Commit Graph

71 Commits

Author SHA1 Message Date
Dmitri Smirnov
3c233ca4ea Fix Windows environment issues
Summary:
Enable directIO on WritableFileImpl::Append
     with offset being current length of the file.
     Enable UniqueID tests on Windows, disable others but
     leeting them to compile. Unique tests are valuable to
     detect failures on different filesystems and upcoming
     ReFS.
     Clear output in WinEnv Getchildren.This is different from
     previous strategy, do not touch output on failure.
     Make sure DBTest.OpenWhenOpen works with windows error message
Closes https://github.com/facebook/rocksdb/pull/1746

Differential Revision: D4385681

Pulled By: IslamAbdelRahman

fbshipit-source-id: c07b702
2017-01-09 15:54:12 -08:00
Maysam Yabandeh
7631734563 Fix the error in ColumnFamiliesTest
Summary:
In the test the last change to AAAZZZ in handles[1] is deleting it. The
result of the get must be NotFound then. Previosuly the test did not
check for the return value of Get and assumed that the status is ok. It
then move ahead asserting the returned value. The passed-by-reference
string value however was not changed (since the key was not found) and
the asserted value is what it contained before doing the Get.
Closes https://github.com/facebook/rocksdb/pull/1753

Differential Revision: D4390982

Pulled By: maysamyabandeh

fbshipit-source-id: dd55a34
2017-01-09 14:09:13 -08:00
Daniel Black
816c1e30ca gcc-7 requires include <functional> for std::function
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
2016-12-16 11:24:18 -08:00
Daniel Black
0ab6fc167f Gcc-7 buffer size insufficient
Summary:
Bunch of commits related to insufficient buffer size. Errors in individual commits.
Closes https://github.com/facebook/rocksdb/pull/1673

Differential Revision: D4332127

Pulled By: IslamAbdelRahman

fbshipit-source-id: 878f73c
2016-12-14 19:24:26 -08:00
Yi Wu
c26a4d8e8a Fix compile error in trasaction_lock_mgr.cc
Summary:
Fix error on mac/windows build since they don't recognize `uint`.
Closes https://github.com/facebook/rocksdb/pull/1624

Differential Revision: D4287139

Pulled By: yiwu-arbug

fbshipit-source-id: b7cc88f
2016-12-06 14:39:16 -08:00
Manuel Ung
2005c88a75 Implement non-exclusive locks
Summary:
This is an implementation of non-exclusive locks for pessimistic transactions. It is relatively simple and does not prevent starvation (ie. it's possible that request for exclusive access will never be granted if there are always threads holding shared access). It is done by changing `KeyLockInfo` to hold an set a transaction ids, instead of just one, and adding a flag specifying whether this lock is currently held with exclusive access or not.

Some implementation notes:
- Some lock diagnostic functions had to be updated to return a set of transaction ids for a given lock, eg. `GetWaitingTxn` and `GetLockStatusData`.
- Deadlock detection is a bit more complicated since a transaction can now wait on multiple other transactions. A BFS is done in this case, and deadlock detection depth is now just a limit on the number of transactions we visit.
- Expirable transactions do not work efficiently with shared locks at the moment, but that's okay for now.
Closes https://github.com/facebook/rocksdb/pull/1573

Differential Revision: D4239097

Pulled By: lth

fbshipit-source-id: da7c074
2016-12-05 17:39:17 -08:00
Manuel Ung
e63350e726 Use more efficient hash map for deadlock detection
Summary:
Currently, deadlock cycles are held in std::unordered_map. The problem with it is that it allocates/deallocates memory on every insertion/deletion. This limits throughput since we're doing this expensive operation while holding a global mutex. Fix this by using a vector which caches memory instead.

