Commit Graph

20 Commits

Author SHA1 Message Date
Maysam Yabandeh
18dcf7f98d WritePrepared Txn: PreReleaseCallback
Summary:
Add PreReleaseCallback to be called at the end of WriteImpl but before publishing the sequence number. The callback is used in WritePrepareTxn to i) update the commit map, ii) update the last published sequence number in the 2nd write queue. It also ensures that all the commits will go to the 2nd queue.
These changes will ensure that the commit map is updated before the sequence number is published and used by reading snapshots. If we use two write queues, the snapshots will use the seq number published by the 2nd queue. If we use one write queue (the default, the snapshots will use the last seq number in the memtable, which also indicates the last published seq number.
Closes https://github.com/facebook/rocksdb/pull/3205

Differential Revision: D6438959

Pulled By: maysamyabandeh

fbshipit-source-id: f8b6c434e94bc5f5ab9cb696879d4c23e2577ab9
2017-11-30 23:50:45 -08:00
Maysam Yabandeh
53863b76f9 WritePrepared Txn: fix bug with Rollback seq
Summary:
The sequence number was not properly advanced after a rollback marker. The patch extends the existing unit tests to detect the bug and also fixes it.
Closes https://github.com/facebook/rocksdb/pull/3157

Differential Revision: D6304291

Pulled By: maysamyabandeh

fbshipit-source-id: 1b519c44a5371b802da49c9e32bd00087a8da401
2017-11-15 08:27:06 -08:00
Maysam Yabandeh
2515266725 WritePrepared Txn: Refactoring TrackKeys
Summary:
This patch clarifies and refactors the logic around tracked keys in transactions.
Closes https://github.com/facebook/rocksdb/pull/3140

Differential Revision: D6290258

Pulled By: maysamyabandeh

fbshipit-source-id: 03b50646264cbcc550813c060b180fc7451a55c1
2017-11-11 13:14:20 -08:00
Maysam Yabandeh
2edc92bc28 WritePrepared Txn: cross-compatibility test
Summary:
Add tests to ensure that WritePrepared and WriteCommitted policies are cross compatible when the db WAL is empty. This is important when the admin want to switch between the policies. In such case, before the switch the admin needs to empty the WAL by i) committing/rollbacking all the pending transactions, ii) FlushMemTables
Closes https://github.com/facebook/rocksdb/pull/3118

Differential Revision: D6227247

Pulled By: maysamyabandeh

fbshipit-source-id: bcde3d92c1e89cda3b9cfa69f6a20af5d8993db7
2017-11-11 11:28:37 -08:00
Maysam Yabandeh
857adf388f WritePrepared Txn: Refactor conf params
Summary:
Summary of changes:
- Move seq_per_batch out of Options
- Rename concurrent_prepare to two_write_queues
- Add allocate_seq_only_for_data_
Closes https://github.com/facebook/rocksdb/pull/3136

Differential Revision: D6304458

Pulled By: maysamyabandeh

fbshipit-source-id: 08e685bfa82bbc41b5b1c5eb7040a8ca6e05e58c
2017-11-10 17:28:12 -08:00
Maysam Yabandeh
60d83df23d WritePrepared Txn: Move DB class to its own file
Summary:
Move  WritePreparedTxnDB from pessimistic_transaction_db.h to its own header, write_prepared_txn_db.h
Closes https://github.com/facebook/rocksdb/pull/3114

Differential Revision: D6220987

Pulled By: maysamyabandeh

fbshipit-source-id: 18893fb4fdc6b809fe117dabb544080f9b4a301b
2017-11-02 11:14:30 -07:00
Maysam Yabandeh
02693f64fc WritePrepared Txn: ValidateSnapshot
Summary:
Implements ValidateSnapshot for WritePrepared txns and also adds a unit test to clarify the contract of this function.
Closes https://github.com/facebook/rocksdb/pull/3101

