#9332: Memory blowing up for strict sum/strict foldl in ghci -------------------------------------+------------------------------------- Reporter: | Owner: artella.coding | Status: closed Type: bug | Milestone: 7.8.4 Priority: high | Version: 7.8.3 Component: GHCi | Keywords: ghci, strict, Resolution: fixed | memory Differential Revisions: | Operating System: Linux Architecture: x86_64 | Type of failure: Runtime (amd64) | performance bug Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | -------------------------------------+------------------------------------- Comment (by simonpj): There is a difficult tension here, described in Chapter 23 of my [http://research.microsoft.com/en-us/um/people/simonpj/papers/slpj- book-1987/index.htm 1987 book], namely the tension between sharing computation and saving space. I do not know of any comprehensive answer. The problem tends to bite less when (as is commonly the case) numbers like `1000000` don't appear in your program but rather are computed from the input or the command line flags. But it's still definitely a problem (e.g. with `[1..]`.) A possible solution might be to revert any CAFs that are retaining a great deal of space, by turning them back into their un-computed form. (Of course, their uncomputed form might retain a great deal of space too!) Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9332#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler