Commit Graph

1131 Commits

Author SHA1 Message Date
sdong
9a8e3f73ed plain table reader: non-mmap mode to keep two recent buffers
Summary: In plain table reader's non-mmap mode, we only keep the most recent read buffer. However, for binary search, it is likely we come back to a location to read. To avoid one pread in such a case, we keep two read buffers. It should cover most of the cases.

Test Plan:
1. run tests
2. check the optimization works through strace when running
./table_reader_bench -mmap_read=false --num_keys2=1 -num_keys1=5000 -table_factory=plain_table --iterator --through_db

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

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51171
2016-01-08 10:53:57 -08:00
sdong
c9e2490bc6 Fix DynamicBloomTest.concurrent_with_perf to pass TSAN
Summary: TSAN fails on DynamicBloomTest.concurrent_with_perf. This change fixes it. Not sure why though.

Test Plan: Run the test with TSAN and make sure no warning shown.

Reviewers: yhchiang, IslamAbdelRahman, anthony, ngbronson, rven

Reviewed By: rven

Subscribers: rven, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52383
2015-12-29 16:28:45 -08:00
sdong
edf1cd497f Not generating "__attribute__((__unused__))" for padding fields if it is not CLANG
Summary: Adding "__attribute__((__unused__))" after padding fields will pass CLANG build but will fail gcc 4.8.1. Fix it by not generating it under GCC 4.8.1.

Test Plan: Build under four combinations of USE_CLANG=0,1 and ROCKSDB_FBCODE_BUILD_WITH_481=0.1.

Reviewers: yhchiang, rven, ngbronson, anthony, IslamAbdelRahman

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52371
2015-12-28 18:37:23 -08:00
sdong
11672df19a Fix CLANG errors introduced by 7d87f02799
Summary: Fix some CLANG errors introduced in 7d87f02799

Test Plan: Build with both of CLANG and gcc

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

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52329
2015-12-28 10:00:58 -08:00
Siying Dong
7fafd52dce Merge pull request #900 from shuzhang1989/hdfs_env_fix
add a factory method for creating hdfs env
2015-12-28 09:28:04 -08:00
Shu Zhang
2b7c810db8 more foramt 2015-12-26 19:52:35 -08:00
Shu Zhang
b79ccbd573 indent 2015-12-26 19:50:28 -08:00
Nathan Bronson
7d87f02799 support for concurrent adds to memtable
Summary:
This diff adds support for concurrent adds to the skiplist memtable
implementations.  Memory allocation is made thread-safe by the addition of
a spinlock, with small per-core buffers to avoid contention.  Concurrent
memtable writes are made via an additional method and don't impose a
performance overhead on the non-concurrent case, so parallelism can be
selected on a per-batch basis.

Write thread synchronization is an increasing bottleneck for higher levels
of concurrency, so this diff adds --enable_write_thread_adaptive_yield
(default off).  This feature causes threads joining a write batch
group to spin for a short time (default 100 usec) using sched_yield,
rather than going to sleep on a mutex.  If the timing of the yield calls
indicates that another thread has actually run during the yield then
spinning is avoided.  This option improves performance for concurrent
situations even without parallel adds, although it has the potential to
increase CPU usage (and the heuristic adaptation is not yet mature).

Parallel writes are not currently compatible with
inplace updates, update callbacks, or delete filtering.
Enable it with --allow_concurrent_memtable_write (and
--enable_write_thread_adaptive_yield).  Parallel memtable writes
are performance neutral when there is no actual parallelism, and in
my experiments (SSD server-class Linux and varying contention and key
sizes for fillrandom) they are always a performance win when there is
more than one thread.

Statistics are updated earlier in the write path, dropping the number
of DB mutex acquisitions from 2 to 1 for almost all cases.

