Summary:
Introduce MaxOperator a simple merge operator that return the max of all operands.
This merge operand help me in benchmarking

Test Plan: Add new unitttests

Reviewers: sdong, andrewkr, yhchiang

Reviewed By: yhchiang

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D57873

Summary:
A couple of notes from the diff:
  - The namespace block I added at the top of table_properties_collector.cc was in reaction to an issue i was having with PutVarint64 and reusing the "val" string.  I'm not sure this is the cleanest way of doing this, but abstracting this out at least results in the correct behavior.
  - I chose "rocksdb.merge.operands" as the property name.  I am open to suggestions for better names.
  - The change to sst_dump_tool.cc seems a bit inelegant to me.  Is there a better way to do the if-else block?

Test Plan:
I added a test case in table_properties_collector_test.cc.  It adds two merge operands and checks to make sure that both of them are reflected by GetMergeOperands.  It also checks to make sure the wasPropertyPresent bool is properly set in the method.

Running both of these tests should pass:
./table_properties_collector_test
./sst_dump_test

Reviewers: IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58119

A couple "New Features" headers needed a blank line before them.

Add db_test2

Summary:
This is a part of effort to reduce the size of db_test.cc. We move the following tests to a separate file `db_io_failure_test.cc`:

* DropWrites
* DropWritesFlush
* NoSpaceCompactRange
* NonWritableFileSystem
* ManifestWriteError
* PutFailsParanoid

Test Plan: Run `make check` to see if the tests are working properly.

Reviewers: sdong, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58341

Summary:
Expose a simple function to convert CompressionType to it's corresponding option string

This is for a diff @yoshinorim is working on for MyRocks

Test Plan: unittest

Reviewers: yhchiang, andrewkr, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, yoshinorim

Differential Revision: https://reviews.facebook.net/D58215

Summary:
NotifyOnCompactionCompleted can unlock the mutex.
That mean that we can schedule a background compaction that will start before we ReleaseCompactionFiles().

Test Plan:
added unittest
existing unittest

Reviewers: yhchiang, sdong

Reviewed By: sdong

Subscribers: yoshinorim, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58065

Summary: This tests that a prepared transaction is not lost after several crashes, restarts, and memtable flushes.

Test Plan: TwoPhaseLongPrepareTest

Reviewers: sdong

Subscribers: hermanlee4, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58185

Summary:
TransactionTest.TwoPhaseMultiThreadTest runs forever under TSAN and our CI builds time out
looks like the reason is that some threads keep running and other threads dont get a chance to increment the counter

Test Plan: run the test under TSAN

Reviewers: sdong, horuff

Reviewed By: horuff

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58359

Summary:
We expect the persistent read cache to perform at speeds upto 8 GB/s. In order
to accomplish that, we need build a index mechanism which operate in the order
of multiple millions per sec rate.

This patch provide the basic data structure to accomplish that:

(1) Hash table implementation with lock contention spread
    It is based on the StripedHashSet<T> implementation in
    The Art of multiprocessor programming by Maurice Henry & Nir Shavit
(2) LRU implementation
    Place holder algorithm for further optimizing
(3) Evictable Hash Table implementation
    Building block for building index data structure that evicts data like files
    etc

TODO:
(1) Figure if the sharded hash table and LRU can be used instead
(2) Figure if we need to support configurable eviction algorithm for
EvictableHashTable

Test Plan: Run unit tests

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D55785

Summary:
make more ColumnFamilyOptions dynamic:
- compression
- soft_pending_compaction_bytes_limit
- hard_pending_compaction_bytes_limit
- min_partial_merge_operands
- report_bg_io_stats
- paranoid_file_checks

Test Plan:
Add sanity check in `db_test.cc` for all above options except for soft_pending_compaction_bytes_limit and hard_pending_compaction_bytes_limit.
All passed.

Reviewers: andrewkr, sdong, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57519

Implement GetUniqueIdFromFile to support new tests and the feature.

Summary:
- Make sure we clean up recovered_transactions_ on DBImpl destructor
- delete leaked txns and env in TransactionTest

Test Plan: Run transaction_test under valgrind

Reviewers: sdong, andrewkr, yhchiang, horuff

Reviewed By: horuff

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58263

Summary:
Added a new abstraction to cache page to RocksDB designed for the read
cache use.

