saw-tooth pattern in entries scanned per second

[Jayesh Patel <jp...@keywcorp.com>]

I am trying to figure out something that I always notice across our Accumulo
instantiations.  It's concerning the Scan (Entries/s) graph in the attached
screenshot from the Accumulo monitor.

For the given time period there is only steady heartbeat activity.  For
every hearbeat received, a relatively small set of Accumulo records are
scanned and a couple of those rows are updated.  Since the number of rows
scanned is constant, the saw-tooth shape doesn't make sense.  

My initial reaction was that the compactions might be affecting the number
of scans, but as you can see the 'notch' in the saw-tooth pattern doesn't
line up with when the minor or major compaction occur.

 

Can anyone shade some light please?  Thank you.