Summary:
When using latest clang (3.6 or 3.7/trunck) rocksdb is failing with many errors. Almost all of them are missing override errors. This diff adds missing override keyword. No manual changes.

Prerequisites: bear and clang 3.5 build with extra tools

```lang=bash
% USE_CLANG=1 bear make all # generate a compilation database http://clang.llvm.org/docs/JSONCompilationDatabase.html
% clang-modernize -p . -include . -add-override
% make format
```

Test Plan:
Make sure all tests are passing.
```lang=bash
% #Use default fb code clang.
% make check
```
Verify less error and no missing override errors.
```lang=bash
% # Have trunk clang present in path.
% ROCKSDB_NO_FBCODE=1 CC=clang CXX=clang++ make
```

Reviewers: igor, kradhakrishnan, rven, meyering, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34077

Summary:
This diff contains trivial fixes for 6 scan-build warnings:

**db/c_test.c**
`db` variable is never read. Removed assignment.
scan-build report:
http://home.fburl.com/~sugak/latest20/report-9b77d2.html#EndPath

**db/db_iter.cc**
`skipping` local variable is assigned to false. Then in the next switch block the only "non return" case assign `skipping` to true, the rest cases don't use it and all do return.
scan-build report:
http://home.fburl.com/~sugak/latest20/report-13fca7.html#EndPath

**db/log_reader.cc**
In `bool Reader::SkipToInitialBlock()` `offset_in_block` local variable is assigned to 0 `if (offset_in_block > kBlockSize - 6)` and then never used. Removed the assignment and renamed it to `initial_offset_in_block` to avoid confusion.
scan-build report:
http://home.fburl.com/~sugak/latest20/report-a618dd.html#EndPath

In `bool Reader::ReadRecord(Slice* record, std::string* scratch)` local variable `in_fragmented_record` in switch case `kFullType` block is assigned to false and then does `return` without use. In the other switch case `kFirstType` block the same `in_fragmented_record` is assigned to false, but later assigned to true without prior use. Removed assignment for both cases.
scan-build reprots:
http://home.fburl.com/~sugak/latest20/report-bb86b0.html#EndPath
http://home.fburl.com/~sugak/latest20/report-a975be.html#EndPath

**table/plain_table_key_coding.cc**
Local variable `user_key_size` is assigned when declared. But then in both places where it is used assigned to `static_cast<uint32_t>(key.size() - 8)`. Changed to initialize the variable to the proper value in declaration.
scan-build report:
http://home.fburl.com/~sugak/latest20/report-9e6b86.html#EndPath

**tools/db_stress.cc**
Missing `break` in switch case block. This seems to be a bug. Added missing `break`.

Test Plan:
Make sure all tests are passing and scan-build does not report 'Dead assignment' and 'Dead initialization' bugs.
```lang=bash
% make check
% make analyze
```

Reviewers: meyering, igor, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D33795

Summary: rockuse more memory that asked to. Monitor and report.

Test Plan: run the pro with conditions to simulate the overusage. It should report that the process is using more memory than needed.

Reviewers: yhchiang, rven, sdong, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D33249

Summary: We don't have plans to work on this in the short term. If we ever resurrect the project, we can find the code in the history. No need for it to linger around

Test Plan: no test

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32349

Summary:
This diff adds BlockBasedTable format_version = 2. New format version brings better compressed block format for these compressions:
1) Zlib -- encode decompressed size in compressed block header
2) BZip2 -- encode decompressed size in compressed block header
3) LZ4 and LZ4HC -- instead of doing memcpy of size_t encode size as varint32. memcpy is very bad because the DB is not portable accross big/little endian machines or even platforms where size_t might be 8 or 4 bytes.

It does not affect format for snappy.

If you write a new database with format_version = 2, it will not be readable by RocksDB versions before 3.10. DB::Open() will return corruption in that case.

Test Plan:
Added a new test in db_test.
I will also run db_bench and verify VSIZE when block_cache == 1GB

Reviewers: yhchiang, rven, MarkCallaghan, dhruba, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D31461

Summary: This will be used to test format changes in https://reviews.facebook.net/D31461

Test Plan: run it

Reviewers: MarkCallaghan, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D31515

benchmark.sh won't run through all tests properly if one specifies wal_dir to be different than db directory.

Summary:
A command line like this to run all the tests:
source benchmark.config.sh && nohup ./benchmark.sh 'bulkload,fillseq,overwrite,filluniquerandom,readrandom,readwhilewriting'
where
benchmark.config.sh is:
export DB_DIR=/data/mysql/rocksdata
export WAL_DIR=/txlogs/rockswal
export OUTPUT_DIR=/root/rocks_benchmarking/output

Will fail for the tests that need a new DB .

Also 1) set disable_data_sync=0 and 2) add debug mode to run through all the tests more quickly

Test Plan: run ./benchmark.sh 'debug,bulkload,fillseq,overwrite,filluniquerandom,readrandom,readwhilewriting' and verify that there are no complaints about WAL dir not being empty.

