Summary:
Recently db_stress starts to use a special Env that keeps all manifest files. This should not apply to checkpoint directory and causes test failure like this:

Verification failed: Checkpoint gave inconsistent state. Status is IO error: While mkdir: /dev/shm/rocksdb/rocksdb_crashtest_whitebox/.checkpoint27.tmp: File exists
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6233

Test Plan: Run crash_test with high chance of checkpoint and make sure it doesn't reproduce.

Differential Revision: D19207250

fbshipit-source-id: 12a931379e2e0572bb84aa658b6d03770c8551d4

Summary:
Listners are one source of bugs because we frequently release some mutex to invoke them, which introduce race conditions. Implement all callback functions in db_stress's listener class, and randomly sleep.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6197

Test Plan: Run crash_test for a while and see no obvious problem.

Differential Revision: D19134015

fbshipit-source-id: b9ea8be9366e4501759119520cd4f204943538f6

Summary:
db_stress to execute DB::GetApproximateSizes() with randomized keys and options. Return value is not validated but error will be reported.
Two ways to generate the range keys: (1) two random keys; (2) a small range.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6213

Test Plan: (1) run "make crash_test" for a while; (2) hack the code to ingest some errors to see it is reported.

Differential Revision: D19204665

fbshipit-source-id: 652db36f13bcb5a3bd8fe4a10c0aa22a77a0bce2

Summary:
Currently, db_stress generates fixed length keys of 8 bytes. This patch adds the ability to generate variable length keys. Most of the db_stress code continues to work with a numeric key randomly generated, and the numeric key also acts as an index into the values_ array. The numeric key is mapped to a variable length string key in a deterministic way. Furthermore, the ordering is preserved.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6165

Test Plan: run make crash_test

Differential Revision: D19204646

Pulled By: anand1976

fbshipit-source-id: d2d46a96615b4832a8be2a981f5913905f0e1ca7

Summary:
Several improvements to crash_test/stress_test:
(1) Stress_test to support an parameter of bottommost compression
(2) Rename those FLAGS_* variables that are not gflags to avoid confusion
(3) Crash_test to randomly generate compression type for bottommost compression with half the chance.
(4) Stress_test to sanitize unsupported compression type to snappy, so that crash_test to cover all possible compression types and people don't need to worry about they don't support all comrpession types in their environment.
(5) In crash_test, when generating db_stress command, sort arguments in alphabeta order, so that it is easier to find value for a specific argument.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6215

Test Plan: Run "make crash_test" for a while and see the botommost option shown in LOG files.

Differential Revision: D19171255

fbshipit-source-id: d7001e246c4ff9ee5760776eea0be97738650735

Summary:
1. Cover SeekToFirst() and SeekToLast().
2. Try to record the history of iterator operations.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6166

Test Plan: Do some manual changes in the code to cover the failure cases and see the error printing is correct and SeekToFirst() and SeekToLast() sometimes show up.

Differential Revision: D19047079

fbshipit-source-id: 1ed616f919fe4d32c0a021fc37932a7bd3063bcd

Summary:
Closes https://github.com/facebook/rocksdb/issues/6183
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6186

Differential Revision: D19201281

Pulled By: pdillinger

fbshipit-source-id: 1c96b4ea09e826f91e44b0009eba3de0991d9053

Summary:
There are no API changes ;-)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6218

Differential Revision: D19200373

Pulled By: pdillinger

fbshipit-source-id: 58d34b01ea53b75a1eccbd72f8b14d6256a7380f

Summary:
Add the verification in operateDB to verify GetLiveFiles, GetSortedWalFiles and GetCurrentWalFile. The test will be called every 1 out of N, N is decided by get_live_files_and_wal_files_one_i, whose default is 1000000.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6224

Test Plan: pass db_stress default run.

