Enable C4307 'operator' : integral constant overflow
  Longs and ints on Windows are 32-bit hence the overflow
  Enable C4309 'conversion' : truncation of constant value
  Enable C4512 'class' : assignment operator could not be generated
  Enable C4701 Potentially uninitialized local variable 'name' used

Summary:
MyRocks testing found an issue that while iterating over keys
that are outside the prefix, sometimes wrong results were seen for keys
outside the prefix. We now tighten the range of keys seen with a new
read option called prefix_seen_at_start. This remembers the starting
prefix and then compares it on a Next for equality of prefix. If they
are from a different prefix, it sets valid to false.

Test Plan: PrefixTest.PrefixValid

Reviewers: IslamAbdelRahman, sdong, yhchiang, anthony

Reviewed By: anthony

Subscribers: spetrunia, hermanlee4, yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D50211

Summary: Run "make format" for some recent commits.

Test Plan: Build and run tests

Reviewers: IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D49707

  introduce a new DBOption random_access_max_buffer_size to limit
  the size of the random access buffer used for unbuffered access.
  Implement read ahead buffering when enabled.
  To that effect propagate compaction_readahead_size and the new option
  to the env options to make it available for the implementation.
  Add Hint() override so SetupForCompaction() call would call Hint()
  readahead can now be setup from both Hint() and EnableReadAhead()
  Add new option random_access_max_buffer_size support
  db_bench, options_helper to make it string parsable
  and the unit test.

Handle multiple batches in single log record - allow app to return a new batch + allow app to return corrupted record status

Signed-off-by: NSage Weil <sage@redhat.com>

Summary:
Added boolean variable to guard fallocate() calls.
Set to false to prevent space leaks when tests fail.

Test Plan:
Compliles
Set to false and ran log device tests

Reviewers: sdong, lovro, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48027

Summary:
Add options.compaction_pri, which specifies the policy about which file to compact first.
kCompactionPriByLargestSeq will compact oldest files first.
Verified the behavior in db_bench but did not write unit tests yet. Also need to make it settable through option string and dynamically changeable.

Test Plan: Will write unit tests

Reviewers: igor, rven, anthony, kradhakrishnan, IslamAbdelRahman, yhchiang, MarkCallaghan

Reviewed By: yhchiang

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D45951

Summary: Change the log level of DB start-up log from Warn to Header.

Test Plan: db_bench and observe the LOG header

Reviewers: igor, anthony, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47067

Summary:
RocksDB options can be dumped to the log file, and
up to this point the max_subcompactions option was not included
in this dump. This fixes that.

Test Plan: makek all && make check

Reviewers: MarkCallaghan, igor, noetzli, anthony, yhchiang, sdong

Reviewed By: yhchiang, sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D46971

Summary:
Valgrind is complaining because we are using hard_rate_limit (when serializing the options) without being initialized
http://our.intern.facebook.com/intern/sandcastle/3962140295/77533971/

Test Plan: run the test under valgrind

Reviewers: kradhakrishnan, yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D46929

Summary: Add an option to stop writes if compaction lefts behind. If estimated pending compaction bytes is more than threshold specified by options.hard_pending_compaction_bytes_liimt, writes will stop until compactions are cleared to under the threshold.

Test Plan: Add unit test DBTest.HardLimit

Reviewers: rven, kradhakrishnan, anthony, IslamAbdelRahman, yhchiang, igor

Reviewed By: igor

Subscribers: MarkCallaghan, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D45999

Summary:
ReadaheadRandomAccessFile acts as a transparent layer on top of RandomAccessFile. When a Read() request is issued, it issues a much bigger request to the OS and caches the result. When a new request comes in and we already have the data cached, it doesn't have to issue any requests to the OS.

We add ReadaheadRandomAccessFile layer only when file is read during compactions.

D45105 was incorrectly closed by Phabricator because I committed it to a separate branch (not master), so I'm resubmitting the diff.

Test Plan: make check

Reviewers: MarkCallaghan, sdong

Reviewed By: sdong

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D45123

Summary:
Up until this point we had DbOptions.num_subcompactions, but
it is semantically more correct to call this max_subcompactions since
we will schedule *up to* DbOptions.max_subcompactions smaller compactions
at a time during a compaction job.

I also added a --subcompactions option to db_bench

Test Plan: make all   make check

Reviewers: sdong, igor, anthony, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D45069

Summary: Currently compaction inputs share the same file descriptor and table reader as other foreground threads. It makes fadvise works less predictable. Add options.new_table_reader_for_compaction_inputs to enforce to create a new file descriptor and new table reader for it.

Test Plan: Add the option.

Reviewers: rven, anthony, kradhakrishnan, IslamAbdelRahman, igor, yhchiang

Reviewed By: igor

Subscribers: igor, MarkCallaghan, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43311

Summary:
Add options.compaction_measure_io_stats to print out / pass to listener accumulated time spent on write calls. Example outputs in info logs:

2015/08/12-16:27:59.463944 7fd428bff700 (Original Log Time 2015/08/12-16:27:59.463922) EVENT_LOG_v1 {"time_micros": 1439422079463897, "job": 6, "event": "compaction_finished", "output_level": 1, "num_output_files": 4, "total_output_size": 6900525, "num_input_records": 111483, "num_output_records": 106877, "file_write_nanos": 15663206, "file_range_sync_nanos": 649588, "file_fsync_nanos": 349614797, "file_prepare_write_nanos": 1505812, "lsm_state": [2, 4, 0, 0, 0, 0, 0]}

Add two more counters in iostats_context.

