Summary:
Add an option to filter out READ or WRITE operations while tracing.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5082

Differential Revision: D14515083

Pulled By: mrmiywj

fbshipit-source-id: 2504c89a9abf1dd629cad44b4104092702d77610

Summary:
Partly addresses https://github.com/facebook/rocksdb/issues/4999
I verified `make static_lib` runs fine.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5077

Differential Revision: D14521101

Pulled By: maysamyabandeh

fbshipit-source-id: ba88e74a51d2d793cac7260d505b1a54254b53af

Summary:
This is a feature to sample data-block compressibility and and report them as stats. 1 in N (tunable) blocks is sampled for compressibility using two algorithms:
1. lz4 or snappy for fast compression
2. zstd or zlib for slow but higher compression.

The stats are reported to the caller as raw-bytes and compressed-bytes. The block continues to be compressed for storage using the specified CompressionType.

The db_bench_tool how has a command line option for specifying the sampling rate. It's default value is 0 (no sampling). To test the overhead for a certain value, users can compare the performance of db_bench_tool, varying the sampling rate. It is unlikely to have a noticeable impact for high values like 20.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4842

Differential Revision: D13629011

Pulled By: shobhitdayal

fbshipit-source-id: 14ca668bcab6499b2a1734edf848eb62a4f4fafa

Summary:
There is a potential failure case in DBImpl::SwitchMemtable() that is not handled properly. The call to cur_log_writer->WriteBuffer() can fail due to an IO error. In that case, we need to call SetBGError() in order set the background error since the WriteBuffer() failure may result in data loss.

Also, the asserts for !new_mem and !new_log are incorrect, as those would have been allocated by the time this failure is detected.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5072

Differential Revision: D14461384

Pulled By: anand1976

fbshipit-source-id: fb59bce9d61378f37d2dfcd28c0b704b0f43c3cf

Summary:
This reverts commit ee181808.

We are not ready to deprecate this feature. revert it for now.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5034

Differential Revision: D14287246

Pulled By: siying

fbshipit-source-id: e4beafdeaee1c94364fdaa6ba198218d158339f7

Summary:
Right now, users can change statistics.stats_level while DB is running, but TSAN may report
data race. We make stats_level_ to be atomic, and access them using accessors.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5030

Differential Revision: D14267519

Pulled By: siying

fbshipit-source-id: 37d7ebeff7a43a406230143422a16af899163f73

Summary:
PreReleaseCallback meant to be called before the writes are visible to the readers. Since the sequence number is known after the WAL write, there is no reason to delay calling PreReleaseCallback to after the memtable write, which would complicates the reader's logic in presence of our memtable writes that are made visible by the other write thread.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5015

Differential Revision: D14221670

Pulled By: maysamyabandeh

fbshipit-source-id: a504dd665cf923226d7af09cc8e9c7739a25edc6

Summary:
Statistics cost too much CPU for some use cases. Add two stats levels
so that people can choose to skip two types of expensive stats, timers and
histograms.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5027

Differential Revision: D14252765

Pulled By: siying

fbshipit-source-id: 75ecec9eaa44c06118229df4f80c366115346592

Summary:
The read path includes a callback function, ReadCallback, which would eventually calls IsInSnapshot to figure if a particular seq is in the reading snapshot or not. This callback is virtual, which adds the cost of multiple virtual function call to each read. The first few checks in IsInSnapshot, however, are quite trivial and take care of majority of the cases. The patch moves those to a non-virtual function in the the parent class, ReadCallback, to lower the virtual callback cost.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5018

Differential Revision: D14226562

Pulled By: maysamyabandeh

fbshipit-source-id: 6feed5b34f3b082e52092c5ef143e29b49c46b44

Summary:
This PR adds public `GetStatsHistory` API to retrieve stats history in the form of an std map. The key of the map is the timestamp in microseconds when the stats snapshot is taken, the value is another std map from stats name to stats value (stored in std string). Two DBOptions are introduced: `stats_persist_period_sec` (default 10 minutes) controls the intervals between two snapshots are taken; `max_stats_history_count` (default 10) controls the max number of history snapshots to keep in memory. RocksDB will stop collecting stats snapshots if `stats_persist_period_sec` is set to 0.

