Fix Allocate test

Summary: For some reason, on a subset of our continuous build machines, preallocation is allocating 8 block more than it should be. Let's relax the test a little bit -- now we require the test to allocate *at least* the number of blocks as we told them to.

Test Plan: no

Reviewers: ljin, haobo, sdong

Reviewed By: ljin

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18141
Added benchmark functionality on the lines of folly/Benchmark.h

Summary: Added benchmark functionality on the lines of folly/Benchmark.h

Test Plan: Added unit tests

Reviewers: igor, haobo, sdong, ljin, yhchiang, dhruba

Reviewed By: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17973
Relax env_test::AllocateTest
Rename "benchmark" back to "bench".

Also, make `benchharness.cc` not compiled into rocksdb library.
[Java] Add Java bindings for memtables and sst format.

Summary:
Add Java bindings for memtables and sst format.  Specifically,
add two abstract Java classses --- MemTableConfig and SstFormatConfig.
Each MemTable / SST implementation should has its own config class
extends MemTableConfig / SstFormatConfig respectively and pass it
to Options via setMemTableConfig / setSstConfig.

Test Plan:
make rocksdbjava
make jdb_test
make jdb_bench
java/jdb_bench.sh \
  --benchmarks=fillseq,readrandom,readwhilewriting \
  --memtablerep=hash_skiplist \
  --use_plain_table=1 \
  --key_size=20 \
  --prefix_size=12 \
  --value_size=100 \
  --cache_size=17179869184 \
  --disable_wal=0 \
  --sync=0 \

Reviewers: haobo, ankgup87, sdong

Reviewed By: haobo

CC: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D17997
Single-threaded asan_crash_test
[Java] Add Java binding and Java test for ReadOptions.

Summary: Add Java binding and test for rocksdb::ReadOptions.

Test Plan:
make rocksdbjava
make jtest

Reviewers: haobo, dhruba, sdong, ankgup87, rsumbaly, swapnilghike, zzbennett

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18129
Move benchmark timing to Env::NowNanos()
Flush before Fsync()/Sync()

Summary: Calling Fsync()/Sync() on a file should give the guarantee that whatever you written to the file is now persisted. This is currently not the case, since we might have some data left in application cache as we do Fsync()/Sync(). For example, BuildTable() calls Fsync() without the flush, assuming all sst data is now persisted, but it's actually not. This may result in big inconsistencies.

Test Plan: no test

Reviewers: sdong, dhruba, haobo, ljin, yhchiang

Reviewed By: sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18159
Fix SIGFAULT when running sst_dump on v2.6 db

Summary: Fix the sigfault when running sst_dump on v2.6 db.

Test Plan:
    git checkout bba6595b1f3f42cf79bb21c2d5b981ede1cc0063
    make clean
    make db_bench
    ./db_bench --db=/tmp/some/db --benchmarks=fillseq
    arc patch D18039
    make clean
    make sst_dump
    ./sst_dump --file=/tmp/some/db --command=check

Reviewers: igor, haobo, sdong

Reviewed By: sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18039