- default Tx is once again RBF, changed from bolt.
- document the RBF code review comments that were not addressed
before #1052 was merged, so they don't get lost.
- they should be easily addressed by replaying the entire WAL file
rather than from the DB meta page 0 notion of the last WalID
- cleanup rbf/cfg/cfg.go stale comments, ensure default0 respected.
1 msec checkpoint time, 1MB wal segment defaults.
- return a specific error, ErrNoMetaFound, from findNextWALMetaPage()
rather than io.EOF, since there actually wasn't any file IO involved.
- add http handlers for /cpu-profile/start and /cpu-profile/stop
in http/handler.go enable CPU profiling at specific time points
during an ingest or other operation.
- we return to checkpointing after every commit, by default.
- the internal rbf logic is not ready to have
checkpoints deferred. Doing so results in
references to WAL segments that are not
in the current slice of live segments.
