Summary:
We used to name private directories like "1.tmp" while BackupEngine populated them, and then rename without the ".tmp" suffix (i.e., rename "1.tmp" to "1") after all files were copied. On glusterfs, directory renames like this require operations across many hosts, and partial failures have caused operational problems.

Fortunately we don't need to rename private directories. We already have a meta-file that uses the tempfile-rename pattern to commit a backup atomically after all its files have been successfully copied. So we can copy private files directly to their final location, so now there's no directory rename.
Closes https://github.com/facebook/rocksdb/pull/3749

Differential Revision: D7705610

Pulled By: ajkr

fbshipit-source-id: fd724a28dd2bf993ce323a5f2cb7e7d6980cc346

Summary:
Use the rsync tempfile naming convention in our `BackupEngine`. The temp file follows the format, `.<filename>.<suffix>`, which is later renamed to `<filename>`. We fix `tmp` as the `<suffix>` as we don't need to use random bytes for now. The benefit is gluster treats this tempfile naming convention specially and applies hashing only to `<filename>`, so the file won't need to be linked or moved when it's renamed. Our gluster team suggested this will make things operationally easier.
Closes https://github.com/facebook/rocksdb/pull/3463

Differential Revision: D6893333

Pulled By: ajkr

fbshipit-source-id: fd7622978f4b2487fce33cde40dd3124f16bcaa8

Summary:
- check most times after calling snprintf that the buffer didn't fill up. Previously we'd proceed and use `buf_size - len` as the length in subsequent calls, which underflowed as those are unsigned size_t.
- replace some memcpys with snprintf for consistency
Closes https://github.com/facebook/rocksdb/pull/3255

Differential Revision: D6541464

Pulled By: ajkr

fbshipit-source-id: 8610ea6a24f38e0a37c6d17bc65b7c712da6d932

Summary:
1. Class BackupMeta
```
52      : timestamp_(0), size_(0), meta_filename_(meta_filename),

CID 1168103 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
2. uninit_member: Non-static class member sequence_number_ is not initialized in this constructor nor in any functions that it calls.
153        file_infos_(file_infos), env_(env) {}
```
2. class BackupEngineImpl
```
513  }
        7. uninit_member: Non-static class member latest_backup_id_ is not initialized in this constructor nor in any functions that it calls.

CID 1322803 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
9. uninit_member: Non-static class member latest_valid_backup_id_ is not initialized in this constructor nor in any functions that it calls.
514}
```
3. struct BackupAfterCopyOrCreateWorkItem
```
368  struct BackupAfterCopyOrCreateWorkItem {
369    std::future<CopyOrCreateResult> result;
        1. member_decl: Class member declaration for shared.
370    bool shared;
        3. member_decl: Class member declaration for needed_to_copy.
371    bool needed_to_copy;
        5. member_decl: Class member declaration for backup_env.
372    Env* backup_env;
373    std::string dst_path_tmp;
374    std::string dst_path;
375    std::string dst_relative;
        2. uninit_member: Non-static class member shared is not initialized in this constructor nor in any functions that it calls.
        4. uninit_member: Non-static class member needed_to_copy is not initialized in this constructor nor in any functions that it calls.

CID 1396122 (#1 of 1): Uninitialized pointer field (UNINIT_CTOR)
6. uninit_member: Non-static class member backup_env is not initialized in this constructor nor in any functions that it calls.
376    BackupAfterCopyOrCreateWorkItem() {}
```
4. struct CopyOrCreateWorkItem
```
318  struct CopyOrCreateWorkItem {
319    std::string src_path;
320    std::string dst_path;
321    std::string contents;
        1. member_decl: Class member declaration for src_env.
322    Env* src_env;
        3. member_decl: Class member declaration for dst_env.
323    Env* dst_env;
        5. member_decl: Class member declaration for sync.
324    bool sync;
        7. member_decl: Class member declaration for rate_limiter.
325    RateLimiter* rate_limiter;
        9. member_decl: Class member declaration for size_limit.
326    uint64_t size_limit;
327    std::promise<CopyOrCreateResult> result;
328    std::function<void()> progress_callback;
329
        2. uninit_member: Non-static class member src_env is not initialized in this constructor nor in any functions that it calls.
        4. uninit_member: Non-static class member dst_env is not initialized in this constructor nor in any functions that it calls.
        6. uninit_member: Non-static class member sync is not initialized in this constructor nor in any functions that it calls.
        8. uninit_member: Non-static class member rate_limiter is not initialized in this constructor nor in any functions that it calls.

CID 1396123 (#1 of 1): Uninitialized pointer field (UNINIT_CTOR)
10. uninit_member: Non-static class member size_limit is not initialized in this constructor nor in any functions that it calls.
330    CopyOrCreateWorkItem() {}
```
5. struct RestoreAfterCopyOrCreateWorkItem
```
struct RestoreAfterCopyOrCreateWorkItem {
410    std::future<CopyOrCreateResult> result;
        1. member_decl: Class member declaration for checksum_value.
411    uint32_t checksum_value;

CID 1396153 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
2. uninit_member: Non-static class member checksum_value is not initialized in this constructor nor in any functions that it calls.
412    RestoreAfterCopyOrCreateWorkItem() {}
```
Closes https://github.com/facebook/rocksdb/pull/3131

