Commit Graph

158 Commits

Author SHA1 Message Date
Dmitri Smirnov
fbe2c05f59 s/NOEXCEPT/ROCKSDB_NOEXCEPT 2015-08-25 16:34:39 -07:00
Dmitri Smirnov
6924d7582b Address noexcept and const integer lambda capture
VS 2013 does not support noexcept.
   Complains about usage of ineteger constant within lambda requiring explicit capture.
2015-08-25 15:17:14 -07:00
Igor Canadi
53b88784df Add throttling to multi-threaded backups
Summary: See internal task t8056182

Test Plan: Added multi-threading in RateLimiter test

Reviewers: benj, AaronFeldman

Reviewed By: AaronFeldman

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45459
2015-08-25 13:32:46 -07:00
agiardullo
064294081b Improved FileExists API
Summary: Add new CheckFileExists method.  Considered changing the FileExists api but didn't want to break anyone's builds.

Test Plan: unit tests

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42003
2015-07-20 17:20:40 -07:00
sdong
6e9fbeb27c Move rate_limiter, write buffering, most perf context instrumentation and most random kill out of Env
Summary: We want to keep Env a think layer for better portability. Less platform dependent codes should be moved out of Env. In this patch, I create a wrapper of file readers and writers, and put rate limiting, write buffering, as well as most perf context instrumentation and random kill out of Env. It will make it easier to maintain multiple Env in the future.

Test Plan: Run all existing unit tests.

Reviewers: anthony, kradhakrishnan, IslamAbdelRahman, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D42321
2015-07-17 16:58:18 -07:00
Dmitri Smirnov
d1a457181d Ensure Windows build w/o port/port.h in public headers
- Remove make file defines from public headers and use _WIN32 because it is compiler defined
 - use __GNUC__ and __clang__ to guard non-portable attributes
 - add #include "port/port.h" to some new .cc files.
 - minor changes in CMakeLists to reflect recent changes
2015-07-16 12:10:16 -07:00
Igor Canadi
8a9fca2619 Better error handling in BackupEngine
Summary:
Couple of changes here:
* NewBackupEngine() and NewReadOnlyBackupEngine() are now removed. They were deprecated since RocksDB 3.8. Changing these to new functions should be pretty straight-forward. As a followup, I'll fix all fbcode callsights
* Instead of initializing backup engine in the constructor, we initialize it in a separate function now. That way, we can catch all errors and return appropriate status code.
* We catch all errors during initializations and return them to the client properly.
* Added new tests to backupable_db_test, to make sure that we can't open BackupEngine when there are Env errors.
* Transitioned backupable_db_test to use BackupEngine rather than BackupableDB. From the two available APIs, judging by the current use-cases, it looks like BackupEngine API won. It's much more flexible since it doesn't require StackableDB.

Test Plan: Added a new unit test to backupable_db_test

Reviewers: yhchiang, sdong, AaronFeldman

Reviewed By: AaronFeldman

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D41925
2015-07-14 20:51:36 +02:00
sdong
f9728640f3 "make format" against last 10 commits
Summary: This helps Windows port to format their changes, as discussed. Might have formatted some other codes too becasue last 10 commits include more.

Test Plan: Build it.

Reviewers: anthony, IslamAbdelRahman, kradhakrishnan, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D41961
2015-07-13 13:50:18 -07:00
Dmitri Smirnov
c903ccc4c2 Merge from github/master 2015-07-09 18:01:08 -07:00
Aaron Feldman
e12b403991 Initialize threads later in constructor
Summary: This addresses a test failure where an exception occured in the constructor's call to CreateDirIfMissing(). The existence of unjoined threads prevented this exception from propogating properly. See http://stackoverflow.com/questions/7381757/c-terminate-called-without-an-active-exception

Test Plan: Re-run tests from task #7626266

Reviewers: sdong, anthony, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D41313
2015-07-07 10:49:16 -07:00
Dmitri Smirnov
d2f0912bd3 Merge the latest changes from github/master 2015-07-02 17:23:41 -07:00
Dmitri Smirnov
feb99c31a4 Merge remote-tracking branch 'origin' into ms_win_port 2015-07-02 13:14:18 -07:00
Aaron Feldman
e70115e71b Fix unity build by removing anonymous namespace
Summary: see title

Test Plan: run 'make unity'

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D41079
2015-07-02 12:27:35 -07:00
Aaron Feldman
a69bc91e37 Multithreaded backup and restore in BackupEngineImpl
Summary:
Add a new field: BackupableDBOptions.max_background_copies.
CreateNewBackup() and RestoreDBFromBackup() will use this number of threads to perform copies.
If there is a backup rate limit, then max_background_copies must be 1.
Update backupable_db_test.cc to test multi-threaded backup and restore.
Update backupable_db_test.cc to test backups when the backup environment is not the same as the database environment.

