Summary:
The concept about early exit in write thread implementation is a confusing one. It means that if early exit is allowed, batch group leader will not responsible to exit the batch group, but the last finished writer do. In case we need to mark log synced, or encounter memtable insert error, early exit is disallowed.

This patch remove such a concept by:
* In all cases, the last finished writer (not necessary leader) is responsible to exit batch group.
* In case of parallel memtable write, leader will also mark log synced after memtable insert and before signal finish (call `CompleteParallelWorker()`). The purpose is to allow mark log synced (which require locking mutex) can run in parallel to memtable insert in other writers.
* The last finish writer should handle memtable insert error (update bg_error_) before exiting batch group.
Closes https://github.com/facebook/rocksdb/pull/2134

Differential Revision: D4869667

Pulled By: yiwu-arbug

fbshipit-source-id: aec170847c85b90f4179d6a4608a4fe1361544e3

Summary:
Move some files under util/ to new directories env/, monitoring/ options/ and cache/
Closes https://github.com/facebook/rocksdb/pull/2090

Differential Revision: D4833681

Pulled By: siying

fbshipit-source-id: 2fd8bef

Summary:
db_impl.cc is too large to manage. Divide db_impl.cc into db/db_impl.cc, db/db_impl_compaction_flush.cc, db/db_impl_files.cc, db/db_impl_open.cc and db/db_impl_write.cc.
Closes https://github.com/facebook/rocksdb/pull/2095

Differential Revision: D4838188

Pulled By: siying

fbshipit-source-id: c5f3059

Summary:
Refactor WriteImpl() so when I plug-in the pipeline write code (which is
an alternative approach for WriteThread), some of the logic can be
reuse. I split out the following methods from WriteImpl():

* PreprocessWrite()
* HandleWALFull() (previous MaybeFlushColumnFamilies())
* HandleWriteBufferFull()
* WriteToWAL()

Also adding a constructor to WriteThread::Writer, and move WriteContext into db_impl.h.
No real logic change in this patch.
Closes https://github.com/facebook/rocksdb/pull/2042

Differential Revision: D4781014

Pulled By: yiwu-arbug

fbshipit-source-id: d45ca18

Summary:
Add two DB properties: rocksdb.actual_delayed_write_rate and rocksdb.is_write_stooped, for people to know whether current writes are being throttled.
Closes https://github.com/facebook/rocksdb/pull/2043

Differential Revision: D4782975

Pulled By: siying

fbshipit-source-id: 6b2f5cf

Summary:
make total_log_size_ atomic to avoid overflow caused by data race.
Closes https://github.com/facebook/rocksdb/pull/2019

Differential Revision: D4751391

Pulled By: siying

fbshipit-source-id: fac01dd

Summary:
PinnableSlice

    Summary:
    Currently the point lookup values are copied to a string provided by the
    user. This incures an extra memcpy cost. This patch allows doing point lookup
    via a PinnableSlice which pins the source memory location (instead of
    copying their content) and releases them after the content is consumed
    by the user. The old API of Get(string) is translated to the new API
    underneath.

    Here is the summary for improvements:

    value 100 byte: 1.8% regular, 1.2% merge values
    value 1k byte: 11.5% regular, 7.5% merge values
    value 10k byte: 26% regular, 29.9% merge values
    The improvement for merge could be more if we extend this approach to
    pin the merge output and delay the full merge operation until the user
    actually needs it. We have put that for future work.

    PS:
    Sometimes we observe a small decrease in performance when switching from
    t5452014 to this patch but with the old Get(string) API. The d
Closes https://github.com/facebook/rocksdb/pull/1756

Differential Revision: D4391738

Pulled By: maysamyabandeh

fbshipit-source-id: 6f3edd3

Summary:
shrink lite size
Closes https://github.com/facebook/rocksdb/pull/1929

Differential Revision: D4622059

Pulled By: siying

fbshipit-source-id: 050b796

Summary:
Seems to me `has_unpersisted_data_` is read from read thread and write
from write thread concurrently without synchronization. Making it an
atomic.

