Remove usage of C runtime API that has file handle limitation

Summary:
This patch fixes two issues in DBTest.ApproximateMemoryUsage:
- It was possible that a flush happened between getting the two properties in
  Phase 1, resulting in different numbers for the properties and failing the
  assertion. This is fixed by waiting for the flush to finish before getting
  the properties.
- There was a similar issue in Phase 2 and additionally there was an issue that
  rocksdb.size-all-mem-tables was not monotonically increasing because it was
  possible that a flush happened just after getting the properties and then
  another flush just before getting the properties in the next round. In this
  situation, the reported memory usage decreased. This is fixed by forcing a
  flush before getting the properties.

Note: during testing, I found that kFlushesPerRound does not seem very
accurate. I added a TODO for this and it would be great to get some input on
what to do there.

Test Plan:
The first issue can be made more likely to trigger by inserting a
`usleep(10000);` between the calls to GetIntProperty() in Phase 1.
The second issue can be made more likely to trigger by inserting a
`if (r != 0) usleep(10000);` before the calls to GetIntProperty() and a
`usleep(10000);` after the calls.
Then execute make db_test && ./db_test --gtest_filter=DBTest.ApproximateMemoryUsage

Reviewers: rven, yhchiang, igor, sdong, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45675

Helper functions to support direct IO

Summary:
This patch adds the helper functions and variables to allow a backend
implementing WritableFile to support direct IO when persisting a
memtable.

Test Plan:
Since there is no upstream implementation of WritableFile supporting
direct IO, the new behavior is disabled.

Tests should be provided by the backend implementing WritableFile.

Summary:
Add argument --show_table_properties to db_bench

  -show_table_properties (If true, then per-level table properties will be
    printed on every stats-interval when stats_interval is set and
    stats_per_interval is on.) type: bool default: false

Test Plan:
./db_bench --show_table_properties=1 --stats_interval=100000 --stats_per_interval=1
./db_bench --show_table_properties=1 --stats_interval=100000 --stats_per_interval=1 --num_column_families=2

Sample Output:

    Compaction Stats [column_family_name_000001]
    Level    Files   Size(MB) Score Read(GB)  Rn(GB) Rnp1(GB) Write(GB) Wnew(GB) Moved(GB) W-Amp Rd(MB/s) Wr(MB/s) Comp(sec) Comp(cnt) Avg(sec) Stall(cnt)  KeyIn KeyDrop
    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------
      L0      3/0          5   0.8      0.0     0.0      0.0       0.0      0.0       0.0   0.0      0.0     86.3         0        17    0.021          0       0      0
      L1      5/0          9   0.9      0.0     0.0      0.0       0.0      0.0       0.0   0.0      0.0      0.0         0         0    0.000          0       0      0
      L2      9/0         16   0.2      0.0     0.0      0.0       0.0      0.0       0.0   0.0      0.0      0.0         0         0    0.000          0       0      0
     Sum     17/0         31   0.0      0.0     0.0      0.0       0.0      0.0       0.0   1.0      0.0     86.3         0        17    0.021          0       0      0
     Int      0/0          0   0.0      0.0     0.0      0.0       0.0      0.0       0.0   1.0      0.0     83.9         0         2    0.022          0       0      0
    Flush(GB): cumulative 0.030, interval 0.004
    Stalls(count): 0 level0_slowdown, 0 level0_numfiles, 0 memtable_compaction, 0 leveln_slowdown_soft, 0 leveln_slowdown_hard

    Level[0]: # data blocks=2571; # entries=84813; raw key size=2035512; raw average key size=24.000000; raw value size=8481300; raw average value size=100.000000; data block size=5690119; index block size=82415; filter block size=0; (estimated) table size=5772534; filter policy name=N/A;
    Level[1]: # data blocks=4285; # entries=141355; raw key size=3392520; raw average key size=24.000000; raw value size=14135500; raw average value size=100.000000; data block size=9487353; index block size=137377; filter block size=0; (estimated) table size=9624730; filter policy name=N/A;
    Level[2]: # data blocks=7713; # entries=254439; raw key size=6106536; raw average key size=24.000000; raw value size=25443900; raw average value size=100.000000; data block size=17077893; index block size=247269; filter block size=0; (estimated) table size=17325162; filter policy name=N/A;
    Level[3]: # data blocks=0; # entries=0; raw key size=0; raw average key size=0.000000; raw value size=0; raw average value size=0.000000; data block size=0; index block size=0; filter block size=0; (estimated) table size=0; filter policy name=N/A;
    Level[4]: # data blocks=0; # entries=0; raw key size=0; raw average key size=0.000000; raw value size=0; raw average value size=0.000000; data block size=0; index block size=0; filter block size=0; (estimated) table size=0; filter policy name=N/A;
    Level[5]: # data blocks=0; # entries=0; raw key size=0; raw average key size=0.000000; raw value size=0; raw average value size=0.000000; data block size=0; index block size=0; filter block size=0; (estimated) table size=0; filter policy name=N/A;
    Level[6]: # data blocks=0; # entries=0; raw key size=0; raw average key size=0.000000; raw value size=0; raw average value size=0.000000; data block size=0; index block size=0; filter block size=0; (estimated) table size=0; filter policy name=N/A;

