Summary:
Use the rsync tempfile naming convention in our `BackupEngine`. The temp file follows the format, `.<filename>.<suffix>`, which is later renamed to `<filename>`. We fix `tmp` as the `<suffix>` as we don't need to use random bytes for now. The benefit is gluster treats this tempfile naming convention specially and applies hashing only to `<filename>`, so the file won't need to be linked or moved when it's renamed. Our gluster team suggested this will make things operationally easier.
Closes https://github.com/facebook/rocksdb/pull/3463
Differential Revision: D6893333
Pulled By: ajkr
fbshipit-source-id: fd7622978f4b2487fce33cde40dd3124f16bcaa8
Summary:
Added a new iterator property: `rocksdb.iterator.internal-key` to get the internal-key (converted to user key) at which the iterator stopped.
Closes https://github.com/facebook/rocksdb/pull/3525
Differential Revision: D7033694
Pulled By: sagar0
fbshipit-source-id: d51e6c00f5e9d766c6276ef79774b81c6c5216f8
Summary:
Deadlock: a memtable flush holds DB::mutex_ and calls ThreadLocalPtr::Scrape(), which locks ThreadLocalPtr mutex; meanwhile, a thread exit handler locks ThreadLocalPtr mutex and calls SuperVersionUnrefHandle, which tries to lock DB::mutex_.
This deadlock is hit all the time on our workload. It blocks our release.
In general, the problem is that ThreadLocalPtr takes an arbitrary callback and calls it while holding a lock on a global mutex. The same global mutex is (at least in some cases) locked by almost all ThreadLocalPtr methods, on any instance of ThreadLocalPtr. So, there'll be a deadlock if the callback tries to do anything to any instance of ThreadLocalPtr, or waits for another thread to do so.
So, probably the only safe way to use ThreadLocalPtr callbacks is to do only do simple and lock-free things in them.
This PR fixes the deadlock by making sure that local_sv_ never holds the last reference to a SuperVersion, and therefore SuperVersionUnrefHandle never has to do any nontrivial cleanup.
I also searched for other uses of ThreadLocalPtr to see if they may have similar bugs. There's only one other use, in transaction_lock_mgr.cc, and it looks fine.
Closes https://github.com/facebook/rocksdb/pull/3510
Reviewed By: sagar0
Differential Revision: D7005346
Pulled By: al13n321
fbshipit-source-id: 37575591b84f07a891d6659e87e784660fde815f
Summary:
We don't do fsync() after truncate in direct I/O writeable file (in fact we don't do any fsync ever). This can cause metadata not persistent to disk after the file is generated. We call it instead.
Closes https://github.com/facebook/rocksdb/pull/3500
Differential Revision: D6981482
Pulled By: siying
fbshipit-source-id: 7e2b591b7e5dd1b96fc0775515b8b9e6092980ef
Summary:
This fixes the following warnings when compiled with GCC7:
util/transaction_test_util.cc: In static member function ‘static rocksdb::Status rocksdb::RandomTransactionInserter::DBGet(rocksdb::DB*, rocksdb::Transaction*, rocksdb::ReadOptions&, uint16_t, uint64_t, bool, uint64_t*, std::__cxx11::string*, bool*)’:
util/transaction_test_util.cc:75:8: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=]
Status RandomTransactionInserter::DBGet(
^~~~~~~~~~~~~~~~~~~~~~~~~
util/transaction_test_util.cc:84:11: note: ‘snprintf’ output between 5 and 6 bytes into a destination of size 5
snprintf(prefix_buf, sizeof(prefix_buf), "%.4u", set_i + 1);
~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
util/transaction_test_util.cc: In static member function ‘static rocksdb::Status rocksdb::RandomTransactionInserter::Verify(rocksdb::DB*, uint16_t, uint64_t, bool, rocksdb::Random64*)’:
util/transaction_test_util.cc:245:8: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=]
Status RandomTransactionInserter::Verify(DB* db, uint16_t num_sets,
^~~~~~~~~~~~~~~~~~~~~~~~~
util/transaction_test_util.cc:268:13: note: ‘snprintf’ output between 5 and 6 bytes into a destination of size 5
snprintf(prefix_buf, sizeof(prefix_buf), "%.4u", set_i + 1);
~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Closes https://github.com/facebook/rocksdb/pull/3295
Differential Revision: D6609411
Pulled By: maysamyabandeh
fbshipit-source-id: 33f0add471056eb59db2f8bd4366e6dfbb1a187d
Summary: Grandfather in super old lint issues to make a clean slate for moving forward that allows us to have stronger enforcement on new issues.