This diff was motivated and inspired by Yahoo's cLSM work.  It is more
conservative than cLSM: RocksDB's write batch group leader role is
preserved (along with all of the existing flush and write throttling
logic) and concurrent writers are blocked until all memtable insertions
have completed and the sequence number has been advanced, to preserve
linearizability.

My test config is "db_bench -benchmarks=fillrandom -threads=$T
-batch_size=1 -memtablerep=skip_list -value_size=100 --num=1000000/$T
-level0_slowdown_writes_trigger=9999 -level0_stop_writes_trigger=9999
-disable_auto_compactions --max_write_buffer_number=8
-max_background_flushes=8 --disable_wal --write_buffer_size=160000000
--block_size=16384 --allow_concurrent_memtable_write" on a two-socket
Xeon E5-2660 @ 2.2Ghz with lots of memory and an SSD hard drive.  With 1
thread I get ~440Kops/sec.  Peak performance for 1 socket (numactl
-N1) is slightly more than 1Mops/sec, at 16 threads.  Peak performance
across both sockets happens at 30 threads, and is ~900Kops/sec, although
with fewer threads there is less performance loss when the system has
background work.

Test Plan:
1. concurrent stress tests for InlineSkipList and DynamicBloom
2. make clean; make check
3. make clean; DISABLE_JEMALLOC=1 make valgrind_check; valgrind db_bench
4. make clean; COMPILE_WITH_TSAN=1 make all check; db_bench
5. make clean; COMPILE_WITH_ASAN=1 make all check; db_bench
6. make clean; OPT=-DROCKSDB_LITE make check
7. verify no perf regressions when disabled

Reviewers: igor, sdong

Reviewed By: sdong

Subscribers: MarkCallaghan, IslamAbdelRahman, anthony, yhchiang, rven, sdong, guyg8, kradhakrishnan, dhruba

Differential Revision: https://reviews.facebook.net/D50589
2015-12-25 11:03:40 -08:00
Shu Zhang
b4aa823661 format 2015-12-24 20:38:35 -08:00
Shu Zhang
4dfdd1d928 format 2015-12-24 20:32:29 -08:00
Siying Dong
298ba27ae2 Merge pull request #846 from yuslepukhin/enble_c4244_lossofdata
Enable MS compiler warning c4244.
2015-12-23 22:59:42 -08:00
Siying Dong
7810aa802a Merge pull request #899 from zhipeng-jia/fix_clang_warning
Fix clang warnings
2015-12-23 22:58:52 -08:00
Zhipeng Jia
ec2664fefd Fix clang compile error under Linux 2015-12-24 12:41:40 +08:00
Shu Zhang
4fd23fb130 add a factory method for creating hdfs env 2015-12-23 17:26:50 -08:00
sdong
15b8902264 Change default options.delayed_write_rate
Summary: We now have a mechanism to further slowdown writes. Double default options.delayed_write_rate to try to keep the default behavior closer to it used to be.

Test Plan: Run all tests.

Reviewers: IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: yhchiang, kradhakrishnan, rven, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52281
2015-12-23 14:51:55 -08:00
sdong
b9f77ba12b When slowdown is triggered, reduce the write rate
Summary: It's usually hard for users to set a value of options.delayed_write_rate. With this diff, after slowdown condition triggers, we greedily reduce write rate if estimated pending compaction bytes increase. If estimated compaction pending bytes drop, we increase the write rate.

Test Plan:
Add a unit test
Test with db_bench setting:
TEST_TMPDIR=/dev/shm/ ./db_bench --benchmarks=fillrandom -num=10000000 --soft_pending_compaction_bytes_limit=1000000000 --hard_pending_compaction_bytes_limit=3000000000 --delayed_write_rate=100000000

and make sure without the commit, write stop will happen, but with the commit, it will not happen.

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

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52131
2015-12-23 11:33:15 -08:00
Igor Canadi
8ac7fb8377 Merge pull request #863 from zhangyybuaa/fix_hdfs_error
Fix build error with hdfs
2015-12-22 09:27:51 +01:00
sdong
167fb919a5 ZSTD to use CompressionOptions.level
Summary: Now ZSTD hard code level 1. Change it to use the compression level setting.