Differential Revision: D6199405

Pulled By: maysamyabandeh

fbshipit-source-id: ace509934c307ea5d26f4bbac5f836d7c80fd240
2017-11-01 19:11:09 -07:00
Maysam Yabandeh
17731a43a6 WritePrepared Txn: Optimize for recoverable state
Summary:
GetCommitTimeWriteBatch is currently used to store some state as part of commit in 2PC. In MyRocks it is specifically used to store some data that would be needed only during recovery. So it is not need to be stored in memtable right after each commit.
This patch enables an optimization to write the GetCommitTimeWriteBatch only to the WAL. The batch will be written to memtable during recovery when the WAL is replayed. To cover the case when WAL is deleted after memtable flush, the batch is also buffered and written to memtable right before each memtable flush.
Closes https://github.com/facebook/rocksdb/pull/3071

Differential Revision: D6148023

Pulled By: maysamyabandeh

fbshipit-source-id: 2d09bae5565abe2017c0327421010d5c0d55eaa7
2017-11-01 17:26:46 -07:00
Maysam Yabandeh
63822eb761 Enable two write queues for transactions
Summary:
Enable concurrent_prepare flag for WritePrepared transactions and extend the existing transaction tests with this config.
Closes https://github.com/facebook/rocksdb/pull/3046

Differential Revision: D6106534

Pulled By: maysamyabandeh

fbshipit-source-id: 88c8d21d45bc492beb0a131caea84a2ac5e7d38c
2017-10-23 14:27:04 -07:00
Yi Wu
8c392a31d7 WritePrepared Txn: Iterator
Summary:
On iterator create, take a snapshot, create a ReadCallback and pass the ReadCallback to the underlying DBIter to check if key is committed.
Closes https://github.com/facebook/rocksdb/pull/2981

Differential Revision: D6001471

Pulled By: yiwu-arbug

fbshipit-source-id: 3565c4cdaf25370ba47008b0e0cb65b31dfe79fe
2017-10-09 17:15:28 -07:00
Maysam Yabandeh
ec6c5383d0 WritePrepared Txn: end-to-end tests
Summary:
Enable WritePrepared policy for existing transaction tests.
Closes https://github.com/facebook/rocksdb/pull/2972

Differential Revision: D5993614

Pulled By: maysamyabandeh

fbshipit-source-id: d1eb53e2920c4e2a56434bb001231c98426f3509
2017-10-06 14:26:45 -07:00
Maysam Yabandeh
4e3c3d8c6a WritePrepared Txn: duplicate keys
Summary:
With WriteCommitted, when the write batch has duplicate keys, the txn db simply inserts them to the db with different seq numbers and let the db ignore/merge the duplicate values at the read time. With WritePrepared all the entries of the batch are inserted with the same seq number which prevents us from benefiting from this simple solution.

This patch applies a hackish solution to unblock the end-to-end testing. The hack is to be replaced with a proper solution soon. The patch simply detects the duplicate key insertions, and mark the previous one as obsolete. Then before writing to the db it rewrites the batch eliminating the obsolete keys. This would incur a memcpy cost. Furthermore handing duplicate merge would require to do FullMerge instead of simply ignoring the previous value, which is not handled by this patch.
Closes https://github.com/facebook/rocksdb/pull/2969

Differential Revision: D5976337

Pulled By: maysamyabandeh

fbshipit-source-id: 114e65b66f137d8454ff2d1d782b8c05da95f989
2017-10-05 07:41:02 -07:00
Maysam Yabandeh
d27258d3a6 WritePrepared Txn: Rollback
Summary:
Implement the rollback of WritePrepared txns. For each modified value, it reads the value before the txn and write it back. This would cancel out the effect of transaction. It also remove the rolled back txn from prepared heap.
Closes https://github.com/facebook/rocksdb/pull/2946

Differential Revision: D5937575

Pulled By: maysamyabandeh

fbshipit-source-id: a6d3c47f44db3729f44b287a80f97d08dc4e888d
2017-10-02 19:59:27 -07:00
Maysam Yabandeh
385049baf2 WritePrepared Txn: Recovery
Summary:
Recover txns from the WAL. Also added some unit tests.
Closes https://github.com/facebook/rocksdb/pull/2901

Differential Revision: D5859596

Pulled By: maysamyabandeh

fbshipit-source-id: 6424967b231388093b4effffe0a3b1b7ec8caeb0
2017-09-28 16:56:45 -07:00
Maysam Yabandeh
60beefd6e0 WritePrepared Txn: Advance seq one per batch
Summary:
By default the seq number in DB is increased once per written key. WritePrepared txns requires the seq to be increased once per the entire batch so that the seq would be used as the prepare timestamp by which the transaction is identified. Also we need to increase seq for the commit marker since it would give a unique id to the commit timestamp of transactions.

