Problem with ScheduledTaskAgent, RestSharp and WriteableBitmap

[yan_]

i miss this point.

[Iacopo]

I think the problem is the HTTP Get + Deserialization of Data + Rendering.... If i try running either Get + Deserialization + Native Tile update it works.... And it also works if i only run Tile update without HTTP Get + Deserialization....

[yan_]

What is the update frequency you want use?

[wizard_hu_]

If you are already into testing these combinations, it may make sense checking their execution time.

[Iacopo]

What is the update frequency you want use?

It should update when the scheduled agents run, i.e. around every 30 minutes, as it happened in the previous version...

[yan_]

ok. So you can do it in two times.
have you try to save your tiles in jpeg ?

[Iacopo]

I finally made it!
What i had to do:
1) Create a Core class for some of my referenced solutions
2) clean up all unused Assmblies
3) Save to jpeg and not png
4) Most important: resort to saving the data to DB AFTER tile generation and after a good GC collect

Thanks everyone for the help!

[JustinLiu]

I finally made it!
What i had to do:
1) Create a Core class for some of my referenced solutions
2) clean up all unused Assmblies
3) Save to jpeg and not png
4) Most important: resort to saving the data to DB AFTER tile generation and after a good GC collect

Thanks everyone for the help!

Hi Iacopo,

Would you mind telling me more about how you did 4)? I am facing a similar issue as my app's wide tile generation throws me with an OutOfMemory exception on WP7.8 while it works fine on WP8. I also store the image in jpeg format.

Many thanks!
Justin

[SB Dev]

WP7.8 allows less memory for the PeriodicUpdateAgents than WP8 does. As for allowing the GC to collect no longer used objects. You have to ensure that everything you no longer need currently isn't referenced in any way by running code. e.g.:

var x = hugeObject;
doSomething(hugeObject);
x = null;//remove reference to hugeObject

GC.Collect();//would run by itself before an OOM occurs but you can give a hint to the Garbage Collector

doSomethingElse();

You have to make sure that there are NO references to the object that is no longer needed. If you don't set the reference to null it will stay alive until the method referencing it has returned (at which point the reference will be removed when the heap is cleaned up).

[JustinLiu]

WP7.8 allows less memory for the PeriodicUpdateAgents than WP8 does. As for allowing the GC to collect no longer used objects. You have to ensure that everything you no longer need currently isn't referenced in any way by running code. e.g.:

var x = hugeObject;
doSomething(hugeObject);
x = null;//remove reference to hugeObject

GC.Collect();//would run by itself before an OOM occurs but you can give a hint to the Garbage Collector

doSomethingElse();

You have to make sure that there are NO references to the object that is no longer needed. If you don't set the reference to null it will stay alive until the method referencing it has returned (at which point the reference will be removed when the heap is cleaned up).

Thanks for the reply!

I just tried this but it doesn't seem to reduce the memory use. Did I do something wrong?

Here is my code in the background agent class.

        protected override void OnInvoke(ScheduledTask task)
        {
            // dunno why but it starts with almost 5MB of memory...
            var shellTile = ShellTile.ActiveTiles.FirstOrDefault();

            // get the ShellTile type so we can call the new version of "Update" that takes the new Tile templates.
            Type shellTileType = Type.GetType("Microsoft.Phone.Shell.ShellTile, Microsoft.Phone");

            if (shellTile == null)
                return;

            var data = new LiveTileData();

            // GetData uses about 3MB of memory, it either gets the data from a web service or get it from Isolated storage
            LiveTileDataManager.Current.GetData(data, () =>
            {
                CustomTile customTile;
                UIElement frontTileTemplate, backTileTemplate, smallFrontTileTemplate, wideFrontTileTemplate, wideBackTileTemplate;

                frontTileTemplate = new FrontTileTemplate
                {
                    Property1 = data.Property1
                };

                backTileTemplate = new BackTileTemplate()
                {
                    Property1 = data.Property1
                };

                smallFrontTileTemplate = new SmallFrontTileTemplate()
                {
                    Property1 = data.Property1
                };

                wideFrontTileTemplate = new WideFrontTileTemplate()
                {
                    Property1 = data.Property1
                };

                wideBackTileTemplate = new WideBackTileTemplate()
                {
                    Property1 = data.Property1
                };

                // free up memory here???
                data = null;
                GC.Collect();

                // pass in the small, normal & wide front tiles
                customTile = CustomTile.GetTemplatedTile(frontTileTemplate, backTileTemplate, smallFrontTileTemplate, wideFrontTileTemplate, wideBackTileTemplate);

                // this functions uses about 2MB of memory, it basically saves all tiles as JPEGs to isolated storage
                var flipTileData = customTile.GetFlipTileData();

                // free up memory here???
                customTile = null;
                frontTileTemplate = null;
                backTileTemplate = null;
                smallFrontTileTemplate = null;
                wideFrontTileTemplate = null;
                wideBackTileTemplate = null;
                GC.Collect();

                // invoke the new version of ShellTile.Update.
                shellTileType.GetMethod("Update").Invoke(shellTile, new Object[] { flipTileData });

                // tell the scheduled agent to complete
                this.NotifyComplete();
            });
        }

[Iacopo]

For calling the GC, try using the following, which allows waiting for resources to be released:

GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();

In my case, though, the most important thing was to clean up all the assemblies used, together with making a smaller version of a referenced class inside my project.... Did you try and add Toast in various points of the code, to see exactly where the background agent is killed?