Fixes valgrind error in GetSnapshotLink. Free checkpoint now.

Summary: Free checkpoint after its directory is removed.

Test Plan: Run valgrind with GetSnapshotLink.

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D29493

Update HISTORY.md for RocksJava

Make PartialCompactionFailure Test more robust again.

Summary:
Make PartialCompactionFailure Test more robust again by
blocking background compaction until we simulate the
file creation error.

Test Plan:
export ROCKSDB_TESTS=PartialCompactionFailure
./db_test

Reviewers: sdong, igor, ljin

Reviewed By: ljin

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28431

dummy var to suppress compiler warning/error

Summary: Revmoed this in D25641, causing compiler complain. put it back

Test Plan: make release

Reviewers: igor, yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27891

Move logging outside of mutex

Hotfix RocksDB 3.5

Summary: We'll release this as 3.5.1

Test Plan: Tested in master

Reviewers: tnovak, yhchiang, sdong, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D24639

update HISTORY.md

Summary: as title

Test Plan: no

Reviewers: igor, sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D22761

Update release note of 3.4

Summary: N/A

Test Plan: N/A

Reviewers: yhchiang, ljin

Reviewed By: ljin

Subscribers: dhruba, leveldb, igor

Differential Revision: https://reviews.facebook.net/D22053

Minor changes to CuckooTableBuilder

Summary:
- Copy the key and value to in-memory hash table during Add operation. Also modified cuckoo_table_reader_test to use this.
- Store only the user_key in in-memory hash table if it is last level file.
- Handle Carryover while chosing unused key in Finish() method in case unused key was never found before Finish() call.

Test Plan:
cuckoo_table_reader_test --enable_perf
cuckoo_table_builder_test
valgrind_check
asan_check

Reviewers: sdong, yhchiang, igor, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20715

[RocksDB] Make block based table hash index more adaptive

Summary: Currently, RocksDB returns error if a db written with prefix hash index, is later opened without providing a prefix extractor. This is uncessarily harsh. Without a prefix extractor, we could always fallback to the normal binary index.

Test Plan: unit test, also manually veried LOG that fallback did occur.

Reviewers: sdong, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19191