Differential Revision: D19183358

Pulled By: zhichao-cao

fbshipit-source-id: 20073cf72ede77a3e0d3cf5f28304f1f605d2b1a

Summary:
As title. We can run non-cf-consistency stress tests with verify_db_one_in>0,
thus remove the check added previously.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6231

Test Plan:
```
make crash_test
```

Differential Revision: D19198295

Pulled By: riversand963

fbshipit-source-id: e874c701bb03ab76eaab00f059dd4032bb2f537f

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/6229

Differential Revision: D19191195

Pulled By: ltamasi

fbshipit-source-id: 2a3c4785299641a46e022fc012460b759a689fce

Summary:
The patch adds support for BlobDB to `db_stress`. Note that BlobDB currently does
not support (amongst other features) Column Families or the `SingleDelete` API,
so for now, those should be disabled on the command line when running `db_stress` in
BlobDB mode (using `-column_families=1` and `-nooverwritepercent=0`,
respectively). Also, some BlobDB features that do not go well with the verification logic
in `db_stress` like TTL and FIFO eviction are not supported currently.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6230

Test Plan:
```
./db_stress -max_key=100000 -use_blob_db -column_families=1 -nooverwritepercent=0 -reopen=1 -blob_db_file_size=1000000 -target_file_size_base=1000000 -blob_db_enable_gc -blob_db_gc_cutoff=0.1 -blob_db_min_blob_size=10 -blob_db_bytes_per_sync=16384
```

Differential Revision: D19191476

Pulled By: ltamasi

fbshipit-source-id: 35840452af8c5e6095249c7fd9a53a119a0985fc

Summary:
Currently, db_stress performs verification by calling `VerifyDb()` at the end of test and optionally before tests start. In case of corruption or incorrect result, it will be too late. This PR adds more verification in two ways.
1. For cf consistency test, each test thread takes a snapshot and verifies every N ops. N is configurable via `-verify_db_one_in`. This option is not supported in other stress tests.
2. For cf consistency test, we use another background thread in which a secondary instance periodically tails the primary (interval is configurable). We verify the secondary. Once an error is detected, we terminate the test and report. This does not affect other stress tests.

