 7637a761f718f323ef0e7da959462e8fb06e7a2b
2020-03-31 16:11:06 -07:00
Zhichao Cao
e8d332d97e Use FileChecksumGenFactory for SST file checksum (#6600)
Summary:
In the current implementation, sst file checksum is calculated by a shared checksum function object, which may make some checksum function hard to be applied here such as SHA1. In this implementation, each sst file will have its own checksum generator obejct, created by FileChecksumGenFactory. User needs to implement its own FilechecksumGenerator and Factory to plugin the in checksum calculation method.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6600

Test Plan: tested with make asan_check

Reviewed By: riversand963

Differential Revision: D20717670

Pulled By: zhichao-cao

fbshipit-source-id: 2a74c1c280ac11a07a1980185b43b671acaa71c6
2020-03-29 15:58:46 -07:00
Zhichao Cao
4246888101 Pass IOStatus to write path and set retryable IO Error as hard error in BG jobs (#6487)
Summary:
In the current code base, we use Status to get and store the returned status from the call. Specifically, for IO related functions, the current Status cannot reflect the IO Error details such as error scope, error retryable attribute, and others. With the implementation of https://github.com/facebook/rocksdb/issues/5761, we have the new Wrapper for IO, which returns IOStatus instead of Status. However, the IOStatus is purged at the lower level of write path and transferred to Status.

The first job of this PR is to pass the IOStatus to the write path (flush, WAL write, and Compaction). The second job is to identify the Retryable IO Error as HardError, and set the bg_error_ as HardError. In this case, the DB Instance becomes read only. User is informed of the Status and need to take actions to deal with it (e.g., call db->Resume()).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6487

Test Plan: Added the testing case to error_handler_fs_test. Pass make asan_check

Reviewed By: anand1976

Differential Revision: D20685017

Pulled By: zhichao-cao

fbshipit-source-id: ff85f042896243abcd6ef37877834e26f36b6eb0
2020-03-27 16:04:43 -07:00
Levi Tamasi
6301dbe7a7 Use function objects as deleters in the block cache (#6545)
Summary:
As the first step of reintroducing eviction statistics for the block
cache, the patch switches from using simple function pointers as deleters
to function objects implementing an interface. This will enable using
deleters that have state, like a smart pointer to the statistics object
that is to be updated when an entry is removed from the cache. For now,
the patch adds a deleter template class `SimpleDeleter`, which simply
casts the `value` pointer to its original type and calls `delete` or
`delete[]` on it as appropriate. Note: to prevent object lifecycle
issues, deleters must outlive the cache entries referring to them;
`SimpleDeleter` ensures this by using the ("leaky") Meyers singleton
pattern.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6545

Test Plan: `make asan_check`

Reviewed By: siying

Differential Revision: D20475823

Pulled By: ltamasi

fbshipit-source-id: fe354c33dd96d9bafc094605462352305449a22a
2020-03-26 16:19:58 -07:00
Mike Kolupaev
963af52f15 Fix iterator reading filter block despite read_tier == kBlockCacheTier (#6562)
Summary:
We're seeing iterators with `ReadOptions::read_tier == kBlockCacheTier` sometimes doing file reads. Stack trace:

```
rocksdb::RandomAccessFileReader::Read(unsigned long, unsigned long, rocksdb::Slice*, char*, bool) const
rocksdb::BlockFetcher::ReadBlockContents()
rocksdb::Status rocksdb::BlockBasedTable::MaybeReadBlockAndLoadToCache<rocksdb::ParsedFullFilterBlock>(rocksdb::FilePrefetchBuffer*, rocksdb::ReadOptions const&, rocksdb::BlockHandle const&, rocksdb::UncompressionDict const&, rocksdb::CachableEntry<rocksdb::ParsedFullFilterBlock>*, rocksdb::BlockType, rocksdb::GetContext*, rocksdb::BlockCacheLookupContext*, rocksdb::BlockContents*) const
rocksdb::Status rocksdb::BlockBasedTable::RetrieveBlock<rocksdb::ParsedFullFilterBlock>(rocksdb::FilePrefetchBuffer*, rocksdb::ReadOptions const&, rocksdb::BlockHandle const&, rocksdb::UncompressionDict const&, rocksdb::CachableEntry<rocksdb::ParsedFullFilterBlock>*, rocksdb::BlockType, rocksdb::GetContext*, rocksdb::BlockCacheLookupContext*, bool, bool) const
rocksdb::FilterBlockReaderCommon<rocksdb::ParsedFullFilterBlock>::ReadFilterBlock(rocksdb::BlockBasedTable const*, rocksdb::FilePrefetchBuffer*, rocksdb::ReadOptions const&, bool, rocksdb::GetContext*, rocksdb::BlockCacheLookupContext*, rocksdb::CachableEntry<rocksdb::ParsedFullFilterBlock>*)
rocksdb::FilterBlockReaderCommon<rocksdb::ParsedFullFilterBlock>::GetOrReadFilterBlock(bool, rocksdb::GetContext*, rocksdb::BlockCacheLookupContext*, rocksdb::CachableEntry<rocksdb::ParsedFullFilterBlock>*) const
rocksdb::FullFilterBlockReader::MayMatch(rocksdb::Slice const&, bool, rocksdb::GetContext*, rocksdb::BlockCacheLookupContext*) const
rocksdb::FullFilterBlockReader::RangeMayExist(rocksdb::Slice const*, rocksdb::Slice const&, rocksdb::SliceTransform const*, rocksdb::Comparator const*, rocksdb::Slice const*, bool*, bool, rocksdb::BlockCacheLookupContext*)
rocksdb::BlockBasedTable::PrefixMayMatch(rocksdb::Slice const&, rocksdb::ReadOptions const&, rocksdb::SliceTransform const*, bool, rocksdb::BlockCacheLookupContext*) const
rocksdb::BlockBasedTableIterator<rocksdb::DataBlockIter, rocksdb::Slice>::SeekImpl(rocksdb::Slice const*)
rocksdb::ForwardIterator::SeekInternal(rocksdb::Slice const&, bool)
rocksdb::DBIter::Seek(rocksdb::Slice const&)
```

`BlockBasedTableIterator::CheckPrefixMayMatch` was missing a check for `kBlockCacheTier`. This PR adds it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6562

Test Plan: deployed it to a logdevice test cluster and looked at logdevice's IO tracing.