Test Plan:
Run ./backupable_db_test
Run valgrind ./backupable_db_test
Run with TSAN and ASAN

Reviewers: yhchiang, rven, anthony, sdong, igor

Reviewed By: igor

Subscribers: yhchiang, anthony, sdong, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D40725
2015-07-02 11:35:51 -07:00
Dmitri Smirnov
18285c1e2f Windows Port from Microsoft
Summary: Make RocksDb build and run on Windows to be functionally
 complete and performant. All existing test cases run with no
 regressions. Performance numbers are in the pull-request.

 Test plan: make all of the existing unit tests pass, obtain perf numbers.

 Co-authored-by: Praveen Rao praveensinghrao@outlook.com
 Co-authored-by: Sherlock Huang baihan.huang@gmail.com
 Co-authored-by: Alex Zinoviev alexander.zinoviev@me.com
 Co-authored-by: Dmitri Smirnov dmitrism@microsoft.com
2015-07-01 16:13:56 -07:00
Igor Canadi
50eab9cf30 Fix BackupEngine
Summary:
In D28521 we removed GarbageCollect() from BackupEngine's constructor. The reason was that opening BackupEngine on HDFS was very slow and in most cases we didn't have any garbage. We allowed the user to call GarbageCollect() when it detects some garbage files in his backup directory.

Unfortunately, this left us vulnerable to an interesting issue. Let's say we started a backup and copied files {1, 3} but the backup failed. On another host, we restore DB from backup and generate {1, 3, 5}. Since {1, 3} is already there, we will not overwrite. However, these files might be from a different database so their contents might be different. See internal task t6781803 for more info.

Now, when we're copying files and we discover a file already there, we check:
1. if the file is not referenced from any backups, we overwrite the file.
2. if the file is referenced from other backups AND the checksums don't match, we fail the backup. This will only happen if user is using a single backup directory for backing up two different databases.
3. if the file is referenced from other backups AND the checksums match, it's all good. We skip the copy and go copy the next file.

Test Plan: Added new test to backupable_db_test. The test fails before this patch.

Reviewers: sdong, rven, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D37599
2015-05-07 17:39:19 -07:00
clark.kang
6ede020dc4 fix typos 2015-04-25 18:14:27 +09:00
sdong
98a44559d5 Build for CYGWIN
Summary:
Make it build for CYGWIN.
Need to define "-std=gnu++11" instead of "-std=c++11" and use some replacement functions.

Test Plan: Build it and run some unit tests in CYGWIN

Reviewers: yhchiang, rven, anthony, kradhakrishnan, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D37605
2015-04-23 21:33:44 -07:00
Igor Canadi
216a9e16f4 Fix compile
Summary: I was pretty sure I compiled this before landing, sorry :/

Test Plan: compiles

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34173
2015-02-27 14:21:16 -08:00
Igor Canadi
b9ff6b050d Fix a bug in ReadOnlyBackupEngine
Summary:
This diff fixes a bug introduced by D28521. Read-only backup engine can delete a backup that is later than the latest -- we never check the condition.

I also added a bunch of logging that will help with debugging cases like this in the future.

See more discussion at t6218248.

Test Plan: Added a unit test that was failing before the change. Also, see new LOG file contents: https://phabricator.fb.com/P19738984

Reviewers: benj, sanketh, sumeet, yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D33897
2015-02-27 14:03:56 -08:00
Igor Sugak
62247ffa3b rocksdb: Add missing override
Summary:
When using latest clang (3.6 or 3.7/trunck) rocksdb is failing with many errors. Almost all of them are missing override errors. This diff adds missing override keyword. No manual changes.