Test plan (devserver)
```
$./db_stress -test_cf_consistency -verify_db_one_in=0 -ops_per_thread=100000 -continuous_verification_interval=100
$./db_stress -test_cf_consistency -verify_db_one_in=1000 -ops_per_thread=10000 -continuous_verification_interval=0
$make crash_test
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6173

Differential Revision: D19047367

Pulled By: riversand963

fbshipit-source-id: aeed584ad71f9310c111445f34975e5ab47a0615

Summary:
BlobDB currently only supports using the default column family. The earlier
code enforces this by comparing the `ColumnFamilyHandle` passed to the
`Get`/`Put`/etc. call with the handle returned by `DefaultColumnFamily`
(which, at the end of the day, comes from `DBImpl::default_cf_handle_`).
Since other `ColumnFamilyHandle`s can also point to the default column
family, this can reject legitimate requests as well. (As an example,
with the earlier code, the handle returned by `BlobDB::Open` cannot
actually be used in API calls.) The patch fixes this by comparing only
the IDs of the column family handles instead of the pointers themselves.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6226

Test Plan: `make check`

Differential Revision: D19187461

Pulled By: ltamasi

fbshipit-source-id: 54ce2e12ebb1f07e6d1e70e3b1e0213dfa94bda2

Summary:
The new Python syntax check could fail if external entities
were cloned or symlinked to a subdir in a rocksdb git clone. (E.g.
Facebook internal LITE build.) Only look for Python files in specific
subdirs
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6225

Test Plan: python tools/check_all_python.py (still 34 files checked)

Reviewed By: gfosco

Differential Revision: D19186110

Pulled By: pdillinger

fbshipit-source-id: 1fefa54e36b32cd5d96d3d1a43e8a2a694c22ea5

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

Summary:
Complete some refactoring called for in https://github.com/facebook/rocksdb/issues/6148. Somehow I got some 'make format' in here for files I didn't change, but that should be OK. (I'm not sure why "hide whitespace changes" doesn't seem to help in review.)

Not addressed in this PR: some operations simply print to stdout rather than failing on discovering a bad status or inconsistency.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6195

Differential Revision: D19131067

Pulled By: pdillinger

fbshipit-source-id: 4f416e6b792023989ef119f385fe122426cb825d

Summary:
This reverts commit 54f9092b.
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

Summary:
We're seeing assertion violations like this in crash test:

db_stress: table/block_based/block_based_table_reader.cc:4129: virtual uint64_t rocksdb::BlockBasedTable::ApproximateSize(const rocksdb::Slice&, const rocksdb::Slice&, rocksdb::TableReaderCaller): Assertion `end_offset >= start_offset' failed.***

And ApproximateSize appears only to be called with the level_compaction_dynamic_level_bytes option.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6217

Test Plan:
temporarily put an assert(false) in ApproximateSize and
briefly run 'make crash_test'

Differential Revision: D19179174

Pulled By: pdillinger

fbshipit-source-id: 506e6549aea0da19b363a1a6da04373c364d92e4

Summary:
Adds a python script to syntax check all python files in the
repository and report any errors.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6209

Test Plan:
'make check' with and without seeded syntax errors. Also look
for "No syntax errors in 34 .py files" on success, and in java_test CI output

Differential Revision: D19166756

Pulled By: pdillinger

fbshipit-source-id: 537df464b767260d66810b4cf4c9808a026c58a4

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

Summary:
The patch makes it possible to set the BlobDB configuration option
`garbage_collection_cutoff` on the command line. In addition, it changes
the `db_bench` code so that the default values of BlobDB related
parameters are taken from the defaults of the actual BlobDB
configuration options (note: this changes the the default of
`blob_db_bytes_per_sync`).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6211

Test Plan: Ran `db_bench` with various values of the new parameter.

Differential Revision: D19166895

Pulled By: ltamasi

fbshipit-source-id: 305ccdf0123b9db032b744715810babdc3e3b7d5

Summary:
level passed into ColumnFamilyData::CalculateSSTWriteHint() can be smaller than base_level in current version, which would cause overflow.
We see ubsan complains:

db/compaction/compaction_job.cc:1511:39: runtime error: load of value 4294967295, which is not a valid value for type 'Env::WriteLifeTimeHint'

and I hope this commit fixes it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6212

Test Plan: Run existing tests and see them to pass.

Differential Revision: D19168442

fbshipit-source-id: bf8fd86f85478ecfa7556db46dc3242de8c83dc9

Summary:
Should fix Travis build error that randomly showed up upon
using Java 13 version of javadoc.

    AdvancedColumnFamilyOptionsInterface.java:257: error:
      unexpected heading used: <H2>, compared to implicit preceding heading: <H3>

According to this reference https://bugs.openjdk.java.net/browse/JDK-8220379
it should work to start at h4, but that didn't work, so avoiding
headings should be fine.

Also fix Java EnvironmentTest for JDK13.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/6208

Test Plan: Travis run on PR (don't have Java 13 handy)

Differential Revision: D19163105

Pulled By: pdillinger

fbshipit-source-id: 4a9419cbe7ef780fba771b8a1508e1ea80d17b3e

Summary:
improve https://github.com/facebook/rocksdb/issues/6147
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6180

Differential Revision: D19148936

fbshipit-source-id: f691c9879fd51d54e96c1a99670cf85ca4485a89

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

Summary:
Fixes syntax error from https://github.com/facebook/rocksdb/pull/6203

Pull Request resolved: https://github.com/facebook/rocksdb/pull/6207

Test Plan: make blackbox_crash_test -> no more syntax error

Differential Revision: D19161752

Pulled By: pdillinger

fbshipit-source-id: b3032f296041ab56307762622b9ef6c03a8379aa

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

Summary:
Add an option to db_stress, verify_checksum_one_in, to call DB::VerifyChecksum() once every N ops.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6203

Differential Revision: D19145753

Pulled By: anand1976

fbshipit-source-id: d09edf21f309ad53aa40dd25b7a563d50665fd8b

Summary:
The bad code was:

