Re: [Haskell-cafe] "Out of memory" if compiled with -O2, why?

Thank you, it is indeed very similar problem. Nevertheless it seems that the lst function is not the direct reason, because: 1) if I inline lst (by hands), the problem is still there 2) size of the list is actially not so large - just 15 millions elements I am almost sure that the reason is Map.fromList - result of the function perhaps somehow memoized and not released by GC. Dmitry. On Wed, Dec 1, 2010 at 8:15 PM, Petr Prokhorenkov wrote:

Hi, Dmitry

I recently had the same problem: http://www.haskell.org/pipermail/haskell-cafe/2010-November/086450.html

Memory is taken by the list returned by your lst function wich is being shared across g,h,i,j,k,l,m,n. Apparently there is no safe and easy way to overcome this yet :(

-- Regards, Petr

On Wed, Dec 1, 2010 at 5:23 PM, Dmitry Kulagin wrote:

...

Hi,

I have problems with memory leaks and can't find out how to avoid them. I tried to reduce sample to demonstrate the following problems: 1) when compiled without -O2 option, it iconsumes 1582MB (!) total memory 2) when compiled with -O2 option it terminates with "out of memory"

Actually I don't understand the reasons, particulary why  GC can't collect already processed objects g,...,n (see code below)?

I would appreciate very much any help with this situation. Thanks!

module Main where

import qualified Data.Map as M

len = 15*1024*1024 lst from = take len $ zip [from..] [0..]

g = M.size $ M.fromList $ lst 0 h = M.size $ M.fromList $ lst 0 i = M.size $ M.fromList $ lst 0 j = M.size $ M.fromList $ lst 0 k = M.size $ M.fromList $ lst 0 l = M.size $ M.fromList $ lst 0 m = M.size $ M.fromList $ lst 0 n = M.size $ M.fromList $ lst 0

main = do    mapM_ print [g,h,i,j,k,l,m,n]

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