| A Compaction encapsulates information
| about a compaction.
|
| Per level compaction stats. stats_[level]
| stores the stats for compactions that
| produced data for the specified “level”.
|
| Information for a manual compaction
|
| Lookup the value for key. If found, store it
| in *val and return OK. Else return a non-OK
| status. Fills *stats.
|
| REQUIRES: lock is not held
| A helper class so we can efficiently apply
| a whole sequence of edits to a particular state
| without creating intermediate Versions that
| contain full copies of the intermediate state.
| Return a human-readable short (single-line)
| summary of the number of files per level.
|
| Uses *scratch as backing store.
|