Emmett Shear
12/8/2006 8:11:00 PM
On 12/8/06, Jamey Cribbs <jcribbs@netpromi.com> wrote:
> Emmett Shear wrote:
> > I've written code for a Splay tree in Ruby, and I'm trying to
> > serialize it using Marshal::dump.
> >
> > If I create a tree with 1,000 or 10,000 nodes, Marshal::dump works
> > perfectly. When I get up to 100,000 nodes, Marshal::dump causes the
> > irb process to die with the error "Illegal Instruction".
> >
> > Is this a known problem? I tried searching for "Marshal::dump" and
> > "Illegal Instruction" it but I didn't turn up anything. I'm on a
> > PowerBook G4, running Ruby version 1.8.5 and IRb version 0.9.5. I've
> > attached the code for the Splay tree; to reproduce, open irb and run:
> >
> > require 'splay'
> > t = SplayTree.new
> > 100000.times {|i| t[i] = i}
> > Marshal::dump t
>
> I remember running into something similar when I started working on
> Mongoose, which is a ruby rdbms that uses SkipLists for it's indexing.
>
> If I tried to serialize the entire SkipList and it had too many keys, I
> would get an error. I ended adding a method that converts the SkipList
> to a hash, then feeds the hash to Marshal.dump, and it worked. I also
> have another method that loads the Marshalled hash and turns it back
> into a SkipList.
>
> Another thing you could do would be to serialize each SplayNode, instead
> of the whole tree.
>
> HTH,
>
> Jamey Cribbs
>
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>
>
Thanks, I tried the to_hash workaround and it worked great. It also
reduced the serialized size by a large margin. I'm still slightly
disturbed by Marshal::dump dying so badly, but that definitely solved
the problem.
Emmett