Reviewed By: siying

Differential Revision: D20529368

Pulled By: al13n321

fbshipit-source-id: 65bf33964b1951464415c900336635fb20919611
2020-03-26 15:21:26 -07:00
Cheng Chang
4fc216649d Support direct IO in RandomAccessFileReader::MultiRead (#6446)
Summary:
By supporting direct IO in RandomAccessFileReader::MultiRead, the benefits of parallel IO (IO uring) and direct IO can be combined.

In direct IO mode, read requests are aligned and merged together before being issued to RandomAccessFile::MultiRead, so blocks in the original requests might share the same underlying buffer, the shared buffers are returned in `aligned_bufs`, which is a new parameter of the `MultiRead` API.

For example, suppose alignment requirement for direct IO is 4KB, one request is (offset: 1KB, len: 1KB), another request is (offset: 3KB, len: 1KB), then since they all belong to page (offset: 0, len: 4KB), `MultiRead` only reads the page with direct IO into a buffer on heap, and returns 2 Slices referencing regions in that same buffer. See `random_access_file_reader_test.cc` for more examples.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6446

Test Plan: Added a new test `random_access_file_reader_test.cc`.

Reviewed By: anand1976

Differential Revision: D20097518

Pulled By: cheng-chang

fbshipit-source-id: ca48a8faf9c3af146465c102ef6b266a363e78d1
2020-03-20 16:33:26 -07:00
sdong
712bc4b6a2 Fix regression bug in partitioned index reseek caused by #6531 (#6551)
Summary:
https://github.com/facebook/rocksdb/pull/6531 removed some code in partitioned index seek logic. By mistake the logic of storing previous index offset is removed, while the logic of using it is preserved, so that the code might use wrong value to determine reseeking condition.
This will trigger a bug, if following a Seek() not going to the last block, SeekToLast() is called, and then Seek() is called which should position the cursor to the block before SeekToLast().
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6551

Test Plan: Add a unit test that reproduces the bug. In the same unit test, also some reseek cases are covered to avoid regression.

Reviewed By: pdillinger

Differential Revision: D20493990

fbshipit-source-id: 3919aa4861c0481ec96844e053048da1a934b91d
2020-03-17 12:33:10 -07:00
Yanqin Jin
098dce2d1a Fix compiler warning treated as error (#6547)
Summary:
Define a private member variable only in debug mode. Without fix, build will fail
```
In file included from table/block_based/partitioned_index_iterator.cc:9:
./table/block_based/partitioned_index_iterator.h:125:32: error: private field 'icomp_' is not used [-Werror,-Wunused-private-field]
  const InternalKeyComparator& icomp_;
```

Test plan (dev server)
1. make check
2. Make sure fixed in Travis
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6547

Reviewed By: siying

Differential Revision: D20480027

Pulled By: pdillinger

fbshipit-source-id: 288bc94280e240c3136335b6c73eb1ccb0db459d
2020-03-17 09:59:28 -07:00
sdong
d66908091d De-template block based table iterator (#6531)
Summary:
Right now block based table iterator is used as both of iterating data for block based table, and for the index iterator for partitioend index. This was initially convenient for introducing a new iterator and block type for new index format, while reducing code change. However, these two usage doesn't go with each other very well. For example, Prev() is never called for partitioned index iterator, and some other complexity is maintained in block based iterators, which is not needed for index iterator but maintainers will always need to reason about it. Furthermore, the template usage is not following Google C++ Style which we are following, and makes a large chunk of code tangled together. This commit separate the two iterators. Right now, here is what it is done:
1. Copy the block based iterator code into partitioned index iterator, and de-template them.
2. Remove some code not needed for partitioned index. The upper bound check and tricks are removed. We never tested performance for those tricks when partitioned index is enabled in the first place. It's unlikelyl to generate performance regression, as creating new partitioned index block is much rarer than data blocks.
3. Separate out the prefetch logic to a helper class and both classes call them.

This commit will enable future follow-ups. One direction is that we might separate index iterator interface for data blocks and index blocks, as they are quite different.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6531

Test Plan: build using make and cmake. And build release

Differential Revision: D20473108

fbshipit-source-id: e48011783b339a4257c204cc07507b171b834b0f
2020-03-16 12:20:50 -07:00
sdong
674cf41732 Divide block_based_table_reader.cc (#6527)
Summary:
block_based_table_reader.cc is a giant file, which makes it hard for users to navigate the code. Divide the files to multiple files.
Some class templates cannot be moved to .cc file. They are moved to .h files. It is still better than including them all in block_based_table_reader.cc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6527

Test Plan: "make all check" and "make release". Also build using cmake.

Differential Revision: D20428455

fbshipit-source-id: ca713c698469f07f35bc0c271358c0874ed4eb28
2020-03-12 21:41:50 -07:00
Yanqin Jin
d93812c9ae Iterator with timestamp (#6255)
Summary:
Preliminary support for iterator with user timestamp. Current implementation does not consider merge operator and reverse iterator. Auto compaction is also disabled in unit tests.

Create an iterator with timestamp.
```
...
read_opts.timestamp = &ts;
auto* iter = db->NewIterator(read_opts);
// target is key without timestamp.
for (iter->Seek(target); iter->Valid(); iter->Next()) {}
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {}
delete iter;
read_opts.timestamp = &ts1;
// lower_bound and upper_bound are without timestamp.
read_opts.iterate_lower_bound = &lower_bound;
read_opts.iterate_upper_bound = &upper_bound;
auto* iter1 = db->NewIterator(read_opts);
// Do Seek or SeekToFirst()
delete iter1;
```

Test plan (dev server)
```
$make check
```

Simple benchmarking (dev server)
1. The overhead introduced by this PR even when timestamp is disabled.
key size: 16 bytes
value size: 100 bytes
Entries: 1000000
Data reside in main memory, and try to stress iterator.
Repeated three times on master and this PR.
- Seek without next
```
./db_bench -db=/dev/shm/rocksdbtest-1000 -benchmarks=fillseq,seekrandom -enable_pipelined_write=false -disable_wal=true -format_version=3
```
master: 159047.0 ops/sec
this PR: 158922.3 ops/sec (2% drop in throughput)
- Seek and next 10 times
```
./db_bench -db=/dev/shm/rocksdbtest-1000 -benchmarks=fillseq,seekrandom -enable_pipelined_write=false -disable_wal=true -format_version=3 -seek_nexts=10
```
master: 109539.3 ops/sec
this PR: 107519.7 ops/sec (2% drop in throughput)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6255