Running the deadlock stress test, this change increased throughput from 39k txns/s -> 49k txns/s. The effect is more noticeable in MyRocks.
Closes https://github.com/facebook/rocksdb/pull/1545

Differential Revision: D4205662

Pulled By: lth

fbshipit-source-id: ff990e4
2016-11-19 11:39:15 -08:00
Reid Horuff
1ca5f6d132 Fix 2PC Recovery SeqId Miscount
Summary:
Originally sequence ids were calculated, in recovery, based off of the first seqid found if the first log recovered. The working seqid was then incremented from that value based on every insertion that took place. This was faulty because of the potential for missing log files or inserts that skipped the WAL. The current recovery scheme grabs sequence from current recovering batch and increments using memtableinserter to track how many actual inserts take place. This works for 2PC batches as well scenarios where some logs are missing or inserts that skip the WAL.
Closes https://github.com/facebook/rocksdb/pull/1486

Differential Revision: D4156064

Pulled By: reidHoruff

fbshipit-source-id: a6da8d9
2016-11-10 11:09:22 -08:00
Reid Horuff
d133b08f68 Use correct sequence number when creating memtable
Summary:
copied from: 5ebfd2623a

Opening existing RocksDB attempts recovery from log files, which uses
wrong sequence number to create the memtable. This is a regression
introduced in change a400336.

This change includes a test demonstrating the problem, without the fix
the test fails with "Operation failed. Try again.: Transaction could not
check for conflicts for operation at SequenceNumber 1 as the MemTable
only contains changes newer than SequenceNumber 2.  Increasing the value
of the max_write_buffer_number_to_maintain option could reduce the
frequency of this error"

This change is a joint effort by Peter 'Stig' Edwards thatsafunnyname
and me.
Closes https://github.com/facebook/rocksdb/pull/1458

Differential Revision: D4143791

Pulled By: reidHoruff

fbshipit-source-id: 5a25033
2016-11-09 12:24:17 -08:00
Reid Horuff
4dfaa6610a Make IsDeadlockDetect() virtual member of Transaction
Summary: Make `IsDeadlockDetect()` virtual member of base class `Transaction` for ease of use in MyRocks

Test Plan: compiles. compiles into MyRocks call-site.

Reviewers: mung

Reviewed By: mung

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D65385
2016-10-21 14:47:59 -07:00
Manuel Ung
4edd39fda2 Implement deadlock detection
Summary: Implement deadlock detection. This is done by maintaining a TxnID -> TxnID map which represents the edges in the wait for graph (this is named `wait_txn_map_`).

Test Plan: transaction_test

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D64491
2016-10-19 19:45:57 -07:00
Reid Horuff
8c55bb87c8 Make Lock Info test multiple column families
Summary: Modifies the lock info export test to test multiple column families after I was experiencing a bug while developing the MyRocks front-end for this.

Test Plan: is test.

Reviewers: mung

Reviewed By: mung

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D64725
2016-10-07 15:04:05 -07:00
Reid Horuff
37737c3a6b Expose Transaction State Publicly
Summary:
This exposes a transactions state through a public api rather than through a public member variable. I also do some name refactoring.
ExecutionStatus => TransactionState
exec_status_ => trx_state_

Test Plan: It compiles and transaction_test passes.

Reviewers: IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, mung, dhruba, sdong

Differential Revision: https://reviews.facebook.net/D64689
2016-10-07 11:58:53 -07:00
Reid Horuff
2c1f95291d Add facility to write only a portion of WriteBatch to WAL
Summary:
When constructing a write batch a client may now call MarkWalTerminationPoint() on that batch. No batch operations after this call will be added written to the WAL but will still be inserted into the Memtable. This facility is used to remove one of the three WriteImpl calls in 2PC transactions. This produces a ~1% perf improvement.

```
RocksDB - unoptimized 2pc, sync_binlog=1, disable_2pc=off
INFO 2016-08-31 14:30:38,814 [main]: REQUEST PHASE COMPLETED. 75000000 requests done in 2619 seconds. Requests/second = 28628

RocksDB - optimized 2pc , sync_binlog=1, disable_2pc=off
INFO 2016-08-31 16:26:59,442 [main]: REQUEST PHASE COMPLETED. 75000000 requests done in 2581 seconds. Requests/second = 29054
```

Test Plan: Two unit tests added.

Reviewers: sdong, yiwu, IslamAbdelRahman

Reviewed By: yiwu

Subscribers: hermanlee4, dhruba, andrewkr

Differential Revision: https://reviews.facebook.net/D64599
2016-10-07 11:32:10 -07:00
Manuel Ung
be1f1092c9 Expose transaction id, lock state information and transaction wait information
Summary:
This diff does 3 things:

Expose TransactionID so that we can identify transactions when we retrieve locking and lock wait information. This is exposed as `Transaction::GetID`.