RocksDB current block cache is more of an object cache. For the persistent read cache
project, what we need is a page cache equivalent. This changes adds a cache
abstraction to RocksDB to cache pages called PersistentCache. PersistentCache can cache
uncompressed pages or raw pages (content as in filesystem). The user can
choose to operate PersistentCache either in  COMPRESSED or UNCOMPRESSED mode.

Blame Rev:

Test Plan: Run unit tests

Reviewers: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D55707

Summary:
So a customized ldb tool can pass it's own Selector.
Such a selector is expected to call LDBCommand::SelectCommand
and then add some of its own customized commands

Test Plan: make ldb

Reviewers: sdong, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D57249

Conditionally retrofit thread_posix for use with std::thread
  and reuse the same logic. Posix users continue using Posix interfaces.
  Enable XPRESS compression in test runs.
  Fix master introduced signed/unsigned mismatch.

Summary: DBTestXactLogIterator.TransactionLogIterator was failing due the sequence gaps. This was caused by an off-by-one error when calculating the new sequence number after recovering from logs.

Test Plan: db_log_iter_test

Reviewers: andrewkr

Subscribers: andrewkr, hermanlee4, dhruba, IslamAbdelRahman

Differential Revision: https://reviews.facebook.net/D58053

Summary: Store SST file compression algorithm as a TableProperty.

Test Plan: Modified and ran the table_test UT that checks for TableProperties

Reviewers: IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: lgalanis, andrewkr, dhruba, IslamAbdelRahman

Differential Revision: https://reviews.facebook.net/D58017

Summary:
The implementation remains where it is. Only the
header is exported. This is so that a customized
ldb tool can print help along with its own
extra commands

Test Plan: make ldb

Reviewers: sdong, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D57255

Summary: Disable backupable_db_test.cc on Windows since EnvChroot is not supported

Test Plan: check ROCKSDB_LITE

Reviewers: andrewkr

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58035

Summary:
- Used ChrootEnv so the database and backup Envs are isolated in the filesystem.
- Removed DifferentEnvs test since now every test uses different Envs

Depends on D57543

Test Plan:
- ran backupable_db_test
- verified backupable_db_test now catches the bug when D57159 is backed out (this bug previously passed through the test cases, which motivated this change)

Reviewers: sdong, lightmark, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57615

Summary:
GetObsoleteFiles() and LogAndApply() functions modify obsolete_manifests_ vector
we need to make sure that the mutex is held when we modify the obsolete_manifests_

Test Plan: run the test under TSAN

Reviewers: andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58011

Summary:
Expose the option so it's easy to run offline tests of compression
dictionary feature.

Test Plan:
verified compression dictionary is loaded into lz4 for below command:

  $ ./ldb compact --compression_type=lz4 --compression_max_dict_bytes=16384 --db=/tmp/feed-compression-test/

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57441

Summary:
1. prepare()
2. crash
3. recover
4. commit()
5. crash
6. data is lost

This is due to the transaction data still only residing in the WAL but because the logs were flushed on the first recovery the data is ignored on the second recovery. We must scan all logs found on recovery and only ignore redundant data at the time of replay. It is not possible to know which logs still contain relevant data at time of recovery. We cannot simply ignore a log because all of the non-2pc data it contains has already been written to L0.

The changes made to MemTableInserter are to ensure that prepared sections are still recovered even if all of the non-2pc data in that log has already been flushed to L0.

Test Plan: Provided test.

Reviewers: sdong

Subscribers: andrewkr, hermanlee4, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57729

Summary:
Consider the following WAL with 4 batch entries prefixed with their sequence at time of memtable insert.
[1: BEGIN_PREPARE, PUT, PUT, PUT, PUT, END_PREPARE(a)]
[1: BEGIN_PREPARE, PUT, PUT, PUT, PUT, END_PREPARE(b)]
[4: COMMIT(a)]
[7: COMMIT(b)]

The first two batches do not consume any sequence numbers so are both prefixed with seq=1.
For 2pc commit, memtable insertion takes place before COMMIT batch is written to WAL.
We can see that sequence number consumption takes place between WAL entries giving us the seemingly sparse sequence prefix for WAL entries.
This is a valid WAL.

