Performance Mystery Solved - IT'S THE DATA STUPID!!

Richard Gaskin ambassador at fourthworld.com
Thu Nov 11 20:31:50 EST 2010


Monte Goulding wrote:

 >> Unless you're explicitly purging the stacks, any access to
 >> a property of a stack file will load it into memory.  The
 >> first access will take a hit only if the stack isn't already
 >> in memory, but subsequent accesses should be about as fast
 >> whether referring to just the stack name or the stack file
 >> path, since they're interchangeable for mainstacks.
 >
 > I don't think this is entirely true. At least it wasn't when
 > I was working on the standalone builder all those years ago.
 > There was a massive difference in speed between looping over
 > the controls of a stack if that stack was invisible toplevel
 > compared to just referencing it as a filename. There was a
 > user that was having extremely slow builds because they had
 > so many controls.

It would make me very happy if that were the case.

A couple years ago there was a long thread here in which I complained 
that if I access a property in a stack but don't explicitly open the 
stack, IMO the behavior should be as it was in SuperCard:  the stack 
file is read into memory to obtain the property value, and then the copy 
in memory is disposed of.

What was happening instead is that the stack file was hanging out in 
memory just the same as if I had opened it, and many here argued that 
that was a good thing.

I haven't tested this myself in a long time - got any current benchmarks?

If the behavior has changed then Trevor, Chipp, Jacque, and a good many 
others who voiced an opinion that leaving it in memory was valuable may 
not like it, but I'll be quite happy indeed. :)

--
  Richard Gaskin
  Fourth World
  LiveCode training and consulting: http://www.fourthworld.com
  Webzine for LiveCode developers: http://www.LiveCodeJournal.com
  LiveCode Journal blog: http://LiveCodejournal.com/blog.irv



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