Commit Graph

260 Commits

Author SHA1 Message Date
sdong
df9069d23f In DB::NewIterator(), try to allocate the whole iterator tree in an arena
Summary:
In this patch, try to allocate the whole iterator tree starting from DBIter from an arena
1. ArenaWrappedDBIter is created when serves as the entry point of an iterator tree, with an arena in it.
2. Add an option to create iterator from arena for following iterators: DBIter, MergingIterator, MemtableIterator, all mem table's iterators, all table reader's iterators and two level iterator.
3. MergeIteratorBuilder is created to incrementally build the tree of internal iterators. It is passed to mem table list and version set and add iterators to it.

Limitations:
(1) Only DB::NewIterator() without tailing uses the arena. Other cases, including readonly DB and compactions are still from malloc
(2) Two level iterator itself is allocated in arena, but not iterators inside it.

Test Plan: make all check

Reviewers: ljin, haobo

Reviewed By: haobo

Subscribers: leveldb, dhruba, yhchiang, igor

Differential Revision: https://reviews.facebook.net/D18513
2014-06-02 17:44:57 -07:00
Igor Canadi
91ddd587cc Only signal cond variable if need to
Summary:
At the end of BackgroundCallCompaction(), we call SignalAll(), even though we don't need to. If compaction hasn't done anything and there's another compaction running, there is no need to signal on the condition variable. Doing so creates a tight feedback loop which results in log files like:

   wait for memtable flush
   compaction nothing to do
   wait for memtable flush
   compaction nothing to do

This change eliminates that

Test Plan:
make check
Also:

    icanadi@dev1440 ~ $ grep "nothing to do" /fast-rocksdb-tmp/rocksdb_test/column_family_test/LOG | wc -l
    7435
    icanadi@dev1440 ~ $ grep "nothing to do" /fast-rocksdb-tmp/rocksdb_test/column_family_test/LOG | wc -l
    372

First version is before the change, second version is after the change.

Reviewers: dhruba, ljin, haobo, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D18855
2014-06-02 17:23:55 -07:00
Lei Jin
388d2054c7 forward iterator
Summary:
Forward iterator puts everything together in a flat structure instead of
a hierarchy of nested iterators. this should simplify the code and
provide better performance. It also enables more optimization since all
information are accessiable in one place.
Init evaluation shows about 6% improvement

Test Plan: db_test and db_bench

Reviewers: dhruba, igor, tnovak, sdong, haobo

Reviewed By: haobo

Subscribers: sdong, leveldb

Differential Revision: https://reviews.facebook.net/D18795
2014-05-30 14:31:55 -07:00
Igor Canadi
df70047669 Flush stale column families
Summary:
Added a new option `max_total_wal_size`. Once the total WAL size goes over that, we make an attempt to flush all column families that still have data in the earliest WAL file.

By default, I calculate `max_total_wal_size` dynamically, that should be good-enough for non-advanced customers.

Test Plan: Added a test

Reviewers: dhruba, haobo, sdong, ljin, yhchiang

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18345
2014-04-30 14:33:40 -04:00
Yueh-Hsuan Chiang
9d9d2965cb Add a new mem-table representation based on cuckoo hash.
Summary:
= Major Changes =
* Add a new mem-table representation, HashCuckooRep, which is based cuckoo hash.
  Cuckoo hash uses multiple hash functions.  This allows each key to have multiple
  possible locations in the mem-table.

  - Put: When insert a key, it will try to find whether one of its possible
    locations is vacant and store the key.  If none of its possible
    locations are available, then it will kick out a victim key and
    store at that location.  The kicked-out victim key will then be
    stored at a vacant space of its possible locations or kick-out
    another victim.  In this diff, the kick-out path (known as
    cuckoo-path) is found using BFS, which guarantees to be the shortest.

 - Get: Simply tries all possible locations of a key --- this guarantees
   worst-case constant time complexity.

 - Time complexity: O(1) for Get, and average O(1) for Put if the
   fullness of the mem-table is below 80%.

 - Default using two hash functions, the number of hash functions used
   by the cuckoo-hash may dynamically increase if it fails to find a
   short-enough kick-out path.

 - Currently, HashCuckooRep does not support iteration and snapshots,
   as our current main purpose of this is to optimize point access.

= Minor Changes =
* Add IsSnapshotSupported() to DB to indicate whether the current DB
  supports snapshots.  If it returns false, then DB::GetSnapshot() will
  always return nullptr.

Test Plan:
Run existing tests.  Will develop a test specifically for cuckoo hash in
the next diff.

Reviewers: sdong, haobo

Reviewed By: sdong

CC: leveldb, dhruba, igor

Differential Revision: https://reviews.facebook.net/D16155
2014-04-29 17:13:46 -07:00
Igor Canadi
dd9eb7a7d5 Cache result of ReadFirstRecord()
Summary:
ReadFirstRecord() reads the actual log file from disk on every call. This diff introduces a cache layer on top of ReadFirstRecord(), which should significantly speed up repeated calls to GetUpdatesSince().

I also cleaned up some stuff, but the whole TransactionLogIterator could use some refactoring, especially if we see increased usage.

Test Plan: make check

Reviewers: haobo, sdong, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18387
2014-04-29 13:27:58 -04:00
Igor Canadi
8ce5492623 Delete superversion and log outside of mutex
Summary: As summary. Add two autovectors that get filled up in MakeRoomForWrite and they get deleted outside of mutex

Test Plan: make check

Reviewers: dhruba, haobo, ljin, sdong

Reviewed By: ljin

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18249
2014-04-25 14:58:02 -04:00
Igor Canadi
7d838856cf Fix compile issues when doing make release 2014-04-15 16:00:10 -07:00
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
e6acb874cd Don't roll empty logs
Summary:
With multiple column families, especially when manual Flush is executed, we might roll the log file, although the current log file is empty (no data has been written to the log).

