cherry-pick #2187 to release-5.1
You can switch your code base to this Pull Request by using git-extras:

# In tics repo:
git pr https://github.com/pingcap/tics/pull/2205

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/tics.git pr/2205:release-5.1-4290c0b5308b

Signed-off-by: JaySon-Huang jayson.hjs@gmail.com

What problem does this PR solve?

Issue Number: related to #2169 , #1552

Problem Summary:
In #1552, we introduce an adaptive aggressive GC strategy for PageStorage. If there are more than 100 legacy files, we will set the gc_max_valid_rate to 1.0 try to compact all PageFiles even if there are no invalid pages inside one PageFile.
It brings some trouble in extreme cases like #2169 more worst and generates more write flow.

What is changed and how it works?

• Add two (no public) variables dt_page_num_max_expect_legacy_files and dt_page_num_max_gc_valid_rate to make then configurable.
• Change the default value of gc_max_valid_rate_bound from 1.00 to 0.95
• Apply those variables for RegionPersister

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
• Need to cherry-pick to the release branch:

Check List

Tests

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

Side effects

Release note

• No release note