Expose lock state information by locking all stripes in all column families and copying their contents to a data structure. This is exposed as `TransactionDB::GetLockStatusData`.

Adds support for tracking the transaction and the key being waited on, and exposes this as `Transaction::GetWaitingTxn`.

Test Plan: unit tests

Reviewers: horuff, sdong

Reviewed By: sdong

Subscribers: vasilep, hermanlee4, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D64413
2016-09-30 11:41:21 -07:00
Wanning Jiang
78837f5d61 TableBuilder / TableReader support for range deletion
Summary: 1. Range Deletion Tombstone structure 2. Modify Add() in table_builder to make it usable for adding range del tombstones 3. Expose NewTombstoneIterator() API in table_reader

Test Plan: table_test.cc (now BlockBasedTableBuilder::Add() only accepts InternalKey. I make table_test only pass InternalKey to BlockBasedTableBuidler. Also test writing/reading range deletion tombstones in table_test )

Reviewers: sdong, IslamAbdelRahman, lightmark, andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D61473
2016-08-19 15:10:31 -07:00
Aaron Gao
76a67cf741 support stackableDB as the baseDB of transactionDB
Summary: make transactionDB working with StackableDB

Test Plan: make all check -j64

Reviewers: andrewkr, yiwu, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D60705
2016-08-11 14:19:33 -07:00
Aaron Gao
7c190070b4 delete unnessary pointer cast in beginInternalTransaction() function
Summary: use of dynamic_cast<TransactionImpl*> is unnecessary and also introduce difficulty for fbrocksdb support of TransactionDB

Test Plan: ./transaction_test

Reviewers: sdong, IslamAbdelRahman, andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D60501
2016-07-07 16:34:41 -07:00
Reid Horuff
892e9d3047 make transaction WriteOptions modifiable 2016-06-27 12:53:30 -07:00
Islam AbdelRahman
05c5c39a7c Fix build 2016-05-18 00:41:14 -07:00
Reid Horuff
a6254f2bd4 Long outstanding prepare test
Summary: This tests that a prepared transaction is not lost after several crashes, restarts, and memtable flushes.

Test Plan: TwoPhaseLongPrepareTest

Reviewers: sdong

Subscribers: hermanlee4, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58185
2016-05-17 18:57:06 -07:00
Islam AbdelRahman
2ead115116 Fix TransactionTest.TwoPhaseMultiThreadTest under TSAN
Summary:
TransactionTest.TwoPhaseMultiThreadTest runs forever under TSAN and our CI builds time out
looks like the reason is that some threads keep running and other threads dont get a chance to increment the counter

Test Plan: run the test under TSAN

Reviewers: sdong, horuff

Reviewed By: horuff

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58359
2016-05-17 18:54:27 -07:00
Islam AbdelRahman
f6aedb62c0 Fix Transaction memory leak
Summary:
- Make sure we clean up recovered_transactions_ on DBImpl destructor
- delete leaked txns and env in TransactionTest

Test Plan: Run transaction_test under valgrind

Reviewers: sdong, andrewkr, yhchiang, horuff

Reviewed By: horuff

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D58263
2016-05-16 16:32:55 -07:00
Reid Horuff
40123b3805 signed vs unsigned comparison fix 2016-05-11 14:22:43 -07:00
Reid Horuff
c27061dae7 [rocksdb] 2PC double recovery bug fix
Summary:
1. prepare()
2. crash
3. recover
4. commit()
5. crash
6. data is lost

This is due to the transaction data still only residing in the WAL but because the logs were flushed on the first recovery the data is ignored on the second recovery. We must scan all logs found on recovery and only ignore redundant data at the time of replay. It is not possible to know which logs still contain relevant data at time of recovery. We cannot simply ignore a log because all of the non-2pc data it contains has already been written to L0.

The changes made to MemTableInserter are to ensure that prepared sections are still recovered even if all of the non-2pc data in that log has already been flushed to L0.

Test Plan: Provided test.

