Support service safe point (#2634)

[ti-chi-bot]

This is an automated cherry-pick of #2634

What problem does this PR solve?

TiSpark does not have a mechanism to check GC. So, you may get the wrong data if your transaction's start_ts behind safe_point

What is changed and how it works?

This PR introduced the service safe point in TiSpark. TiKV will use the min service safe point among all service (including TiDB).

TiSpark will generate a new serviceId for every spark session. Every spark session will register the min start_ts as its' service safe point to PD. Thus, the safe point will not exceed the min start_ts among all spark applications.

Test

It is hard to write IT. Here are the results I test locally.

1. PD logs show TiSpark register service safe point successfully

2. TiKV metric shows TiSpark service safe point can change the safe point: TiSpark register 439743565061947392 (17:02:55) as safe point. This makes the GC safe point turns from 16:57:39 to 17:02:55 rather than 17:07:39

3. TiKV metric shows TiSpark service safe point can pause the safe point.

4. TiKV metric shows safe point will recovery after the TiSpark finished: The GC safe point turns from 17:02:55 to 17:18:39. which means TiSpark will not block it anymore.

5. When the start_ts have already less than the current safe point. TiSpark will throw exceptions directly

6. now-start_ts > spark.tispark.gc_max_wait_time will throw exception
   

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• shiyuhang0
• zhangyangyu

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[shiyuhang0]

/run-all-tests

[shiyuhang0]

/run-all-tests

[shiyuhang0]

/merge

[ti-chi-bot]

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

Commit hash: 2c1cbc8