[DNM] *: Enable tiflash_fastscan variable and remove fast mode alter statment

[hongyunyan]

What problem does this PR solve?

Issue Number: ref #35850

Problem Summary:

1. remove the code related to the ddl 'alter table xx set tiflash mode fast/normal'.
2. add session/global variable tiflash_fastscan to control whether use fast scan in tiflash.
3. change the telemetry statistic for fast scan.

[Should merge after the PR(https://github.com/pingcap/tipb/pull/272/files) merged]

What is changed and how it works?

Check List

Tests

• [ ] Unit test
• [ ] Integration test
• [ ] Manual test (add detailed scripts or steps below)
• [ ] No code

Side effects

• [ ] Performance regression: Consumes more CPU
• [ ] Performance regression: Consumes more Memory
• [ ] Breaking backward compatibility

Documentation

• [ ] Affects user behaviors
• [ ] Contains syntax changes
• [ ] Contains variable changes
• [ ] Contains experimental features
• [ ] Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• breezewish
• xhebox

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[sre-bot]

Please follow PR Title Format:

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[sre-bot]

Please follow PR Title Format:

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[sre-bot]

Please follow PR Title Format:

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[sre-bot]

Please follow PR Title Format:

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After you have format title, you can leave a comment /run-check_title to recheck it

[hongyunyan]

/run-check_title

[hongyunyan]

/rebuild

[hawkingrei]

/run-all-tests

[ti-chi-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/81b4d82b1f53bc91991160640ec8ac429fbd9862

[hongyunyan]

/cc @breezewish

[ti-chi-bot]

@AstroProfundis: Thanks for your review. The bot only counts approvals from reviewers and higher roles in list, but you're still welcome to leave your comments.

In response to this:

The telemetry part LGTM

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[hongyunyan]

/cc @xhebox

[hongyunyan]

/cc @pingcap/tidb-configuration-reviewer

[hongyunyan]

/run-mysql-test

[xhebox]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 111b27d32e9a8f2050f6e4696b187cff6162ed85

[hongyunyan]

/rebuild

[sre-bot]

TiDB MergeCI notify

🔴 Bad News! [2] CI still failing after this pr merged. These failed integration tests don't seem to be introduced by the current PR.

CI Name	Result	Duration	Compare with Parent commit
idc-jenkins-ci-tidb/integration-common-test	🔴 failed 2, success 15, total 17	16 min	Existing failure
idc-jenkins-ci-tidb/common-test	🔴 failed 2, success 9, total 11	14 min	Existing failure
idc-jenkins-ci/integration-cdc-test	🟢 all 36 tests passed	32 min	Existing passed
idc-jenkins-ci-tidb/tics-test	🟢 all 1 tests passed	7 min 3 sec	Existing passed
idc-jenkins-ci-tidb/integration-ddl-test	🟢 all 6 tests passed	6 min 15 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-2	🟢 all 28 tests passed	5 min 45 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-1	🟢 all 26 tests passed	5 min 13 sec	Existing passed
idc-jenkins-ci-tidb/mybatis-test	🟢 all 1 tests passed	3 min 22 sec	Existing passed
idc-jenkins-ci-tidb/integration-compatibility-test	🟢 all 1 tests passed	3 min 9 sec	Existing passed
idc-jenkins-ci-tidb/plugin-test	🟢 build success, plugin test success	4min	Existing passed

[solotzg]

@hongyunyan PTAL https://ci.pingcap.net/blue/organizations/jenkins/tiflash-ghpr-integration-tests/detail/tiflash-ghpr-integration-tests/8414/pipeline

[2022-08-29T09:53:59.517Z]   File: fullstack-test2/ddl/alter_table_tiflash_replica_and_mode.test

[2022-08-29T09:53:59.517Z]   Error line: 35

[2022-08-29T09:53:59.517Z]   Error: alter table test.t set tiflash mode fast

[2022-08-29T09:53:59.517Z]   Result:

[2022-08-29T09:53:59.517Z]     ERROR 1064 (42000) at line 1: You have an error in your SQL syntax; check the manual that corresponds to your TiDB version for the right syntax to use line 1 column 35 near "mode fast"

[2022-08-29T09:53:59.517Z]   Expected:

[2022-08-29T09:53:59.517Z]     <nothing>