That makes BackupableDBTest.NoDoubleCopy test error.

Summary:
This diff introduces some features that were requested by two internal customers:
* Ability for backups not to share table files, because we can't guarantee that equal filename means equal content accross replicas
* Ability for two threads to call EnableFileDeletions() and DisableFileDeletions()
* Ability to stop backup from another thread and not slow down the DB close
* Copy the files to the temporary folder first and then atomically rename

Test Plan: Added some tests to backupable_db_test

Reviewers: dhruba, sanketh, muthu, sdong, haobo

Reviewed By: haobo

CC: leveldb, sanketh, muthu

Differential Revision: https://reviews.facebook.net/D14769

Summary:
We don't want two threads to clash if they concurrently call DisableFileDeletions() and EnableFileDeletions(). I'm adding a counter that will enable file deletions only after all DisableFileDeletions() calls have been negated with EnableFileDeletions().

However, we also don't want to break the old behavior, so I added a parameter force to EnableFileDeletions(). If force is true, we will still enable file deletions after every call to EnableFileDeletions(), which is what is happening now.

Test Plan: make check

Reviewers: dhruba, haobo, sanketh

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14781

Summary:
I realized that manifest will get deleted by PurgeObsoleteFiles in DBImpl, but it is sill cleaner to delete
files before we restore the backup

Test Plan: backupable_db_test

Reviewers: dhruba

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14619

Summary: We now delete backups with newer sequence number, so the clients don't have to handle confusing situations when they restore from backup.

Test Plan: added a unit test

Reviewers: dhruba

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14547

Summary: Valgrind complained about BackupableDB. This fixes valgrind errors. Also, I cleaned up some code.

Test Plan: valgrind does not complain anymore

Reviewers: dhruba

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14529

Summary:
In this diff I present you BackupableDB v1. You can easily use it to backup your DB and it will do incremental snapshots for you.
Let's first describe how you would use BackupableDB. It's inheriting StackableDB interface so you can easily construct it with your DB object -- it will add a method RollTheSnapshot() to the DB object. When you call RollTheSnapshot(), current snapshot of the DB will be stored in the backup dir. To restore, you can just call RestoreDBFromBackup() on a BackupableDB (which is a static method) and it will restore all files from the backup dir. In the next version, it will even support automatic backuping every X minutes.

There are multiple things you can configure:
1. backup_env and db_env can be different, which is awesome because then you can easily backup to HDFS or wherever you feel like.
2. sync - if true, it *guarantees* backup consistency on machine reboot
3. number of snapshots to keep - this will keep last N snapshots around if you want, for some reason, be able to restore from an earlier snapshot. All the backuping is done in incremental fashion - if we already have 00010.sst, we will not copy it again. *IMPORTANT* -- This is based on assumption that 00010.sst never changes - two files named 00010.sst from the same DB will always be exactly the same. Is this true? I always copy manifest, current and log files.
4. You can decide if you want to flush the memtables before you backup, or you're fine with backing up the log files -- either way, you get a complete and consistent view of the database at a time of backup.
5. More things you can find in BackupableDBOptions

Here is the directory structure I use:

   backup_dir/CURRENT_SNAPSHOT - just 4 bytes holding the latest snapshot
               0, 1, 2, ... - files containing serialized version of each snapshot - containing a list of files
               files/*.sst - sst files shared between snapshots - if one snapshot references 00010.sst and another one needs to backup it from the DB, it will just reference the same file
               files/ 0/, 1/, 2/, ... - snapshot directories containing private snapshot files - current, manifest and log files

All the files are ref counted and deleted immediatelly when they get out of scope.

Some other stuff in this diff:
1. Added GetEnv() method to the DB. Discussed with @haobo and we agreed that it seems right thing to do.
2. Fixed StackableDB interface. The way it was set up before, I was not able to implement BackupableDB.

Test Plan:
I have a unittest, but please don't look at this yet. I just hacked it up to help me with debugging. I will write a lot of good tests and update the diff.