Reviewed By: yiwu-arbug
Differential Revision: D6821806
fbshipit-source-id: 22797d31ec58e9eb0255d3b66fedfcfcb0dc127c
Summary:
Allow StackableDB optionally takes a shared_ptr on construction and thus hold shared ownership of the underlying DB.
Closes https://github.com/facebook/rocksdb/pull/3423
Differential Revision: D6824163
Pulled By: yiwu-arbug
fbshipit-source-id: dbdc30c42e007533a987ef413785e192340f03eb
Summary:
Java build on PPC64le has been broken since a few months, due to #2716. Fixing it with the least amount of changes.
(We should cleanup a little around this code when time permits).
This should fix the build failures seen in http://140.211.168.68:8080/job/Rocksdb/ .
Closes https://github.com/facebook/rocksdb/pull/3359
Differential Revision: D6712938
Pulled By: sagar0
fbshipit-source-id: 3046e8f072180693de2af4762934ec1ace309ca4
Summary:
Flush() call could be waiting indefinitely if min_write_buffer_number_to_merge is used. Consider the sequence:
1. User call Flush() with flush_options.wait = true
2. The manual flush started in the background
3. New memtable become immutable because of writes. The new memtable will not trigger flush if min_write_buffer_number_to_merge is not reached.
4. The manual flush finish.
Because of the new memtable created at step 3 not being flush, previous logic of WaitForFlushMemTable() keep waiting, despite the memtables it intent to flush has been flushed.
Here instead of checking if there are any more memtables to flush, WaitForFlushMemTable() also check the id of the earliest memtable. If the id is larger than that of latest memtable at the time flush was initiated, it means all the memtable at the time of flush start has all been flush.
Closes https://github.com/facebook/rocksdb/pull/3378
Differential Revision: D6746789
Pulled By: yiwu-arbug
fbshipit-source-id: 35e698f71c7f90b06337a93e6825f4ea3b619bfa
Summary:
added support for C and asm files as required for e612e317409e8a9d74cf05db0bd733403305f459.
Closes https://github.com/facebook/rocksdb/pull/3299
Differential Revision: D6612479
Pulled By: ajkr
fbshipit-source-id: 6263ed7c1602f249460421825c76b5721f396163
Summary:
With the ZSTD dictionary generator support added in #3057
`PORTABLE=1 ROCKSDB_NO_FBCODE=1 make rocksdbjavastatic` fails as it can't find zdict.h. Specifically due to:
e3a06f12d2/util/compression.h (L39)
In java static builds zstd code gets directly downloaded from https://github.com/facebook/zstd , and in there zdict.h is under dictBuilder directory. So, I modified libzstd.a target to use `make install` to collect all the header files into a single location and used that as the zstd's include path.
Closes https://github.com/facebook/rocksdb/pull/3260
Differential Revision: D6669850
Pulled By: sagar0
fbshipit-source-id: f8a7562a670e5aed4c4fb6034a921697590d7285
Summary:
The macro was added by mistake in #2372
Closes https://github.com/facebook/rocksdb/pull/3343
Differential Revision: D6681356
Pulled By: yiwu-arbug
fbshipit-source-id: 4180172fb0eaef4189c07f219241e0c261c03461
Summary:
Most popular versions of GCC can't identify platform on ARM if "-march=native" is specified. Remove it to unblock most people.
Closes https://github.com/facebook/rocksdb/pull/3346
Differential Revision: D6690544
Pulled By: siying
fbshipit-source-id: bbaba9fe2645b6b37144b36ea75beeff88992b49
Summary:
I experienced weird segfault because of this mismatch of type in log formatting. Fix it.
Closes https://github.com/facebook/rocksdb/pull/3345
Differential Revision: D6687224
Pulled By: siying
fbshipit-source-id: c51fb1c008b7ebc3efdc353a4adad3e8f5b3e9de
Summary:
**# Summary**
RocksDB uses SSE crc32 intrinsics to calculate the crc32 values but it does it in single way fashion (not pipelined on single CPU core). Intel's whitepaper () published an algorithm that uses 3-way pipelining for the crc32 intrinsics, then use pclmulqdq intrinsic to combine the values. Because pclmulqdq has overhead on its own, this algorithm will show perf gains on buffers larger than 216 bytes, which makes RocksDB a perfect user, since most of the buffers RocksDB call crc32c on is over 4KB. Initial db_bench show tremendous CPU gain.