Differential Revision: D19438227

Pulled By: riversand963

fbshipit-source-id: b66b4979486f8474619f4aa6bdd88598870b0746
2020-03-06 16:24:27 -08:00
Michael R. Crusoe
051696bf98 fix some spelling typos (#6464)
Summary:
Found from Debian's "Lintian" program
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6464

Differential Revision: D20162862

Pulled By: zhichao-cao

fbshipit-source-id: 06941ee2437b038b2b8045becbe9d2c6fbff3e12
2020-02-28 14:14:03 -08:00
Andrew Kryczka
69679e7375 Fix range deletion tombstone ingestion with global seqno (#6429)
Summary:
Original author: jeffrey-xiao

If we are writing a global seqno for an ingested file, the range
tombstone metablock gets accessed and put into the cache during
ingestion preparation. At the time, the global seqno of the ingested
file has not yet been determined, so the cached block will not have a
global seqno. When the file is ingested and we read its range tombstone
metablock, it will be returned from the cache with no global seqno. In
that case, we use the actual seqnos stored in the range tombstones,
which are all zero, so the tombstones cover nothing.

This commit removes global_seqno_ variable from Block. When iterating
over a block, the global seqno for the block is determined by the
iterator instead of storing this mutable attribute in Block.
Additionally, this commit adds a regression test to check that keys are
deleted when ingesting a file with a global seqno and range deletion
tombstones.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6429

Differential Revision: D19961563

Pulled By: ajkr

fbshipit-source-id: 5cf777397fa3e452401f0bf0364b0750492487b7
2020-02-25 15:31:48 -08:00
Yanqin Jin
890d87fadc Some minor fix-ups (#6440)
Summary:
Cleanup some code without any real change in functionality.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6440

Differential Revision: D20015891

Pulled By: riversand963

fbshipit-source-id: 33e18754b0f002006a6d4805e9aaf84c0c8ad25a
2020-02-21 15:09:56 -08:00
sdong
fdf882ded2 Replace namespace name "rocksdb" with ROCKSDB_NAMESPACE (#6433)
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433

Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.

Differential Revision: D19977691

fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
2020-02-20 12:09:57 -08:00
anand76
3e49249d30 Ensure all MultiGet IO errors are propagated to user (#6403)
Summary:
Unrevert the previous fix to propagate error status, and an additional fix to not treat a memtable lookup MergeInProgress status as an error.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6403

Test Plan:
Unit tests
Tried running stress tests but couldn't repro the stress failure

Differential Revision: D19846721

Pulled By: anand1976

fbshipit-source-id: 7db10cccbdc863d9b559497f0a46b608d2488ca4
2020-02-11 17:27:22 -08:00
anand76
35ed530d2c Revert "Check KeyContext status in MultiGet (#6387)" (#6401)
Summary:
This reverts commit d70011bccc. The commit is causing some stress test failure due to unexpected Status::MergeInProgress() return for some keys.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6401

Differential Revision: D19826623

Pulled By: anand1976

fbshipit-source-id: edd634cede9cb7bdd2cb8f46e662ea709b16d2f1
2020-02-10 22:23:36 -08:00
Zhichao Cao
4369f2c7bb Checksum for each SST file and stores in MANIFEST (#6216)
Summary:
In the current code base, RocksDB generate the checksum for each block and verify the checksum at usage. Current PR enable SST file checksum. After a SST file is generated by Flush or Compaction, RocksDB generate the SST file checksum and store the checksum value and checksum method name in the vs_info and MANIFEST as part for the FileMetadata.

Added the enable_sst_file_checksum to Options to enable or disable file checksum. Added sst_file_checksum to Options such that user can plugin their own SST file checksum calculate method via overriding the SstFileChecksum class. The checksum information inlcuding uint32_t checksum value and a checksum name (string).  A new tool is added to LDB such that user can dump out a list of file checksum information from MANIFEST. If user enables the file checksum but does not provide the sst_file_checksum instance, RocksDB will use the default crc32checksum implemented in table/sst_file_checksum_crc32c.h
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6216

Test Plan: Added the testing case in table_test and ldb_cmd_test to verify checksum is correct in different level. Pass make asan_check.

Differential Revision: D19171461

Pulled By: zhichao-cao

fbshipit-source-id: b2e53479eefc5bb0437189eaa1941670e5ba8b87
2020-02-10 15:52:52 -08:00
anand76
d70011bccc Check KeyContext status in MultiGet (#6387)
Summary:
Currently, any IO errors and checksum mismatches while reading data
blocks, are being ignored by the batched MultiGet. Its only looking at
the GetContext state. Fix that.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6387

Test Plan: Add unit tests

Differential Revision: D19799819

Pulled By: anand1976

fbshipit-source-id: 46133dccbb04e64067b9fe6cda73e282203db969
2020-02-07 16:48:16 -08:00
sdong
8f2bee6747 Add ReadOptions.auto_prefix_mode (#6314)
Summary:
Add a new option ReadOptions.auto_prefix_mode. When set to true, iterator should return the same result as total order seek, but may choose to do prefix seek internally, based on iterator upper bounds. Also fix two previous bugs when handling prefix extrator changes: (1) reverse iterator should not rely on upper bound to determine prefix. Fix it with skipping prefix check. (2) block-based filter is not handled properly.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6314

Test Plan: (1) add a unit test; (2) add the check to stress test and run see whether it can pass at least one run.

Differential Revision: D19458717

fbshipit-source-id: 51c1bcc5cdd826c2469af201979a39600e779bce
2020-01-28 14:44:05 -08:00
sdong
f10f135938 Fix regression bug of hash index with iterator total order seek (#6328)
Summary:
https://github.com/facebook/rocksdb/pull/6028 introduces a bug for hash index in SST files. If a table reader is created when total order seek is used, prefix_extractor might be passed into table reader as null. While later when prefix seek is used, the same table reader used, hash index is checked but prefix extractor is null and the program would crash.
Fix the issue by fixing http://github.com/facebook/rocksdb/pull/6028 in the way that prefix_extractor is preserved but ReadOptions.total_order_seek is checked

Also, a null pointer check is added so that a bug like this won't cause segfault in the future.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6328

Test Plan: Add a unit test that would fail without the fix. Stress test that reproduces the crash would pass.