(This PR is the in-memory part of https://github.com/facebook/rocksdb/pull/4535)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4748

Differential Revision: D13961471

Pulled By: miasantreble

fbshipit-source-id: ac836d401ecb84ea92216bf9966f969dedf4ad04

Summary:
DBTest2.PresetCompressionDict is flaky. Temparily disable it for now.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5003

Differential Revision: D14139505

Pulled By: siying

fbshipit-source-id: ebf1872d364b76b2cb021b489ea2f17ee997116a

Summary:
Use C++11’s override and remove virtual where applicable.
Change are automatically generated.

bypass-lint
drop-conflicts

Reviewed By: igorsugak

Differential Revision: D14131816

fbshipit-source-id: f20e7f7cecf2e699d70f5fa036f72c0e3f59b50e

Summary:
MyRocks calls `GetForUpdate` on `INSERT`, for unique key check, and in almost all cases GetForUpdate returns empty result. For such cases, whole key bloom filter is helpful.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4985

Differential Revision: D14118257

Pulled By: miasantreble

fbshipit-source-id: d35cb7109c62fd5ad541a26968e3a3e16d3e85ea

Summary:
The info log header feature never worked well, because log level Header was not
translated to Logger::LogHeader() call. Fix it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4980

Differential Revision: D14087283

Pulled By: siying

fbshipit-source-id: 7e7d03ce35fa8d13d4ee549f46f7326f7bc0006d

Summary:
Right now when a flush is triggered, the memory consumption is logged but data size is not.
It's useful to log both when we debug unexpected small flushed file size.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4979

Differential Revision: D14071979

Pulled By: siying

fbshipit-source-id: 0cd60449c5205eb00e0fbc299084418f609904ed

Summary:
We introduced ttl option in CompactionOptionsFIFO when ttl-based file
deletion (compaction) was supported only as part of FIFO Compaction. But
with the extension of ttl semantics even to Level compaction,
CompactionOptionsFIFO.ttl can now be deprecated. Instead we will start
using ColumnFamilyOptions.ttl for FIFO compaction as well.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4965

Differential Revision: D14072960

Pulled By: sagar0

fbshipit-source-id: c98cc2ae695a28136295787cd88d36a220fc219e

Summary:
Use C++11’s override and remove virtual where applicable.
Change are automatically generated.

Reviewed By: Orvid

Differential Revision: D14090024

fbshipit-source-id: 1e9432e87d2657e1ff0028e15370a85d1739ba2a

Summary:
If `CompressionOptions::max_dict_bytes` and/or `CompressionOptions::zstd_max_train_bytes` are set, `SstFileWriter` will now generate files respecting those options.

I refactored the logic a bit for deciding when to use dictionary compression. Previously we plumbed `is_bottommost_level` down to the table builder and used that. However it was kind of confusing in `SstFileWriter`'s context since we don't know what level the file will be ingested to. Instead, now the higher-level callers (e.g., flush, compaction, file writer) are responsible for building the right `CompressionOptions` to give the table builder.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4978

Differential Revision: D14060763

Pulled By: ajkr

fbshipit-source-id: dc802c327896df2b319dc162d6acc82b9cdb452a

Summary:
if an operation just involves a single column family, then we do
not have to set the kInAtomicGroup tag when writing to MANIFEST. This change
can fix a compatibility test failure, i.e. 5.15 and earlier cannot recognize
kInAtomicGroup tag.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4981

Differential Revision: D14072687

Pulled By: riversand963

fbshipit-source-id: 46b0c61e399f16c6b7169de0b33430d0ed90d6d4

Summary:
Make file ingestion atomic.

 as title.
Ingesting external SST files into multiple column families should be atomic. If
a crash occurs and db reopens, either all column families have successfully
ingested the files before the crash, or non of the ingestions have any effect
on the state of the db.

Also add unit tests for atomic ingestion.

Note that the unit test here does not cover the case of incomplete atomic group
in the MANIFEST, which is covered in VersionSetTest already.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4895

Differential Revision: D13718245

Pulled By: riversand963

fbshipit-source-id: 7df97cc483af73ad44dd6993008f99b083852198

Summary:
Previously, stats were logged in warning level. This was done in that way because
people reported that it wasn't logged in MyRocks. However, later we learned that it turns
out to be due to a bug in MyRocks, which is fixed in
https://github.com/facebook/mysql-5.6/commit/79bb705e74b239d7030b724ea6bbd635eceec531

Now we revert the stats logging to INFO level, so that it doesn't pollute the warning
level logging.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4977

Differential Revision: D14058485

Pulled By: siying

fbshipit-source-id: 19fab323c19d9bc88184287f209551f9a77ca0e6

Summary:
In `DBImpl::AtomicFlushMemTablesToOutputFiles`, we need to call fsync only once
on the same data directory. If two column families share a common directory for
their data, we call fsync only once.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4817

Differential Revision: D13543689

Pulled By: riversand963

fbshipit-source-id: 4701d77c96a47802fbf6cb9f3337ee65d46b95f5

Summary:
Our previous approach was to train one compression dictionary per compaction, using the first output SST to train a dictionary, and then applying it on subsequent SSTs in the same compaction. While this was great for minimizing CPU/memory/I/O overhead, it did not achieve good compression ratios in practice. In our most promising potential use case, moderate reductions in a dictionary's scope make a major difference on compression ratio.