Prerequisites: bear and clang 3.5 build with extra tools

```lang=bash
% USE_CLANG=1 bear make all # generate a compilation database http://clang.llvm.org/docs/JSONCompilationDatabase.html
% clang-modernize -p . -include . -add-override
% make format
```

Test Plan:
Make sure all tests are passing.
```lang=bash
% #Use default fb code clang.
% make check
```
Verify less error and no missing override errors.
```lang=bash
% # Have trunk clang present in path.
% ROCKSDB_NO_FBCODE=1 CC=clang CXX=clang++ make
```

Reviewers: igor, kradhakrishnan, rven, meyering, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34077
2015-02-26 11:28:41 -08:00
Igor Canadi
173c52a97f Fix build on older compilers -- emplace() is not available 2015-01-29 13:43:09 -08:00
Igor Canadi
5257c9c42c Merge pull request #452 from robertabcd/backupable-mem
Reduce memory footprint in backupable db.
2015-01-28 10:53:46 -08:00
Igor Canadi
a52dd00243 Fix ASAN failure with backupable DB
Summary: It looks like ASAN with gcc 4.9 works better than 4.8.1. It detected this possibility of heap buffer overflow. This was in our codebase for a year :)

Test Plan: COMPILE_WITH_ASAN=1 make backupable_db && ./backupable_db

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D32085
2015-01-23 15:02:43 -08:00
Robert
628a67b007 Reduce memory footprint in backupable db.
* Use emplace when possible.
* Make FileInfo shared among all BackupMeta, instead of storing filenames.
* Make checksum_value in FileInfo constant.
* Reserve space beforehand if container size is known.
* Make FileInfo and BackupMeta non-copyable and non-assignable to prevent future logic errors.
  It is very dangerous to copy BackupMeta without careful handling refcounts of FileInfo.
* Remove a copy of BackupMeta when detected corrupt backup.
2015-01-09 16:58:13 +08:00
Robert
49376bfe87 Fix errors when using -Wshorten-64-to-32. 2015-01-05 21:21:04 +08:00
Robert
a8c5564a9d Do not issue extra GetFileSize() calls when loading BackupMeta. 2015-01-04 12:20:49 +08:00
Robert
caa1fd0e0e Improve performance when loading BackupMeta.
* Use strtoul() and strtoull() instead of sscanf().
  glibc's sscanf() will do a implicit strlen().

* Move implicit construction of Slice("crc32 ") out of loop.
2015-01-04 12:19:32 +08:00
Hasnain Lakhani
31b02dc21d Improve Backup Engine.
Summary:
Improve the backup engine by not deleting the corrupted
backup when it is detected; instead leaving it to the client
to delete the corrupted backup.

Also add a BackupEngine::Open() call.

Test Plan:
Add check to CorruptionTest inside backupable_db_test
to check that the corrupt backups are not deleted. The previous
version of the code failed this test as backups were deleted,
but after the changes in this commit, this test passes.

Run make check to ensure that no other tests fail.

Reviewers: sdong, benj, sanketh, sumeet, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28521
2014-11-13 09:51:41 -08:00
Igor Canadi
767777c2bd Turn on -Wshorten-64-to-32 and fix all the errors
Summary:
We need to turn on -Wshorten-64-to-32 for mobile. See D1671432 (internal phabricator) for details.

This diff turns on the warning flag and fixes all the errors. There were also some interesting errors that I might call bugs, especially in plain table. Going forward, I think it makes sense to have this flag turned on and be very very careful when converting 64-bit to 32-bit variables.

Test Plan: compiles

Reviewers: ljin, rven, yhchiang, sdong

Reviewed By: yhchiang

Subscribers: bobbaldwin, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28689
2014-11-11 16:47:22 -05:00
Igor Canadi
a52cecb56c Fix Mac compile 2014-09-09 18:42:35 -07:00
Xiaozheng Tie
6cc12860f0 Added a few statistics for BackupableDB
Summary:
Added the following statistics to BackupableDB:

1. Number of successful and failed backups in class BackupStatistics
2. Time taken to do a backup
3. Number of files in a backup

1 is implemented in the BackupStatistics class
2 and 3 are added in the BackupMeta and BackupInfo class

Test Plan:
1 can be tested using BackupStatistics::ToString(),
2 and 3 can be tested in the BackupInfo class

Reviewers: sdong, igor2, ljin, igor

Reviewed By: igor

Differential Revision: https://reviews.facebook.net/D22785
2014-09-09 13:44:42 -07:00
liuhuahang
bb6ae0f80c fix more compile warnings
N/A

Change-Id: I5b6f9c70aea7d3f3489328834fed323d41106d9f
Signed-off-by: liuhuahang <liuhuahang@zerus.co>
2014-09-05 14:14:37 +08:00
Igor Canadi
0ff183a0d9 Move include/utilities/*.h to include/rocksdb/utilities/*.h
Summary:
All public headers need to be under `include/rocksdb` directory. Otherwise, clients include our header files like this:

    #include <rocksdb/db.h>
    #include <utilities/backupable_db.h> // still our public header!