Differential Revision: D19586751

fbshipit-source-id: 8de77690167ddf5a77a01e167cf89430b1bfba42
2020-01-27 15:44:54 -08:00
Peter Dillinger
986df37135 Clean up PartitionedFilterBlockBuilder (#6299)
Summary:
Remove the redundant PartitionedFilterBlockBuilder::num_added_ and ::NumAdded since the parent class, FullFilterBlockBuilder, already provides them.
Also rename filters_in_partition_ and filters_per_partition_ to keys_added_to_partition_ and keys_per_partition_ to improve readability.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6299

Test Plan: make check

Differential Revision: D19413278

Pulled By: pdillinger

fbshipit-source-id: 04926ee7874477d659cb2b6ae03f2d995fb747e5
2020-01-27 13:15:14 -08:00
Peter Dillinger
8aa99fc71e Warn on excessive keys for legacy Bloom filter with 32-bit hash (#6317)
Summary:
With many millions of keys, the old Bloom filter implementation
for the block-based table (format_version <= 4) would have excessive FP
rate due to the limitations of feeding the Bloom filter with a 32-bit hash.
This change computes an estimated inflated FP rate due to this effect
and warns in the log whenever an SST filter is constructed (almost
certainly a "full" not "partitioned" filter) that exceeds 1.5x FP rate
due to this effect. The detailed condition is only checked if 3 million
keys or more have been added to a filter, as this should be a lower
bound for common bits/key settings (< 20).

Recommended remedies include smaller SST file size, using
format_version >= 5 (for new Bloom filter), or using partitioned
filters.

This does not change behavior other than generating warnings for some
constructed filters using the old implementation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6317

Test Plan:
Example with warning, 15M keys @ 15 bits / key: (working_mem_size_mb is just to stop after building one filter if it's large)

    $ ./filter_bench -quick -impl=0 -working_mem_size_mb=1 -bits_per_key=15 -average_keys_per_filter=15000000 2>&1 | grep 'FP rate'
    [WARN] [/block_based/filter_policy.cc:292] Using legacy SST/BBT Bloom filter with excessive key count (15.0M @ 15bpk), causing estimated 1.8x higher filter FP rate. Consider using new Bloom with format_version>=5, smaller SST file size, or partitioned filters.
    Predicted FP rate %: 0.766702
    Average FP rate %: 0.66846

Example without warning (150K keys):

    $ ./filter_bench -quick -impl=0 -working_mem_size_mb=1 -bits_per_key=15 -average_keys_per_filter=150000 2>&1 | grep 'FP rate'
    Predicted FP rate %: 0.422857
    Average FP rate %: 0.379301
    $

With more samples at 15 bits/key:
  150K keys -> no warning; actual: 0.379% FP rate (baseline)
  1M keys -> no warning; actual: 0.396% FP rate, 1.045x
  9M keys -> no warning; actual: 0.563% FP rate, 1.485x
  10M keys -> warning (1.5x); actual: 0.564% FP rate, 1.488x
  15M keys -> warning (1.8x); actual: 0.668% FP rate, 1.76x
  25M keys -> warning (2.4x); actual: 0.880% FP rate, 2.32x

At 10 bits/key:
  150K keys -> no warning; actual: 1.17% FP rate (baseline)
  1M keys -> no warning; actual: 1.16% FP rate
  10M keys -> no warning; actual: 1.32% FP rate, 1.13x
  25M keys -> no warning; actual: 1.63% FP rate, 1.39x
  35M keys -> warning (1.6x); actual: 1.81% FP rate, 1.55x

At 5 bits/key:
  150K keys -> no warning; actual: 9.32% FP rate (baseline)
  25M keys -> no warning; actual: 9.62% FP rate, 1.03x
  200M keys -> no warning; actual: 12.2% FP rate, 1.31x
  250M keys -> warning (1.5x); actual: 12.8% FP rate, 1.37x
  300M keys -> warning (1.6x); actual: 13.4% FP rate, 1.43x

The reason for the modest inaccuracy at low bits/key is that the assumption of independence between a collision between 32-hash values feeding the filter and an FP in the filter is not quite true for implementations using "simple" logic to compute indices from the stock hash result. There's math on this in my dissertation, but I don't think it's worth the effort just for these extreme cases (> 100 million keys and low-ish bits/key).

Differential Revision: D19471715

Pulled By: pdillinger

fbshipit-source-id: f80c96893a09bf1152630ff0b964e5cdd7e35c68
2020-01-20 21:31:47 -08:00
Peter Dillinger
4b86fe1123 Log warning for high bits/key in legacy Bloom filter (#6312)
Summary:
Help users that would benefit most from new Bloom filter
implementation by logging a warning that recommends the using
format_version >= 5.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6312

Test Plan:
$ (for BPK in 10 13 14 19 20 50; do ./filter_bench -quick -impl=0 -bits_per_key=$BPK -m_queries=1 2>&1; done) | grep 'its/key'
    Bits/key actual: 10.0647
    Bits/key actual: 13.0593
    [WARN] [/block_based/filter_policy.cc:546] Using legacy Bloom filter with high (14) bits/key. Significant filter space and/or accuracy improvement is available with format_verion>=5.
    Bits/key actual: 14.0581
    [WARN] [/block_based/filter_policy.cc:546] Using legacy Bloom filter with high (19) bits/key. Significant filter space and/or accuracy improvement is available with format_verion>=5.
    Bits/key actual: 19.0542
    [WARN] [/block_based/filter_policy.cc:546] Using legacy Bloom filter with high (20) bits/key. Dramatic filter space and/or accuracy improvement is available with format_verion>=5.
    Bits/key actual: 20.0584
    [WARN] [/block_based/filter_policy.cc:546] Using legacy Bloom filter with high (50) bits/key. Dramatic filter space and/or accuracy improvement is available with format_verion>=5.
    Bits/key actual: 50.0577

