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5f99158889
We are currently suspecting that the bloom filter false positive ratio is not being respected. While trying to debug that, I found out that we have a more basic problem: The numbers are all meaningless, because the stats are wrong. We are accumulating by summing the ratios together. It's easy to see how this doesn't work, if we look at an example where the ratio for some CFs is zero: SST1: false = 1, total = 2. ratio = 0.5 SST2: false = 0, total = 98 . ratio = 0. The real ratio in this example is 1 / (98 + 2) = 1 %, but the displayed ratio will be 0.5 + 0 = 0.5. This patch will map reduce all the sstables together keeping both numerator and denominator, yielding the right value at the end. To do that, we'll reuse the existing ratio_holder class, which already does exactly what we want. Signed-off-by: Glauber Costa <glauber@scylladb.com> Message-Id: <20170518222333.16307-1-glauber@scylladb.com>