I update the logic not because seeing any problem with it, but it just
feel confusing.
Closes https://github.com/facebook/rocksdb/pull/1869

Differential Revision: D4555837

Pulled By: yiwu-arbug

fbshipit-source-id: eff2ab8

Summary:
Added method that returns approx num of entries as well as size for memtables.
Closes https://github.com/facebook/rocksdb/pull/1841

Differential Revision: D4511990

Pulled By: VitaliyLi

fbshipit-source-id: 9a4576e

Summary:
GetAndRefSuperVersionUnlocked
ReturnAndCleanupSuperVersionUnlocked
GetColumnFamilyHandleUnlocked

Are dead code that are not used any where
Closes https://github.com/facebook/rocksdb/pull/1802

Differential Revision: D4459948

Pulled By: IslamAbdelRahman

fbshipit-source-id: 30fa89d

Summary:
Added an option to GetApproximateSizes to exclude file stats, as MyRocks has those counted exactly and we need only stats from memtables.
Closes https://github.com/facebook/rocksdb/pull/1787

Differential Revision: D4441111

Pulled By: IslamAbdelRahman

fbshipit-source-id: c11f4c3

Summary:
Consider the following single column family scenario:
prepare in log A
commit in log B
*WAL is too large, flush all CFs to releast log A*
*CFA is on log B so we do not see CFA is depending on log A so no flush is requested*

To fix this we must also consider the log containing the prepare section when determining what log a CF is dependent on.
Closes https://github.com/facebook/rocksdb/pull/1768

Differential Revision: D4403265

Pulled By: reidHoruff

fbshipit-source-id: ce800ff

Summary:
This reverts commit 54d94e9c.

The pull request was landed by mistake.
Closes https://github.com/facebook/rocksdb/pull/1755

Differential Revision: D4391678

Pulled By: maysamyabandeh

fbshipit-source-id: 36d5149

Summary:
Currently the point lookup values are copied to a string provided by the user.
This incures an extra memcpy cost. This patch allows doing point lookup
via a PinnableSlice which pins the source memory location (instead of
copying their content) and releases them after the content is consumed
by the user. The old API of Get(string) is translated to the new API
underneath.

 Here is the summary for improvements:
 1. value 100 byte: 1.8%  regular, 1.2% merge values
 2. value 1k   byte: 11.5% regular, 7.5% merge values
 3. value 10k byte: 26% regular,    29.9% merge values

 The improvement for merge could be more if we extend this approach to
 pin the merge output and delay the full merge operation until the user
 actually needs it. We have put that for future work.

PS:
Sometimes we observe a small decrease in performance when switching from
t5452014 to this patch but with the old Get(string) API. The difference
is a little and could be noise. More importantly it is safely
cancelled
Closes https://github.com/facebook/rocksdb/pull/1732

Differential Revision: D4374613

Pulled By: maysamyabandeh

fbshipit-source-id: a077f1a

Summary:
If 2PC is enabled, checkpoint may not copy previous log files that contain uncommitted prepare records. In this diff we keep those files.
Closes https://github.com/facebook/rocksdb/pull/1724

Differential Revision: D4368319

Pulled By: siying

fbshipit-source-id: cc2c746

Summary:
Add EventListener::OnExternalFileIngested() to allow user to subscribe to external file ingestion events
Closes https://github.com/facebook/rocksdb/pull/1623

Differential Revision: D4285844

Pulled By: IslamAbdelRahman

fbshipit-source-id: 0b95a88

Summary:
Made delete_obsolete_files_period_micros option dynamic. It can be updating using DB::SetDBOptions().
Closes https://github.com/facebook/rocksdb/pull/1595

Differential Revision: D4246569

Pulled By: tonek

fbshipit-source-id: d23f560

Summary:
If the WriteOptions.no_slowdown flag is set AND we need to wait or sleep for
the write request, then fail immediately with Status::Incomplete().
Closes https://github.com/facebook/rocksdb/pull/1527

Differential Revision: D4191405

Pulled By: maysamyabandeh

fbshipit-source-id: 7f3ce3f

Summary: Closes https://github.com/facebook/rocksdb/pull/1509

Differential Revision: D4176426

Pulled By: yiwu-arbug

fbshipit-source-id: b57689d

Summary:
Currently the compaction stats are printed to stdout. We want to export the compaction stats in a map format so that the upper layer apps (e.g., MySQL) could present
the stats in any format required by the them.
Closes https://github.com/facebook/rocksdb/pull/1477

