The purpose of this Jira is to propose a work plan for connecting Omid to Phoenix.
Each task of the following will be handled in a seperate sub Jira. Subtasks 4.* are related to augmenting Omid to support features required by Phoenix and therefore, their corresponding Jiras will appear under Omid and not under Phoenix.
Each task is completed by a commit.
Task 1: Adding transaction abstraction layer (TAL) - Currently Tephra calls are integrated inside Phoenix code. Therefore, in order to support both Omid and Tephra, we need to add another abstraction layer that later-on will be connected to both Tephra and Omid. The first tasks is to define such an interface.
Task 2: Implement TAL functionality for Tephra.
Task 3: Refactor Phoenix to use TAL instead of direct calls to Tephra.
Task 4: Implement Omid required features for Phoenix:
Task 4.1: Add checkpoints to Omid. A checkpoint is a point in a transaction where every write occurs after the checkpoint is not visible by the transaction. Explanations for this feature can be seen in
Task 4.2: Add an option to mark a key as non-conflicting. The motivation is to reduce the size of the write set needed by the transaction manager upon commit as well as reduce the conflict detection work.
Task 4.3: Add support for transactions that never abort. Such transactions will only make other inflight transactions abort and will abort only in case of a transaction manager failure.
These transactions are needed for ‘create index’ and the scenario was discussed in
TEPHRA-157 and PHOENIX-2478. Augmenting Omid with this kind of transactions was also discussed in OMID-56.
Task 4.4: Add support for returning multiple versions in a scan. The use case is described in
Task 4.5: Change Omid's timestamp mechanism to return real time based timestamp, while keeping monotonicity.
Task 5: Implement TAL functionality for Omid.
Task 6: Implement performance tests and tune Omid for Phoenix use. This task requires understanding of common usage scenarios in Phoenix as well as defining the tradeoff between throughput and latency.
Could you please review the proposed work plan?
Also, could you please let me know whether I missed any augmentation needed for Omid in order to support Phoenix operations?
I opened a jira
OMID-82 that encapsulates all Omid related development for Phoenix.