Reviewers: sdong, yhchiang, rven, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D30909

Summary:
Priliminary diff to solicit comments.
Given DB path, dump all SST files (key/value and properties), WAL file and manifest
files. What command options do we need to support for this command? Maybe
output_hex for keys?

Test Plan: Create additional ldb unit tests.

Reviewers: sdong, rven

Reviewed By: rven

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D29547

Summary: as title

Test Plan: ran it

Reviewers: yhchiang, igor, sdong, MarkCallaghan

Reviewed By: MarkCallaghan

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D25563

Summary:
Fix compile warning in db_stress

Test Plan:
make db_stress

Summary:
Fix the following compile warning in db_stress.cc on Mac
tools/db_stress.cc:1688:52: error: format specifies type 'unsigned long' but the argument has type '::google::uint64' (aka 'unsigned long long') [-Werror,-Wformat]
    fprintf(stdout, "DB-write-buffer-size: %lu\n", FLAGS_db_write_buffer_size);
                                           ~~~     ^~~~~~~~~~~~~~~~~~~~~~~~~~
                                           %llu

Test Plan:
make

Summary:
Introduces a new class for managing write buffer memory across column
families.  We supplement ColumnFamilyOptions::write_buffer_size with
ColumnFamilyOptions::write_buffer, a shared pointer to a WriteBuffer
instance that enforces memory limits before flushing out to disk.

Test Plan: Added SharedWriteBuffer unit test to db_test.cc

Reviewers: sdong, rven, ljin, igor

Reviewed By: igor

Subscribers: tnovak, yhchiang, dhruba, xjin, MarkCallaghan, yoshinorim

Differential Revision: https://reviews.facebook.net/D22581

Summary:
In some environment such as android, the c++ library does not have
std::to_string.  This path adds rocksdb::ToString(), which wraps std::to_string
when std::to_string is not available, and implements std::to_string
in the other case.

Test Plan:
make dbg -j32
./db_test
make clean
make dbg OPT=-DOS_ANDROID -j32
./db_test

Reviewers: ljin, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D29181

Summary: First commit for rdb shell

Test Plan: unit_test.js does simple assertions on most of the main functionality; will update with rest of tests

Reviewers: igor, rven, lijn, yhciang, sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28749

Summary:
Make db_stress built for ROCKSDB_LITE.
The test doesn't pass tough. It seg fault quickly. But I took a look and it doesn't seem to be related to lite version. Likely to be a bug inside RocksDB.

Test Plan: make db_stress

Reviewers: yhchiang, rven, ljin, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D28797

Summary:
We need to turn on -Wshorten-64-to-32 for mobile. See D1671432 (internal phabricator) for details.

This diff turns on the warning flag and fixes all the errors. There were also some interesting errors that I might call bugs, especially in plain table. Going forward, I think it makes sense to have this flag turned on and be very very careful when converting 64-bit to 32-bit variables.

Test Plan: compiles

Reviewers: ljin, rven, yhchiang, sdong

Reviewed By: yhchiang

Subscribers: bobbaldwin, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28689

Summary:
Refactor sst_dump to follow the same structure as ldb. Introduce a
SSTDump interface.

Test Plan: built sst_dump and tried it manually.

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28485

Summary: Previously I made `make check` work with -Wshadow, but there are some tools that are not compiled using `make check`.

Test Plan: make all

Reviewers: yhchiang, rven, ljin, sdong

Reviewed By: ljin, sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28497

Summary: as title

Test Plan: ./db_test

Reviewers: sdong, yhchiang, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28269

This reverts commit bc9f36fd.

Summary: Fix lint errors and coding style of ldb related codes.

Test Plan: ./ldb

Reviewers: ljin, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28125

Summary:
Added two flags which operate as follows:
in_place_update: enable in_place_update for default column family
set_in_place_one_in: toggles the value of the option inplace_update_support with a probability of 1/N

Test Plan:
Run db_stress with the two flags above set.
Specifically tried in_place_update set to true and set_in_place_one_in set to 10,000.

Reviewers: ljin, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28029

Summary: RocksDB already depends on C++11, so we might as well all the goodness that C++11 provides. This means that we don't need AtomicPointer anymore. The less things in port/, the easier it will be to port to other platforms.

Test Plan: make check + careful visual review verifying that NoBarried got memory_order_relaxed, while Acquire/Release methods got memory_order_acquire and memory_order_release

Reviewers: rven, yhchiang, ljin, sdong

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D27543

Summary: Allow SetOptions() during db_stress test

Test Plan: make crash_test

Reviewers: sdong, yhchiang, rven, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D25497

Summary: Try to match some parameters from Dhruba's benchmarks on github

Test Plan: ran it

Reviewers: sdong, yhchiang, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D24687

Summary: Those were introduced with https://github.com/facebook/rocksdb/commit/2fb1fea30fd027bbd824a26b682d04d91a8661dc because the flushing behavior changed when max_background_flushes is > 0.