```
mutex.Lock(); // `mutex` protects `container`
for (auto& x : container) {
  mutex.Unlock();
  // do stuff to x
  mutex.Lock();
}
```

It's incorrect because both `x` and the iterator may become invalid if another thread modifies the container while this thread is not holding the mutex.

Broken by https://github.com/facebook/rocksdb/pull/5796 - it replaced a `while (!container.empty())` loop with a `for (auto x : container)`.

(RocksDB code does a lot of such unlocking+re-locking of mutexes, and this type of bugs comes up a lot :/ )
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6193

Test Plan: Ran some logdevice integration tests that were crashing without this fix.

Differential Revision: D19116874

Pulled By: al13n321

fbshipit-source-id: 9672bc4227c1b68f46f7436db2b96811adb8c703

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/6202

Differential Revision: D19144158

Pulled By: ltamasi

fbshipit-source-id: 3e2522ced458568e3a2a045663704e30ab0ac223

Summary:
Fix two crash test issues:
1. sync mode should not run with disable_wal=true
2. disable "compaction_readahead_size" for now. With it on, some block checksum verification failure will happen in compaction paths. Not sure why, but disable it for now to keep the test clean.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6200

Test Plan: Run "make crash_test" and "make crash_test_with_atomic_flush" and see it runs way longer than before the fix without failing.

Differential Revision: D19143493

fbshipit-source-id: 438fad52fbda60aafd142e1b65578addbe7d72b1

Summary:
Cuts about 30-60 seconds to from each Travis Linux build, and about 15 minutes from each macOS build
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6181

Differential Revision: D19098357

Pulled By: pdillinger

fbshipit-source-id: 863dd1ab09076ad9b03c2b7914908359628315ae

Summary:
I found that CleanupSuperVersion() may block Get() for 30ms+ （per MemTable is 256MB）.

Then I found "delete sv" in ~SuperVersion() takes the time.

The backtrace looks like this

DBImpl::GetImpl() -> DBImpl::ReturnAndCleanupSuperVersion() ->
DBImpl::CleanupSuperVersion() : delete sv; -> ~SuperVersion()

I think it's better to delete in a background thread,  please review it。
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6146

Differential Revision: D18972066

fbshipit-source-id: 0f7b0b70b9bb1e27ad6fc1c8a408fbbf237ae08c

Summary:
With https://github.com/facebook/rocksdb/pull/6121, errors returned by `PrepareBlobValue`
result in `CompactionIterator::status_` being set to `Corruption` or `IOError`
as appropriate, however, `valid_` is not set to `false`. The error is eventually propagated in
`CompactionJob::ProcessKeyValueCompaction` but only after the main loop completes.
Setting `valid_` to `false` upon errors enables us to terminate the loop early and fail the
compaction sooner.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6170

Test Plan:
Ran `make check` and used `db_bench` in BlobDB mode.

fbshipit-source-id: a2ca88a3ca71115e2605bd34a4c795d8a28bef27

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/6192

Test Plan:
Add a unit test that fails without the fix and passes now
make check

Differential Revision: D19124781

Pulled By: anand1976

fbshipit-source-id: 8c8cb6fa16c3fc23ec011e168561a13f76bbd783

Summary:
As title. Previous assumption was that the underlying lib can always return
a shared_ptr<Env>. This is too strong. Therefore, we use Env::LoadEnv to relax
it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6196

Test Plan: make check

Differential Revision: D19133199

Pulled By: riversand963

fbshipit-source-id: c83a0c02a42610d077054f2de1acfc45126b3a75

Summary:
In https://github.com/facebook/rocksdb/issues/6174 we fixed the stress test to respect the CancelAllBackgroundWork + Close order for WritePrepared transactions. The fix missed to take into account that some invocation of CancelAllBackgroundWork are with wait=false parameter which essentially breaks the order.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6191

Differential Revision: D19102709

Pulled By: maysamyabandeh

fbshipit-source-id: f4e7b5fdae47ff1c1ac284ba1cf67d5d3f3d03eb

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

Summary:
Several options are trivially added to crash test and random values are picked.
Made simple test run non-dynamic level and normal test run dynamic level.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6176

Test Plan: Run crash_test and watch the printing

Differential Revision: D19053955

fbshipit-source-id: 958cb43c968541ebd87ed4d91e778bd1d40e7502