Summary:
This PR adds user property collector factory `CompactForTieringCollectorFactory` to support observe SST file and mark it as need compaction for fast tracking data to the proper tier.
A triggering ratio `compaction_trigger_ratio_` can be configured to achieve the following:
1) Setting the ratio to be equal to or smaller than 0 disables this collector
2) Setting the ratio to be within (0, 1] will write the number of observed eligible entries into a user property and marks a file as need-compaction when aforementioned condition is met.
3) Setting the ratio to be higher than 1 can be used to just writes the user table property, and not mark any file as need compaction.
For a column family that does not enable tiering feature, even if an effective configuration is provided, this collector is still disabled. For a file that is already on the last level, this collector is also disabled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/12760
Test Plan: Added unit tests
Reviewed By: pdillinger
Differential Revision: D58734976
Pulled By: jowlyzhang
fbshipit-source-id: 6daab2c4f62b5c6689c3c03e3b3907bbbe6b7a81
c73cf7a878