Because with 2PC markers one WriteBatch points to another batch containing its inserts a writebatch can consume more or less sequence numbers than the number of sequence consuming entries that it contains.

We can see that, given the entries in the WAL, 6 sequence ids were consumed. Yet on recovery the maximum sequence consumed would be 7 + 3 (the number of sequence numbers consumed by COMMIT(b))

So, now upon recovery we must track the actual consumption of sequence numbers.
In the provided scenario there will be no sequence gaps, but it is possible to produce a sequence gap. This should not be a problem though. correct?

Test Plan: provided test.

Reviewers: sdong

Subscribers: andrewkr, leveldb, dhruba, hermanlee4

Differential Revision: https://reviews.facebook.net/D57645

Summary:
Two Phase Commit addition to RocksDB.

See wiki: https://github.com/facebook/rocksdb/wiki/Two-Phase-Commit-Implementation
Quip: https://fb.quip.com/pxZrAyrx53r3

Depends on:
WriteBatch modification: https://reviews.facebook.net/D54093
Memtable Log Referencing and Prepared Batch Recovery: https://reviews.facebook.net/D56919

Test Plan:
- SimpleTwoPhaseTransactionTest
- PersistentTwoPhaseTransactionTest.
- TwoPhaseRollbackTest
- TwoPhaseMultiThreadTest
- TwoPhaseLogRollingTest
- TwoPhaseEmptyWriteTest
- TwoPhaseExpirationTest

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: leveldb, hermanlee4, andrewkr, vasilep, dhruba, santoshb

Differential Revision: https://reviews.facebook.net/D56925

Summary:
This diff is built on top of WriteBatch modification: https://reviews.facebook.net/D54093 and adds the required functionality to rocksdb core necessary for rocksdb to support 2PC.

modfication of DBImpl::WriteImpl()
- added two arguments *uint64_t log_used = nullptr, uint64_t log_ref = 0;
- *log_used is an output argument which will return the log number which the incoming batch was inserted into, 0 if no WAL insert took place.
-  log_ref is a supplied log_number which all memtables inserted into will reference after the batch insert takes place. This number will reside in 'FindMinPrepLogReferencedByMemTable()' until all Memtables insertinto have flushed.

- Recovery/writepath is now aware of prepared batches and commit and rollback markers.

Test Plan: There is currently no test on this diff. All testing of this functionality takes place in the Transaction layer/diff but I will add some testing.

Reviewers: IslamAbdelRahman, sdong

Subscribers: leveldb, santoshb, andrewkr, vasilep, dhruba, hermanlee4

Differential Revision: https://reviews.facebook.net/D56919

Summary: Adds three new WriteBatch data types: Prepare(xid), Commit(xid), Rollback(xid). Prepare(xid) should precede the (single) operation to which is applies. There can obviously be multiple Prepare(xid) markers. There should only be one Rollback(xid) or Commit(xid) marker yet not both. None of this logic is currently enforced and will most likely be implemented further up such as in the memtableinserter. All three markers are similar to PutLogData in that they are writebatch meta-data, ie stored but not counted. All three markers differ from PutLogData in that they will actually be written to disk. As for WriteBatchWithIndex, Prepare, Commit, Rollback are all implemented just as PutLogData and none are tested just as PutLogData.

Test Plan: single unit test in write_batch_test.

Reviewers: hermanlee4, sdong, anthony

Subscribers: leveldb, dhruba, vasilep, andrewkr

Differential Revision: https://reviews.facebook.net/D57867

Summary:
On Mac OS X, the chroot directory we typically use ("/tmp") is actually
a symlink for "/private/tmp". Since we dereference symlinks in user-defined
paths, we must also dereference symlinks in chroot_dir_ such that we can perform
string comparisons on those paths.

Test Plan: ran env_test on Mac OS X and devserver

Reviewers: sdong, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57957

Summary: Fix lite build

Test Plan: run under lite

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D57945

Summary:
Add a new option that can be used to set a specific compression algorithm for bottommost level.
This option will only affect levels larger than base level.