Reviewers: anthony, IslamAbdelRahman, MarkCallaghan, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45651

Summary:
This patch adds GetStringFromColumnFamilyOptions(), the inverse function
of the existing GetColumnFamilyOptionsFromString(), and improves
the implementation of GetColumnFamilyOptionsFromString().

Test Plan: Add a test in options_test.cc

Reviewers: igor, sdong, anthony, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: noetzli, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45009

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:
Currently, mmap returns IOError when user tries to read data past the end of the file. This diff changes the behavior. Now, we return just the bytes that we can, and report the size we returned via a Slice result. This is consistent with non-mmap behavior and also pread() system call.

This diff is taken out of D45123.

Test Plan: make check

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45645

DBIter to out extra keys with higher sequence numbers when changing direction from forward to backward

Summary:
When DBIter changes iterating direction from forward to backward, it might see some much larger keys with higher sequence ID. With this commit, these rows will be actively filtered out. It should fix existing disabled tests in db_iter_test.

This may not be a perfect fix, but it introduces least impact on existing codes, in order to be safe.

Test Plan:
Enable existing tests and make sure they pass. Add a new test DBIterWithMergeIterTest.InnerMergeIteratorDataRace8.
Also run all existing tests.

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

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D45567

Summary:
DBTest.GetProperty was failing occasionally (see task #8131266). The reason was
that the test closed the database before the compaction was done. When the test
reopened the database, RocksDB would schedule a compaction which in turn
created table readers and lead the test to fail the assertion that
rocksdb.estimate-table-readers-mem is 0. In most cases, GetIntProperty() of
rocksdb.estimate-table-readers-mem happened before the compaction created the
table readers, hiding the problem. This patch changes the
WaitForFlushMemTable() to WaitForCompact(). WaitForFlushMemTable() is not
necessary because it is already being called a couple of lines before without
any insertions in-between.

Test Plan:
Insert `usleep(10000);` just after `Reopen(options);` on line 2333 to make the issue more likely, then run:
make db_test && while ./db_test --gtest_filter=DBTest.GetProperty; do true; done

Reviewers: rven, yhchiang, anthony, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45603

Address noexcept and const integer lambda capture on win

Summary:
"rocksdb.aggregated-table-properties" and "rocksdb.aggregated-table-properties-at-level<N>"
should belong to GetProperty() instead of GetIntProperty(), but the comment mistakenly
classifies them to GetIntProperty().

This patch fix this comment error.

Test Plan: no code change.

Reviewers: sdong, anthony, IslamAbdelRahman, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D45561

  VS 2013 does not support noexcept.
   Complains about usage of ineteger constant within lambda requiring explicit capture.

Summary:
It was pointed out to me that the members of SubCompactionState
'earliest_snapshot', 'latest_snapshot' and 'visible_at_tip' are never
modified by the subcompactions, so they can stay as global varaibles
instead to make things simpler.

Test Plan: make all && make check

Reviewers: sdong, igor, noetzli, anthony, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D45477

Summary: There was a bad merge during refresh.

Test Plan: make -j all; make check

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D45555

Summary:
We have earlier added a feature to delete file iterators when the
current key is over the iterate upper bound. We now add a whitebox test
to check if the file iterators were actually deleted.

Test Plan: Add check for a range which has deleted iterators.

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45321

Summary:
After deleting file iterators which are over the iterate upper
bound, we also need to check for null pointers in
ResetIncompletIterators.

Test Plan: db_tailing_iter_test.TailingIteratorTrimSeekToNext

Reviewers: tnovak, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45525

Summary: See internal task t8056182

Test Plan: Added multi-threading in RateLimiter test

Reviewers: benj, AaronFeldman

Reviewed By: AaronFeldman

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45459

Summary:
See task #7983654. The example was triggering an assert in compaction job
because the compaction was not marked as manual. With this patch,
CompactionPicker::FormCompaction() marks compactions as manual. This patch
also fixes a couple of typos, adds optimistic_transaction_example to
.gitignore and librocksdb as a dependency for examples. Adding librocksdb as
a dependency makes sure that the examples are built with the latest changes
in librocksdb.