After the diff, we won't create new log file if current is empty.

Next, I will write an algorithm that will flush column families that reference old log files (i.e., that weren't flushed in a while)

Test Plan: Added an unit test. Confirmed that unit test failes in master

Reviewers: dhruba, haobo, ljin, sdong

Reviewed By: ljin

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17631
2014-04-15 09:57:25 -07:00
Lei Jin
82b37a18bd thread local for tailing iterator
Summary:
replace the super version acquisision in tailing itrator with thread
local

Test Plan: will post results

Reviewers: igor, haobo, sdong, yhchiang, dhruba

Reviewed By: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17757
2014-04-14 10:48:01 -07:00
Igor Canadi
d1e2bce42d CallFlushDuringCompaction 2014-04-07 15:03:15 -07:00
Igor Canadi
3d2fe844ab Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/db_impl.h
	db/memtable_list.cc
	db/version_set.cc
2014-04-07 11:31:11 -07:00
sdong
ea0198fe9a Create log::Writer out of DB Mutex
Summary: Our measurement shows that sometimes new log::Write's constructor can take hundreds of milliseconds. It's unclear why but just simply move it out of DB mutex.

Test Plan: make all check

Reviewers: haobo, ljin, igor

Reviewed By: haobo

CC: nkg-, yhchiang, leveldb

Differential Revision: https://reviews.facebook.net/D17487
2014-04-04 15:46:28 -07:00
sdong
b9767d0e09 Move several more logging inside DB mutex to log buffer
Summary: Move several some common logging still in DB mutex to log buffer.

Test Plan: make all check

Reviewers: haobo, igor, ljin, nkg-

Reviewed By: nkg-

CC: nkg-, yhchiang, leveldb

Differential Revision: https://reviews.facebook.net/D17439
2014-04-03 10:47:18 -07:00
Haobo Xu
48bc0c6ad3 [RocksDB] Fix a race condition in GetSortedWalFiles
Summary: This patch fixed a race condition where a log file is moved to archived dir in the middle of GetSortedWalFiles. Without the fix, the log file would be missed in the result, which leads to transaction log iterator gap. A test utility SyncPoint is added to help reproducing the race condition.

Test Plan: TransactionLogIteratorRace; make check

Reviewers: dhruba, ljin

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17121
2014-04-02 22:12:29 -07:00
Igor Canadi
ddbd1ece88 Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/db_test.cc
	db/internal_stats.cc
	db/internal_stats.h
	db/version_edit.cc
	db/version_edit.h
	db/version_set.cc
	include/rocksdb/options.h
	util/options.cc
2014-03-31 13:39:24 -07:00
Haobo Xu
a92194e5b2 [RocksDB] Add db property "rocksdb.cur-size-active-mem-table"
Summary: as title

Test Plan: db_test

Reviewers: sdong

Reviewed By: sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17217
2014-03-27 15:14:04 -07:00
Igor Canadi
e8168382c4 Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	include/rocksdb/options.h
	util/options.cc
2014-03-25 11:09:40 -07:00
Danny Guo
b47812fba6 [rocksdb] new CompactionFilterV2 API
Summary:
This diff adds a new CompactionFilterV2 API that roll up the
decisions of kv pairs during compactions. These kv pairs must share the
same key prefix. They are buffered inside the db.

    typedef std::vector<Slice> SliceVector;
    virtual std::vector<bool> Filter(int level,
                                 const SliceVector& keys,
                                 const SliceVector& existing_values,
                                 std::vector<std::string>* new_values,
                                 std::vector<bool>* values_changed
                                 ) const = 0;

Application can override the Filter() function to operate
on the buffered kv pairs. More details in the inline documentation.

Test Plan:
make check. Added unit tests to make sure Keep, Delete,
Change all works.

Reviewers: haobo

CCs: leveldb

Differential Revision: https://reviews.facebook.net/D15087
2014-03-24 20:47:53 -07:00
Igor Canadi
ac328a86b9 Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/db_test.cc
2014-03-20 14:41:37 -07:00
Igor Canadi
e67241f0b9 Sanity check on Open
Summary:
Everytime a client opens a DB, we do a sanity check that:
* checks the existance of all the necessary files
* verifies that file sizes are correct

Some of the code was stolen from https://reviews.facebook.net/D16935

Test Plan: added a unit test

Reviewers: dhruba, haobo, sdong

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17097
2014-03-20 14:18:29 -07:00
Igor Canadi
e20fa3f8a4 Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/internal_stats.cc
	db/internal_stats.h
	db/version_set.cc
2014-03-19 17:22:20 -07:00
sdong
71e6a34271 Add a DB property to indicate number of background errors encountered
Summary: Add a property to calculate number of background errors encountered to help users build their monitoring

Test Plan: Add a unit test. make all check

Reviewers: haobo, igor, dhruba

Reviewed By: igor

CC: ljin, nkg-, yhchiang, leveldb

Differential Revision: https://reviews.facebook.net/D16959
2014-03-18 14:28:30 -07:00
Igor Canadi
3055a15b29 Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/version_edit.cc
	db/version_edit.h
	db/version_set.cc
2014-03-18 13:24:27 -07:00
Igor Canadi
ae25742af9 Fix race condition in manifest roll
Summary:
When the manifest is getting rolled the following happens:
1) manifest_file_number_ is assigned to a new manifest number (even though the old one is still current)
2) mutex is unlocked
3) SetCurrentFile() creates temporary file manifest_file_number_.dbtmp
4) SetCurrentFile() renames manifest_file_number_.dbtmp to CURRENT
5) mutex is locked

If FindObsoleteFiles happens between (3) and (4) it will:
1) Delete manifest_file_number_.dbtmp (because it's not in pending_outputs_)
2) Delete old manifest (because the manifest_file_number_ already points to a new one)

I introduce the concept of prev_manifest_file_number_ that will avoid the race condition.