Also, internally, we include:

    #include "utilities/backupable/backupable_db.h" // internal header
    #include "utilities/backupable_db.h" // public header

which is confusing.

This way, when we install rocksdb as a system library, we can just copy `include/rocksdb` directory to system's header files. We can't really copy `utilities` directory to system's header files.

Test Plan: compiles

Reviewers: dhruba, ljin, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20409
2014-07-23 10:21:38 -04:00
Lei Jin
5ef1ba7ff5 generic rate limiter
Summary:
A generic rate limiter that can be shared by threads and rocksdb
instances. Will use this to smooth out write traffic generated by
compaction and flush. This will help us get better p99 behavior on flash
storage.

Test Plan:
unit test output
==== Test RateLimiterTest.Rate
request size [1 - 1023], limit 10 KB/sec, actual rate: 10.374969 KB/sec, elapsed 2002265
request size [1 - 2047], limit 20 KB/sec, actual rate: 20.771242 KB/sec, elapsed 2002139
request size [1 - 4095], limit 40 KB/sec, actual rate: 41.285299 KB/sec, elapsed 2202424
request size [1 - 8191], limit 80 KB/sec, actual rate: 81.371605 KB/sec, elapsed 2402558
request size [1 - 16383], limit 160 KB/sec, actual rate: 162.541268 KB/sec, elapsed 3303500

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19359
2014-07-08 11:41:57 -07:00
Igor Canadi
b2cf95fe38 Call EnableFileDeletions with false as argument 2014-05-20 14:28:51 -07:00
Benjamin Renard
41e5cf2392 Add share_files_with_cheksum option to BackupEngine
Summary: added a new option to BackupEngine: if share_files_with_checksum is set to true, sst files are stored in shared_checksum/ and are identified by the triple (file name, checksum, file size) instead of just the file name. This option is targeted at distributed databases that want to backup their primary replica.

Test Plan: unit tests and tested backup and restore on a distributed rocksdb

Reviewers: igor

Reviewed By: igor

Differential Revision: https://reviews.facebook.net/D18393
2014-05-02 17:08:55 -07:00
Igor Canadi
fe331c8886 fix valgrind 2014-04-26 14:23:15 -07:00
Igor Canadi
a618691a3b Read-only BackupEngine
Summary: Read-only BackupEngine can connect to the same backup directory that is already running BackupEngine. That enables some interesting use-cases (i.e. restoring replica from primary's backup directory)

Test Plan: added a unit test

Reviewers: dhruba, haobo, ljin

Reviewed By: ljin

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18297
2014-04-25 15:49:29 -04:00
Igor Canadi
588bca2020 RocksDBLite
Summary:
Introducing RocksDBLite! Removes all the non-essential features and reduces the binary size. This effort should help our adoption on mobile.

Binary size when compiling for IOS (`TARGET_OS=IOS m static_lib`) is down to 9MB from 15MB (without stripping)

Test Plan: compiles :)

Reviewers: dhruba, haobo, ljin, sdong, yhchiang

Reviewed By: yhchiang

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17835
2014-04-15 13:39:26 -07:00
Igor Canadi
b253f24403 Rate limiter for BackupableDB
Summary: Might be useful if client doesn't want to effect running system during backup too much.

Test Plan: added a test case

Reviewers: dhruba, haobo, ljin

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17091
2014-03-24 11:38:44 -07:00
Igor Canadi
9caeff516e keep_log_files option in BackupableDB
Summary:
Added an option to BackupableDB implementation that allows users to persist in-memory databases. When the restore happens with keep_log_files = true, it will
*) Not delete existing log files in wal_dir
*) Move log files from archive directory to wal_dir, so that DB can replay them if necessary

Test Plan: Added an unit test

Reviewers: dhruba, ljin

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16941
2014-03-17 15:39:23 -07:00
Igor Canadi
9db8c4c556 Fix share_table_files bug
Summary: constructor wasn't properly constructing BackupableDBOptions

Test Plan: no test

Reviewers: benj

Reviewed By: benj

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16749
2014-03-10 14:42:03 -07:00
Igor Canadi
b04c75d244 Dump options in backupable DB
Summary: We should dump options in backupable DB log, just like with to with RocksDB. This will aid debugging.