Test Plan: make check

Reviewers: ljin, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D23577

Summary:
Hope these scripts will allow people to run/repro benchmark easily
I think it is time to re-run flash benchmarks and report results
Please comment if any other benchmark runs are needed

Test Plan: ran it

Reviewers: yhchiang, igor, sdong

Reviewed By: igor

Subscribers: dhruba, MarkCallaghan, leveldb

Differential Revision: https://reviews.facebook.net/D23139

Summary:
The compilers we use treat char as signed. However, this is not guarantee of C standard and some compilers (for ARM platform for example), treat char as unsigned. Code that assumes that char is either signed or unsigned is wrong.

This change explicitly casts the char to signed version. This will not break any of our use cases on x86, which, I believe are all of them. In case somebody out there is using RocksDB on ARM AND using bloom filters, they're going to have a bad time. However, it is very unlikely that this is the case.

Test Plan: sanity test with previous commit (with new sanity test)

Reviewers: yhchiang, ljin, sdong

Reviewed By: ljin

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D22767

Summary:
1. Make filter_block.h a base class. Derive block_based_filter_block and full_filter_block. The previous one is the traditional filter block. The full_filter_block is newly added. It would generate a filter block that contain all the keys in SST file.

2. When querying a key, table would first check if full_filter is available. If not, it would go to the exact data block and check using block_based filter.

3. User could choose to use full_filter or tradional(block_based_filter). They would be stored in SST file with different meta index name. "filter.filter_policy" or "full_filter.filter_policy". Then, Table reader is able to know the fllter block type.

4. Some optimizations have been done for full_filter_block, thus it requires a different interface compared to the original one in filter_policy.h.

5. Actual implementation of filter bits coding/decoding is placed in util/bloom_impl.cc

Benchmark: base commit 1d23b5c4
Command:
db_bench --db=/dev/shm/rocksdb --num_levels=6 --key_size=20 --prefix_size=20 --keys_per_prefix=0 --value_size=100 --write_buffer_size=134217728 --max_write_buffer_number=2 --target_file_size_base=33554432 --max_bytes_for_level_base=1073741824 --verify_checksum=false --max_background_compactions=4 --use_plain_table=0 --memtablerep=prefix_hash --open_files=-1 --mmap_read=1 --mmap_write=0 --bloom_bits=10 --bloom_locality=1 --memtable_bloom_bits=500000 --compression_type=lz4 --num=393216000 --use_hash_search=1 --block_size=1024 --block_restart_interval=16 --use_existing_db=1 --threads=1 --benchmarks=readrandom —disable_auto_compactions=1
Read QPS increase for about 30% from 2230002 to 2991411.

Test Plan:
make all check
valgrind db_test
db_stress --use_block_based_filter = 0
./auto_sanity_test.sh

Reviewers: igor, yhchiang, ljin, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D20979

Summary:
As a preparation to support updating some options dynamically, I'd like
to first introduce ImmutableOptions, which is a subset of Options that
cannot be changed during the course of a DB lifetime without restart.

ColumnFamily will keep both Options and ImmutableOptions. Any component
below ColumnFamily should only take ImmutableOptions in their
constructor. Other options should be taken from APIs, which will be
allowed to adjust dynamically.

I am yet to make changes to memtable and other related classes to take
ImmutableOptions in their ctor. That can be done in a seprate diff as
this one is already pretty big.

Test Plan: make all check

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D22545

Summary:
1. assert db->Put to be true in db_stress
2. begin column family with name "1".

Test Plan: 1. ./db_stress

Reviewers: ljin, yhchiang, dhruba, sdong, igor

Reviewed By: sdong, igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D22659

Summary:
I will move compression related options in a separate diff since this
diff is already pretty lengthy.
I guess I will also need to change JNI accordingly :(

Test Plan: make all check

Reviewers: yhchiang, igor, sdong

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21915

Summary:
1. fix segment error when dumping old sst format (no properties nor stats)
2. Enable dumpping old sst format

Test Plan:
Generate block based sst file with "properties", and one with "stats" and one without neither.
Read it using sst_dump

Reviewers: ljin, igor, yhchiang, dhruba, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21837

Summary:
All public headers need to be under `include/rocksdb` directory. Otherwise, clients include our header files like this:

    #include <rocksdb/db.h>
    #include <utilities/backupable_db.h> // still our public header!

Also, internally, we include:

    #include "utilities/backupable/backupable_db.h" // internal header
    #include "utilities/backupable_db.h" // public header

which is confusing.

This way, when we install rocksdb as a system library, we can just copy `include/rocksdb` directory to system's header files. We can't really copy `utilities` directory to system's header files.

Test Plan: compiles

Reviewers: dhruba, ljin, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20409

Summary:
Since we have a lot of options for PlainTable, add a struct PlainTableOptions
to manage them

Test Plan: make all check

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20175

Summary:
Seems like NewTotalOrderPlainTableFactory is useless and is semantically incorrect.
Total order mode indicator is prefix_extractor == nullptr,
but NewTotalOrderPlainTableFactory doesn't set it to be nullptr. That's why some tests
in plain_table_db_tests is incorrect.

Test Plan: make all check

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19587