This change uses the 3-way SSE algorithm by default. The old SSE algorithm is now behind a compiler tag NO_THREEWAY_CRC32C. If user compiles the code with NO_THREEWAY_CRC32C=1 then the old SSE Crc32c algorithm would be used. If the server does not have SSE4.2 at the run time the slow way (Non SSE) will be used.
**# Performance Test Results**
We ran the FillRandom and ReadRandom benchmarks in db_bench. ReadRandom is the point of interest here since it calculates the CRC32 for the in-mem buffers. We did 3 runs for each algorithm.
Before this change the CRC32 value computation takes about 11.5% of total CPU cost, and with the new 3-way algorithm it reduced to around 4.5%. The overall throughput also improved from 25.53MB/s to 27.63MB/s.
1) ReadRandom in db_bench overall metrics
PER RUN
Algorithm | run | micros/op | ops/sec |Throughput (MB/s)
3-way | 1 | 4.143 | 241387 | 26.7
3-way | 2 | 3.775 | 264872 | 29.3
3-way | 3 | 4.116 | 242929 | 26.9
FastCrc32c|1 | 4.037 | 247727 | 27.4
FastCrc32c|2 | 4.648 | 215166 | 23.8
FastCrc32c|3 | 4.352 | 229799 | 25.4
AVG
Algorithm | Average of micros/op | Average of ops/sec | Average of Throughput (MB/s)
3-way | 4.01 | 249,729 | 27.63
FastCrc32c | 4.35 | 230,897 | 25.53
2) Crc32c computation CPU cost (inclusive samples percentage)
PER RUN
Implementation | run | TotalSamples | Crc32c percentage
3-way | 1 | 4,572,250,000 | 4.37%
3-way | 2 | 3,779,250,000 | 4.62%
3-way | 3 | 4,129,500,000 | 4.48%
FastCrc32c | 1 | 4,663,500,000 | 11.24%
FastCrc32c | 2 | 4,047,500,000 | 12.34%
FastCrc32c | 3 | 4,366,750,000 | 11.68%
**# Test Plan**
make -j64 corruption_test && ./corruption_test
By default it uses 3-way SSE algorithm
NO_THREEWAY_CRC32C=1 make -j64 corruption_test && ./corruption_test
make clean && DEBUG_LEVEL=0 make -j64 db_bench
make clean && DEBUG_LEVEL=0 NO_THREEWAY_CRC32C=1 make -j64 db_bench
Closes https://github.com/facebook/rocksdb/pull/3173
Differential Revision: D6330882
Pulled By: yingsu00
fbshipit-source-id: 8ec3d89719533b63b536a736663ca6f0dd4482e9
Summary:
NUMBER_BLOCK_DECOMPRESSED and NUMBER_BLOCK_COMPRESSED are not reported unless the stats level contain detailed timers, which is wrong. They are normal counters. Fix it.
Closes https://github.com/facebook/rocksdb/pull/3263
Differential Revision: D6552519
Pulled By: siying
fbshipit-source-id: 40899ccea7b2856bb39752616657c0bfd432f6f9
Summary:
There were a few places where MSVC's implicit truncation warnings were getting triggered, which was causing the MSVC build to fail due to warnings being treated as errors. This resolves the issues by making the truncations in some places explicit, and by making it so there are no truncations of literals.
Fixes#3239
Supersedes #3259
Closes https://github.com/facebook/rocksdb/pull/3273
Reviewed By: yiwu-arbug
Differential Revision: D6569204
Pulled By: Orvid
fbshipit-source-id: c188cf1cf98d9acb6d94b71875041cc81f8ff088
Summary:
A data race is caught by tsan_crash test between compaction and DropColumnFamily:
https://gist.github.com/yiwu-arbug/5a2b4baae05eeb99ae1719b650f30a44 Compaction checks if the column family has been dropped on each key input, while user can issue DropColumnFamily which updates cfd->dropped_, causing the data race. Fixing it by making cfd->dropped_ an atomic.