Test Plan: Run it with hacked codes of sst_dump and show ZSTD compression sizes with different levels.

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

Reviewed By: IslamAbdelRahman

Subscribers: yoshinorim, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52041
2015-12-16 16:58:04 -08:00
Islam AbdelRahman
aececc209e Introduce ReadOptions::pin_data (support zero copy for keys)
Summary:
This patch update the Iterator API to introduce new functions that allow users to keep the Slices returned by key() valid as long as the Iterator is not deleted

ReadOptions::pin_data : If true keep loaded blocks in memory as long as the iterator is not deleted
Iterator::IsKeyPinned() : If true, this mean that the Slice returned by key() is valid as long as the iterator is not deleted

Also add a new option BlockBasedTableOptions::use_delta_encoding to allow users to disable delta_encoding if needed.

Benchmark results (using https://phabricator.fb.com/P20083553)

```
// $ du -h /home/tec/local/normal.4K.Snappy/db10077
// 6.1G    /home/tec/local/normal.4K.Snappy/db10077

// $ du -h /home/tec/local/zero.8K.LZ4/db10077
// 6.4G    /home/tec/local/zero.8K.LZ4/db10077

// Benchmarks for shard db10077
// _build/opt/rocks/benchmark/rocks_copy_benchmark \
//      --normal_db_path="/home/tec/local/normal.4K.Snappy/db10077" \
//      --zero_db_path="/home/tec/local/zero.8K.LZ4/db10077"

// First run
// ============================================================================
// rocks/benchmark/RocksCopyBenchmark.cpp          relative  time/iter  iters/s
// ============================================================================
// BM_StringCopy                                                 1.73s  576.97m
// BM_StringPiece                                   103.74%      1.67s  598.55m
// ============================================================================
// Match rate : 1000000 / 1000000

// Second run
// ============================================================================
// rocks/benchmark/RocksCopyBenchmark.cpp          relative  time/iter  iters/s
// ============================================================================
// BM_StringCopy                                              611.99ms     1.63
// BM_StringPiece                                   203.76%   300.35ms     3.33
// ============================================================================
// Match rate : 1000000 / 1000000
```

Test Plan: Unit tests

Reviewers: sdong, igor, anthony, yhchiang, rven

Reviewed By: rven

Subscribers: dhruba, lovro, adsharma

Differential Revision: https://reviews.facebook.net/D48999
2015-12-16 12:08:30 -08:00
Venkatesh Radhakrishnan
030215bf01 Running manual compactions in parallel with other automatic or manual compactions in restricted cases
Summary:
This diff provides a framework for doing manual
compactions in parallel with other compactions. We now have a deque of manual compactions. We also pass manual compactions as an argument from RunManualCompactions down to
BackgroundCompactions, so that RunManualCompactions can be reentrant.
Parallelism is controlled by the two routines
ConflictingManualCompaction to allow/disallow new parallel/manual
compactions based on already existing ManualCompactions. In this diff, by default manual compactions still have to run exclusive of other compactions. However, by setting the compaction option, exclusive_manual_compaction to false, it is possible to run other compactions in parallel with a manual compaction. However, we are still restricted to one manual compaction per column family at a time. All of these restrictions will be relaxed in future diffs.
I will be adding more tests later.