Two unit tests are added to verify our understanding of how the seq should be increased. The recovery path requires much more work and is left to another patch.
Closes https://github.com/facebook/rocksdb/pull/2885

Differential Revision: D5837843

Pulled By: maysamyabandeh

fbshipit-source-id: a08960b93d727e1cf438c254d0c2636fb133cc1c
2017-09-18 14:45:08 -07:00
Maysam Yabandeh
09713a64b3 WritePrepared Txn: Lock-free CommitMap
Summary:
We had two proposals for lock-free commit maps. This patch implements the latter one that was simpler. We can later experiment with both proposals.

In this impl each entry is an std::atomic of uint64_t, which are accessed via memory_order_acquire/release. In x86_64 arch this is compiled to simple reads and writes from memory.
Closes https://github.com/facebook/rocksdb/pull/2861

Differential Revision: D5800724

Pulled By: maysamyabandeh

fbshipit-source-id: 41abae9a4a5df050a8eb696c43de11c2770afdda
2017-09-13 12:12:11 -07:00
Maysam Yabandeh
f46464d383 write-prepared txn: call IsInSnapshot
Summary:
This patch instruments the read path to verify each read value against an optional ReadCallback class. If the value is rejected, the reader moves on to the next value. The WritePreparedTxn makes use of this feature to skip sequence numbers that are not in the read snapshot.
Closes https://github.com/facebook/rocksdb/pull/2850

Differential Revision: D5787375

Pulled By: maysamyabandeh

fbshipit-source-id: 49d808b3062ab35e7ae98ad388f659757794184c
2017-09-11 09:14:48 -07:00
Maysam Yabandeh
9a4df72994 WritePrepared Txn: CommitBatch
Summary:
Implements CommitBatch and CommitWithoutPrepare for WritePreparedTxn
Closes https://github.com/facebook/rocksdb/pull/2854

Differential Revision: D5793999

Pulled By: maysamyabandeh

fbshipit-source-id: d8b9858221162c6ac7a1f6912cbd3481d0d8a503
2017-09-08 15:56:39 -07:00
Maysam Yabandeh
eb6425303e Update WritePrepared with the pseudo code
Summary:
Implement the main body of WritePrepared pseudo code. This includes PrepareInternal and CommitInternal, as well as AddCommitted which updates the commit map. It also provides a IsInSnapshot method that could be later called form the read path to decide if a version is in the read snapshot or it should other be skipped.

This patch lacks unit tests and does not attempt to offer an efficient implementation. The idea is that to have the API specified so that we can work on related tasks in parallel.
Closes https://github.com/facebook/rocksdb/pull/2713

Differential Revision: D5640021

Pulled By: maysamyabandeh

fbshipit-source-id: bfa7a05e8d8498811fab714ce4b9c21530514e1c
2017-08-16 16:57:47 -07:00
Maysam Yabandeh
bdc056f8aa Refactor PessimisticTransaction
Summary:
This patch splits Commit and Prepare into lock-related logic and db-write-related logic. It moves lock-related logic to PessimisticTransaction to be reused by all children classes and movies the existing impl of db-write-related to PrepareInternal, CommitSingleInternal, and CommitInternal in WriteCommittedTxnImpl.
Closes https://github.com/facebook/rocksdb/pull/2691

Differential Revision: D5569464

Pulled By: maysamyabandeh

fbshipit-source-id: d1b8698e69801a4126c7bc211745d05c636f5325
2017-08-07 16:12:29 -07:00