Closes https://github.com/facebook/rocksdb/pull/3250
Differential Revision: D6535991
Pulled By: yiwu-arbug
fbshipit-source-id: 5571df020beae7fa7db6fff5ad0d598f49962895
Summary:
Let me know if more test coverage is needed
Closes https://github.com/facebook/rocksdb/pull/3213
Differential Revision: D6457165
Pulled By: miasantreble
fbshipit-source-id: 3f944abff28aa7775237f1c4f61c64ccbad4eea9
Summary:
Refactor BlobDB open logic. List of changes:
Major:
* On reopen, mark blob files found as immutable, do not use them for writing new keys.
* Not to scan the whole file to find file footer. Instead just seek to the end of the file and try to read footer.
Minor:
* Move most of the real logic from blob_db.cc to blob_db_impl.cc.
* Not to hold shared_ptr of event listeners in global maps in blob_db.cc
* Some changes to BlobFile interface.
* Improve logging and error handling.
Closes https://github.com/facebook/rocksdb/pull/3246
Differential Revision: D6526147
Pulled By: yiwu-arbug
fbshipit-source-id: 9dc4cdd63359a2f9b696af817086949da8d06952
Summary:
db/compaction_job.cc:
ReportStartedCompaction(compaction);
CID 1419863 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
2. uninit_member: Non-static class member bottommost_level_ is not initialized in this constructor nor in any functions that it calls.
db/compaction_picker_universal.cc:
7struct InputFileInfo {
2. uninit_member: Non-static class member level is not initialized in this constructor nor in any functions that it calls.
CID 1405355 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
4. uninit_member: Non-static class member index is not initialized in this constructor nor in any functions that it calls.
38 InputFileInfo() : f(nullptr) {}
db/dbformat.h:
ParsedInternalKey()
84 : sequence(kMaxSequenceNumber) // Make code analyzer happy
CID 1168095 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
2. uninit_member: Non-static class member type is not initialized in this constructor nor in any functions that it calls.
85 {} // Intentionally left uninitialized (for speed)
Closes https://github.com/facebook/rocksdb/pull/3091
Differential Revision: D6534558
Pulled By: yiwu-arbug
fbshipit-source-id: 5ada975956196d267b3f149386842af71eda7553
Summary:
Fix a race condition when we create a thread and immediately destroy
This case should be supported.
What happens is that the thread function needs the Data instance
to actually run but has no shared ownership and must rely on the
WindowsThread instance to continue existing.
To address this we change unique_ptr to shared_ptr and then
acquire an additional refcount for the threadproc which destroys it
just before the thread exit.
We choose to allocate shared_ptr instance on the heap as this allows
the original thread to continue w/o waiting for the new thread to start
running.
Closes https://github.com/facebook/rocksdb/pull/3240
Differential Revision: D6511324
Pulled By: yiwu-arbug
fbshipit-source-id: 4633ff7996daf4d287a9fe34f60c1dd28cf4ff36
Summary:
db/version_builder.cc:
117 base_vstorage_->InternalComparator();
CID 1351713 (#1 of 1): Uninitialized pointer field (UNINIT_CTOR)
2. uninit_member: Non-static class member field level_zero_cmp_.internal_comparator is not initialized in this constructor nor in any functions that it calls.
db/version_edit.h:
145 FdWithKeyRange()
146 : fd(),
147 smallest_key(),
148 largest_key() {
CID 1418254 (#1 of 1): Uninitialized pointer field (UNINIT_CTOR)
2. uninit_member: Non-static class member file_metadata is not initialized in this constructor nor in any functions that it calls.
149 }
db/version_set.cc:
120 }
CID 1322789 (#1 of 1): Uninitialized pointer field (UNINIT_CTOR)
4. uninit_member: Non-static class member curr_file_level_ is not initialized in this constructor nor in any functions that it calls.
121 }
db/write_batch.cc:
939 assert(cf_mems_);
CID 1419862 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
3. uninit_member: Non-static class member rebuilding_trx_seq_ is not initialized in this constructor nor in any functions that it calls.
940 }
Closes https://github.com/facebook/rocksdb/pull/3092
Differential Revision: D6505666
Pulled By: yiwu-arbug
fbshipit-source-id: fd2c68948a0280772691a419d72ac7e190951d86
Summary:
table/block.cc:
420 }
CID 1396127 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
7. uninit_member: Non-static class member restart_offset_ is not initialized in this constructor nor in any functions that it calls.