Differential Revision: D4149836

Pulled By: maysamyabandeh

fbshipit-source-id: b3df19f

Summary:
Note: reviewed in  https://reviews.facebook.net/D65115

- DBIter maintains a range tombstone accumulator. We don't cleanup obsolete tombstones yet, so if the user seeks back and forth, the same tombstones would be added to the accumulator multiple times.
- DBImpl::NewInternalIterator() (used to make DBIter's underlying iterator) adds memtable/L0 range tombstones, L1+ range tombstones are added on-demand during NewSecondaryIterator() (see D62205)
- DBIter uses ShouldDelete() when advancing to check whether keys are covered by range tombstones
Closes https://github.com/facebook/rocksdb/pull/1464

Differential Revision: D4131753

Pulled By: ajkr

fbshipit-source-id: be86559

Summary:
change ioptions.comparator to user_comparator instread of internal_comparator.
Also change Comparator* to InternalKeyComparator* to make its type explicitly.

Test Plan: make all check -j64

Reviewers: andrewkr, sdong, yiwu

Reviewed By: yiwu

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D65121

Summary:
Changes in the diff

API changes:
- Introduce IngestExternalFile to replace AddFile (I think this make the API more clear)
- Introduce IngestExternalFileOptions (This struct will encapsulate the options for ingesting the external file)
- Deprecate AddFile() API

Logic changes:
- If our file overlap with the memtable we will flush the memtable
- We will find the first level in the LSM tree that our file key range overlap with the keys in it
- We will find the lowest level in the LSM tree above the the level we found in step 2 that our file can fit in and ingest our file in it
- We will assign a global sequence number to our new file
- Remove AddFile restrictions by using global sequence numbers

Other changes:
- Refactor all AddFile logic to be encapsulated in ExternalSstFileIngestionJob

Test Plan:
unit tests (still need to add more)
addfile_stress (https://reviews.facebook.net/D65037)

Reviewers: yiwu, andrewkr, lightmark, yhchiang, sdong

Reviewed By: sdong

Subscribers: jkedgar, hcz, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D65061

Summary:
MyRocks hit a regression, @mung generated perf reports showing that the reason is the cost of calling `GetDBOptions()` inside `GetFromBatchAndDB()`
This diff avoid calling `GetDBOptions` and use the `ImmutableDBOptions` instead

Test Plan: make check -j64

Reviewers: sdong, yiwu

Reviewed By: yiwu

Subscribers: andrewkr, dhruba, mung

Differential Revision: https://reviews.facebook.net/D65151

Summary:
Add DB::SetDBOptions to dynamic change max_background_compactions and base_background_compactions.
I'll add more dynamic changeable options soon.

Test Plan: unit test.

Reviewers: yhchiang, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D64749

Summary:
Issue scenario:
(1) We have 3 files in L1 and we issue a compaction that will compact them into 1 file in L2
(2) While compaction (1) is running, we flush a file into L0 and trigger another compaction that decide to move this file to L1 and then move it again to L2 (this file don't overlap with any other files)
(3) compaction (1) finishes and install the file it generated in L2, but this file overlap with the file we generated in (2) so we break the LSM consistency

Looks like this issue can be triggered by using non-exclusive manual compaction or AddFile()

Test Plan: unit tests

Reviewers: sdong

Reviewed By: sdong

Subscribers: hermanlee4, jkedgar, andrewkr, dhruba, yoshinorim

Differential Revision: https://reviews.facebook.net/D64947

Summary:
Fix the conflict bug between AddFile() and CompactRange() by
- Make sure that no AddFile calls are running when asking CompactionPicker to pick compaction for manual compaction
- If AddFile() run after we pick the compaction for the manual compaction it will be aware of it since we will add the manual compaction to running_compactions_ after picking it

This will solve these 2 scenarios
- If AddFile() is running, we will wait for it to finish before we pick a compaction for the manual compaction
- If we already picked a manual compaction and then AddFile() started ... we ensure that it never ingest a file in a level that will overlap with the manual compaction