However, we should discuss the future of MANIFEST file rolling. We found some race conditions with it last week and who knows how many more are there. Nobody is using it in production because we don't trust the implementation. Should we even support it?

Test Plan: make check

Reviewers: ljin, dhruba, haobo, sdong

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16929
2014-03-17 21:50:15 -07:00
Igor Canadi
dff9214165 Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	tools/db_stress.cc
2014-03-12 10:17:41 -07:00
sdong
bd45633b71 Fix data race against logging data structure because of LogBuffer
Summary:
@igor pointed out that there is a potential data race because of the way we use the newly introduced LogBuffer. After "bg_compaction_scheduled_--" or "bg_flush_scheduled_--", they can both become 0. As soon as the lock is released after that, DBImpl's deconstructor can go ahead and deconstruct all the states inside DB, including the info_log object hold in a shared pointer of the options object it keeps. At that point it is not safe anymore to continue using the info logger to write the delayed logs.

With the patch, lock is released temporarily for log buffer to be flushed before "bg_compaction_scheduled_--" or "bg_flush_scheduled_--". In order to make sure we don't miss any pending flush or compaction, a new flag bg_schedule_needed_ is added, which is set to be true if there is a pending flush or compaction but not scheduled because of the max thread limit. If the flag is set to be true, the scheduling function will be called before compaction or flush thread finishes.

Thanks @igor for this finding!

Test Plan: make all check

Reviewers: haobo, igor

Reviewed By: haobo

CC: dhruba, ljin, yhchiang, igor, leveldb

Differential Revision: https://reviews.facebook.net/D16767
2014-03-11 16:09:53 -07:00
Igor Canadi
457c78eb89 [CF] db_stress for column families
Summary:
I had this diff for a while to test column families implementation. Last night, I ran it sucessfully for 10 hours with the command:

   time ./db_stress --threads=30 --ops_per_thread=200000000 --max_key=5000 --column_families=20 --clear_column_family_one_in=3000000 --verify_before_write=1  --reopen=50 --max_background_compactions=10 --max_background_flushes=10 --db=/tmp/db_stress

It is ready to be committed :)

Test Plan: Ran it for 10 hours

Reviewers: dhruba, haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16797
2014-03-11 12:06:12 -07:00
Igor Canadi
9634ba42ac Merge branch 'master' into columnfamilies
Conflicts:
	db/compaction_picker.cc
	db/db_impl.cc
	db/db_impl.h
	db/tailing_iter.cc
	db/version_set.h
	include/rocksdb/options.h
	util/options.cc
2014-03-10 17:26:09 -07:00
Haobo Xu
9e0e6aa7f6 [RocksDB] make sure KSVObsolete does not get accessed as a valid pointer.
Summary: KSVObsolete is no longer nullptr and needs to be checked explicitly. Also did some minor code cleanup and added a stat counter to track superversion cleanups incurred in the foreground.

Test Plan: make check

Reviewers: ljin

Reviewed By: ljin

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16701
2014-03-10 12:55:25 -07:00
Haobo Xu
66da467983 [RocksDB] LogBuffer Cleanup
Summary: Moved LogBuffer class to an internal header. Removed some unneccesary indirection. Enabled log buffer for BackgroundCallFlush. Forced log buffer flush right after Unlock to improve time ordering of info log.

Test Plan: make check; db_bench compare LOG output

Reviewers: sdong

Reviewed By: sdong

CC: leveldb, igor

Differential Revision: https://reviews.facebook.net/D16707
2014-03-10 11:05:44 -07:00
Igor Canadi
9f15092ebd [CF] NewIterators
Summary: Adding the last missing function -- NewIterators(). Pretty simple implementation

Test Plan: added a unit test

Reviewers: dhruba, haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16689
2014-03-07 16:15:25 -08:00
Lei Jin
e5fa4944fc use CAS when returning SuperVersion to ThreadLocal
Summary:
Add a check at the end of GetImpl to release SuperVersion if it becomes
obsolete. Also do Scrape() inside InstallSuperVersion so it happens more
frequent.

Test Plan:
make all check
running asan_check now

Reviewers: igor, haobo, sdong, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16641
2014-03-07 14:43:22 -08:00
Igor Canadi
80a207fc90 Merge branch 'master' into columnfamilies
Conflicts:
	db/compaction_picker.cc
	db/compaction_picker.h
	db/db_impl.cc
	db/version_set.cc
	db/version_set.h
	include/rocksdb/options.h
	util/options.cc
2014-03-05 16:59:22 -08:00
sdong
ecb1ffa2a8 Buffer info logs when picking compactions and write them out after releasing the mutex
Summary: Now while the background thread is picking compactions, it writes out multiple info_logs, especially for universal compaction, which introduces a chance of waiting log writing in mutex, which is bad. To remove this risk, write all those info logs to a buffer and flush it after releasing the mutex.

Test Plan:
make all check
check the log lines while running some tests that trigger compactions.

Reviewers: haobo, igor, dhruba

Reviewed By: dhruba

CC: i.am.jin.lei, dhruba, yhchiang, leveldb, nkg-

Differential Revision: https://reviews.facebook.net/D16515
2014-03-05 15:36:32 -08:00
Igor Canadi
9d0577a6be Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/db_impl.h
	db/transaction_log_impl.cc
	db/transaction_log_impl.h
	include/rocksdb/options.h
	util/env.cc
	util/options.cc
2014-03-03 18:29:03 -08:00
Yueh-Hsuan Chiang
a77527f2af Add ReadOptions to TransactionLogIterator.
Summary:
Add an optional input parameter ReadOptions to DB::GetUpdateSince(),
which allows the verification of checksums to be disabled by setting
ReadOptions::verify_checksums to false.

Test Plan: Tests are done off-line and will not be included in the regular unit test.

Reviewers: igor

Reviewed By: igor

CC: leveldb, xjin, dhruba

Differential Revision: https://reviews.facebook.net/D16305
2014-02-28 11:50:36 -08:00
Lei Jin
ad0c3747cb cache SuperVersion in thread local storage to avoid mutex lock
Summary: as title

Test Plan:
asan_check
will post results later

Reviewers: haobo, igor, dhruba, sdong

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16257
2014-02-27 11:38:55 -08:00
Igor Canadi
9bce2b2a84 [CF] Fix lint errors in CF code
Summary: Big CF diff uncovered some lint errors. This diff fixes some of them. Not much to see here

Test Plan: make check

Reviewers: dhruba, haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16347
2014-02-26 10:10:00 -08:00
Igor Canadi
5a91746277 log file is uint64_t 2014-02-25 12:57:43 -08:00
Igor Canadi
b69e7d99d5 [CF] Better handling of memtable logs
Summary: DBImpl now keeps a list of alive_log_files_. On every FindObsoleteFiles, it deletes all alive log files that are smaller than versions_->MinLogNumber()

Test Plan:
make check passes
no specific unit tests yet, will add

Reviewers: dhruba, haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16293
2014-02-25 09:55:13 -08:00
Igor Canadi
422bb09cb0 Fix table properties
Summary: Adapt table properties to column family world

Test Plan: make check

Reviewers: kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16161
2014-02-14 17:13:10 -08:00
Igor Canadi
76c048183c Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/db_test.cc
	include/rocksdb/db.h
2014-02-14 16:46:03 -08:00
Igor Canadi
c67d48c852 [CF] DB test to run on non-default column family
Summary:
This is a huge diff and it was hectic, but the idea is actually quite simple. Every operation (Put, Get, etc.) done on default column family in DBTest is now forwarded to non-default ("pikachu"). The good news is that we had zero test failures! Column families look stable so far.

One interesting test that I adapted for column families is MultiThreadedTest. I replaced every Put() with a WriteBatch writing to all column families concurrently. Every Put in the write batch contains unique_id. Instead of Get() I do a multiget across all column families with the same key. If atomicity holds, I expect to see the same unique_id in all column families.

Test Plan: This is a test!

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16149
2014-02-14 16:08:59 -08:00
kailiu
63690625cd Expose the table properties to application
Summary: Provide a public API for users to access the table properties for each SSTable.

Test Plan: Added a unit tests to test the function correctness under differnet conditions.

Reviewers: haobo, dhruba, sdong

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16083
2014-02-13 16:28:21 -08:00
Igor Canadi
ccdb93e775 Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/db_impl.h
	db/memtable_list.cc
	db/memtable_list.h
	db/version_set.cc
	db/version_set.h
2014-02-12 14:01:30 -08:00
Igor Canadi
b06840aa7d [CF] Rethinking ColumnFamilyHandle and fix to dropping column families
Summary:
The change to the public behavior:
* When opening a DB or creating new column family client gets a ColumnFamilyHandle.
* As long as column family handle is alive, client can do whatever he wants with it, even drop it
* Dropped column family can still be read from (using the column family handle)
* Added a new call CloseColumnFamily(). Client has to close all column families that he has opened before deleting the DB
* As soon as column family is closed, any calls to DB using that column family handle will fail (also any outstanding calls)

Internally:
* Ref-counting ColumnFamilyData
* New thread-safety for ColumnFamilySet
* Dropped column families are now completely dropped and their memory cleaned-up

Test Plan: added some tests to column_family_test

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16101
2014-02-12 13:47:09 -08:00
Lei Jin
5fbf2ef42d preload table handle on Recover() when max_open_files == -1
Summary: This covers existing table files before DB open happens and avoids contention on table cache

Test Plan: db_test

Reviewers: haobo, sdong, igor, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16089
2014-02-12 10:43:27 -08:00
Igor Canadi
0143abdbb0 Merge branch 'master' into columnfamilies
Conflicts:
	HISTORY.md
	db/db_impl.cc
	db/db_impl.h
	db/db_iter.cc
	db/db_test.cc
	db/dbformat.h
	db/memtable.cc
	db/memtable_list.cc
	db/memtable_list.h
	db/table_cache.cc
	db/table_cache.h
	db/version_edit.h
	db/version_set.cc
	db/version_set.h
	db/write_batch.cc
	db/write_batch_test.cc
	include/rocksdb/options.h
	util/options.cc
2014-02-06 15:58:20 -08:00
kailiu
84f8185fc0 Merge branch 'master' into performance
Conflicts:
	HISTORY.md
	db/db_impl.cc
	db/memtable.cc
2014-02-05 21:21:00 -08:00
Igor Canadi
f276e0e59d [CF] Options -> DBOptions
Summary: Replaced most of occurrences of Options with more specific DBOptions. This brings us very close to supporting different configuration options for each column family.