Also, `make asan_check`

Reviewers: dhruba, haobo, emayanke

Reviewed By: dhruba

CC: leveldb, haobo

Differential Revision: https://reviews.facebook.net/D14295

Summary: Now DBWithTTL takes DB* and can behave more like StackableDB. This saves us a lot of duplicate work by defining interfaces

Test Plan: ttl_test with ASAN - OK

Reviewers: emayanke

Reviewed By: emayanke

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14481

Summary: As title

Test Plan: make clean and make

Reviewers: igor

Reviewed By: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14469

Summary: We need access to options for BackupableDB

Test Plan: make check

Reviewers: dhruba

Reviewed By: dhruba

CC: leveldb, reconnect.grayhat

Differential Revision: https://reviews.facebook.net/D14331

Summary: This is part of https://reviews.facebook.net/D14295 -- smaller diff that is easier to review

Test Plan: make asan_check

Reviewers: dhruba, haobo, emayanke

Reviewed By: emayanke

CC: leveldb, kailiu, reconnect.grayhat

Differential Revision: https://reviews.facebook.net/D14301

Summary:
Sure, let me put 8 bytes in that int32_t.

Brought to you by ASAN!

Test Plan: ttl_test

Reviewers: dhruba, haobo, kailiu, emayanke

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14193

Fixing the warning messages captured under mac os # Consider using `git commit -m 'One line title' && arc diff`. # You will save time by running lint and unit in the background.

Summary: The work to make sure mac os compiles rocksdb is not completed yet. But at least we can start cleaning some warnings captured only by g++ from mac os..

Test Plan: ran make in mac os

Reviewers: dhruba

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14049

Summary:
strict essentially means that we MUST find the startsequence. Thus we should return if starteSequence is not found in the first file in case strict is set. This will take care of ending the iterator in case of permanent gaps due to corruptions in the log files
Also created NextImpl function that will have internal variable to distinguish whether Next is being called from StartSequence or by application.
Set NotFoudn::gaps status to give an indication of gaps happeneing.
Polished the inline documentation at various places

Test Plan:
* db_repl_stress test
* db_test relating to transaction log iterator
* fbcode/wormhole/rocksdb/rocks_log_iterator
* sigma production machine sigmafio032.prn1

Reviewers: dhruba

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13689

Summary: This is to give application compaction filter a chance to access context information of a specific compaction run. For example, depending on whether a compaction goes through all data files, the application could do things differently.

Test Plan: make check

Reviewers: dhruba, kailiu, sdong

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13683

Summary:
This is to simplify rocksdb public APIs and improve the code quality.
Created an additional parameter to ParseFileName for log sub type and improved the code for deleting a wal file.
Wrote exhaustive unit-tests in delete_file_test
Unification of other redundant APIs can be taken up in a separate diff

Test Plan: Expanded delete_file test

Reviewers: dhruba, haobo, kailiu, sdong

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13647

Summary:
Add appropriate LICENSE and Copyright message.

Test Plan:
make check

Reviewers:

CC:

Task ID: #

Blame Rev:

Summary: Migrate names of properties from 'leveldb' prefix to 'rocksdb' prefix.

Test Plan: make check

Reviewers: emayanke, haobo

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13311

Summary:
Change namespace from leveldb to rocksdb. This allows a single
application to link in open-source leveldb code as well as
rocksdb code into the same process.

Test Plan: compile rocksdb

Reviewers: emayanke

Reviewed By: emayanke

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13287

Summary:
As explained in comments in GetLiveFiles in db.h, this option will cause flush to be skipped in GetLiveFiles because some use-cases use GetSortedWalFiles after GetLiveFiles to generate more complete snapshots.
Using GetSortedWalFiles after GetLiveFiles allows us to not Flush in GetLiveFiles first because wals have everything.
Note: file deletions will be disabled before calling GLF or GSWF so live logs will not move to archive logs or get delted.
Note: Manifest file is truncated to a proper value in GLF, so it will always reply from the proper wal files on a restart

Test Plan: make

Reviewers: dhruba, haobo

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13257

This reverts commit 5f2c136c.

