Making Reshard work smoothly with Atomic Transactions

[GuptaManan100]

Description

This PR makes the changes required to make Reshard work with Atomic transactions. Before these changes, Resharding won't wait for prepared atomic transactions to go through, and we could be in a situation where a prepared transaction is unable to commit on the source shards because we have stopped query service on it. At the same time, that prepared transaction won't exist on the target shards, leading to us being unable to commit a prepared transaction altogether.

This PR fixes this situation by changing the RefreshState RPC that Resharding is using. Now, when vttablet is executing the RefreshState RPC, if it decides that query service needs to be stopped, it first turns off the two pc engine from accepting new prepared transactions and then waits for the current prepared transactions until they're resolved. This ensures Resharding doesn't proceed until all the prepared transactions have concluded.

This PR adds fuzzer and stress tests to verify that the changes work as intended. The changes in this PR are different from the ones proposed in the RFC https://github.com/vitessio/vitess/issues/16245#issuecomment-2273836571, because we found that this solution is more elegant and easier to implement than the one proposed there.

Related Issue(s)

• Fixes #16245

Checklist

• [ ] "Backport to:" labels have been added if this change should be back-ported to release branches
• [ ] If this change is to be back-ported to previous releases, a justification is included in the PR description
• [ ] Tests were added or are not required
• [ ] Did the new or modified tests pass consistently locally and on CI?
• [ ] Documentation was added or is not required

Deployment Notes

[vitess-bot[bot]]

Review Checklist

Hello reviewers! :wave: Please follow this checklist when reviewing this Pull Request.

General

• [ ] Ensure that the Pull Request has a descriptive title.
• [ ] Ensure there is a link to an issue (except for internal cleanup and flaky test fixes), new features should have an RFC that documents use cases and test cases.

Tests

• [ ] Bug fixes should have at least one unit or end-to-end test, enhancement and new features should have a sufficient number of tests.

Documentation

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• [ ] New features should be documented.
• [ ] There should be some code comments as to why things are implemented the way they are.
• [ ] There should be a comment at the top of each new or modified test to explain what the test does.

New flags

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If a workflow is added or modified:

• [ ] Each item in Jobs should be named in order to mark it as required.
• [ ] If the workflow needs to be marked as required, the maintainer team must be notified.

Backward compatibility

• [ ] Protobuf changes should be wire-compatible.
• [ ] Changes to _vt tables and RPCs need to be backward compatible.
• [ ] RPC changes should be compatible with vitess-operator
• [ ] If a flag is removed, then it should also be removed from vitess-operator and arewefastyet, if used there.
• [ ] vtctl command output order should be stable and awk-able.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 70.90909% with 16 lines in your changes missing coverage. Please review.

Project coverage is 69.44%. Comparing base (3743f09) to head (d664547). Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
go/vt/vttablet/tabletserver/tabletserver.go	23.07%	10 Missing :warning:
go/vt/vttablet/tabletmanager/rpc_replication.go	0.00%	3 Missing :warning:
go/vt/vttablet/tabletmanager/tm_state.go	86.66%	2 Missing :warning:
go/vt/vttablet/tabletmanager/tm_init.go	75.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #16844 +/- ## ======================================== Coverage 69.44% 69.44% ======================================== Files 1571 1571 Lines 203004 203113 +109 ======================================== + Hits 140974 141052 +78 - Misses 62030 62061 +31 ```

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