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15933
2014-02-05 14:56:09 -08:00
Igor Canadi
c24d8c4e90 [CF] Rethink table cache
Summary:
Adapting table cache to column families is interesting. We want table cache to be global LRU, so if some column families are use not as often as others, we want them to be evicted from cache. However, current TableCache object also constructs tables on its own. If table is not found in the cache, TableCache automatically creates new table. We want each column family to be able to specify different table factory.

To solve the problem, we still have a single LRU, but we provide the LRUCache object to TableCache on construction. We have one TableCache per column family, but the underyling cache is shared by all TableCache objects.

This allows us to have a global LRU, but still be able to support different table factories for different column families. Also, in the future it will also be able to support different directories for different column families.

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15915
2014-02-05 11:55:30 -08:00
Igor Canadi
7b9f134959 [CF] Move InternalStats to ColumnFamilyData
Summary: InternalStats is a messy thing, keeping both DB data and column family data. However, it's better off living in ColumnFamilyData than in DBImpl. For now, at least.

Test Plan: make check

Reviewers: dhruba, kailiu, haobo, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15879
2014-02-04 17:59:50 -08:00
Igor Canadi
73f62255c1 [CF] Split SanitizeOptions into two
Summary:
There are three SanitizeOption-s now : one for DBOptions, one for ColumnFamilyOptions and one for Options (which just calls the other two)

I have also reshuffled some options -- table_cache options and info_log should live in DBOptions, for example.

Test Plan: make check doesn't complain

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15873
2014-02-04 17:26:51 -08:00
Igor Canadi
5e2c4fe766 Get rid of DBImpl::user_comparator()
Summary: user_comparator() is a Column Family property, not DBImpl

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15855
2014-02-03 17:50:47 -08:00
Igor Canadi
0e22badc08 [column families] Iterator and MultiGet
Summary: Support for different column families in Iterator and MultiGet code path.

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15849
2014-02-03 17:44:40 -08:00
Lei Jin
5b3b6549d6 use super_version in NewIterator() and MultiGet() function
Summary:
Use super_version insider NewIterator to avoid Ref() each component
separately under mutex
The new added bench shows NewIterator QPS increases from 515K to 719K
No meaningful improvement for multiget I guess due to its relatively small
cost comparing to 90 keys fetch in the test.

Test Plan: unit test and db_bench

Reviewers: igor, sdong

Reviewed By: igor

CC: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D15609
2014-02-03 13:13:36 -08:00
Igor Canadi
27a8856c23 Compacting column families
Summary: This diff enables non-default column families to get compacted both automatically and also by calling CompactRange()

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15813
2014-01-31 19:54:03 -08:00
Igor Canadi
3615f534d1 Enable flushing memtables from arbitrary column families
Summary: Removed default_cfd_ from all flush code paths. This means we can now flush memtables from arbitrary column families!

Test Plan: Added a new unit test

Reviewers: dhruba, haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15789
2014-01-31 14:42:52 -08:00
Igor Canadi
6973bb1722 MakeRoomForWrite() support for column families
Summary: Making room for write will be the hardest part of the column family implementation. For now, I just iterate through all column families and run MakeRoomForWrite() for every one.

Test Plan: make check does not complain

Reviewers: dhruba, haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15597
2014-01-30 16:12:08 -08:00
Igor Canadi
c37e7de669 Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/db_impl.h
2014-01-30 11:47:23 -08:00
Igor Canadi
ac92420fc5 Merge branch 'master' into performance
Conflicts:
	db/db_impl.h
2014-01-30 10:09:23 -08:00
Igor Canadi
3c0dcf0e25 InternalStatistics
Summary:
In DBImpl we keep track of some statistics internally and expose them via GetProperty(). This diff encapsulates all the internal statistics into a class InternalStatisics. Most of it is copy/paste.

Apart from cleaning up db_impl.cc, this diff is also necessary for Column families, since every column family should have its own CompactionStats, MakeRoomForWrite-stall stats, etc. It's much easier to keep track of it in every column family if it's nicely encapsulated in its own class.

Test Plan: make check

Reviewers: dhruba, kailiu, haobo, sdong, emayanke

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15273
2014-01-29 20:40:41 -08:00
Igor Canadi
fa99d53e55 Change ColumnFamilyData from struct to class
Summary: ColumnFamilyData grew a lot, there's much more data that it holds now. It makes more sense to encapsulate it better by making it a class.

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15579
2014-01-29 15:18:36 -08:00
Igor Canadi
f24a3ee52d Read from and write to different column families
Summary: This one is big. It adds ability to write to and read from different column families (see the unit test). It also supports recovery of different column families from log, which was the hardest part to reason about. We need to make sure to never delete the log file which has unflushed data from any column family. To support that, I added another concept, which is versions_->MinLogNumber()

Test Plan: Added a unit test in column_family_test

Reviewers: dhruba, haobo, sdong, kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15537
2014-01-29 11:38:16 -08:00
kailiu
a5e220f5ef Merge branch 'master' into performance
Conflicts:
	Makefile
	db/db_impl.cc
	db/db_test.cc
	db/memtable_list.cc
	db/memtable_list.h
	table/block_based_table_reader.cc
	table/table_test.cc
	util/cache.cc
	util/coding.cc
2014-01-28 10:35:55 -08:00
Igor Canadi
4bf25357ae [column families] Removing VersionSet::current()
Summary: Instead of VersionSet::current(), DBImpl uses default_cfd_->current directly.