Differential Revision: D6428556

Pulled By: sagar0

fbshipit-source-id: a86675444543eff028e3cae6942197a143a112c4

Summary:
There are internal users who open BackupEngine for writing new backups only, and they don't care whether old backups can be read or not. The condition `BackupableDBOptions::max_valid_backups_to_open == 0` should be supported (previously in df74b775 I made the mistake of choosing 0 as a special value to disable the limit).
Closes https://github.com/facebook/rocksdb/pull/2819

Differential Revision: D5751599

Pulled By: ajkr

fbshipit-source-id: e73ac19eb5d756d6b68601eae8e43407ee4f2752

Summary:
Backup engine is intentionally openable even when some backups are corrupt. Previously the engine could write new backups as long as the most recent backup wasn't corrupt. This PR makes the backup engine able to create new backups even when the most recent one is corrupt.

We now maintain two ID instance variables:

- `latest_backup_id_` is used when creating backup to choose the new ID
- `latest_valid_backup_id_` is used when restoring latest backup since we want most recent valid one
Closes https://github.com/facebook/rocksdb/pull/2804

Differential Revision: D5734148

Pulled By: ajkr

fbshipit-source-id: db440707b31df2c7b084188aa5f6368449e10bcf

Summary:
This reverts the previous commit 1d7048c5, which broke the build.

Did a `git revert 1d7048c5`.
Closes https://github.com/facebook/rocksdb/pull/2627

Differential Revision: D5476473

Pulled By: sagar0

fbshipit-source-id: 4756ff5c0dfc88c17eceb00e02c36176de728d06

Summary: This uses `clang-tidy` to comment out unused parameters (in functions, methods and lambdas) in fbcode. Cases that the tool failed to handle are fixed manually.

Reviewed By: igorsugak

Differential Revision: D5454343

fbshipit-source-id: 5dee339b4334e25e963891b519a5aa81fbf627b2

Summary: Closes https://github.com/facebook/rocksdb/pull/2589

Differential Revision: D5431502

Pulled By: siying

fbshipit-source-id: 8ebf8c87883daa9daa54b2303d11ce01ab1f6f75

Summary:
Allow users to rate limit background work based on read bytes, written bytes, or sum of read and written bytes. Support these by changing the RateLimiter API, so no additional options were needed.
Closes https://github.com/facebook/rocksdb/pull/2433

Differential Revision: D5216946

Pulled By: ajkr

fbshipit-source-id: aec57a8357dbb4bfde2003261094d786d94f724e

Summary:
Disable direct reads for log and manifest. Direct reads should not affect sequential_file
Also add kDirectIO for option_config_ in db_test_util
Closes https://github.com/facebook/rocksdb/pull/2337

Differential Revision: D5100261

Pulled By: lightmark

fbshipit-source-id: 0ebfd13b93fa1b8f9acae514ac44f8125a05868b

Summary: Closes https://github.com/facebook/rocksdb/pull/2226

Differential Revision: D4967547

Pulled By: siying

fbshipit-source-id: dd3b58ae1e7a106ab6bb6f37ab5c88575b125ab4

Summary:
These code paths forked when checkpoint was introduced by copy/pasting the core backup logic. Over time they diverged and bug fixes were sometimes applied to one but not the other (like fix to include all relevant WALs for 2PC), or it required extra effort to fix both (like fix to forge CURRENT file). This diff reunites the code paths by extracting the core logic into a function, CreateCustomCheckpoint(), that is customizable via callbacks to implement both checkpoint and backup.