So, this PR changes compression dictionary to be scoped per-SST. It accepts the tradeoff during table building to use more memory and CPU. Important changes include:

- The `BlockBasedTableBuilder` has a new state when dictionary compression is in-use: `kBuffered`. In that state it accumulates uncompressed data in-memory whenever `Add` is called.
- After accumulating target file size bytes or calling `BlockBasedTableBuilder::Finish`, a `BlockBasedTableBuilder` moves to the `kUnbuffered` state. The transition (`EnterUnbuffered()`) involves sampling the buffered data, training a dictionary, and compressing/writing out all buffered data. In the `kUnbuffered` state, a `BlockBasedTableBuilder` behaves the same as before -- blocks are compressed/written out as soon as they fill up.
- Samples are now whole uncompressed data blocks, except the final sample may be a partial data block so we don't breach the user's configured `max_dict_bytes` or `zstd_max_train_bytes`. The dictionary trainer is supposed to work better when we pass it real units of compression. Previously we were passing 64-byte KV samples which was not realistic.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4952

Differential Revision: D13967980

Pulled By: ajkr

fbshipit-source-id: 82bea6f7537e1529c7a1a4cdee84585f5949300f

Summary:
If IsInSnapshot(seq2, snapshot) determines that the snapshot is released, the future queries IsInSnapshot(seq1, snapshot) could still return a definitive answer of true if for example seq1 is too old that is determined visible in all snapshots. This violates a recently added assert statement to compaction iterator. The patch relaxes the assert.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4969

Differential Revision: D14030998

Pulled By: maysamyabandeh

fbshipit-source-id: 6db53db0e37d0a20e8997ef2c1004b8627614ab9

Summary:
Always enable properties block checksum verification for block-based table. For external SST file ingested with 'write_global_seqno==true', we use 'DecodeEntrySlow' to parse its blocks' contents so that the process will not die upon failing the assertion possibly caused by corruption.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4956

Differential Revision: D14012741

Pulled By: riversand963

fbshipit-source-id: 8b766e6f54b36f8f9e074c0e19e0926ec3cce186

Summary:
https://github.com/facebook/rocksdb/pull/4960 introduced ignorable manfiest
record. Adding a test to it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4964

Differential Revision: D14012667

Pulled By: siying

fbshipit-source-id: e5f10ecc68dec2716e178d44f0fe2b76c3d857ef

Summary:
Implement trace sampling to allow user to specify the sampling frequency, i.e. save one per how many requests, so that a user does not need to log all if he/she is interested in only a sampled set.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4963

Differential Revision: D14011190

Pulled By: tang-jianfeng

fbshipit-source-id: 078b631d9319b67cb089dd2c30e21d0df8dc406a

Summary:
We want to reserve some right that some extra information added manifest
in the future can be forward compatible by previous versions. Now we create a
place holder for that. A bit in tag is added to indicate that a field can be
safely ignored.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4960

Differential Revision: D14000484

Pulled By: siying

fbshipit-source-id: cbf5bad3f9d5ec798f789806f244d1c20d3b66d6

Summary:
We found that the behavior of CompactionFilter::IgnoreSnapshots() = false isn't
what we have expected. We thought that snapshot will always be preserved.
However, we just realized that, if no snapshot is created while compaction
starts, and a snapshot is created after that, the data seen from the snapshot
can successfully be dropped by the compaction. This creates a strange behavior
to the feature, which is hard to explain. Like what is documented in code
comment, this feature is not very useful with snapshot anyway. The decision
is to deprecate the feature.