Test Plan: make check

Reviewers: dhruba, haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15483
2014-01-27 17:04:46 -08:00
Igor Canadi
eb055609e4 [column families] Move memtable and immutable memtable list to column family data
Summary: All memtables and immutable memtables are moved from DBImpl to ColumnFamilyData. For now, they are all referenced from default column family in DBImpl. It shouldn't be hard to get them from custom column family.

Test Plan: make check

Reviewers: dhruba, kailiu, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15459
2014-01-27 13:37:14 -08:00
Igor Canadi
ae16606f98 Merge branch 'master' into columnfamilies
Conflicts:
	db/version_set.cc
	db/version_set.h
2014-01-27 11:11:51 -08:00
Igor Canadi
832158e7f7 Fsync directory after we create a new file
Summary:
@dhruba, I'm not sure where we need to sync the directory. I implemented the function in Env() and added the dir sync just after we close the newly created file in the builder.

Should I also add FsyncDir() to new files that get created by a compaction?

Test Plan: Confirmed that FsyncDir is returning Status::OK()

Reviewers: dhruba, haobo

Reviewed By: dhruba

CC: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D14751
2014-01-27 11:02:21 -08:00
Igor Canadi
1423e7c9de Merge branch 'master' into columnfamilies
Conflicts:
	db/version_set.cc
	db/version_set_reduce_num_levels.cc
	util/ldb_cmd.cc
2014-01-24 15:03:54 -08:00
Igor Canadi
c583157d49 MemTableListVersion
Summary:
MemTableListVersion is to MemTableList what Version is to VersionSet. I took almost the same ideas to develop MemTableListVersion. The reason is to have copying std::list done in background, while flushing, rather than in foreground (MultiGet() and NewIterator()) under a mutex! Also, whenever we copied MemTableList, we copied also some MemTableList metadata (flush_requested_, commit_in_progress_, etc.), which was wasteful.

This diff avoids std::list copy under a mutex in both MultiGet() and NewIterator(). I created a small database with some number of immutable memtables, and creating 100.000 iterators in a single-thread (!) decreased from {188739, 215703, 198028} to {154352, 164035, 159817}. A lot of the savings come from code under a mutex, so we should see much higher savings with multiple threads. Creating new iterator is very important to LogDevice team.

I also think this diff will make SuperVersion obsolete for performance reasons. I will try it in the next diff. SuperVersion gave us huge savings on Get() code path, but I think that most of the savings came from copying MemTableList under a mutex. If we had MemTableListVersion, we would never need to copy the entire object (like we still do in NewIterator() and MultiGet())

Test Plan: `make check` works. I will also do `make valgrind_check` before commit

Reviewers: dhruba, haobo, kailiu, sdong, emayanke, tnovak

Reviewed By: kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15255
2014-01-24 14:52:08 -08:00
Igor Canadi
28d1a0c6f5 Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/db_impl.h
	db/db_impl_readonly.h
	db/db_test.cc
	include/rocksdb/db.h
	include/utilities/stackable_db.h
2014-01-24 09:27:29 -08:00
Lei Jin
aba2acb5ec CompactRange() to return status
Summary: as title

Test Plan:
make all check
What else tests shall I cover?

Reviewers: igor, haobo

CC:

Differential Revision: https://reviews.facebook.net/D15339
2014-01-23 16:41:46 -08:00
Kai Liu
054c5dda8c Merge branch 'master' into performance
Conflicts:
	db/db_impl.cc
	db/db_test.cc
	db/memtable.cc
	db/version_set.cc
	include/rocksdb/statistics.h
	util/statistics_imp.h
2014-01-23 16:32:49 -08:00
Tomislav Novak
81c9cc9b3b Tailing iterator
Summary:
This diff implements a special type of iterator that doesn't create a snapshot
(can be used to read newly inserted data) and is optimized for doing sequential
reads.

TailingIterator uses current superversion number to determine whether to
invalidate its internal iterators. If the version hasn't changed, it can often
avoid doing expensive seeks over immutable structures (sst files and immutable
memtables).

Test Plan:
* new unit tests
* running LD with this patch

Reviewers: igor, dhruba, haobo, sdong, kailiu

Reviewed By: sdong

CC: leveldb, lovro, march

Differential Revision: https://reviews.facebook.net/D15285
2014-01-23 16:26:08 -08:00
Igor Canadi
92a022ad07 Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/db_impl.h
	db/db_impl_readonly.cc
	db/version_set.cc
2014-01-22 10:59:07 -08:00
Igor Canadi
6fe9b57748 Refactor Recover() code
Summary:
This diff does two things:
* Rethinks how we call Recover() with read_only option. Before, we call it with pointer to memtable where we'd like to apply those changes to. This memtable is set in db_impl_readonly.cc and it's actually DBImpl::mem_. Why don't we just apply updates to mem_ right away? It seems more intuitive.
* Changes when we apply updates to manifest. Before, the process is to recover all the logs, flush it to sst files and then do one giant commit that atomically adds all recovered sst files and sets the next log number. This works good enough, but causes some small troubles for my column family approach, since I can't have one VersionEdit apply to more than single column family[1]. The change here is to commit the files recovered from logs right away. Here is the state of the world before the change:
1. Recover log 5, add new sst files to edit
2. Recover log 7, add new sst files to edit
3. Recover log 8, add new sst files to edit
4. Commit all added sst files to manifest and mark log files 5, 7 and 8 as recoverd (via SetLogNumber(9) function)
After the change, we'll do:
1. Recover log 5, commit the new sst files and set log 5 as recovered
2. Recover log 7, commit the new sst files and set log 7 as recovered
3. Recover log 8, commit the new sst files and set log 8 as recovered

The added (small) benefit is that if we fail after (2), the new recovery will only have to recover log 8. In previous case, we'll have to restart the recovery from the beginning. The bigger benefit will be to enable easier integration of multiple column families in Recovery code path.