Related changes:

- flush_before_backup is now forcibly enabled when 2PC is enabled
- Extracted CheckpointImpl class definition into a header file. This is so the function, CreateCustomCheckpoint(), can be called by internal rocksdb code but not exposed to users.
- Implemented more functions in DummyDB/DummyLogFile (in backupable_db_test.cc) that are used by CreateCustomCheckpoint().
Closes https://github.com/facebook/rocksdb/pull/1932

Differential Revision: D4622986

Pulled By: ajkr

fbshipit-source-id: 157723884236ee3999a682673b64f7457a7a0d87

Summary:
This was requested by a customer who wants to proactively monitor whether any valid backups are available. The existing performance was poor because Open() serially reads every small meta-file (one per backup), which was slow on HDFS.

Now we only read the minimum number of meta-files to find `max_valid_backups_to_open` valid backups. The customer mentioned above can just set it to one.
Closes https://github.com/facebook/rocksdb/pull/2151

Differential Revision: D4882564

Pulled By: ajkr

fbshipit-source-id: cb0edf9e8ac693e4d5f24902e725a011ed8c0c2f

Summary:
It is confusing to have auto_roll_logger to stay under db/, which has nothing to do with database. Move filename together as it is a dependency.
Closes https://github.com/facebook/rocksdb/pull/2080

Differential Revision: D4821141

Pulled By: siying

fbshipit-source-id: ca7d768

Summary:
previously we only cleaned up .tmp files under "shared/" and "private/" directories in case the previous backup failed. we need to do the same for "shared_checksum/"; otherwise, the subsequent backup will fail if it tries to backup at least one of the same files.
Closes https://github.com/facebook/rocksdb/pull/2062

Differential Revision: D4805599

Pulled By: ajkr

fbshipit-source-id: eaa6088

Summary:
Changed the naming of backup engine threads from "ldb" to "backup_engine"
Closes https://github.com/facebook/rocksdb/pull/2053

Differential Revision: D4799325

Pulled By: ajkr

fbshipit-source-id: 046893f

Summary:
current logging
```
2017/03/14-14:20:30.393432 7fedde9f5700 (Original Log Time 2017/03/14-14:20:30.393414) [default] Level summary: base level 1 max bytes base 268435456 files[1 0 0 0 0 0 0] max score 0.25
2017/03/14-14:20:30.393438 7fedde9f5700 [JOB 2] Try to delete WAL files size 61417909, prev total WAL file size 73820858, number of live WAL files 2.
2017/03/14-14:20:30.393464 7fedde9f5700 [DEBUG] [JOB 2] Delete /dev/shm/old_logging//MANIFEST-000001 type=3 #1 -- OK
2017/03/14-14:20:30.393472 7fedde9f5700 [DEBUG] [JOB 2] Delete /dev/shm/old_logging//000003.log type=0 #3 -- OK
2017/03/14-14:20:31.427103 7fedd49f1700 [default] New memtable created with log file: #9. Immutable memtables: 0.
2017/03/14-14:20:31.427179 7fedde9f5700 [JOB 3] Syncing log #6
2017/03/14-14:20:31.427190 7fedde9f5700 (Original Log Time 2017/03/14-14:20:31.427170) Calling FlushMemTableToOutputFile with column family [default], flush slots available 1, compaction slots allowed 1, compaction slots scheduled 1
2017/03/14-14:20:31.
Closes https://github.com/facebook/rocksdb/pull/1990

Differential Revision: D4708695

Pulled By: IslamAbdelRahman

fbshipit-source-id: cb8968f

Summary:
This is the metric I plan to use for adaptive rate limiting. The statistics are updated only if the rate limiter is drained by flush or compaction. I believe (but am not certain) that this is the normal case.

The Statistics object is passed in RateLimiter::Request() to avoid requiring changes to client code, which would've been necessary if we passed it in the RateLimiter constructor.
Closes https://github.com/facebook/rocksdb/pull/1946

Differential Revision: D4646489

Pulled By: ajkr

fbshipit-source-id: d8e0161

Summary:
InsertPathnameToSizeBytes() is called on shared/ and shared_checksum/ directories, which only exist for certain configurations. If we try to list a non-existent directory's contents, some Envs will dump an error message. Let's avoid this by checking whether the directory exists before listing its contents.
Closes https://github.com/facebook/rocksdb/pull/1895

Differential Revision: D4596301

Pulled By: ajkr

fbshipit-source-id: c809679

Summary:
As the last step in backup creation, the .tmp directory is renamed omitting the .tmp suffix. In case the process terminates before this, the .tmp directory will be left behind. Even if this happens, we want future backups to succeed, so I added some checks/cleanup for this case.
Closes https://github.com/facebook/rocksdb/pull/1896

Differential Revision: D4597323

Pulled By: ajkr

fbshipit-source-id: 48900d8

Summary:
introduce new methods into a public threadpool interface,
- allow submission of std::functions as they allow greater flexibility.
- add Joining methods to the implementation to join scheduled and submitted jobs with
  an option to cancel jobs that did not start executing.
- Remove ugly `#ifdefs` between pthread and std implementation, make it uniform.
- introduce pimpl for a drop in replacement of the implementation
- Introduce rocksdb::port::Thread typedef which is a replacement for std::thread.  On Posix Thread defaults as before std::thread.
- Implement WindowsThread that allocates memory in a more controllable manner than windows std::thread with a replaceable implementation.
- should be no functionality changes.
Closes https://github.com/facebook/rocksdb/pull/1823

Differential Revision: D4492902

Pulled By: siying

fbshipit-source-id: c74cb11

Summary:
Since the backup work as snapshot, we should only copy
 the bytes of the wal while we get the alive files.
Closes https://github.com/facebook/rocksdb/pull/1733

Differential Revision: D4373457

Pulled By: ajkr

fbshipit-source-id: 389318f

Summary:
rocksdb direct io support