Reviewers: sdong

Subscribers: andrewkr, hermanlee4, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57729
2016-05-10 14:06:07 -07:00
Reid Horuff
a657ee9a9c [rocksdb] Recovery path sequence miscount fix
Summary:
Consider the following WAL with 4 batch entries prefixed with their sequence at time of memtable insert.
[1: BEGIN_PREPARE, PUT, PUT, PUT, PUT, END_PREPARE(a)]
[1: BEGIN_PREPARE, PUT, PUT, PUT, PUT, END_PREPARE(b)]
[4: COMMIT(a)]
[7: COMMIT(b)]

The first two batches do not consume any sequence numbers so are both prefixed with seq=1.
For 2pc commit, memtable insertion takes place before COMMIT batch is written to WAL.
We can see that sequence number consumption takes place between WAL entries giving us the seemingly sparse sequence prefix for WAL entries.
This is a valid WAL.

Because with 2PC markers one WriteBatch points to another batch containing its inserts a writebatch can consume more or less sequence numbers than the number of sequence consuming entries that it contains.

We can see that, given the entries in the WAL, 6 sequence ids were consumed. Yet on recovery the maximum sequence consumed would be 7 + 3 (the number of sequence numbers consumed by COMMIT(b))

So, now upon recovery we must track the actual consumption of sequence numbers.
In the provided scenario there will be no sequence gaps, but it is possible to produce a sequence gap. This should not be a problem though. correct?

Test Plan: provided test.

Reviewers: sdong

Subscribers: andrewkr, leveldb, dhruba, hermanlee4

Differential Revision: https://reviews.facebook.net/D57645
2016-05-10 14:06:07 -07:00
Reid Horuff
8a66c85e90 [rocksdb] Two Phase Transaction
Summary:
Two Phase Commit addition to RocksDB.

See wiki: https://github.com/facebook/rocksdb/wiki/Two-Phase-Commit-Implementation
Quip: https://fb.quip.com/pxZrAyrx53r3

Depends on:
WriteBatch modification: https://reviews.facebook.net/D54093
Memtable Log Referencing and Prepared Batch Recovery: https://reviews.facebook.net/D56919

Test Plan:
- SimpleTwoPhaseTransactionTest
- PersistentTwoPhaseTransactionTest.
- TwoPhaseRollbackTest
- TwoPhaseMultiThreadTest
- TwoPhaseLogRollingTest
- TwoPhaseEmptyWriteTest
- TwoPhaseExpirationTest

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: leveldb, hermanlee4, andrewkr, vasilep, dhruba, santoshb

Differential Revision: https://reviews.facebook.net/D56925
2016-05-10 14:06:07 -07:00
Li Peng
6d4832a998 Merge pull request #1101 from flyd1005/wip-fix-typo
fix typos and remove duplicated words
2016-04-28 02:30:44 -07:00
SherlockNoMad
f11b0df121 Fix AppVeyor build error 2016-03-15 10:57:33 -07:00
agiardullo
790252805d Add multithreaded transaction test
Summary: Refactored db_bench transaction stress tests so that they can be called from unit tests as well.

Test Plan: run new unit test as well as db_bench

Reviewers: yhchiang, IslamAbdelRahman, sdong

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D55203
2016-03-11 15:16:52 -08:00
agiardullo
2200295ee1 optimistic transactions support for reinitialization
Summary: Extend optimization in D53835 to optimistic transactions for completeness.

Test Plan: added test

Reviewers: sdong, IslamAbdelRahman, horuff, jkedgar

Reviewed By: horuff

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D55059
2016-03-07 19:03:09 -08:00
agiardullo
200080ed72 Improve snapshot handling for Transaction reinitialization
Summary: Previously, reusing a transaction (by passing it as an argument to BeginTransaction) would not clear the transaction's snapshot.  This is not a clear, well-definited behavior.

Test Plan: improved test

Reviewers: sdong, IslamAbdelRahman, horuff, jkedgar

Reviewed By: jkedgar

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D55053
2016-03-07 13:28:11 -08:00
agiardullo
5ea9aa3c14 TransactionDB:ReinitializeTransaction
Summary: Add function to reinitialize a transaction object so that it can be reused.  This is an optimization so users can potentially avoid reallocating transaction objects.