Test Plan: Rocksdb regression + new tests + valgrind

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

Reviewed By: sdong

Subscribers: yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47973
2015-12-14 11:20:34 -08:00
Dmitri Smirnov
aca403d2b5 Fix another rebase problems. 2015-12-11 17:33:40 -08:00
Dmitri Smirnov
236fe21c92 Enable MS compiler warning c4244.
Mostly due to the fact that there are differences in sizes of int,long
  on 64 bit systems vs GNU.
2015-12-11 16:47:34 -08:00
Yueh-Hsuan Chiang
00d6edf6a0 Ensure the destruction order of PosixEnv and ThreadLocalPtr
Summary:
By default, RocksDB initializes the singletons of ThreadLocalPtr first, then initializes PosixEnv
via static initializer.  Destructor terminates objects in reverse order, so terminating PosixEnv
(calling pthread_mutex_lock), then ThreadLocal (calling pthread_mutex_destroy).

However, in certain case, application might initialize PosixEnv first, then ThreadLocalPtr.
This will cause core dump at the end of the program (eg. https://github.com/facebook/mysql-5.6/issues/122)

This patch fix this issue by ensuring the destruction order by moving the global static singletons
to function static singletons.  Since function static singletons are initialized when the function is first
called, this property allows us invoke to enforce the construction of the static PosixEnv and the
singletons of ThreadLocalPtr by calling the function where the ThreadLocalPtr singletons belongs
right before we initialize the static PosixEnv.

Test Plan: Verified in the MyRocks.

Reviewers: yoshinorim, IslamAbdelRahman, rven, kradhakrishnan, anthony, sdong, MarkCallaghan

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51789
2015-12-11 00:21:58 -08:00
charsyam
c30b499541 fix typos in comments 2015-12-11 01:54:48 +09:00
sdong
56e77f0967 Deprecate options.soft_rate_limit and add options.soft_pending_compaction_bytes_limit
Summary: Deprecate options.soft_rate_limit, which is hard to tune, with options.soft_pending_compaction_bytes_limit, which would trigger the slowdown if estimated pending compaction bytes exceeds the threshold. The hope is to make it more striaght-forward to tune.

Test Plan: Modify DBTest.SoftLimit to cover options.soft_pending_compaction_bytes_limit instead; run all unit tests.

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

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51117
2015-12-09 18:22:45 -08:00
sdong
d6e1035a1f A new compaction picking priority that optimizes for write amplification for random updates.
Summary: Introduce a compaction picking priority that picks files who contains the oldest rows to compact. This is a mode that slightly improves write amplification for random update cases.

Test Plan: Add a unit test and run it in valgrind too.

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

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51459
2015-12-09 18:13:03 -08:00
yuslepukhin
49957f9a98 Prefer integer arithmetics
The code had conversion to double then casting to size_t
  and then casting uint32_t which caused compiler warning (VS15).
2015-12-09 14:06:23 -08:00
Siying Dong
9c227923c6 Merge pull request #788 from OpenChannelSSD/to_fb_master2
Move posix threads into a library
2015-12-08 18:06:38 -08:00
Siying Dong
fa3dbf203f Merge pull request #853 from Vaisman/enable_C4267_warning
Enable C4267 warning
2015-12-08 17:59:24 -08:00
Siying Dong
56bbecc316 Merge pull request #867 from SherlockNoMad/CacheFix
Replace malloc with new for LRU Cache Handle
2015-12-08 17:58:29 -08:00
Yueh-Hsuan Chiang
774b80e99e Resubmit the fix for a race condition in persisting options
Summary:
This patch fix a race condition in persisting options which will cause a crash when:

* Thread A obtain cf options and start to persist options based on that cf options.
* Thread B kicks in and finish DropColumnFamily and delete cf_handle.
* Thread A wakes up and tries to finish the persisting options and crashes.

Test Plan: Add a test in column_family_test that can reproduce the crash

Reviewers: anthony, IslamAbdelRahman, rven, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51717
2015-12-08 17:01:02 -08:00
sdong
ea11923550 Upgrade to ZSTD 0.4.2
Summary: Change to call the new compression function.

Test Plan: build and run db_bench with the compression to make sure it compresses.