Test Plan: make clean && cd examples && make all && ./compact_files_example

Reviewers: rven, sdong, anthony, igor, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45117

Summary:
This patch adds "rocksdb.aggregated-table-properties"
and "rocksdb.aggregated-table-properties-at-levelN", the former
returns the aggreated table properties of a column family,
while the later returns the aggregated table properties
of the specified level N.

Test Plan: Added tests in db_test

Reviewers: igor, sdong, IslamAbdelRahman, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45087

Summary: wrong filename

Test Plan: none

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45531

Summary:
As I keep adding new features to transactions, I keep creating more duplicate code.  This diff cleans this up by creating a base implementation class for Transaction and OptimisticTransaction to inherit from.

The code in TransactionBase.h/.cc is all just copied from elsewhere.  The only entertaining part of this class worth looking at is the virtual TryLock method which allows OptimisticTransactions and Transactions to share the same common code for Put/Get/etc.

The rest of this diff is mostly red and easy on the eyes.

Test Plan: No functionality change.  existing tests pass.

Reviewers: sdong, jkedgar, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45135

Summary:
This patch fixes a race condition in DBTEst.DynamicMemtableOptions. In rare cases,
it was possible that the main thread would fill up both memtables before the flush
job acquired its work. Then, the flush job was flushing both memtables together,
producing only one L0 file while the test expected two. Now, the test waits for
flushes to finish earlier, to make sure that the memtables are flushed in separate
flush jobs.

Test Plan:
Insert "usleep(10000);" after "IOSTATS_SET_THREAD_POOL_ID(Env::Priority::HIGH);" in BGWorkFlush()
to make the issue more likely. Then test with:
make db_test && time while ./db_test --gtest_filter=*DynamicMemtableOptions; do true; done

Reviewers: rven, sdong, yhchiang, anthony, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45429

Summary: As title

Test Plan: make check

Reviewers: yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45447

Summary:
Currently, we only purge duplicate keys and deletions during flush if `earliest_seqno_in_memtable <= newest_snapshot`. This means that the newest snapshot happened before we first created the memtable. This is almost never true for MyRocks and MongoRocks.

This patch makes purging during flush able to understand snapshots. The main logic is copied from compaction_job.cc, although the logic over there is much more complicated and extensive. However, we should try to merge the common functionality at some point.

I need this patch to implement no_overwrite_i_promise functionality for flush. We'll also need this to support SingleDelete() during Flush(). @yoshinorim requested the feature.

Test Plan:
make check
I had to adjust some unit tests to understand this new behavior

Reviewers: yhchiang, yoshinorim, anthony, sdong, noetzli

Reviewed By: noetzli

Subscribers: yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42087

Summary:
db_bench output now displays Percentile many times with --statistics after
read IO latency histograms were added. So I only need the last one in the report output.

Task ID: #

Blame Rev:

Test Plan:
run run_flash_bench.sh

Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D45093

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: Add more test cases of data race causing wrong iterating results. Tag tests not passing as DISABLED_

Test Plan: Run the tests

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

Reviewed By: yhchiang

Subscribers: tnovak, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D44907

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 a counter of estimated bytes the DB needs to compact for all the compactions to finish. Expose it as a DB Property.
In the future, we can use threshold of this counter to replace soft rate limit and hard rate limit. A single threshold of estimated compaction debt in bytes will be easier for users to reason about when should slow down and stopping than more abstract soft and hard rate limits.

Test Plan: Add unit tests

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

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D44205

Summary:
Changes include:
* don't sync-on-commit for single writer thread in readwhile... tests
* make default block size 8kb rather than 4kb to avoid too small blocks after compression
* use snappy instead of zlib to avoid stalls from compression latency
* disable statistics
* use bytes_per_sync=8M to reduce throughput loss on disk
* use open_files=-1 to reduce mutex contention

Task ID: #

Blame Rev:

Test Plan:
run benchmark

Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D44961

Summary:
Currently, ThreadStatusFlush uses two sync-points to ensure
there's a flush currently running when calling GetThreadList().
However, one of the sync-point is inside db-mutex, which could
cause deadlock in case there's a DB::Get() call.

This patch fix this issue by moving the sync-point to a better
place where the flush job does not hold the mutex.

Test Plan: db_test

Reviewers: igor, sdong, anthony, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45045

Address windows build issues caused by introducing Subcompaction

Merge branch 'address_windows_build' of https://github.com/yuslepukhin/rocksdb into address_windows_build

 Intro SubCompactionState move functionality
 =delete copy functionality
 #ifdef SyncPoint in tests for Windows Release builds

  Intro SubCompactionState move functionality
  =delete copy functionality
  #ifdef SyncPoint in tests for Windows Release builds