Test Plan: added tests

Reviewers: yhchiang, kradhakrishnan, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: jkedgar, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D53835
2016-02-29 16:27:32 -08:00
agiardullo
d08d50295c Fix transaction locking
Summary: Broke transaction locking in 4.4 in D52197.  Will cherry-pick this change into 4.4 (which hasn't yet been fully released).  Repro'd using db_bench.

Test Plan: unit tests and db_Bench

Reviewers: sdong, yhchiang, kradhakrishnan, ngbronson

Reviewed By: ngbronson

Subscribers: ngbronson, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D54021
2016-02-16 17:15:05 -08:00
reid horuff
5bcf952a87 Fix WriteImpl empty batch hanging issue
Summary: There is an issue in DBImpl::WriteImpl where if an empty writebatch comes in and sync=true then the logs will be marked as being synced yet the sync never actually happens because there is no data in the writebatch. This causes the next incoming batch to hang while waiting for the logs to complete syncing. This fix syncs logs even if the writebatch is empty.

Test Plan: DoubleEmptyBatch unit test in transaction_test.

Reviewers: yoshinorim, hermanlee4, sdong, ngbronson, anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D54057
2016-02-16 12:21:33 -08:00
Igor Canadi
c90d63a23d can_unlock set but not used
Test Plan: I couldn't repro, but I hope this fixes it. See the error here: https://evergreen.mongodb.com/task_log_raw/mongodb_mongo_master_ubuntu1404_rocksdb_compile_6e9fd902d5cb25aef992363efa128640affd5196_16_02_11_04_33_37/0?type=T

Reviewers: yhchiang, andrewkr, sdong, anthony

Reviewed By: anthony

Subscribers: meyering, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D54123
2016-02-16 11:24:40 -08:00
Yueh-Hsuan Chiang
3a67bffaa8 Fix an ASAN error in transaction_test.cc
Summary:
One test in transaction_test.cc forgets to call SyncPoint::DisableProcessing().
As a result, a program might to access the SyncPoint singleton after it
already goes out of scope.

This patch fix this error by calling SyncPoint::DisableProcessing().

Test Plan: transaction_test

Reviewers: sdong, IslamAbdelRahman, kradhakrishnan, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D54033
2016-02-10 12:06:59 -08:00
Baraa Hamodi
21e95811d1 Updated all copyright headers to the new format. 2016-02-09 15:12:00 -08:00
agiardullo
fe93bf9b5d Transaction::UndoGetForUpdate
Summary: MyRocks wants to be able to un-lock a key that was just locked by GetForUpdate().  To do this safely, I am now keeping track of the number of reads(for update) and writes for each key in a transaction.  UndoGetForUpdate() will only unlock a key if it hasn't been written and the read count reaches 0.

Test Plan: more unit tests

Reviewers: igor, rven, yhchiang, spetrunia, sdong

Reviewed By: spetrunia, sdong

Subscribers: spetrunia, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47043
2016-02-09 10:46:11 -08:00
reid horuff
6f71d3b68b Improve perf of Pessimistic Transaction expirations (and optimistic transactions)
Summary:
copy from task 8196669:

1) Optimistic transactions do not support batching writes from different threads.
2) Pessimistic transactions do not support batching writes if an expiration time is set.

In these 2 cases, we currently do not do any write batching in DBImpl::WriteImpl() because there is a WriteCallback that could decide at the last minute to abort the write.  But we could support batching write operations with callbacks if we make sure to process the callbacks correctly.

To do this, we would first need to modify write_thread.cc to stop preventing writes with callbacks from being batched together.  Then we would need to change DBImpl::WriteImpl() to call all WriteCallback's in a batch, only write the batches that succeed, and correctly set the state of each batch's WriteThread::Writer.

Test Plan: Added test WriteWithCallbackTest to write_callback_test.cc which creates multiple client threads and verifies that writes are batched and executed properly.

Reviewers: hermanlee4, anthony, ngbronson

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D52863
2016-02-05 10:44:13 -08:00
Gabriela Jacques da Silva
0c2bd5cb4b Removing data race from expirable transactions
Summary:
Doing inline checking of transaction expiration instead of
using a callback.

