Summary:
This PR fix the issue that deletion of obsolete files during DB::Open are not rate limited.
The root cause is slow deletion is disabled if trash/db size ratio exceeds the configured `max_trash_db_ratio` d610e14f93/include/rocksdb/sst_file_manager.h (L126) however, the current handling in DB::Open starts with tracking nothing but the obsolete files. This will make the ratio always look like it's 1.
In order for the deletion rate limiting logic to work properly, we should only start deleting files after `SstFileManager` has finished tracking the whole DB, so the main fix is to move these two places that attempts to delete file after the tracking are done: 1) the `DeleteScheduler::CleanupDirectory` call in `SanitizeOptions`, 2) the `DB::DeleteObsoleteFiles` call.
There are some other aesthetic changes like refactoring collecting all the DB paths into a function, rename `DBImp::DeleteUnreferencedSstFiles` to `DBImpl:: MaybeUpdateNextFileNumber` as it doesn't actually delete the files.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/12590
Test Plan: Added unit test and verified with manual testing
Reviewed By: anand1976
Differential Revision: D56830519
Pulled By: jowlyzhang
fbshipit-source-id: 8a38a21b1ea11c5371924f2b88663648f7a17885
241253053a