421}
table/block_based_table_builder.cc:
CID 1418259 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
7. uninit_member: Non-static class member compressed_cache_key_prefix_size is not initialized in this constructor nor in any functions that it calls.
table/block_based_table_reader.h:
3. uninit_member: Non-static class member index_type is not initialized in this constructor nor in any functions that it calls.
CID 1396147 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
5. uninit_member: Non-static class member hash_index_allow_collision is not initialized in this constructor nor in any functions that it calls.
413 global_seqno(kDisableGlobalSequenceNumber) {}
414
table/cuckoo_table_reader.cc:
55 if (hash_funs == user_props.end()) {
56 status_ = Status::Corruption("Number of hash functions not found");
5. uninit_member: Non-static class member is_last_level_ is not initialized in this constructor nor in any functions that it calls.
7. uninit_member: Non-static class member identity_as_first_hash_ is not initialized in this constructor nor in any functions that it calls.
9. uninit_member: Non-static class member use_module_hash_ is not initialized in this constructor nor in any functions that it calls.
11. uninit_member: Non-static class member num_hash_func_ is not initialized in this constructor nor in any functions that it calls.
13. uninit_member: Non-static class member key_length_ is not initialized in this constructor nor in any functions that it calls.
15. uninit_member: Non-static class member user_key_length_ is not initialized in this constructor nor in any functions that it calls.
17. uninit_member: Non-static class member value_length_ is not initialized in this constructor nor in any functions that it calls.
19. uninit_member: Non-static class member bucket_length_ is not initialized in this constructor nor in any functions that it calls.
21. uninit_member: Non-static class member cuckoo_block_size_ is not initialized in this constructor nor in any functions that it calls.
23. uninit_member: Non-static class member cuckoo_block_bytes_minus_one_ is not initialized in this constructor nor in any functions that it calls.
CID 1322785 (#2 of 2): Uninitialized scalar field (UNINIT_CTOR)
25. uninit_member: Non-static class member table_size_ is not initialized in this constructor nor in any functions that it calls.
57 return;
table/plain_table_index.h:
2. uninit_member: Non-static class member index_size_ is not initialized in this constructor nor in any functions that it calls.
CID 1322801 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
4. uninit_member: Non-static class member sub_index_size_ is not initialized in this constructor nor in any functions that it calls.
128 huge_page_tlb_size_(huge_page_tlb_size) {}
129
Closes https://github.com/facebook/rocksdb/pull/3113
Differential Revision: D6505719
Pulled By: yiwu-arbug
fbshipit-source-id: 38f44d8f9dfefb4c2e25d83b8df25a5201c75618
Summary:
error message was
```
==3095==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7ffd18216c40 at pc 0x0000005edda1 bp 0x7ffd18215550 sp 0x7ffd18214d00
...
Address 0x7ffd18216c40 is located in stack of thread T0 at offset 1952 in frame
#0 internal_repo_rocksdb/db_compaction_test.cc:1520 rocksdb::DBCompactionTest_DeleteFileRangeFileEndpointsOverlapBug_Test::TestBody()
```
It was unsafe to have slices referring to the temporary string objects' buffers, as those strings were destroyed before the slices were used. Fixed it by assigning the strings returned by `Key()` to local variables.
Closes https://github.com/facebook/rocksdb/pull/3238
Differential Revision: D6507864
Pulled By: ajkr
fbshipit-source-id: dd07de1a0070c6748c1ab4f3d7bd31f9a81889d0
Summary:
clang-analyzer complaint about db_ being nullptr, but it couldn't be because it checks exec_stats before proceed. Add an assert to get around the false-positive.
Test Plan
`make analyze`
Closes https://github.com/facebook/rocksdb/pull/3236
Differential Revision: D6505417
Pulled By: yiwu-arbug
fbshipit-source-id: e5b65764ea994dd9e4bab3e697b97dc70dc22cab
Summary:
`GetCurrentTime()` is used to populate `creation_time` table property during flushes and compactions. It is safe to ignore `GetCurrentTime()` failures here but they should be logged.
(Note that `creation_time` property was introduced as part of TTL-based FIFO compaction in #2480.)
Tes Plan:
`make check`
Closes https://github.com/facebook/rocksdb/pull/3231
Differential Revision: D6501935
Pulled By: sagar0
fbshipit-source-id: 376adcf4ab801d3a43ec4453894b9a10909c8eb6
Summary:
I browsed through the history since 5.9 was released and found some changes worth mentioning in HISTORY.md.
