armon / bloomd

C network daemon for bloom filters
http://armon.github.io/bloomd
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Why does the probability value (FP) decrease from initial setting. #57

Open tonkapango opened 4 years ago

tonkapango commented 4 years ago

Thanks armon, this is a very helpful project! My lack of full understanding of stable bloom filters is probably the cause of this issue. But i see the "default" probability that i provide when creating a new sbf change from .00000001 to .0001000 on subsequent restarts.

I am not sure if when successive plain bloom filters are created and with the probability reduction (default .9) the overall error probability tends towards the original prob value specified (.0000001) as we approach the capacity (in this case 1B); and the probability specified from the info command after initial start is the probability value of latest plain filter in the sbf array?

repo

$ bloomd & $ echo "create test capacity=1000000000 prob=0.0000001" | nc 127.0.0.1 8673 $ echo "info test" | nc 127.0.0.1 8673 START capacity 1000000000 checks 0 check_hits 0 check_misses 0 in_memory 1 page_ins 0 page_outs 0 probability 0.0000001000 sets 0 set_hits 0 set_misses 0 size 0 storage 4792529701 END

$ kill -9 ps | grep bloomd | awk '{print $1}' $ bloomd & $ echo "info test" | nc 127.0.0.1 8673 START capacity 1000000000 checks 0 check_hits 0 check_misses 0 in_memory 1 page_ins 0 page_outs 0 probability 0.0001000000 sets 0 set_hits 0 set_misses 0 size 0 storage 4792529701 END