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

Reviewed By: yhchiang

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51603
2015-12-08 16:33:26 -08:00
sdong
770dea9325 Fix occasional failure of DBTest.DynamicCompactionOptions
Summary: DBTest.DynamicCompactionOptions ocasionally fails during valgrind run. We sent a sleeping task to block compaction thread pool but we don't wait it to run.

Test Plan: Run the test multiple times in an environment which can cause failure.

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

Reviewed By: yhchiang

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51687
2015-12-07 18:38:39 -08:00
sdong
f307036bde Revert "Fix a race condition in persisting options"
This reverts commit 2fa3ed5180. It breaks RocksDB lite build
2015-12-07 17:09:12 -08:00
Yueh-Hsuan Chiang
2fa3ed5180 Fix a race condition in persisting options
Summary:
This patch fix a race condition in persisting options which will cause a crash when:

* Thread A obtain cf options and start to persist options based on that cf options.
* Thread B kicks in and finish DropColumnFamily and delete cf_handle.
* Thread A wakes up and tries to finish the persisting options and crashes.

Test Plan: Add a test in column_family_test that can reproduce the crash

Reviewers: anthony, IslamAbdelRahman, rven, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51609
2015-12-07 15:25:12 -08:00
Javier González
b2863017b1 Move posix threads into a library
Summary: This patch moves all posix thread logic to a separate library.
The motivation is to allow another environments to easily reuse posix
threads. HDFS wraps already posix threads; this split would simplify
this code.

Test Plan: No new functionality is added to posix Env or the threading
library, thus the current tests should suffice.
2015-12-07 12:03:38 +01:00
SherlockNoMad
3a98a7ae7f Replace malloc with new for LRU Cache Handle 2015-12-04 15:12:07 -08:00
Zhang Yangyang
4687ced5db fix ToString() not declared error 2015-12-02 21:45:28 +08:00
sdong
d27ea4c9e5 Initialize options.row_cache
Summary: options.row_cache should already been initialized as null by default. Still try to set it following current convention, because one valgrind failure reports a failure related to it.

Test Plan: Run all unit tests

Reviewers: yhchiang, kradhakrishnan, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51303
2015-11-30 10:30:35 -08:00
Nathan Bronson
9a9d4759b2 InlineSkipList part 3/3 - new skiplist type that colocates key and node
Summary:
This diff completes the creation of InlineSkipList<Cmp>, which is like
SkipList<const char*, Cmp> but it always allocates the key contiguously
with the node.  This allows us to remove the pointer from the node
to the key.  As a result the memory usage of the skip list is reduced
(by 1 to sizeof(void*) bytes depending on the padding required to align
the key storage), cache locality is improved, and we halve the number
of calls to the allocator.

For skip lists whose keys are freshly-allocated const char*,
InlineSkipList is stricly preferrable to SkipList.  This diff doesn't
replace SkipList, however, because some of the use cases of SkipList in
RocksDB are either character sequences that are not allocated at the
same time as the skip list node allocation (for example
hash_linklist_rep) or have different key types (for example
write_batch_with_index).  Taking advantage of inline allocation for
those cases is left to future work.

The perf win is biggest for small values.  For single-threaded CPU-bound
(32M fillrandom operations with no WAL log) with 16 byte keys and 0 byte
values, the db_bench perf goes from ~310k ops/sec to ~410k ops/sec.  For
large values the improvement is less pronounced, but seems to be between
5% and 10% on the same configuration.

Test Plan: make check

Reviewers: igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D51123
2015-11-24 15:16:02 -08:00
Vasili Svirski
41b32c6059 Enable C4267 warning
* conversion from 'size_t' to 'type', by add static_cast

Tested:
* by build solution on Windows, Linux locally,
* run tests
* build CI system successful
2015-11-24 16:33:09 +03:00
yuslepukhin
047bd22aae Build on Visual Studio 2015 Update 1 2015-11-20 15:31:47 -08:00
Dmitri Smirnov
89bacb7e7d Enable MS Warning C4804 : unsafe use of type 'bool' in operation 2015-11-18 16:23:19 -08:00
Islam AbdelRahman
4159ab8169 Merge pull request #839 from SherlockNoMad/memtableOption
Support Memtable Factory Parse in option_helper.cc
2015-11-17 17:09:49 -08:00
sdong
6170fec251 Fix build broken by previous commit of "option helper refactor"
Summary:
The commit of option helper refactor broken the build:
(1) a git merge problem
(2) some uncaught compiler warning
Fix it.