We keep the function to avoid to break users code. However, we will fail
compactions if false is returned.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4954

Differential Revision: D13981900

Pulled By: siying

fbshipit-source-id: 2db8c2c3865acd86a28dca625945d1481b1d1e36

Summary:
Cuckoo Hash is less useful than we initially expected. Remove it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4953

Differential Revision: D13979264

Pulled By: siying

fbshipit-source-id: 2a60afdaa989f045357398b43a1cc5d46f4492ed

Summary:
This will fix the following build error:

> db/db_test.cc: In member function ‘virtual void rocksdb::DBTest_CompactFilesShouldTriggerAutoCompaction_Test::TestBody()’:
> db/db_test.cc:5462:8: error: ‘class rocksdb::DB’ has no member named ‘GetColumnFamilyMetaData’
>    db_->GetColumnFamilyMetaData(db_->DefaultColumnFamily(), &cf_meta_data);
> db/db_test.cc:5490:8: error: ‘class rocksdb::DB’ has no member named ‘GetColumnFamilyMetaData’
>    db_->GetColumnFamilyMetaData(db_->DefaultColumnFamily(), &cf_meta_data);
> db/db_test.cc:5499:8: error: ‘class rocksdb::DB’ has no member named ‘GetColumnFamilyMetaData’
>    db_->GetColumnFamilyMetaData(db_->DefaultColumnFamily(), &cf_meta_data);
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4950

Differential Revision: D13965378

Pulled By: miasantreble

fbshipit-source-id: a975435476fe555b1cd9d5da263ee3da3acdea56

Summary:
Existing implementation of PerfContext does not define copy constructor or assignment operator, which could potentially cause problems when user create copies and resets the builtin one. This PR address the issue by providing these two constructors with deep copy semantics.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4919

Differential Revision: D13960406

Pulled By: miasantreble

fbshipit-source-id: 36aab5aaee65d4480f537e4e22148faa45e8e334

Summary:
CompactFiles() may block auto compaction which could cuase DB hang when it
reachs level0_stop_writes_trigger.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4940

Differential Revision: D13929648

Pulled By: cooldoger

fbshipit-source-id: 10842df38df3bebf862cd1a120a88ce961fdd381

Summary:
In NotFound cases, stats BYTES_READ and perf_context.get_read_bytes is still be increased. The amount increased will be
whatever size of the string or PinnableSlice that users passed in as the output data structure. This is wrong. Fix this by not
increasing these two counters.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4938

Differential Revision: D13908963

Pulled By: siying

fbshipit-source-id: 60bce42e4fbb9862bba3da36dbc27b2963ea6162

Summary:
Fix the ouput overlap bug when using subcompactions, the upper bound of output
file was extended incorrectly.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4898

Differential Revision: D13736107

Pulled By: ajkr

fbshipit-source-id: 21dca09f81d5f07bf2766bf566f9b50dcab7d8e3

Summary:
The patch fixes the following analyze error by checking the return status of ParseInternalKey.
```
db/merge_helper.cc:306:23: warning: The right operand of '==' is a garbage value
    assert(kTypeMerge == orig_ikey.type);
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4937

Differential Revision: D13908506

Pulled By: maysamyabandeh

fbshipit-source-id: 68d7771e75519da3d4bd807fd231675ec12093f6

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/4927

Differential Revision: D13889458

Pulled By: mzhaom

fbshipit-source-id: d6b66db85901a9eb90748fba6a9dc4e7457b9c5e

Summary:
1. this commit fixes our handling of a combination of two separate edge
cases. If a flush job does not pick any memtable to flush (because another
flush job has already picked the same memtables), and the column family
assigned to the flush job is dropped right before RocksDB calls
rocksdb::InstallMemtableAtomicFlushResults, our original code passes
a FileMetaData object whose file number is 0, failing the assertion in
rocksdb::InstallMemtableAtomicFlushResults (assert(m->GetFileNumber() > 0)).
2. Also piggyback a small change: since we already create a local copy of column family's mutable CF options to eliminate potential race condition with `SetOptions` call, we might as well use the local copy in other function calls in the same scope.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4932

Differential Revision: D13901322

Pulled By: riversand963

fbshipit-source-id: b936580af7c127ea0c6c19ea10cd5fcede9fb0f9

Summary:
FlushMemTablesToOutputFiles calls FlushMemTableToOutputFile for each column family. The patch moves the take-snapshot logic to outside FlushMemTableToOutputFile so that it does it once for all the flushes. This also addresses a deadlock issue for resetting the managed snapshot of job_snapshot in the 2nd call to FlushMemTableToOutputFile.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4934

Differential Revision: D13900747

Pulled By: maysamyabandeh

fbshipit-source-id: f3cd650c5fff24cf95c1aaf8a10c149d42bf042c

Summary:
Measure CPU time consumed for a compaction and report it in the stats report
Enable NowCPUNanos() to work for MacOS
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4889

Differential Revision: D13701276

Pulled By: zinoale

fbshipit-source-id: 5024e5bbccd4dd10fd90d947870237f436445055