Disposing of variables to free script memory

[w1zard]

What's the best way to dispose of a variable, like a list, to free script memory.

existingList=[""]; //Doesnt seem to help

[Rolig Loon]

No, that won't remove the variable.  You can empty the contents of a list by writing  existing_list = []; , which will save you memory that was being used to store any previously loaded values, but it will leave the variable itself intact. 

[w1zard]

The memory usage displayed using
 

(string)llGetFreeMemory()

 Doesnt give a higher value after using
 

existing_list = []; 

 either. Does this mean that once you have used memory, it is not possible to dispose of that memory?

[Darkie Minotaur]

The value knows only one directtion: Down. It's a well known bug

[w1zard]

Oh, My, Days. :robotmad:

[w1zard]

So if I hit 100% memory usage, and even though I clear the list using = [];  ,I will get memory usage errors when I start adding to the list, because the old data is still being held in memory by the script instance? or do you mean that just the llGetFreeMemory counter doesnt go back up again? Please say its the later.

[Rolig Loon]

You'll get an error and the script will hang.

See http://wiki.secondlife.com/wiki/LlGetFreeMemory 

and http://wiki.secondlife.com/wiki/LSL_Script_Memory

[Void Singer]

in LSO it's a high water mark (the most memory used so far), in MONO it's what the script is currently using, including memory for items that have not been garbage collected yet.

so in LSO clearing a list won't show, but that memory IS available again (with minor caveats for fragmentation), in MONO it will read correctly AFTER garbage collection, but is still usable in some scenarios (like reassigning a just cleared variable). Garbage collection in MONO should happen on event exit or state change, so reading free memory after one of those should give proper results.

[w1zard]

Ahhh so there is garbage collection. Thank you for the explanation Void, very usefull.

[Void Singer]

some, not the level you might be used to in other languages though... list space and string space, but not the variables themselves.... much like ecmascript only less collapsible.

[Miranda Umino]

1)

If you compile in mono , you may replace llGetFreeMemory by llGetUsedMemory

http://wiki.secondlife.com/wiki/LlGetUsedMemory

 

llGetFreeMemory returns the top of the used stack  and doens t pay attention to the fragmentation of memory .

llGetUsedMemory returns the memory used and pays attention to the fragmentation of memory

 

2) if you use some huge lists or some huge strings , and if you call some functions with list or string in parameters , you may fail in stack heap collision even if you have got enough memory .

It s because the arguments of functions are passed by value and not by reference

write

myList = llDeleteSubList((myList=[])+myList, 0, 0);

instead

myList = llDeleteSubList(myList, 0, 0);

[Void Singer]

---

Miranda Umino wrote:

write

myList = llDeleteSubList((myList=[])+myList, 0, 0);

instead

myList = llDeleteSubList(myList, 0, 0);

---

this trick is only effective in LSO, testing as of ~6mos ago shows it does not work in MONO