```
[gzh@dev11575.prn2 ~/rocksdb] ./db_bench -benchmarks=fillseq --num=1000000
Initializing RocksDB Options from the specified file
Initializing RocksDB Options from command-line flags
RocksDB:    version 5.0
Date:       Wed Nov 23 13:17:43 2016
CPU:        40 * Intel(R) Xeon(R) CPU E5-2660 v2 @ 2.20GHz
CPUCache:   25600 KB
Keys:       16 bytes each
Values:     100 bytes each (50 bytes after compression)
Entries:    1000000
Prefix:    0 bytes
Keys per prefix:    0
RawSize:    110.6 MB (estimated)
FileSize:   62.9 MB (estimated)
Write rate: 0 bytes/second
Compression: Snappy
Memtablerep: skip_list
Perf Level: 1
WARNING: Assertions are enabled; benchmarks unnecessarily slow
------------------------------------------------
Initializing RocksDB Options from the specified file
Initializing RocksDB Options from command-line flags
DB path: [/tmp/rocksdbtest-112628/dbbench]
fillseq      :       4.393 micros/op 227639 ops/sec;   25.2 MB/s

[gzh@dev11575.prn2 ~/roc
Closes https://github.com/facebook/rocksdb/pull/1564

Differential Revision: D4241093

Pulled By: lightmark

fbshipit-source-id: 98c29e3

Summary:
Fixes compile error:

In file included from ./util/statistics.h:17:0,
                 from ./util/stop_watch.h:8,
                 from ./util/perf_step_timer.h:9,
                 from ./util/iostats_context_imp.h:8,
                 from ./util/posix_logger.h:27,
                 from ./port/util_logger.h:18,
                 from ./db/auto_roll_logger.h:15,
                 from db/auto_roll_logger.cc:6:
./util/thread_local.h:65:16: error: 'function' in namespace 'std' does not name a template type
   typedef std::function<void(void*, void*)> FoldFunc;
Closes https://github.com/facebook/rocksdb/pull/1656

Differential Revision: D4318702

Pulled By: yiwu-arbug

fbshipit-source-id: 8c5d17a

Summary:
We used to treat any failure to read a backup's meta-file as if the backup were corrupted; however, we should distinguish corruption errors from errors in the backup Env. This fixes an issue where callers would get inconsistent results from GetBackupInfo() if they called it on an engine that encountered Env error during initialization. Now we fail Initialize() in this case so callers cannot invoke GetBackupInfo() on such engines.
Closes https://github.com/facebook/rocksdb/pull/1654

Differential Revision: D4318573

Pulled By: ajkr

fbshipit-source-id: f7a7c54

Summary:
Some users are assuming NotFound means the backup does not
exist at the provided path, which is a reasonable assumption. We need to
stop returning NotFound for system errors.

