In giving an empty file a score of 0, a race condition was exposed. A file might not be active, but might still be rolling - and then cna get scored as 0, and immediately compacted. It will then be removed from the journal manifest.
Check each file is not rolling before making it a candidate for rolling.
Initial test included for running with recallc, and also transition from retain to recalc.
Moves all logic for startup fold into leveled_bookie - avoid the Inker requiring any direct knowledge about implementation of the Penciller.
Also:
Sort the output from an 'all' fetch one loop at a time
Make sure the test of scoring na empty file is scoring an empty file
If it is an emtpy file we want to compact the fragment away - in which case it should score 0.0 not 100.0
Change the penciller check so that it returns current/replaced/missing not just true/false.
Reduce unnecessary penciller checks for non-standard keys that will always be retained - and remove redunandt code.
Expand tests of retain and recover to make sure that compaction on delete is well covered.
Also move the SQN number laong during initial loads - to stop aggressive loop to find starting SQN every file.
When we want to be sure a file has been written before proceeding - we need a safer (that `file:write_file/2`) mechanism to be sure that it is written before proceeding.
This will:
open, write, sync, rename and then optionally read-back.
Changed so that manifest writing uses the safest form (including read back), and that sst writing uses a slightly looser form (with no read back to avoid performance issues).
Two reasons for logging this:
- to assist in sizing the ledger cache;
- to resolve the mystery when there appear to be no fetches from the penciller (as the penciller does not report fetches from the ledger cache)
Improve the speed of leveled_cdb tests by disabling sync on write.
Improve the strength of check of the correct behaviour when compacting with a reduced journal size.
