Hi, I'm observing something I find quite strange. I have a program that normally streams through a file, and it runs in the expected constant space, consuming about 5MB, according to 'top'. When I uncomment a certain block of code in the library it uses, space consumption appears to grow linearly with the input size. This is a bit surprising to me, since the code in question isn't used by the program at all, and yesterday, Cale confirmed this behavior on a recent GHC (6.10.3, I think - mine is 6.8.2 as shipped with Ubuntu 9.04). Since this appears to be reproducible, I put together a test case. The steps are: darcs get http://malde.org/~ketil/biohaskell/biolib-unstable darcs get http://malde.org/~ketil/biohaskell/flower Build them using the usual incantations (./Setup.hs configure/build/install). Download the test input file: wget http://malde.org/~ketil/test.sff Run for instance this command line: fselect "And (Func GT len 100) (Func GT k2 0.5)" test.sff This should now run in constant space. To observe the linear growth space, unpull the last patch from biolib, i.e. this one: Fri Jul 31 00:14:09 CEST 2009 Ketil Malde * comment out recover functionality - otherwise FSelect leaks memory! M ./Bio/Sequence/SFF.hs -1 +7 This uncomments some otherwise unused code, which apparently triggers this behavior. I'm unable to see what causes this, so any suggestions welcome. -k -- If I haven't seen further, it is by standing in the footprints of giants