Why not keep track of the hash of blocks already stored and discard 
duplicates blocks from memory asap ?

I am talking here of keeping blocks as Clojure structures so the hash will be
consistent between two identical blocks.

Do you store them away as soon as you can ? Or are you trying to keep them
around somehow in memory ?

Luc

> I'm loading data files of about 1-2G, which are composed of a bunch of 
> numeric data blocks. I need to store the data blocks w/o storing 
> duplicates. They arrive as vectors of floats, and are stored as primitive 
> byte arrays.
> 
> I first tried memoizing the function that saves a block (returning an id), 
> with the core memoize function. This failed because every block became a 
> different key in the memoization, regardless of the content. It looks like 
> clojure treats variables referencing primitive arrays as equal only if they 
> refer to the same array. Note:
> 
> cavm.core=> ({[1 2 3] "foo"} [1 2 3])
> "foo"
> cavm.core=> ({(float-array [1 2 3]) "foo"} (float-array [1 2 3]))
> nil
> cavm.core=> (let [a (float-array [1 2 3])] ({a "foo"} a))
> "foo"
> 
> 
> 
> I next tried memoizing over the vector of floats, however performance 
> became pathologically slow, and the process threw an OOM. I'm guessing this 
> is due to the memory requirements of a clojure vector of floats vs. a 
> primitive array of bytes holding the same data. Is there an easy way to 
> compare the storage requirements?
> 
> Any suggestions on how better to handle this?
> 
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