Differential Revision: D19457191

Pulled By: pdillinger

fbshipit-source-id: 073d94cde5c70e03a160f953e1100c15ea83eda4
2020-01-17 19:37:35 -08:00
sdong
d87cffaea4 Fix another bug caused by recent hash index fix (#6305)
Summary:
Recent bug fix related to hash index introduced a new bug: hash index can return NotFound but it is not handled by BlockBasedTable::Get(). The end result is that Get() stops being executed too early. Fix it by ignoring NotFound code in Get().
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6305

Test Plan: A problematic DB used to return NotFound incorrectly, and now able to return correct result. Will try to construct a unit test too.0

Differential Revision: D19438925

fbshipit-source-id: e751afa8c13728d56511cfeb1bc811ecb99f3217
2020-01-17 01:41:04 -08:00
sdong
f8b5ef85ec Fix a bug caused by recent fix of Prefix Hash (#6302)
Summary:
Recent fix to Prefix Hash https://github.com/facebook/rocksdb/pull/6292 caused a bug that the newly created NotFound status in hash index is never reset. This causes reseek or implict reseek to return wrong results sometimes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6302

Test Plan:
Add a unit test that would fail. Not fix.
crash test with hash test would fail in several seconds. With the fix, it will run about several minutes before failing with another failure.

Differential Revision: D19424572

fbshipit-source-id: c5276f36a95fd0e2837e30190476d2fe21ed8566
2020-01-16 10:47:20 -08:00
sdong
d2b4d42d4b Fix kHashSearch bug with SeekForPrev (#6297)
Summary:
When prefix is enabled the expected behavior when the prefix of the target does not exist is for Seek is to seek to any key larger than target and SeekToPrev to any key less than the target.
Currently. the prefix index (kHashSearch) returns OK status but sets Invalid() to indicate two cases: a prefix of the searched key does not exist, ii) the key is beyond the range of the keys in SST file. The SeekForPrev implementation in BlockBasedTable thus does not have enough information to know when it should set the index key to first (to return a key smaller than target). The patch fixes that by returning NotFound status for cases that the prefix does not exist. SeekForPrev in BlockBasedTable accordingly SeekToFirst instead of SeekToLast on the index iterator.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6297

Test Plan: SeekForPrev of non-exsiting prefix is added to block_test.cc, and a test case is added in db_test2, which fails without the fix.

Differential Revision: D19404695

fbshipit-source-id: cafbbf95f8f60ff9ede9ccc99d25bfa1cf6fcdc3
2020-01-15 14:28:39 -08:00
Maysam Yabandeh
d4b7fbf0d5 kHashSearch incompatible with index_block_restart_interval>1 (#6294)
Summary:
kHashSearch index type is incompatible with index_block_restart_interval larger than 1. The patch asserts that and also resets index_block_restart_interval value if it is incompatible with kHashSearch.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6294

Differential Revision: D19394229

Pulled By: maysamyabandeh

fbshipit-source-id: 8a12712ab25e81094a7f71ecd43f773dd4fb6acd
2020-01-14 11:21:27 -08:00
sdong
f295b099f6 BlockBasedTable::ApproximateSize() should use total order seek (#6222)
Summary:
Right now BlockBasedTable::ApproximateSize() uses default setting about whether to use total order seek. There is no reason for that. There is no reason to do any filtering for approximate size boundary key, and it may introduce bugs. Disable it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6222

Test Plan: Run existing tests

Differential Revision: D19184787

fbshipit-source-id: 64180660bd2800914fff75104172b61c06f0b1c9
2019-12-19 14:56:38 -08:00
Maysam Yabandeh
77d5ba7887 Revert "Add kHashSearch to stress tests (#6210)" (#6220)
Summary:
This reverts commit 54f9092b0c.
It making our daily stress tests fail. Revert it until the issues are fixed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6220

Differential Revision: D19179881

Pulled By: maysamyabandeh

fbshipit-source-id: 99de0eaf776567fa81110b9ad2608234a16083ce
2019-12-19 10:46:55 -08:00
Maysam Yabandeh
54f9092b0c Add kHashSearch to stress tests (#6210)
Summary:
Beside extending index_type to kHashSearch, it clarifies in the code base that this feature is incompatible with index_block_restart_interval > 1.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6210