Summary: should delete the proper variable

Test Plan: make all check

Reviewers: haobo, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D12921

Summary: Ttl-write makes a new writebatch and calls Write on the base db. It should recognize LogData also

Test Plan: make

Reviewers: dhruba, haobo

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D12747

Summary:
Add new command "change_compaction_style" to ldb tool. For
universal->level, it shows "nothing to do". For level->universal, it
compacts all files into a single one and moves the file to level 0.

Also add check for number of files at level 1+ when opening db with
universal compaction style.

Test Plan:
'make all check'. New unit test for internal convertion function. Also manully test various
cmd like:

./ldb change_compaction_style --old_compaction_style=0
--new_compaction_style=1 --db=/tmp/leveldbtest-3088/db_test

Reviewers: haobo, dhruba

Reviewed By: haobo

CC: vamsi, emayanke

Differential Revision: https://reviews.facebook.net/D12603

Summary: PutValues calls Flush in ttl_test which clears memtables. KeyMayExist called after that will not be able to read those key-values

Test Plan: make all check OPT=-g

Reviewers:leveldb

Summary: value needed to be filtered of timestamp

Test Plan: ./ttl_test

Reviewers: dhruba, haobo, vamsi

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D12657

Summary: Replace include/leveldb with include/rocksdb.

Test Plan:
make clean; make check
make clean; make release

Differential Revision: https://reviews.facebook.net/D12489

Summary: added "#pragma once" in the .h files

Test Plan: make and run: stringappend_test, redis_test

Reviewers: emayanke, haobo

Reviewed By: emayanke

CC: leveldb

Differential Revision: https://reviews.facebook.net/D12495

Test Plan:
- make all check;
- make release;
- make stringappend_test; ./stringappend_test

Reviewers: haobo, emayanke

Reviewed By: haobo

CC: leveldb, kailiu

Differential Revision: https://reviews.facebook.net/D12381

Summary: Also expanded class LogFile to have startSequene and FileSize and exposed it publicly

Test Plan: make all check

Reviewers: dhruba, haobo

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D12087

Summary:
-Added null checks and revisions to DBIter::MergeValuesNewToOld()
-Added DBIter test to stringappend_test
-Major fix with Merge and TTL
More plans for fixes later.

Test Plan:
-make clean; make stringappend_test -j 32; ./stringappend_test
-make all check;

Reviewers: haobo, emayanke, vamsi, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D12315

Summary:
Updated db_bench and utilities/merge_operators.h to allow for dynamic benchmarking
of merge operators in db_bench. Added a new test (--benchmarks=mergerandom), which performs
a bunch of random Merge() operations over random keys. Also added a "--merge_operator=" flag
so that the tester can easily benchmark different merge operators. Currently supports
the PutOperator and UInt64Add operator. Support for stringappend or list append may come later.

Test Plan:
	1. make db_bench
	2. Test the PutOperator (simulating Put) as follows:
./db_bench --benchmarks=fillrandom,readrandom,updaterandom,readrandom,mergerandom,readrandom --merge_operator=put
--threads=2

3. Test the UInt64AddOperator (simulating numeric addition) similarly:
./db_bench --value_size=8 --benchmarks=fillrandom,readrandom,updaterandom,readrandom,mergerandom,readrandom
--merge_operator=uint64add --threads=2

Reviewers: haobo, dhruba, zshao, MarkCallaghan

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D11535

Summary:
With Merge returning bool, it can keep failing silently(eg. While faling to fetch timestamp in TTL). We need to detect this through a rocksdb counter which can get bumped whenever Merge returns false. This will also be super-useful for the mcrocksdb-counter service where Merge may fail.
Added a counter NUMBER_MERGE_FAILURES and appropriately updated db/merge_helper.cc

I felt that it would be better to directly add counter-bumping in Merge as a default function of MergeOperator class but user should not be aware of this, so this approach seems better to me.

Test Plan: make all check

Reviewers: dnicholas, haobo, dhruba, vamsi

CC: leveldb

Differential Revision: https://reviews.facebook.net/D12129