Closes https://github.com/facebook/rocksdb/pull/3237
Differential Revision: D6506472
Pulled By: ajkr
fbshipit-source-id: 627ce9f94ca33df9f0f231a9c5ced3624b05506c
Summary:
Fix for #2833.
- In `DeleteFilesInRange`, use `GetCleanInputsWithinInterval` instead of `GetOverlappingInputs` to make sure we get a clean cut set of files to delete.
- In `GetCleanInputsWithinInterval`, support nullptr as `begin_key` or `end_key`.
- In `GetOverlappingInputsRangeBinarySearch`, move the assertion for non-empty range away from `ExtendFileRangeWithinInterval`, which should be allowed to return an empty range (via `end_index < begin_index`).
Closes https://github.com/facebook/rocksdb/pull/2843
Differential Revision: D5772387
Pulled By: ajkr
fbshipit-source-id: e554e8461823c6be82b21a9262a2da02b3957881
Summary:
This is to fix tools/check_format_compatible.sh. The tool try to open
old versions of rocksdb with the provided options file. When options
file is missing (e.g. rocksdb 2.2), it should still proceed with default
options.
Closes https://github.com/facebook/rocksdb/pull/3232
Differential Revision: D6503955
Pulled By: yiwu-arbug
fbshipit-source-id: e44cfcce7ddc7d12cf83466ed3f3fe7624aa78b8
Summary:
Add recent versions for format compatible test. We should probably update the script to auto include available versions (by looking at include/rocksdb/versions.h and deduce branch names), but we can do it later.
Closes https://github.com/facebook/rocksdb/pull/3233
Differential Revision: D6503631
Pulled By: yiwu-arbug
fbshipit-source-id: e2b01d1ef6e784ff6ffa1bd75d741755e3c69a8c
Summary:
Since #1665, on merge error, iterator will be set to corrupted status, but it doesn't invalidate the iterator. Fixing it.
Closes https://github.com/facebook/rocksdb/pull/3226
Differential Revision: D6499094
Pulled By: yiwu-arbug
fbshipit-source-id: 80222930f949e31f90a6feaa37ddc3529b510d2c
Summary:
In the past Facebook didn't promote including a Code of Conduct when creating new projects, and many projects skipped this important document. Let's fix it. :)
**why make this change?:**
Facebook Open Source provides a Code of Conduct statement for all
projects to follow, to promote a welcoming and safe open source community.
Exposing the COC via a separate markdown file is a standard being
promoted by Github via the Community Profile in order to meet their Open
Source Guide's recommended community standards.
As you can see, adding this file will improve [the rocksdb community profile](https://github.com/facebook/rocksdb/community)
checklist and increase the visibility of our COC.
**test plan:**
Viewing it on my branch -
<img width="1008" alt="screen shot 2017-12-03 at 5 05 45 pm" src="https://user-images.githubusercontent.com/1114467/33532198-66012a56-d84c-11e7-8fab-29ed410bd600.png">
<img width="1015" alt="screen shot 2017-12-03 at 5 05 59 pm" src="https://user-images.githubusercontent.com/1114467/33532199-661813d8-d84c-11e7-941e-94754dd481e5.png">
**issue:**
internal task t23481323
Closes https://github.com/facebook/rocksdb/pull/3219
Reviewed By: yiwu-arbug
Differential Revision: D6494234
Pulled By: flarnie
fbshipit-source-id: 55b59db335cc5546f3a1c968322b9281a3dc3aaf
Summary:
The Options header file recommends using max_background_jobs rather than
directly setting max_background_compactions or max_background_flushes.
I've personally seen a performance problem where stalls were happening
because the one background flushing thread was blocked that was fixed
by this change -
https://github.com/cockroachdb/cockroach/issues/19699#issuecomment-347672485
Closes https://github.com/facebook/rocksdb/pull/3208
Differential Revision: D6473178
Pulled By: ajkr
fbshipit-source-id: 67c892ceb7b1909d251492640cb15a0f2262b7ed
Summary:
We should use it if available otherwise the tools builds never work. Thanks to #3212, we can set -DGFLAGS=1 and it'll be independent of the namespace with which gflags was compiled.
Closes https://github.com/facebook/rocksdb/pull/3214
Differential Revision: D6462214
Pulled By: ajkr
fbshipit-source-id: db4e5f1b905322e3119554a9d01b57532c499384
