This function is used to estimate number of points in interval
[-inf,b]. It will be useful for estimating droppable tombstone
ratio in a given sstable.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
This bug was introduced when converting java code. Return value
of map::erase() was used as if it were the value of the removed
entry, but it's actually the number of removed entries.
update() also relies on ordered keys, so map is used instead
by histogram.
In addition, histograms will be written in sorted order (like C*
does) such that we can detect bad histograms, using disk_array.
disk_array is also used from now on to read histograms.
The conversion from array to map is fine because histograms for
sstables are limited to 100 elements.
Coming patch will detect bad histograms (generated only by us)
and discard them, because we can't rely on their information.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
