pdClient (ticdc): Enable the pdClient forwarding function to make cdc more stable during network isolation between the PD leader

[asddongmen]

What problem does this PR solve?

Issue Number: close #10849

What is changed and how it works?

Enable pdClient's forwarding function, make it can forward request to PD follower if cdc is network isolated with PD Leader.

Enabling forwarding will introduce additional network round trips between the PD follower and PD leader. However, since TiCDC doesn't call the PD API frequently, it won't affect TiCDC's performance.

So we decide to enable it by default.

Check List

Tests

• Manual test (add detailed scripts or steps below)

This PR has been tested multiple times in the HA case [ha-ticdc-non-owner-random-to-pdleader-network-partition-last-for-10m]. The results indicate that it functions as expected:

The changefeed's lag is not affected by the network partition between CDC and the PD leader anymore.

Questions

Will it cause performance regression or break compatibility?

Do you need to update user documentation, design documentation or monitoring documentation?

Release note

Enable the pdClient forwarding function to make cdc more stable during network isolation between the PD leader.

[ti-chi-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CharlesCheung96, sdojjy

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [CharlesCheung96,sdojjy]
• cdc/api/v2/OWNERS [sdojjy]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-05-13 06:41:41.896796992 +0000 UTC m=+1462655.653932565: ☑️ agreed by sdojjy.
• 2024-05-13 06:50:23.711830914 +0000 UTC m=+1463177.468966488: ☑️ agreed by CharlesCheung96.

[asddongmen]

/hold

[asddongmen]

/test all

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 57.5924%. Comparing base (0332357) to head (b508919).
Report is 3 commits behind head on master.

Additional details and impacted files

Components	Coverage Δ
cdc	62.0251% <0.0000%> (+0.3686%)	⬆️
dm	51.2593% <ø> (+0.0293%)	⬆️
engine	63.4020% <ø> (+0.0141%)	⬆️

Flag	Coverage Δ
unit	57.5924% <0.0000%> (+0.1998%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

@@               Coverage Diff                @@
##             master     #11076        +/-   ##
================================================
+ Coverage   57.3926%   57.5924%   +0.1998%     
================================================
  Files           851        851                
  Lines        125612     125855       +243     
================================================
+ Hits          72092      72483       +391     
+ Misses        48108      47990       -118     
+ Partials       5412       5382        -30     

[asddongmen]

/unhold

[asddongmen]

/retest

[asddongmen]

/retest

[asddongmen]

/retest

[asddongmen]

/retest

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #11084.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.1: #11086.