efficient/cuckoofilter

PackedTable with bits_per_item 5,7,9 does not work

vidhoonv opened this issue · 4 comments

vidhoonv commented

Hi,

Thanks for writing this library for cuckoo filter. I tried to do some benchmarking and found that while setting bits per item to 5 or 7 or 9 with Packedtable config - the filter does not work. It ends up saying that filter does not contain the item that was added (false negatives). Is this known issue ? The issue can be reproduced by using the test.cc file in the repo and changing line 52 to configure the filter to PackedTable and bits per item to 5 or 7 or 9.

jbapple-cloudera commented

See also #6. That said, this should have a static_assert.

vidhoonv commented

Thanks @jbapple-cloudera for the suggestion. The suggestion in #6 applies for SingleTable. I see that PackedTable supports bits_per_tag = 5,7,8,9,13,17 from PackedTable.h.

vidhoonv commented

@jbapple-cloudera I am not sure how your commit d17dda3 would address my question/issue. In the case of PackedTable, bits_per_tag = 5,7,8,9,13,17 are supported and valid to use. But the filter fails while testing an item for its presence. I think it is an issue with the PackedTable implementation.

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jbapple commented

@vidhoonv Good point.