Summary:
This patch takes advantage of memtable being able to detect duplicate <key,seq> and returning TryAgain to handle duplicate keys in WritePrepared Txns. Through WriteBatchWithIndex's index it detects existence of at least a duplicate key in the write batch. If duplicate key was reported, it then pays the cost of counting the number of sub-patches by iterating over the write batch and pass it to DBImpl::Write. DB will make use of the provided batch_count to assign proper sequence numbers before sending them to the WAL. When later inserting the batch to the memtable, it increases the seq each time memtbale reports a duplicate (a sub-patch in our counting) and tries again.
Closes https://github.com/facebook/rocksdb/pull/3455
Differential Revision: D6873699
Pulled By: maysamyabandeh
fbshipit-source-id: db8487526c3a5dc1ddda0ea49f0f979b26ae648d
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
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
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
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
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
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
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