Test Plan: unit tests

Reviewers: sdong

Reviewed By: sdong

Subscribers: andrewkr, yoshinorim, jkedgar, dhruba

Differential Revision: https://reviews.facebook.net/D64449

Summary:
Since AddFile unlock/lock the mutex inside LogAndApply() we need to ensure that during this period other compactions cannot run since such compactions are not aware of the file we are ingesting and could create a compaction that overlap wit this file

this diff add
- WaitForAddFile() call that will ensure that no AddFile() calls are being processed right now
- Call `WaitForAddFile()` in 3 locations
-- When doing manual Compaction
-- When starting automatic Compaction
-- When  doing CompactFiles()

Test Plan: unit test

Reviewers: lightmark, yiwu, andrewkr, sdong

Reviewed By: sdong

Subscribers: andrewkr, yoshinorim, jkedgar, dhruba

Differential Revision: https://reviews.facebook.net/D64383

Summary: Use ImmutableDBOptions/MutableDBOptions internally and DBOptions only for user-facing APIs. MutableDBOptions is barely a placeholder for now. I'll start to move options to MutableDBOptions in following diffs.

Test Plan:
  make all check

Reviewers: yhchiang, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D64065

Summary:
Revert the behavior where we don't read sequence id from WAL, but increase it as we replay the log. We still keep the behave for 2PC for now but will fix later.

This change fixes github issue 1339, where some writes come with WAL disabled and we may recover records with wrong sequence id.

Test Plan: Added unit test.

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D64275

Summary: WritableFile::SetPreallocationBlockSize() requires parameter as size_t, and options used in DBImpl::GetWalPreallocateBlockSize() are all size_t. WritableFile::SetPreallocationBlockSize() should return size_t to avoid build break if size_t is not uint64_t.

Test Plan: Run existing tests.

Reviewers: andrewkr, IslamAbdelRahman, yiwu

Reviewed By: yiwu

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D64137

Summary: Currently the WAL file preallocation size is 1.1 * write_buffer_size. This, however, will be over-estimated if options.db_write_buffer_size or options.max_total_wal_size is set and is much smaller.

Test Plan: Add a unit test.

Reviewers: andrewkr, yiwu

Reviewed By: yiwu

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D63957

Summary: DB::GetOptions() reflect dynamic changed options.

Test Plan: See the new unit test.

Reviewers: yhchiang, sdong, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D63903

Summary:
Temporarily revert commits for supporting prefix Prev() to unblock MyRocks and RocksDB release

These are the commits reverted

  - 6a14d55b
  - b18f9c9e
  - db74b1a2
  - 2482d5fb

Test Plan: make check -j64

Reviewers: sdong, lightmark

Reviewed By: lightmark

Subscribers: andrewkr, dhruba, yoshinorim

Differential Revision: https://reviews.facebook.net/D63789

Summary: As title, make sure Prev() works as expected with Next() when the current iter->key() in the range of the same prefix in prefix seek mode

Test Plan: make all check -j64 (add prefix_test with PrefixSeekModePrev test case)

Reviewers: andrewkr, sdong, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: yoshinorim, andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D61419

Summary: 1. Range Deletion Tombstone structure 2. Modify Add() in table_builder to make it usable for adding range del tombstones 3. Expose NewTombstoneIterator() API in table_reader

Test Plan: table_test.cc (now BlockBasedTableBuilder::Add() only accepts InternalKey. I make table_test only pass InternalKey to BlockBasedTableBuidler. Also test writing/reading range deletion tombstones in table_test )

Reviewers: sdong, IslamAbdelRahman, lightmark, andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D61473

read_options.background_purge_on_iterator_cleanup to cover forward iterator and log file closing too.

Summary: With read_options.background_purge_on_iterator_cleanup=true, File deletion and closing can still happen in forward iterator, or WAL file closing. Cover those cases too.

Test Plan: I am adding unit tests.

Reviewers: andrewkr, IslamAbdelRahman, yiwu

Reviewed By: yiwu

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D61503

* Added check_snapshot option in the DB's AddFile function

* change check_snapshot to skip_snapshot_check

* add unit test for skip_snapshot_check

* Add skip_snapshot_check comment

Summary:
My understanding is that the purpose of write stall triggers are to wait for auto-compaction to catch up. Without auto-compaction, we don't need to stall writes.

Also with this diff, flush/compaction conditions are recalculated on dynamic option change. Previously the conditions are recalculate only when write stall options are changed.

Test Plan: See the new test. Removed two tests that are no longer valid.

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D61437