Remove malloc from FormatFileNumber

Summary: Replace unnecessary malloc with stack allocation

Test Plan: make all check

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21771
log db path info before open

Summary: 1. write db MANIFEST, CURRENT, IDENTITY, sst files, log files to log before open

Test Plan: run db and check LOG file

Reviewers: ljin, yhchiang, igor, dhruba, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21459
Add histogram for DB_SEEK

Summary: as title

Test Plan: make release

Reviewers: sdong, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21717
print compaction_filter name in Options.Dump

Summary:
Was looking at an issue. All options are the same except
compaction_filter was missed from a newer package. Our option dump does
not capture that

Test Plan: make release

Reviewers: sdong, igor, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21765
fix_valgrind_error_caused_in_db_info_dummper

Summary: 1. add default value to FileType type, thus avoid valgrind error

Test Plan: valgrind ./db_test

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21807
Allow env_posix to lower background thread IO priority

Summary: This is a linux-specific system call.

Test Plan: ran db_bench

Reviewers: igor, yhchiang, sdong

Reviewed By: sdong

Subscribers: haobo, leveldb

Differential Revision: https://reviews.facebook.net/D21183
fix compile error under Mac OS X
fix_sst_dump_for_old_sst_format

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
[Java] Add purgeOldBackups API

Summary:
1. Check status of CreateNewBackup. If status is not OK, then throw.
2. Add purgeOldBackups API

Test Plan:
make test
make sample

Reviewers: haobo, sdong, zzbennett, swapnilghike, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21753
Support purging logs from separate log directory

Summary:
1. Support purging info logs from a separate paths from DB path. Refactor the codes of generating info log prefixes so that it can be called when generating new files and scanning log directory.
2. Fix the bug of not scanning multiple DB paths (should only impact multiple DB paths)

Test Plan:
Add unit test for generating and parsing info log files
Add end-to-end test in db_test

Reviewers: yhchiang, ljin

Reviewed By: ljin

Subscribers: leveldb, igor, dhruba

Differential Revision: https://reviews.facebook.net/D21801
Fix autovector iterator increment/decrement comments

Summary: The prefix and postfix operators were mixed up in the autovector class.

Test Plan: Inspection

Reviewers: sdong, kailiu

Reviewed By: kailiu

Differential Revision: https://reviews.facebook.net/D21873
Fix typo huage => huge

Test Plan: Inspection

Reviewers: sdong

Reviewed By: sdong

Differential Revision: https://reviews.facebook.net/D21891
Merge pull request #234 from bbiao/master

fix compile error under Mac OS X
Ignore IntelliJ idea project files and ignore java/out folder
Feature - Implement Java API for Comparator and Slice. Allows use of
either byte[] or DirectByteBuffer for accessing underlying data.
Add locking to comparator jni callback methods which must be thread-safe