Test Plan: Make sure "make all" passes

Reviewers: anthony, IslamAbdelRahman, rven, kradhakrishnan, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D50943
2015-11-17 16:52:54 -08:00
Siying Dong
3a6643c2fd Merge pull request #805 from SherlockNoMad/OptionHelperFix
Option Helper Refactoring
2015-11-17 16:24:52 -08:00
SherlockNoMad
bd7be035e0 Support Memtable Factory Parse in option_helper.cc 2015-11-17 14:29:01 -08:00
Islam AbdelRahman
a163cc2d5a Lint everything
Summary:
```
arc2 lint --everything
```

run the linter on the whole code repo to fix exisitng lint issues

Test Plan: make check -j64

Reviewers: sdong, rven, anthony, kradhakrishnan, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D50769
2015-11-16 12:56:21 -08:00
Yueh-Hsuan Chiang
e11f676e34 Add OptionsUtil::LoadOptionsFromFile() API
Summary:
This patch adds OptionsUtil::LoadOptionsFromFile() and
OptionsUtil::LoadLatestOptionsFromDB(), which allow developers
to construct DBOptions and ColumnFamilyOptions from a RocksDB
options file.  Note that most pointer-typed options such as
merge_operator will not be constructed.

With this API, developers no longer need to remember all the
options in order to reopen an existing rocksdb instance like
the following:

  DBOptions db_options;
  std::vector<std::string> cf_names;
  std::vector<ColumnFamilyOptions> cf_opts;

  // Load primitive-typed options from an existing DB
  OptionsUtil::LoadLatestOptionsFromDB(
      dbname, &db_options, &cf_names, &cf_opts);

  // Initialize necessary pointer-typed options
  cf_opts[0].merge_operator.reset(new MyMergeOperator());
  ...

  // Construct the vector of ColumnFamilyDescriptor
  std::vector<ColumnFamilyDescriptor> cf_descs;
  for (size_t i = 0; i < cf_opts.size(); ++i) {
    cf_descs.emplace_back(cf_names[i], cf_opts[i]);
  }

  // Open the DB
  DB* db = nullptr;
  std::vector<ColumnFamilyHandle*> cf_handles;
  auto s = DB::Open(db_options, dbname, cf_descs,
                    &handles, &db);

Test Plan:
Augment existing tests in column_family_test
options_test
db_test

Reviewers: igor, IslamAbdelRahman, sdong, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D49095
2015-11-12 06:52:43 -08:00
Yueh-Hsuan Chiang
e114f0abb8 Enable RocksDB to persist Options file.
Summary:
This patch allows rocksdb to persist options into a file on
DB::Open, SetOptions, and Create / Drop ColumnFamily.
Options files are created under the same directory as the rocksdb
instance.

In addition, this patch also adds a fail_if_missing_options_file in DBOptions
that makes any function call return non-ok status when it is not able to
persist options properly.

  // If true, then DB::Open / CreateColumnFamily / DropColumnFamily
  // / SetOptions will fail if options file is not detected or properly
  // persisted.
  //
  // DEFAULT: false
  bool fail_if_missing_options_file;

Options file names are formatted as OPTIONS-<number>, and RocksDB
will always keep the latest two options files.

Test Plan:
Add options_file_test.

options_test
column_family_test

Reviewers: igor, IslamAbdelRahman, sdong, anthony

Reviewed By: anthony

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48285
2015-11-10 22:58:01 -08:00