[Haskell-cafe] Re: Hashtable woes

Jan-Willem Maessen jmaessen at alum.mit.edu
Wed Feb 15 12:48:49 EST 2006

On Feb 15, 2006, at 3:42 AM, Ketil Malde wrote:

> Not sure how relevant this is, but I see there is a recently released
> hash library here that might be a candidate for FFIing?
> https://sourceforge.net/projects/goog-sparsehash/

The real issue isn't the algorithms involved; I saw the best  
performance from the stupidest hash algorithm (well, and switching to  
multiplicative hashing rather than mod-k).  The problem is GC of hash  
table elements.  FFI-ing this library would give us really good  
algorithms, but the GC would all indirect through the FFI and I'd  
expect that to make things *worse*, not better.


> | An extremely memory-efficient hash_map implementation. 2 bits/entry
> | overhead! The SparseHash library contains several hash-map
> | implementations, including implementations that optimize for space
> | or speed.
> -k
> -- 
> If I haven't seen further, it is by standing in the footprints of  
> giants
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