Also add a parameter of db_bench.

Test Plan: Add a unit test. Also manually verify LOG outputs in db_bench

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D44115

Summary: Add a new option that all LoadTableHandlers to use multiple threads to load files on DB Open and Recover

Test Plan:
make check -j64
COMPILE_WITH_TSAN=1 make check -j64
DISABLE_JEMALLOC=1 make all valgrind_check -j64 (still running)

Reviewers: yhchiang, anthony, rven, kradhakrishnan, igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43755

Summary:
wal_recovery_mode setting was not written to LOG. This diff
adds the log message

Test Plan: manually checked

Reviewers: kradhakrishnan, sdong, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43953

Summary:
Introduce DeleteScheduler that allow enforcing a rate limit on file deletion
Instead of deleting files immediately, files are moved to trash directory and deleted in a background thread that apply sleep penalty between deletes if needed.

I have updated PurgeObsoleteFiles and PurgeObsoleteWALFiles to use the delete_scheduler instead of env_->DeleteFile

Test Plan:
added delete_scheduler_test
existing unit tests

Reviewers: kradhakrishnan, anthony, rven, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43221

Summary:
UpdateAccumulatedStats() is used to optimize compaction decision
esp. when the number of deletion entries are high, but this function
can slowdown DBOpen esp. in disk environment.

This patch adds DBOptions::skip_sats_update_on_db_open, which skips
UpdateAccumulatedStats() in DB::Open() time when it's set to true.

Test Plan: Add DBCompactionTest.SkipStatsUpdateTest

Reviewers: igor, anthony, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: tnovak, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42843

Summary:
As of now compactions involving files from Level 0 and Level 1 are single
threaded because the files in L0, although sorted, are not range partitioned like
the other levels. This means that during L0-L1 compaction each file from L1
needs to be merged with potentially all the files from L0.

This attempt to parallelize the L0-L1 compaction assigns a thread and a
corresponding iterator to each L1 file that then considers only the key range
found in that L1 file and only the L0 files that have those keys (and only the
specific portion of those L0 files in which those keys are found). In this way
the overlap is minimized and potentially eliminated between different iterators
focusing on the same files.

The first step is to restructure the compaction logic to break L0-L1 compactions
into multiple, smaller, sequential compactions. Eventually each of these smaller
jobs will be run simultaneously. Areas to pay extra attention to are

  # Correct aggregation of compaction job statistics across multiple threads
  # Proper opening/closing of output files (make sure each thread's is unique)
  # Keys that span multiple L1 files
  # Skewed distributions of keys within L0 files

Test Plan: Make and run db_test (newer version has separate compaction tests) and compaction_job_stats_test

Reviewers: igor, noetzli, anthony, sdong, yhchiang

Reviewed By: yhchiang

Subscribers: MarkCallaghan, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42699

Summary:
When we first started, max_background_flushes was 0 by default and compaction thread was executing flushes (since there was no flush thread). Then, we switched the default max_background_flushes to 1. However, we still support the case where there is no flush thread and flushes are done in compaction. This is making our code a bit more complicated. By not supporting this use-case we can make our code simpler.

We have a special case that when you set max_background_flushes to 0, we
schedule the flush to execute on the compaction thread.

Test Plan: make check (there might be some unit tests that depend on this behavior)

Reviewers: IslamAbdelRahman, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D41931

Summary: It has been around for a while and it looks like it never found any uses in the wild. It's also complicating our compaction_job code quite a bit. We're deprecating it in 3.13, but will put it back in 3.14 if we actually find users that need this feature.

Test Plan: make check

Reviewers: noetzli, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42405

Summary: This option is guarding the feature implemented 2 and a half years ago: D8991. The feature was enabled by default back then and has been running without issues. There is no reason why any client would turn this feature off. I found no reference in fbcode.

Test Plan: none

Reviewers: sdong, yhchiang, anthony, dhruba

Reviewed By: dhruba

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42063

Summary: This helps Windows port to format their changes, as discussed. Might have formatted some other codes too becasue last 10 commits include more.

Test Plan: Build it.

Reviewers: anthony, IslamAbdelRahman, kradhakrishnan, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D41961

 invalid suffix on literal
 no return statement in function returning non-void CuckooStep::operator=
 extra qualification ‘rocksdb::spatial::Variant::
 dereferencing type-punned pointer will break strict-aliasing rules

 Summary: Make RocksDb build and run on Windows to be functionally
 complete and performant. All existing test cases run with no
 regressions. Performance numbers are in the pull-request.

 Test plan: make all of the existing unit tests pass, obtain perf numbers.

