Performance of adding 2M key chunks (~ 1700 keys).

Originally ~ 30 mins with 0.0.2.

After adding an index on keyid for onak_keys:
        Command being timed: "/u2/noodles/onak-0.0.3/onak"
        User time (seconds): 75.12
        System time (seconds): 76.08
        Percent of CPU this job got: 3%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 1:18:17
        Major (requiring I/O) page faults: 630
        Minor (reclaiming a frame) page faults: 1238

Making deletion in the same transaction as readding:
        Command being timed: "/u2/noodles/onak-0.0.3/onak"
        User time (seconds): 67.28
        System time (seconds): 75.74
        Percent of CPU this job got: 2%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 1:22:08
        Major (requiring I/O) page faults: 617
        Minor (reclaiming a frame) page faults: 1241

Making merge_keys all one transaction:
        Command being timed: "/u2/noodles/onak-0.0.3/onak"
        User time (seconds): 74.45
        System time (seconds): 69.82
        Percent of CPU this job got: 2%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 1:29:28
        Major (requiring I/O) page faults: 610
        Minor (reclaiming a frame) page faults: 1237

Only delete old key if we know it exists:
	Command being timed: "/u2/noodles/onak-0.0.3/onak"
        User time (seconds): 77.47
        System time (seconds): 75.06
        Percent of CPU this job got: 3%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 1:16:41
        Major (requiring I/O) page faults: 610
        Minor (reclaiming a frame) page faults: 1239