schrodinger/bank2 failure in the master branch

[JaySon-Huang]

It may be introduced by #2704

http://172.16.4.180:31714/workflows/test-store/tipocket-debug-tiflash-jrck4?tab=workflow&nodeId=tipocket-debug-tiflash-jrck4&nodePanelView=inputs-outputs

[JaySon-Huang]

Blocked by pingcap/tidb#28096, will try to use an older TiDB version.

[JaySon-Huang]

The reason is:

• After TiFlash restarts, tmt.checkRunning return false (proxy is not ready yet), and it will make a "default read index result" with all Raft index are 0
  https://github.com/pingcap/tics/blob/84cf3607b4d769920a5d460c4d58ccd097884a80/dbms/src/Storages/Transaction/LearnerRead.cpp#L213-L247
• Later we do Region->waitIndex with Raft index 0, it will directly return WaitIndexResult::Finished cause 0 is always less than a normal Raft index
  https://github.com/pingcap/tics/blob/84cf3607b4d769920a5d460c4d58ccd097884a80/dbms/src/Storages/Transaction/LearnerRead.cpp#L313-L320
• And we will continue to resolve lock and read data from the storage layer without strong consistent assurance, which cause inconsistent query result with TiKV.

[JaySon-Huang]

release-5.0/5.1/5.2 are also suffered from a similar bug, but it is less likely to happen since those versions check tmt.checkRunning after each Region->waitIndex
But still, there could be a chance those versions produce inconsistent query results right after restarts:

• After TiFlash restarts, tmt.checkRunning return false, and make a "default read index result"
  https://github.com/pingcap/tics/blob/98b1151545ecee6c25fd26dd7a3ec79d16111417/dbms/src/Storages/Transaction/LearnerRead.cpp#L206-L240
• When TiFlash run into Region->waitIndex with Raft index 0, it directly return without any waiting, and this time, TiFlash-proxy has been setup and tmt.checkRunning return true. Then we still suffer from an inconsistent query result with TiKV
  https://github.com/pingcap/tics/blob/98b1151545ecee6c25fd26dd7a3ec79d16111417/dbms/src/Storages/Transaction/LearnerRead.cpp#L291-L297

[solotzg]

To fix such problem we should change https://github.com/pingcap/tics/blob/84cf3607b4d769920a5d460c4d58ccd097884a80/dbms/src/Storages/Transaction/LearnerRead.cpp#L213-L218

to

        const auto & make_default_batch_read_index_result = [&](bool with_region_error) {
            for (const auto & req : batch_read_index_req)
            {
                auto resp = kvrpcpb::ReadIndexResponse();
                if (with_region_error)
                    resp.mutable_region_error();
                batch_read_index_result.emplace(req.context().region_id(), std::move(resp));
            }
        };