Test Plan:
```
make -j32 crash_test

Differential Revision: D19166567

Pulled By: maysamyabandeh

fbshipit-source-id: 3aaf75a70a8b462d372d43aac69dbd10df303ec7
2019-12-18 18:09:30 -08:00
sdong
02193ce406 Prevent file prefetch when mmap is enabled. (#6206)
Summary:
Right now, sometimes file prefetching is still on when mmap is enabled. This causes bug of reading wrong data. In this commit, we remove all those possible paths.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6206

Test Plan: make crash_test with compaction_readahead_size, which used to fail. RUn all existing tests.

Differential Revision: D19149429

fbshipit-source-id: 9e18ea8c566e416aac9647bdd05afe596634791b
2019-12-18 11:01:29 -08:00
Zhichao Cao
c399704c7a Fix: remove the potential dead store variable in block_based_table_reader.cc (#6204)
Summary:
buf_offset does not need to get the value from req.len for othe final block. It can cause test fail for clan_analyze. Remove it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6204

Test Plan: pass make asan_check

Differential Revision: D19145335

Pulled By: zhichao-cao

fbshipit-source-id: 8f6e74565746381b5c5ef598b97d746517b36e5b
2019-12-18 01:23:07 -08:00
Zhichao Cao
cddd637997 Merge adjacent file block reads in RocksDB MultiGet() and Add uncompressed block to cache (#6089)
Summary:
In the current MultiGet, if the KV-pairs do not belong to the data blocks in the block cache, multiple blocks are read from a SST. It will trigger one block read for each block request and read them in parallel. In some cases, if some data blocks are adjacent in the SST, the reads for these blocks can be combined to a single large read, which can reduce the system calls and reduce the read latency if possible.

Considering to fill the block cache, if multiple data blocks are in the same memory buffer, we need to copy them to the heap separately. Therefore, only in the case that 1) data block compression is enabled, and 2) compressed block cache is null, we can do combined read. Otherwise, extra memory copy is needed, which may cause extra overhead. In the current case, data blocks will be uncompressed to a new memory space.

Also, in the case that 1) data block compression is enabled, and 2) compressed block cache is null, it is possible the data block is actually not compressed. In the current logic, these data blocks will not be added to the uncompressed_cache. So if memory buffer is shared and the data block is not compressed, the data block are copied to the head and fill the cache.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6089

Test Plan: Added test case to ParallelIO.MultiGet. Pass make asan_check

Differential Revision: D18734668

Pulled By: zhichao-cao

fbshipit-source-id: 67c5615ed373e51e42635fd74b36f8f3a66d5da4
2019-12-16 16:26:03 -08:00
Peter Dillinger
a92bd0a183 Optimize memory and CPU for building new Bloom filter (#6175)
Summary:
The filter bits builder collects all the hashes to add in memory before adding them (because the number of keys is not known until we've walked over all the keys). Existing code uses a std::vector for this, which can mean up to 2x than necessary space allocated (and not freed) and up to ~2x write amplification in memory. Using std::deque uses close to minimal space (for large filters, the only time it matters), no write amplification, frees memory while building, and no need for large contiguous memory area. The only cost is more calls to allocator, which does not appear to matter, at least in benchmark test.

For now, this change only applies to the new (format_version=5) Bloom filter implementation, to ease before-and-after comparison downstream.

Temporary memory use during build is about the only way the new Bloom filter could regress vs. the old (because of upgrade to 64-bit hash) and that should only matter for full filters. This change should largely mitigate that potential regression.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6175

Test Plan:
Using filter_bench with -new_builder option and 6M keys per filter is like large full filter (improvement). 10k keys and no -new_builder is like partitioned filters (about the same). (Corresponding configurations run simultaneously on devserver.)

std::vector impl (before)

    $ /usr/bin/time -v ./filter_bench -impl=2 -quick -new_builder -working_mem_size_mb=1000 -
    average_keys_per_filter=6000000
    Build avg ns/key: 52.2027
    Maximum resident set size (kbytes): 1105016
    $ /usr/bin/time -v ./filter_bench -impl=2 -quick -working_mem_size_mb=1000 -
    average_keys_per_filter=10000
    Build avg ns/key: 30.5694
    Maximum resident set size (kbytes): 1208152

std::deque impl (after)

    $ /usr/bin/time -v ./filter_bench -impl=2 -quick -new_builder -working_mem_size_mb=1000 -
    average_keys_per_filter=6000000
    Build avg ns/key: 39.0697
    Maximum resident set size (kbytes): 1087196
    $ /usr/bin/time -v ./filter_bench -impl=2 -quick -working_mem_size_mb=1000 -
    average_keys_per_filter=10000
    Build avg ns/key: 30.9348
    Maximum resident set size (kbytes): 1207980

Differential Revision: D19053431

Pulled By: pdillinger

fbshipit-source-id: 2888e748723a19d9ea40403934f13cbb8483430c
2019-12-15 21:31:08 -08:00
anand76
afa2420c2b Introduce a new storage specific Env API (#5761)
Summary:
The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc.

This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO.

The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before.

This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection.

The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761

Differential Revision: D18868376

Pulled By: anand1976

fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
2019-12-13 14:48:41 -08:00
sdong
a68dff5c35 Apply formatter to some recent commits (#6138)
Summary:
Formatter somehow complains some recent lines changed. Apply them to make the formatter happy.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6138

Test Plan: See CI passes.

Differential Revision: D18895950

fbshipit-source-id: 7d1696cf3e3a682bc10a30cdca748a23c6565255
2019-12-09 15:49:49 -08:00
Peter Dillinger
e43d2c4424 Fix & test rocksdb_filterpolicy_create_bloom_full (#6132)
Summary:
Add overrides needed in FilterPolicy wrapper to fix
rocksdb_filterpolicy_create_bloom_full (see issue https://github.com/facebook/rocksdb/issues/6129). Re-enabled
assertion in BloomFilterPolicy::CreateFilter that was being violated.
Expanded c_test to identify Bloom filter implementations by FP counts.
(Without the fix, updated test will trigger assertion and fail otherwise
without the assertion.)

Fixes https://github.com/facebook/rocksdb/issues/6129
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6132

Test Plan: updated c_test, also run under valgrind.

Differential Revision: D18864911

Pulled By: pdillinger

fbshipit-source-id: 08e81d7b5368b08e501cd402ef5583f2650c19fa
2019-12-09 12:21:14 -08:00
Ziyue Yang
7e2f831924 Fix wrong ExtractUserKey usage in BlockBasedTableBuilder::EnterUnbuff… (#6100)
Summary:
BlockBasedTableBuilder uses ExtractUserKey in EnterUnbuffered. This would
cause index filter building error, since user-provided timestamp is supported
by ExtractUserKeyAndStripTimestamp, and it's used in Add. This commit changes
ExtractUserKey to ExtractUserKeyAndStripTimestamp.

A test case is also added by modifying DBBasicTestWithTimestampWithParam_
PutAndGet test in db_basic_test to cover ExtractUserKeyAndStripTimestamp usage
in both kBuffered and kUnbuffered state of BlockBasedTableBuilder.

Before the ExtractUserKeyAndStripTimstamp fix:

```
$ ./db_basic_test --gtest_filter="*PutAndGet*"
Note: Google Test filter = *PutAndGet*
[==========] Running 2 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 2 tests from Timestamp/DBBasicTestWithTimestampWithParam
[ RUN      ] Timestamp/DBBasicTestWithTimestampWithParam.PutAndGet/0
db/db_basic_test.cc:2109: Failure
db_->Get(ropts, cfh, "key" + std::to_string(j), &value)
NotFound:
db/db_basic_test.cc:2109: Failure
db_->Get(ropts, cfh, "key" + std::to_string(j), &value)
NotFound:
db/db_basic_test.cc:2109: Failure
db_->Get(ropts, cfh, "key" + std::to_string(j), &value)
NotFound:
db/db_basic_test.cc:2109: Failure
db_->Get(ropts, cfh, "key" + std::to_string(j), &value)
NotFound:
db/db_basic_test.cc:2109: Failure
db_->Get(ropts, cfh, "key" + std::to_string(j), &value)
NotFound:
[  FAILED  ] Timestamp/DBBasicTestWithTimestampWithParam.PutAndGet/0, where GetParam() = false (1177 ms)
[ RUN      ] Timestamp/DBBasicTestWithTimestampWithParam.PutAndGet/1
[       OK ] Timestamp/DBBasicTestWithTimestampWithParam.PutAndGet/1 (1056 ms)
[----------] 2 tests from Timestamp/DBBasicTestWithTimestampWithParam (2233 ms total)