I have also updated CompactionJobInfo to include the compression algorithm used in compaction

Test Plan:
added new unittest
existing unittests

Reviewers: andrewkr, yhchiang, sdong

Reviewed By: sdong

Subscribers: lightmark, andrewkr, dhruba, yoshinorim

Differential Revision: https://reviews.facebook.net/D57669

Summary: Currently we estimate bytes needed for compaction by assuming fanout value to be level multiplier. It overestimates when size of a level exceeds the target by large. We estimate by the ratio of actual sizes in levels instead.

Test Plan: Fix existing test cases and add a new one.

Reviewers: IslamAbdelRahman, igor, yhchiang

Reviewed By: yhchiang

Subscribers: MarkCallaghan, leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D57789

Summary: see title

Test Plan:
  $ /mnt/gvfs/third-party2/valgrind/af85c56f424cd5edfc2c97588299b44ecdec96bb/3.10.0/gcc-4.9-glibc-2.20/e9936bf/bin/valgrind --error-exitcode=2 --leak-check=full ./env_test

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57897

Summary:
This diff includes an initial script running a set of benchmarks for
regression test.  The script does the following things:

  checkout the specified rocksdb commit (or origin/master as default)
  make clean && DEBUG_LEVEL=0 make db_bench
  setup test directories
  run set of benchmarks and store results

Currently, the script will run couple benchmarks, store all the benchmark
output, extract micros per op and percentile information for each benchmark
and store them in a single SUMMARY.csv file.  The SUMMARY.csv will make the
follow-up regression detection easier.

In addition, the current script only takes env arguments to set important
attributes of db_bench.  Will follow-up with a patch that allows db_bench
to construct options from an options file.

Test Plan:
NUM_KEYS=100 ./tools/regression_test.sh

  Sample SUMMARY.csv file:

                                     commit id,                      benchmark,  ms-per-op,        p50,        p75,        p99,      p99.9,     p99.99
      7e23ddf575890510e7d2fc7a79b31a1bbf317917,                        fillseq,      15.28,      54.66,      77.14,    5000.00,   17900.00,   18483.00
      7e23ddf575890510e7d2fc7a79b31a1bbf317917,                      overwrite,      13.54,      57.69,      86.39,    3000.00,   15600.00,   17013.00
      7e23ddf575890510e7d2fc7a79b31a1bbf317917,                     readrandom,       1.04,       0.80,       1.67,     293.33,     395.00,     504.00
      7e23ddf575890510e7d2fc7a79b31a1bbf317917,               readwhilewriting,       2.75,       1.01,       1.87,     200.00,     460.00,     485.00
      7e23ddf575890510e7d2fc7a79b31a1bbf317917,                   deleterandom,       3.64,      48.12,      70.09,     200.00,     336.67,     347.00
      7e23ddf575890510e7d2fc7a79b31a1bbf317917,                     seekrandom,      24.31,     391.87,     513.69,     872.73,     990.00,    1048.00
      7e23ddf575890510e7d2fc7a79b31a1bbf317917,         seekrandomwhilewriting,      14.02,     185.14,     294.15,     700.00,    1440.00,    1527.00

Reviewers: sdong, IslamAbdelRahman, kradhakrishnan, yiwu, andrewkr, gunnarku

Reviewed By: gunnarku

Subscribers: gunnarku, MarkCallaghan, andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57597

Summary:
Pass --index_block_restart_interval flag to block_based_options in db_bench tool.

Test Plan: none

Reviewers: sdong, kradhakrishnan

Reviewed By: kradhakrishnan

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D57699

Summary: Fixing error with win build where we compare int64_t with size_t.

Test Plan: make check

Reviewers: andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57885

Summary:
Fix below error:

  use of undeclared identifier 'errno'

Test Plan: doitlive

Reviewers: IslamAbdelRahman, sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57849

Summary:
For testing backups, we needed an Env that is fully isolated from other
Envs on the same machine. Our in-memory Envs (MockEnv and InMemoryEnv) were
insufficient because they don't implement most directory operations.

This diff introduces a new Env, "ChrootEnv", that translates paths such that the
chroot directory appears to be the root directory. This way, multiple Envs can
be isolated in the filesystem by using different chroot directories. Since we
use the filesystem, all directory operations are trivially supported.

Test Plan:
I parameterized the existing EnvPosixTest so it runs tests on ChrootEnv
except the ioctl-related cases.

Reviewers: sdong, lightmark, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57543