Depends on #1644
Closes https://github.com/facebook/rocksdb/pull/1645

Differential Revision: D4312233

Pulled By: ajkr

fbshipit-source-id: 5343c10

Summary:
This has been unused since D42069 but kept around for backward
compatibility. I think it is unlikely anyone will use a much older version of
RocksDB for restore than they use for backup, so I propose removing it. It is
also causing recurring confusion, e.g., https://www.facebook.com/groups/rocksdb.dev/permalink/980454015386446/

Ported from https://reviews.facebook.net/D60735
Closes https://github.com/facebook/rocksdb/pull/1529

Differential Revision: D4194199

Pulled By: ajkr

fbshipit-source-id: 82f9bf4

Summary: #title

Test Plan: n/a

Reviewers: uddipta, ldemailly, andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D60393

Summary: LockFile is unnecessary in unit test

Test Plan: env_basic_test.cc

Reviewers: andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D60285

Summary: Read only backup engine return NotFound() on missing meta dir (for e2e test)

Test Plan: backupable_db_test

Reviewers: andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D60273

Summary: during backup, writable file should call close() before reset()

Test Plan: backupable_db_test.cc

Reviewers: andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D60195

Summary: Backup options file to private directory

Test Plan:
backupable_db_test.cc, BackupOptions
	   Modify DB options by calling OpenDB for 3 times. Check the latest options file is in the right place. Also check no redundent files are backuped.

Reviewers: andrewkr

Reviewed By: andrewkr

Subscribers: leveldb, dhruba, andrewkr

Differential Revision: https://reviews.facebook.net/D59373

Summary:
Rocksdb backup and restore rate limiting is currently done per backup/restore.
So, it is difficult to control rate across multiple backup/restores. With this
change, a throttler can be provided. If a throttler is provided, it is used.
Otherwise, a new throttler is created based on the actual rate limits specified
in the options.

Test Plan: Added unit tests

Reviewers: ldemailly, andrewkr, sdong

Reviewed By: andrewkr

Subscribers: igor, yiwu, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D56265

Summary:
Google C++ Style writes: In particular, prefer to write lambda captures explicitly when capturing this or if the lambda will escape the current scope.
Here it is the case for both.

Test Plan: Run all test suites.

Reviewers: andrewkr, dhruba

Reviewed By: andrewkr, dhruba

Subscribers: yhchiang, IslamAbdelRahman, leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58515

Summary:
When db_env_ != backup_env_, InsertPathnameToSizeBytes() would
use the wrong Env during backup creation. This happened because this function
used backup_env_ instead of db_env_ to get WAL/data file sizes.

This diff adds an argument to InsertPathnameToSizeBytes() indicating which Env
to use.

Test Plan: ran @anirbanb's BackupTestTool

Reviewers: sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57159

Summary:
This interface is redundant and has been deprecated for a while.
It's also unused internally. Let's delete it.

I moved the comments to the corresponding functions in BackupEngine/
BackupEngineReadOnly. This caused the diff tool to not work cleanly.

Test Plan:
unit tests

  $ ./backupable_db_test

Reviewers: yhchiang, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D56331

Summary:
Several of backupable_db_test fails if running standalone, because of directory missing. Fix it by:
(1) garbage collector skips shared directory if it doesn't exit
(2) BackupableDBTest.Issue921Test to create the parent directory of the backup directory fist.

Test Plan: Run the tests individually and make sure they pass

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D56829

Summary:
- Need to use unsigned long long for 64-bit literals on windows
- Need size_t for backup meta-file length since clang doesn't let us assign size_t to int

Test Plan: backupable_db_test and options_test

Reviewers: IslamAbdelRahman, yhchiang, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D56391

Summary:
Rocksdb backup engine maintains metadata about backups in separate files. But,
there was no way to add extra application specific data to it. Adding support
for that.
In some use cases, applications decide to restore a backup based on some
metadata. This will help those cases to cheaply decide whether to restore or
not.

Test Plan:
Added a unit test. Existing ones are passing

Sample meta file for BinaryMetadata test-

```

1459454043
0
metadata 6162630A64656600676869
2
private/1/MANIFEST-000001 crc32 1184723444
private/1/CURRENT crc32 3505765120

```

Reviewers: sdong, ldemailly, andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba, ldemailly

Differential Revision: https://reviews.facebook.net/D56007