[1] I'm happy to dicuss this decison, but I believe this is the cleanest way to go. It also makes backward compatibility much easier. We don't have a requirement of adding multiple column families atomically.

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong

Reviewed By: kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15237
2014-01-22 10:45:26 -08:00
Igor Canadi
23f6791c9e Merge branch 'master' into columnfamilies
Conflicts:
	db/db_impl.cc
	db/db_impl_readonly.cc
	db/db_test.cc
	db/version_edit.cc
	db/version_edit.h
	db/version_set.cc
	db/version_set.h
	db/version_set_reduce_num_levels.cc
2014-01-21 17:01:52 -08:00
Igor Canadi
8079dd5d24 Merge branch 'master' into performance 2014-01-17 12:20:07 -08:00
Mark Callaghan
439e36db21 Fix SlowdownAmount
Summary:
This had a few bugs.
1) bottom and top were reversed. top is for the max value but the callers were passing the max
value to bottom. The result is that the max sleep is used when n >= bottom.
2) one of the callers passed values with type double and these values are frequently between
1.0 and 2.0 so rounding will do some bad things
3) sometimes the function returned 0 when there should be a stall

With this change and one other diff (out for review soon) there are slightly fewer stalls on one workload.

With the fix.
Stalls(secs): 160.166 level0_slowdown, 0.000 level0_numfiles, 0.000 memtable_compaction, 58.495 leveln_slowdown
Stalls(count): 910261 level0_slowdown, 0 level0_numfiles, 0 memtable_compaction, 54526 leveln_slowdown

Without the fix.
Stalls(secs): 172.227 level0_slowdown, 0.000 level0_numfiles, 0.000 memtable_compaction, 56.538 leveln_slowdown
Stalls(count): 160831 level0_slowdown, 0 level0_numfiles, 0 memtable_compaction, 52845 leveln_slowdown

Task ID: #

Blame Rev:

Test Plan:
run db_bench for --benchmarks=overwrite with IO-bound database

Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: haobo

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15243
2014-01-17 10:15:30 -08:00
kailiu
1304d8c8ce Merge branch 'master' into performance
Conflicts:
	Makefile
	db/db_impl.cc
	db/db_impl.h
	db/db_test.cc
	db/memtable.cc
	db/memtable.h
	db/version_edit.h
	db/version_set.cc
	include/rocksdb/options.h
	util/hash_skiplist_rep.cc
	util/options.cc
2014-01-15 23:12:31 -08:00
Igor Canadi
2f4eda7890 Move functions from VersionSet to Version
Summary:
There were some functions in VersionSet that had no reason to be there instead of Version. Moving them to Version will make column families implementation easier.

The functions moved are:
* NumLevelBytes
* LevelSummary
* LevelFileSummary
* MaxNextLevelOverlappingBytes
* AddLiveFiles (previously AddLiveFilesCurrentVersion())
* NeedSlowdownForNumLevel0Files

The diff continues on (and depends on) D15171

Test Plan: make check

Reviewers: dhruba, haobo, kailiu, sdong, emayanke

Reviewed By: sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15183
2014-01-15 16:18:04 -08:00
Igor Canadi
d9cd7a063f Fix CompactRange to apply filter to every key
Summary:
When doing CompactRange(), we should first flush the memtable and then calculate max_level_with_files. Also, we want to compact all the levels that have files, including level `max_level_with_files`.

This patch fixed the unit test.

Test Plan: Added a failing unit test and a fix, so it's not failing anymore.

Reviewers: dhruba, haobo, sdong

Reviewed By: haobo

CC: leveldb, xjin

Differential Revision: https://reviews.facebook.net/D14421
2014-01-14 16:19:09 -08:00
Igor Canadi
7d9f21cf23 BuildBatchGroup -- memcpy outside of lock
Summary: When building batch group, don't actually build a new batch since it requires heavy-weight mem copy and malloc. Only store references to the batches and build the batch group without lock held.

Test Plan:
`make check`

I am also planning to run performance tests. The workload that will benefit from this change is readwhilewriting. I will post the results once I have them.

Reviewers: dhruba, haobo, kailiu

Reviewed By: haobo

CC: leveldb, xjin

Differential Revision: https://reviews.facebook.net/D15063
2014-01-14 14:49:31 -08:00
Igor Canadi
151f9e144f Merge branch 'master' into columnfamilies 2014-01-13 09:09:51 -08:00
Mark Callaghan
50994bf699 Don't always compress L0 files written by memtable flush
Summary:
Code was always compressing L0 files written by a memtable flush
when compression was enabled. Now this is done when
min_level_to_compress=0 for leveled compaction and when
universal_compaction_size_percent=-1 for universal compaction.