 Co-authored-by: Praveen Rao praveensinghrao@outlook.com
 Co-authored-by: Sherlock Huang baihan.huang@gmail.com
 Co-authored-by: Alex Zinoviev alexander.zinoviev@me.com
 Co-authored-by: Dmitri Smirnov dmitrism@microsoft.com

Summary:
Implementation of a table-level row cache.
It only caches point queries done through the `DB::Get` interface, queries done through the `Iterator` interface will completely skip the cache.

Supports snapshots and merge operations.

Test Plan: Ran `make valgrind_check commit-prereq`

Reviewers: igor, philipp, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D39849

Summary:
The "one size fits all" approach with WAL recovery will only introduce inconvenience for our varied clients as we go forward. The current recovery is a bit heuristic. We introduce the following levels of consistency while replaying the WAL.

1. RecoverAfterRestart (kTolerateCorruptedTailRecords)

This mocks the current recovery mode.

2. RecoverAfterCleanShutdown (kAbsoluteConsistency)

This is ideal for unit test and cases where the store is shutdown cleanly. We tolerate no corruption or incomplete writes.

3. RecoverPointInTime (kPointInTimeRecovery)

This is ideal when using devices with controller cache or file systems which can loose data on restart. We recover upto the point were is no corruption or incomplete write.

4. RecoverAfterDisaster (kSkipAnyCorruptRecord)

This is ideal mode to recover data. We tolerate corruption and incomplete writes, and we hop over those sections that we cannot make sense of salvaging as many records as possible.

Test Plan:
(1) Run added unit test to cover all levels.
(2) Run make check.

Reviewers: leveldb, sdong, igor

Subscribers: yoshinorim, dhruba

Differential Revision: https://reviews.facebook.net/D38487

Summary:
Currently RocksDB silently ignores this issue and doesn't compress the data. Based on discussion, we agree that this is pretty bad because it can cause confusion for our users.

This patch fails DB::Open() if we don't support the compression that is specified in the options.

Test Plan: make check with LZ4 not present. If Snappy is not present all tests will just fail because Snappy is our default library. We should make Snappy the requirement, since without it our default DB::Open() fails.

Reviewers: sdong, MarkCallaghan, rven, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D39687

Summary: Currently we dump DBOptions for each column family options we dump. This leads to duplicate lines in our LOG file. This diff fixes that.

Test Plan: Check out the LOG

Reviewers: sdong, rven, yhchiang

Reviewed By: yhchiang

Subscribers: IslamAbdelRahman, yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D39729

Summary:
We slow down data into the database to the rate of options.delayed_write_rate (a new option) with this patch.

The thread synchronization approach I take is to still synchronize write controller by DB mutex and GetDelay() is inside DB mutex. Try to minimize the frequency of getting time in GetDelay(). I verified it through db_bench and it seems to work

hard_rate_limit is deprecated.

options.delayed_write_rate is still not dynamically changeable. Need to work on it as a follow-up.

Test Plan: Add new unit tests in db_test

Reviewers: yhchiang, rven, kradhakrishnan, anthony, MarkCallaghan, igor

Reviewed By: igor

Subscribers: ikabiljo, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D36351

Summary:
Replacing the default value for compaction_filter_factory and compaction_filter_factory_v2 to be nullptr instead of DefaultCompactionFilterFactory / DefaultCompactionFilterFactoryV2
The reason for this is to be able to determine easily if we have compaction filter factory or not without depending on RTTI

Test Plan: make check

Reviewers: yoshinorim, ott, igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D39693

Summary: Include EventListener in stress test.

Test Plan: make blackbox_crash_test whitebox_crash_test

Reviewers: anthony, igor, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D39105

Summary:
For transactions, we are using the memtables to validate that there are no write conflicts.  But after flushing, we don't have any memtables, and transactions could fail to commit.  So we want to someone keep around some extra history to use for conflict checking.  In addition, we want to provide a way to increase the size of this history if too many transactions fail to commit.

After chatting with people, it seems like everyone prefers just using Memtables to store this history (instead of a separate history structure).  It seems like the best place for this is abstracted inside the memtable_list.  I decide to create a separate list in MemtableListVersion as using the same list complicated the flush/installalflushresults logic too much.

This diff adds a new parameter to control how much memtable history to keep around after flushing.  However, it sounds like people aren't too fond of adding new parameters.  So I am making the default size of flushed+not-flushed memtables be set to max_write_buffers.  This should not change the maximum amount of memory used, but make it more likely we're using closer the the limit.  (We are now postponing deleting flushed memtables until the max_write_buffer limit is reached).  So while we might use more memory on average, we are still obeying the limit set (and you could argue it's better to go ahead and use up memory now instead of waiting for a write stall to happen to test this limit).

However, if people are opposed to this default behavior, we can easily set it to 0 and require this parameter be set in order to use transactions.

Test Plan: Added a xfunc test to play around with setting different values of this parameter in all tests.  Added testing in memtablelist_test and planning on adding more testing here.

Reviewers: sdong, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D37443

Summary: Move listeners from ColumnFamilyOptions to DBOptions

Test Plan:
listener_test
compact_files_test

Reviewers: rven, anthony, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D39087