Examples of hashset.

[amosbird]

Is there an example of libcuckoo hashset? Or should I just use cuckoohash_map<int, bool> Table;? Regards.

[dnbaker]

You could save space by defining an empty struct and using it instead of bool. For example:

struct empty {};
cuckoohash_map<int, empty> Table;

[amosbird]

Hmm, it takes much more memory than std::unordered_map (60GB) and std::map (80GB) . It gets oom killed after claiming 120GB memory.

[manugoyal]

Hey! Sorry for the late reply.

Note that due to the design of the table, it will double in capacity every time it needs to do a resize. So it's possible that if your table is filled to capacity at 60G, then another insert would trigger an expansion of the table to capacity 120G. Unfortunately, there's not much we have in the works right now about providing alternative resize factors instead of 2 (see #7), though in the future this may be possible.

One thing I'm unclear about though is the number of elements actually present in your table. If your table type is a mapping from int to bool (or whatever value type), shouldn't there only be 2^32 possible key values, which should limit the size of your key-memory to 2^32 * 2^2 ~ 16G? If you could post a code snippet illustrating the table running out of memory that'd be super useful.

[manugoyal]

Closing due to inactivity. Please feel free to reopen if you have more questions!