Task ID: #3416472

Blame Rev:

Test Plan:
ran db_bench with compression options

Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: dhruba, igor, sdong

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14757
2014-01-07 21:50:26 -08:00
Igor Canadi
72918efffe [column families] Implement DB::OpenWithColumnFamilies()
Summary:
In addition to implementing OpenWithColumnFamilies, this diff also includes some minor changes:
* Changed all column family names from Slice() to std::string. The performance of column family name handling is not critical, and it's more convenient and cleaner to have names as std::strings
* Implemented ColumnFamilyOptions(const Options&) and DBOptions(const Options&)
* Added ColumnFamilyOptions to VersionSet::ColumnFamilyData. ColumnFamilyOptions are specified on OpenWithColumnFamilies() and CreateColumnFamily()

I will keep the diff in the Phabricator for a day or two and will push to the branch then. Feel free to comment even after the diff has been pushed.

Test Plan: Added a simple unit test

Reviewers: dhruba, haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15033
2014-01-07 11:05:50 -08:00
Igor Canadi
d3a2ba9c64 Merge branch 'master' into columnfamilies 2014-01-07 11:05:03 -08:00
Igor Canadi
17a222670b Merge branch 'master' into performance 2014-01-07 11:04:21 -08:00
Tomislav Novak
9f690ec62c Fix a deadlock in CompactRange()
Summary:
The way DBImpl::TEST_CompactRange() throttles down the number of bg compactions
can cause it to deadlock when CompactRange() is called concurrently from
multiple threads. Imagine a following scenario with only two threads
(max_background_compactions is 10 and bg_compaction_scheduled_ is initially 0):

   1. Thread #1 increments bg_compaction_scheduled_ (to LargeNumber), sets
      bg_compaction_scheduled_ to 9 (newvalue), schedules the compaction
      (bg_compaction_scheduled_ is now 10) and waits for it to complete.
   2. Thread #2 calls TEST_CompactRange(), increments bg_compaction_scheduled_
      (now LargeNumber + 10) and waits on a cv for bg_compaction_scheduled_ to
      drop to LargeNumber.
   3. BG thread completes the first manual compaction, decrements
      bg_compaction_scheduled_ and wakes up all threads waiting on bg_cv_.
      Thread #1 runs, increments bg_compaction_scheduled_ by LargeNumber again
      (now 2*LargeNumber + 9). Since that's more than LargeNumber + newvalue,
      thread #2 also goes to sleep (waiting on bg_cv_), without resetting
      bg_compaction_scheduled_.

This diff attempts to address the problem by introducing a new counter
bg_manual_only_ (when positive, MaybeScheduleFlushOrCompaction() will only
schedule manual compactions).

Test Plan:
I could pretty much consistently reproduce the deadlock with a program that
calls CompactRange(nullptr, nullptr) immediately after Write() from multiple
threads. This no longer happens with this patch.

Tests (make check) pass.

Reviewers: dhruba, igor, sdong, haobo

Reviewed By: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14799
2014-01-07 10:37:34 -08:00
Igor Canadi
ef6ad1708d [column families] Support to create and drop column families
Summary:
This diff provides basic implementations of CreateColumnFamily(), DropColumnFamily() and ListColumnFamilies(). It builds on top of https://reviews.facebook.net/D14733

It also includes a bug fix for DBImplReadOnly, where Get implementation would be redirected to DBImpl instead of DBImplReadOnly.

Test Plan: Added unit test

Reviewers: dhruba, haobo, kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15021
2014-01-03 01:12:16 -08:00
Kai Liu
774ed89c24 Replace vector with autovector
Summary: this diff only replace the cases when we need to frequently create vector with small amount of entries. This diff doesn't aim to improve performance of a specific area, but more like a small scale test for the autovector and see how it works in real life.

Test Plan:
make check

I also ran the performance tests, however there is no performance gain/loss. All performance numbers are pretty much the same before/after the change.

Reviewers: dhruba, haobo, sdong, igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14985
2014-01-02 16:43:35 -08:00
kailiu
e72aa37cc5 Merge branch 'master' into performance
Conflicts:
	db/table_cache.cc
2014-01-02 16:34:59 -08:00
kailiu
476416c27c Some minor refactoring on the code
Summary: I made some cleanup while reading the source code in `db`. Most changes are about style, naming or C++ 11 new features.

Test Plan: ran `make check`

Reviewers: haobo, dhruba, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15009
2014-01-02 16:32:31 -08:00
Igor Canadi
6de1b5b83e Merge branch 'master' into columnfamilies 2014-01-02 04:18:07 -08:00
Igor Canadi
b60c14f6ee Support multi-threaded DisableFileDeletions() and EnableFileDeletions()
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
2014-01-02 03:33:42 -08:00
kailiu
f1cec73a76 Merge branch 'master' into performance
Conflicts:
	db/db_impl.cc
	db/db_test.cc
	db/memtable.cc
	db/version_set.cc
	include/rocksdb/statistics.h
2013-12-27 12:23:17 -08:00
Igor Canadi
1fdb3f7dc6 [RocksDB] Optimize locking for Get
Summary:
Instead of locking and saving a DB state, we can cache a DB state and update it only when it changes. This change reduces lock contention and speeds up read operations on the DB.

Performance improvements are substantial, although there is some cost in no-read workloads. I ran the regression tests on my devserver and here are the numbers:

  overwrite                    56345  ->   63001
  fillseq                      193730 ->  185296
  readrandom                   771301 -> 1219803 (58% improvement!)
  readrandom_smallblockcache   677609 ->  862850
  readrandom_memtable_sst      710440 -> 1109223
  readrandom_fillunique_random 221589 ->  247869
  memtablefillrandom           105286 ->   92643
  memtablereadrandom           763033 -> 1288862

Test Plan:
make asan_check
I am also running db_stress

Reviewers: dhruba, haobo, sdong, kailiu

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D14679
2013-12-20 09:57:58 -08:00