Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/13370
We have a class called `DefaultSecondaryIndex` in `TransactionTest.SecondaryIndexPutDelete` that contains generally useful functionality. The patch generalizes it a bit to make the column name configurable, renames it to `SimpleSecondaryIndex`, and moves it to the public API so applications can use it.
Reviewed By: jowlyzhang
Differential Revision: D69147890
fbshipit-source-id: 0d2d1cc5adcde01f3978a450ec841c9e990d2170