[----------] Global test environment tear-down
[==========] 2 tests from 1 test case ran. (2233 ms total)
[  PASSED  ] 1 test.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] Timestamp/DBBasicTestWithTimestampWithParam.PutAndGet/0, where GetParam() = false

 1 FAILED TEST
```

After the ExtractUserKeyAndStripTimstamp fix:

```
$ ./db_basic_test --gtest_filter="*PutAndGet*"
Note: Google Test filter = *PutAndGet*
[==========] Running 2 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 2 tests from Timestamp/DBBasicTestWithTimestampWithParam
[ RUN      ] Timestamp/DBBasicTestWithTimestampWithParam.PutAndGet/0
[       OK ] Timestamp/DBBasicTestWithTimestampWithParam.PutAndGet/0 (1417 ms)
[ RUN      ] Timestamp/DBBasicTestWithTimestampWithParam.PutAndGet/1
[       OK ] Timestamp/DBBasicTestWithTimestampWithParam.PutAndGet/1 (1041 ms)
[----------] 2 tests from Timestamp/DBBasicTestWithTimestampWithParam (2458 ms total)

[----------] Global test environment tear-down
[==========] 2 tests from 1 test case ran. (2458 ms total)
[  PASSED  ] 2 tests.
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6100

Differential Revision: D18769654

Pulled By: riversand963

fbshipit-source-id: 76c2cf2c9a5e0d85db95d98e812e6af0c2a15c6b
2019-12-09 10:57:02 -08:00
Peter Dillinger
6db57bc37f Disable new Bloom filter assertion (#6128)
Summary:
A longstanding bug in our C interface can trigger this
assertion; see issue https://github.com/facebook/rocksdb/issues/6129. Disabling the assertion for now
(for 6.6.0) and will re-enable on fix of that bug.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6128

Differential Revision: D18854899

Pulled By: pdillinger

fbshipit-source-id: 9eb5294b9f11b208dc1a8cc148aaa31e47ff892b
2019-12-06 10:28:02 -08:00
Peter Dillinger
ca3b6c28c9 Expose and elaborate FilterBuildingContext (#6088)
Summary:
This change enables custom implementations of FilterPolicy to
wrap a variety of NewBloomFilterPolicy and select among them based on
contextual information such as table level and compaction style.

* Moves FilterBuildingContext to public API and elaborates it with more
useful data. (It would be nice to put more general options-like data,
but at the time this object is constructed, we are using internal APIs
ImmutableCFOptions and MutableCFOptions and don't have easy access to
ColumnFamilyOptions that I can tell.)

* Renames BloomFilterPolicy::GetFilterBitsBuilderInternal to
GetBuilderWithContext, because it's now public.

* Plumbs through the table's "level_at_creation" for filter building
context.

* Simplified some tests by adding GetBuilder() to
MockBlockBasedTableTester.

* Adds test as DBBloomFilterTest.ContextCustomFilterPolicy, including
sample wrapper class LevelAndStyleCustomFilterPolicy.

* Fixes a cross-test bug in DBBloomFilterTest.OptimizeFiltersForHits
where it does not reset perf context.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6088

Test Plan: make check, valgrind on db_bloom_filter_test

Differential Revision: D18697817

Pulled By: pdillinger

fbshipit-source-id: 5f987a2d7b07cc7a33670bc08ca6b4ca698c1cf4
2019-11-26 18:24:10 -08:00
Peter Dillinger
57f3032285 Allow fractional bits/key in BloomFilterPolicy (#6092)
Summary:
There's no technological impediment to allowing the Bloom
filter bits/key to be non-integer (fractional/decimal) values, and it
provides finer control over the memory vs. accuracy trade-off. This is
especially handy in using the format_version=5 Bloom filter in place
of the old one, because bits_per_key=9.55 provides the same accuracy as
the old bits_per_key=10.

This change not only requires refining the logic for choosing the best
num_probes for a given bits/key setting, it revealed a flaw in that logic.
As bits/key gets higher, the best num_probes for a cache-local Bloom
filter is closer to bpk / 2 than to bpk * 0.69, the best choice for a
standard Bloom filter. For example, at 16 bits per key, the best
num_probes is 9 (FP rate = 0.0843%) not 11 (FP rate = 0.0884%).
This change fixes and refines that logic (for the format_version=5
Bloom filter only, just in case) based on empirical tests to find
accuracy inflection points between each num_probes.

Although bits_per_key is now specified as a double, the new Bloom
filter converts/rounds this to "millibits / key" for predictable/precise
internal computations. Just in case of unforeseen compatibility
issues, we round to the nearest whole number bits / key for the
legacy Bloom filter, so as not to unlock new behaviors for it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6092

Test Plan: unit tests included

Differential Revision: D18711313

Pulled By: pdillinger

fbshipit-source-id: 1aa73295f152a995328cb846ef9157ae8a05522a
2019-11-26 15:59:34 -08:00
Peter Dillinger
f059c7d9b9 New Bloom filter implementation for full and partitioned filters (#6007)
Summary:
Adds an improved, replacement Bloom filter implementation (FastLocalBloom) for full and partitioned filters in the block-based table. This replacement is faster and more accurate, especially for high bits per key or millions of keys in a single filter.

Speed

The improved speed, at least on recent x86_64, comes from
* Using fastrange instead of modulo (%)
* Using our new hash function (XXH3 preview, added in a previous commit), which is much faster for large keys and only *slightly* slower on keys around 12 bytes if hashing the same size many thousands of times in a row.
* Optimizing the Bloom filter queries with AVX2 SIMD operations. (Added AVX2 to the USE_SSE=1 build.) Careful design was required to support (a) SIMD-optimized queries, (b) compatible non-SIMD code that's simple and efficient, (c) flexible choice of number of probes, and (d) essentially maximized accuracy for a cache-local Bloom filter. Probes are made eight at a time, so any number of probes up to 8 is the same speed, then up to 16, etc.
* Prefetching cache lines when building the filter. Although this optimization could be applied to the old structure as well, it seems to balance out the small added cost of accumulating 64 bit hashes for adding to the filter rather than 32 bit hashes.