Test Plan: To be added

Reviewers: anthony

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D53673
2016-02-02 18:37:44 -08:00
agiardullo
45768ade4f transaction allocation perf improvements
Summary: Removed a couple of memory allocations

Test Plan: changes covered by existing tests

Reviewers: rven, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D53523
2016-01-28 17:32:28 -08:00
agiardullo
eff309867e Do not use timed_mutex in TransactionDB
Summary: Stopped using std::timed_mutex as it has known issues in older versiong of gcc.  Ran into these problems when testing MongoRocks.

Test Plan: unit tests.  Manual mongo testing on gcc 4.8.

Reviewers: igor, yhchiang, rven, IslamAbdelRahman, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D52197
2015-12-18 17:26:02 -08:00
Dmitri Smirnov
b6d19adcf7 Use port size_t formatting 2015-12-15 11:34:22 -08:00
agiardullo
84f98792d6 Transaction::SetWriteOptions()
Summary: Add support to change write options after creating a transaction.  This is needed for MongoRocks.

Test Plan: added test

Reviewers: sdong, rven, kradhakrishnan, IslamAbdelRahman, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51867
2015-12-11 16:08:25 -08:00
agiardullo
3bfd3d39a3 Use SST files for Transaction conflict detection
Summary:
Currently, transactions can fail even if there is no actual write conflict.  This is due to relying on only the memtables to check for write-conflicts.  Users have to tune memtable settings to try to avoid this, but it's hard to figure out exactly how to tune these settings.

With this diff, TransactionDB will use both memtables and SST files to determine if there are any write conflicts.  This relies on the fact that BlockBasedTable stores sequence numbers for all writes that happen after any open snapshot.  Also, D50295 is needed to prevent SingleDelete from disappearing writes (the TODOs in this test code will be fixed once the other diff is approved and merged).

Note that Optimistic transactions will still rely on tuning memtable settings as we do not want to read from SST while on the write thread.  Also, memtable settings can still be used to reduce how often TransactionDB needs to read SST files.

Test Plan: unit tests, db bench

Reviewers: rven, yhchiang, kradhakrishnan, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb, yoshinorim

Differential Revision: https://reviews.facebook.net/D50475
2015-12-11 12:34:11 -08:00
agiardullo
e5c5f23814 Support marking snapshots for write-conflict checking - Take 2
Summary:
D51183 was reverted due to breaking the LITE build.

This diff is the same as D51183 but with a fix for the LITE BUILD(D51693)

Test Plan: run all unit tests

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51711
2015-12-08 16:47:31 -08:00
sdong
1d63c3d610 Revert "Support marking snapshots for write-conflict checking"
This reverts commit ec704aafdc for it broke RocksDB LITE build.
2015-12-08 09:27:17 -08:00
agiardullo
ec704aafdc Support marking snapshots for write-conflict checking
Summary:
D50475 enables using SST files for transaction write-conflict checking.  In order for this to work, we need to make sure not to compact out SingleDeletes when there is an earlier transaction snapshot(D50295).  If there is a long-held snapshot, this could reduce the benefit of the SingleDelete optimization.

This diff allows Transactions to mark snapshots as being used for write-conflict checking.  Then, during compaction, we will be able to optimize SingleDeletes better in the future.

This diff adds a flag to SnapshotImpl which is used by Transactions.  This diff also passes the earliest write-conflict snapshot's sequence number to CompactionIterator.  This diff does not actually change Compaction (after this diff is pushed, D50295 will be able to use this information).

Test Plan: no behavior change, ran existing tests

Reviewers: rven, kradhakrishnan, yhchiang, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51183
2015-12-07 19:40:51 -08:00
Jay Edgar
b28b7c6dd9 Added callback notification when a snapshot is created
Summary: When SetSnapshot() is used the caller immediately knows a snapshot has been created, but when SetSnapshotOnNextOperation() is used the caller needs a way to get notified when that snapshot has been generated.  This creates an interface that the client can implement that will be called at the time the snapshot is created.

Test Plan: Added a new SetSnapshotOnNextOperationWithNotification test into the transaction_test.

Reviewers: sdong, anthony

Reviewed By: anthony

Subscribers: yoshinorim, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51177
2015-12-04 10:20:36 -08:00