Test Plan: checked the log

Reviewers: ljin

Reviewed By: ljin

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16719
2014-03-10 12:09:54 -07:00
Igor Canadi
e3f396f1ea Some fixes to BackupableDB
Summary:
(1) Report corruption if backup meta file has tailing data that was not read. This should fix: https://github.com/facebook/rocksdb/issues/81 (also, @sdong reported similar issue)
(2) Don't use OS buffer when copying file to backup directory. We don't need the file in cache since we won't be reading it twice
(3) Don't delete newer backups when somebody tries to backup the diverged DB (restore from older backup, add new data, try to backup). Rather, just fail the new backup.

Test Plan: backupable_db_test

Reviewers: ljin, dhruba, sdong

Reviewed By: ljin

CC: leveldb, sdong

Differential Revision: https://reviews.facebook.net/D16287
2014-03-04 17:02:25 -08:00
Lei Jin
994c327b86 IOError cleanup
Summary: Clean up IOErrors so that it only indicates errors talking to device.

Test Plan: make all check

Reviewers: igor, haobo, dhruba, emayanke

Reviewed By: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15831
2014-02-12 11:42:54 -08:00
Igor Canadi
e5ec7384a0 Better interface to create BackupEngine
Summary: I think it looks nicer. In RocksDB we have both styles, but I think that static method is the more common version.

Test Plan: backupable_db_test

Reviewers: ljin, benj, swk

Reviewed By: ljin

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15519
2014-01-28 16:01:53 -08:00
Igor Canadi
ec2fa4a690 Export BackupEngine
Summary:
Lots of clients have problems with using StackableDB interface. It's nice to have BackupableDB as a layer on top of DB, but not necessary.

This diff exports BackupEngine, which can be used to create backups without forcing clients to use StackableDB interface.

Test Plan: backupable_db_test

Reviewers: dhruba, ljin, swk

Reviewed By: ljin

CC: leveldb, benj

Differential Revision: https://reviews.facebook.net/D15477
2014-01-28 11:26:07 -08:00
Lei Jin
9dc29414e3 add checksum for backup files
Summary: Keep checksum of each backuped file in meta file. When it restores these files, compute their checksum on the fly and compare against what is in the meta file. Fail the restore process if checksum mismatch.

Test Plan: unit test

Reviewers: haobo, igor, sdong, kailiu

Reviewed By: igor

CC: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D15381
2014-01-28 09:43:36 -08:00
Siying Dong
8477255da3 Moving Some includes from options.h to forward declaration
Summary: By removing some includes form options.h and reply on forward declaration, we can more easily reason the dependencies.

Test Plan: make all check

Reviewers: kailiu, haobo, igor, dhruba

Reviewed By: kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15411
2014-01-24 17:16:22 -08:00
ono_matope
f8642dacde Fix share_table_files condition in BackupEngine constructor.
That makes BackupableDBTest.NoDoubleCopy test error.
2014-01-11 05:12:07 +09:00
Igor Canadi
cb37ddf229 Feature requests for BackupableDB
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
2014-01-09 12:24:28 -08:00
Igor Canadi
417b453fa6 [backupable db] Delete db_dir children when restoring backup
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
2013-12-12 14:57:18 -08:00
Igor Canadi
249e736bc5 portable %lu printing 2013-12-12 08:13:47 -08:00
Igor Canadi
5e4ab767cf BackupableDB delete backups with newer seq number
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
2013-12-10 20:49:28 -08:00
Igor Canadi
7cf5728440 Cleaning up BackupableDB + fix valgrind errors
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
2013-12-10 10:35:06 -08:00
Igor Canadi
784e62f98d Fix unused variable warning 2013-12-09 16:44:47 -08:00
Igor Canadi
fb9fce4fc3 [RocksDB] BackupableDB
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
2013-12-09 14:06:52 -08:00