Here's nominal speed data from filter_bench (200MB in filters, about 10k keys each, 10 bits filter data / key, 6 probes, avg key size 24 bytes, includes hashing time) on Skylake DE (relatively low clock speed):

$ ./filter_bench -quick -impl=2 -net_includes_hashing # New Bloom filter
Build avg ns/key: 47.7135
Mixed inside/outside queries...
  Single filter net ns/op: 26.2825
  Random filter net ns/op: 150.459
    Average FP rate %: 0.954651
$ ./filter_bench -quick -impl=0 -net_includes_hashing # Old Bloom filter
Build avg ns/key: 47.2245
Mixed inside/outside queries...
  Single filter net ns/op: 63.2978
  Random filter net ns/op: 188.038
    Average FP rate %: 1.13823

Similar build time but dramatically faster query times on hot data (63 ns to 26 ns), and somewhat faster on stale data (188 ns to 150 ns). Performance differences on batched and skewed query loads are between these extremes as expected.

The only other interesting thing about speed is "inside" (query key was added to filter) vs. "outside" (query key was not added to filter) query times. The non-SIMD implementations are substantially slower when most queries are "outside" vs. "inside". This goes against what one might expect or would have observed years ago, as "outside" queries only need about two probes on average, due to short-circuiting, while "inside" always have num_probes (say 6). The problem is probably the nastily unpredictable branch. The SIMD implementation has few branches (very predictable) and has pretty consistent running time regardless of query outcome.

Accuracy

The generally improved accuracy (re: Issue https://github.com/facebook/rocksdb/issues/5857) comes from a better design for probing indices
within a cache line (re: Issue https://github.com/facebook/rocksdb/issues/4120) and improved accuracy for millions of keys in a single filter from using a 64-bit hash function (XXH3p). Design details in code comments.

Accuracy data (generalizes, except old impl gets worse with millions of keys):
Memory bits per key: FP rate percent old impl -> FP rate percent new impl
6: 5.70953 -> 5.69888
8: 2.45766 -> 2.29709
10: 1.13977 -> 0.959254
12: 0.662498 -> 0.411593
16: 0.353023 -> 0.0873754
24: 0.261552 -> 0.0060971
50: 0.225453 -> ~0.00003 (less than 1 in a million queries are FP)

Fixes https://github.com/facebook/rocksdb/issues/5857
Fixes https://github.com/facebook/rocksdb/issues/4120

Unlike the old implementation, this implementation has a fixed cache line size (64 bytes). At 10 bits per key, the accuracy of this new implementation is very close to the old implementation with 128-byte cache line size. If there's sufficient demand, this implementation could be generalized.

Compatibility

Although old releases would see the new structure as corrupt filter data and read the table as if there's no filter, we've decided only to enable the new Bloom filter with new format_version=5. This provides a smooth path for automatic adoption over time, with an option for early opt-in.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6007

Test Plan: filter_bench has been used thoroughly to validate speed, accuracy, and correctness. Unit tests have been carefully updated to exercise new and old implementations, as well as the logic to select an implementation based on context (format_version).

Differential Revision: D18294749

Pulled By: pdillinger

fbshipit-source-id: d44c9db3696e4d0a17caaec47075b7755c262c5f
2019-11-13 16:44:01 -08:00
Peter Dillinger
42b5494ec8 Fix BloomFilterPolicy changes for unsigned char (ARM) (#6024)
Summary:
Bug in PR https://github.com/facebook/rocksdb/issues/5941 when char is unsigned that should only affect
assertion on unused/invalid filter metadata.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6024

Test Plan: on ARM: ./bloom_test && ./db_bloom_filter_test && ./block_based_filter_block_test && ./full_filter_block_test && ./partitioned_filter_block_test

Differential Revision: D18461206

Pulled By: pdillinger

fbshipit-source-id: 68a7c813a0b5791c05265edc03cdf52c78880e9a
2019-11-12 15:29:15 -08:00
anand76
03ce7fb292 Fix a buffer overrun problem in BlockBasedTable::MultiGet (#6014)
Summary:
The calculation in BlockBasedTable::MultiGet for the required buffer length for reading in compressed blocks is incorrect. It needs to take the 5-byte block trailer into account.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6014

Test Plan: Add a unit test DBBasicTest.MultiGetBufferOverrun that fails in asan_check before the fix, and passes after.

Differential Revision: D18412753

Pulled By: anand1976

fbshipit-source-id: 754dfb66be1d5f161a7efdf87be872198c7e3b72
2019-11-11 16:59:15 -08:00
anand76
9836a1fa33 Fix MultiGet crash when no_block_cache is set (#5991)
Summary:
This PR fixes https://github.com/facebook/rocksdb/issues/5975. In ```BlockBasedTable::RetrieveMultipleBlocks()```, we were calling ```MaybeReadBlocksAndLoadToCache()```, which is a no-op if neither uncompressed nor compressed block cache are configured.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5991

Test Plan:
1. Add unit tests that fail with the old code and pass with the new
2. make check and asan_check

Cc spetrunia

Differential Revision: D18272744

Pulled By: anand1976

fbshipit-source-id: e62fa6090d1a6adf84fcd51dfd6859b03c6aebfe
2019-11-07 12:02:21 -08:00
Yanqin Jin
67e735dbf9 Rename BlockBasedTable::ReadMetaBlock (#6009)
Summary:
According to
https://github.com/facebook/rocksdb/wiki/Rocksdb-BlockBasedTable-Format,
the block read by BlockBasedTable::ReadMetaBlock is actually the meta index
block. Therefore, it is better to rename the function to ReadMetaIndexBlock.

This PR also applies some format change to existing code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6009

Test Plan: make check

Differential Revision: D18333238

Pulled By: riversand963

fbshipit-source-id: 2c4340a29b3edba53d19c132cbfd04caf6242aed
2019-11-05 17:19:11 -08:00