Local/Global Transaction Txn Allocator in Cross-DC Deployment Roadmap

[JmPotato]

RFC: Local/Global Transaction in Cross-DC Deployment (In Chinese)
Issue: pingcap/tidb#18253

Refactoring Phase

• Wrap the election mechanism to improve its reusability to introduce the election of TSO Allocator more easily. (member: refactor election #2767 + election, member: adjust some election methods #2831 + member, server: remove some invalid function parameters #2883)
• Modify the tso package to be more extendable, maybe using interface. (tso: refactor the tso service #2803 + tso: remove the use of atomic.Value #2842 + tso: introduce the AllocatorManager #2859)

Implementation Phase

New Configuration

• Introduce the new DC location configuration. (config: introduce the dc-location config #2925)
• Write configuration into etcd for persistence. (tso, config, test: persist dc-location config in the cluster #2939)
• Implement the ctl command and API to create and update the configuration.

Allocator Manager

• Introduce the new Allocator Manager to concurrently manage multi allocations in one PC server. (tso: introduce the AllocatorManager #2859)
• Implement the basic election of the TSO Allocator. (tso: add basic election logic for Local TSO Allocator #2894 + tso: add the allocator checker #2992)
• Implement the election priority check. (tso: add election priority for Local TSO Allocator #2953)
• Implement the differentiation mechanism by using the low bits of TSO's logical part to distinguish the same TSO of different DCs. (tso: make the TSO unique while member changing #3267 + tso: refine the codes of TSO and TSO tests #3290)

Local TSO Allocator

• Implement the internal logic of the Local TSO Allocator. (tso: add basic TSO generation logic for the local allocator #2986)

Global TSO Allocator

• Implement the new RPC methods used to synchronize TSO between PD servers. (tso: add SyncMaxTS RPC method #2988)
• Be compatible with the old Global TSO Allocator. (tso: implement the global TSO generation algorithm #3033)
• Implement the internal logic of the Global TSO Allocator. (tso: implement the global TSO generation algorithm #3033)
• Implement the unit tests. (tso: implement the global TSO generation algorithm #3033)

PD Client

• Implement the new Local/Global TSO acquisition mechanism for PD Client. (client: support to get the local TSO #3045)

Test Phase

• Have an instance-level verification with TiDB.

Notice

The goal of the refactoring phase is doing some preparation work to make the implementation phase can go smoothly and easily. Some of these ideas are not mature yet. So this roadmap's content above may change at any time during the process of development.

[lhy1024]

@JmPotato Can we close it?

[JmPotato]

@JmPotato Can we close it?

It has not been released yet, I think we can keep it open.

[okJiang]

@JmPotato How about closing it now?👀

[JmPotato]

Close due to the stall of this project.