Built-in GWT widgets rely on the browser to garbage collect a detached
DOM tree. In older browsers like IE6/7 we found a number of cases
where this didn't work completely, so we opted for manual destroy().
It's possible that as of IE8/9 all such leaks are gone (personally I
find this unlikely :), but, we're not really interested in finding
out.
And yes, we have tools that make leaks obvious - the Watch Tab in the
Developer Console, which shows a tree of all components. You tend to
spot leaked components right away while using the tool for other
purposes.
On Sep 3, 5:12 am, Joel Webber <j...@google.com> wrote:
> @Marcos:
> I wish I could do more to help with memory leaks in SmartGWT, but
> that's way beyond the knowledge of anyone on our team. SmartGWT's a
> wrapper around a huge Javascript library that, from your earlier post,
> appears to require destroy() calls on widgets as part of its memory-
> leak strategy (IIUC). That strategy's rife with problems and very hard
> for users to get right in practice (I've tried it in other frameworks,
> and always found myself squashing leaks ad infinitum). Do the SmartGWT
> tools not provide some mechanism for tracing and finding leaks?
>
> On Aug 30, 9:10 am, chrisr <chris.robert.rowl...@gmail.com> wrote:
>
> > This may be a valid solution, however its not an ideal one, as this
> > application is already significantly large, and its not going to be
> > easy to refactor all of the existing code to work this way. It will
> > be easy to keep this in mind while going forward, however.
>
> > As I said above, I was trying to reproduce the way a lot of the code
> > I'm working with has been written. Also, while I thought this was
> > reproducing the situation we are seeing in our live app (using GWT
> > 1.5.4) it turns out this only produces the memory leak in development
> > mode using the most recent GWT. I will have to see if this produces a
> > leak when compiled using 1.5.4. If not then I'll probably need to
> > find a new simple case that reproduces the leak we're seeing.
>
> > On Aug 28, 11:48 am, Michael W <mwang_2...@yahoo.com> wrote:
>
> > > I doubt following code causing the memory leak.
> > > In reloadRight method, you create and assign new DecoratedTabPanel()
> > > to tabPanel every time.
>
> > > protected void reloadRight(){
> > > ++rightPanelCount;
> > > rPanel.clear();
>
> > > tabPanel = new DecoratedTabPanel();
>
> > > You may reuse existing tabPanel instead of create new one.
>
> > > On Aug 27, 4:21 pm, chrisr <chris.robert.rowl...@gmail.com> wrote:
>
> > > > Hi Joel, i appreciate your help.
>
> > > > I was running in development mode and it appears that this memory
> > > > bloat goes away when not using development mode.
> > > > We have been developing our application using older GWT (1.5.4 I
> > > > belive) so I'm used to using the old hosted mode. I didn't realize
> > > > the in browser development mode might have this side effect.
>
> > > > The goal of this was to reproduce a memory leak that we have in our
> > > > application (when compiled, of course) using as simple a case as
> > > > possible, in the newest version of GWT, if possible. I erroneously
> > > > thought this was accomplishing that.
>
> > > > Does the fact that this growth occurs in development mode suggest
> > > > anything about why I might see similar growth in a compiled GWT 1.5.4
> > > > application?
>
> > > > On Aug 27, 12:52 pm, Joel Webber <j...@google.com> wrote:
>
> > > > > Hmm... I've tried to reproduce this on IE7 and IE8 (both quirks &
> > > > > standards), to no avail. I doubt it's anything in the outer HTML file,
> > > > > but just in case, here's what I used:
>
> > > > > <!DOCTYPE HTML>
> > > > > <html>
> > > > > <head>
> > > > > <title>Hello</title>
> > > > > <script type="text/javascript" language="javascript" src="hello/
> > > > > hello.nocache.js"></script>
> > > > > </head>
> > > > > <body>
> > > > > <div id='container'></div>
> > > > > </body>
> > > > > </html>
>
> > > > > The initial calls to getSomeText() were causing a huge number of slow-
> > > > > script warnings on IE, so I was only able to run through a few
> > > > > iterations. I then dropped the count by a factor of 10 to get the SSWs
> > > > > under control, and the memory usage appears quite stable after a
> > > > > couple of hundred clicks. (~30MB). Can you think of anything else that
> > > > > might be different in your setup?
>
> > > > > On 27 août, 08:20, chrisr <chris.robert.rowl...@gmail.com> wrote:
>
> > > > > > Sorry for posting this twice. If a moderator wants to/can remove the
> > > > > > duplicate go ahead.
>
> > > > > > On Aug 25, 2:56 pm, chrisr <chris.robert.rowl...@gmail.com> wrote:
>
> > > > > > > I created a simple application in an attempt to reproduce a memory
> > > > > > > leak issue in our decently large GWT application.
>
> > > > > > > This test application basically contains a split panel with a button
> > > > > > > on the left, and a tab panel full of large blocks of text on the
> > > > > > > right.
> > > > > > > Clicking the reload button fires the reloadRight method, and does a
> > > > > > > panel.clear() to remove the old tab panel and a panel.add() to add a
> > > > > > > new tab panel to the right panel. Doing this repeatedly causes memory
> > > > > > > consumption to increase without bounds.
>
> > > > > > > For example, on the initial load IE7 uses around 35 MB. 125 clicks
> > > > > > > later its using nearly 1.5GB.
>
> > > > > > > Is this example doing something in a fundamentally incorrect way?
> > > > > > > How can I keep memory usage from exploding like this?
>
> > > > > > > /* Example Below */
>
> > > > > > > package com.example.myproject.client;
>
> > > > > > > import com.google.gwt.core.client.EntryPoint;
> > > > > > > import com.google.gwt.event.dom.client.ClickEvent;
> > > > > > > import com.google.gwt.event.dom.client.ClickHandler;
> > > > > > > import com.google.gwt.user.client.ui.Button;
> > > > > > > import com.google.gwt.user.client.ui.DecoratedTabPanel;
> > > > > > > import com.google.gwt.user.client.ui.DecoratorPanel;
> > > > > > > import com.google.gwt.user.client.ui.HTML;
> > > > > > > import com.google.gwt.user.client.ui.HTMLPanel;
> > > > > > > import com.google.gwt.user.client.ui.HorizontalSplitPanel;
> > > > > > > import com.google.gwt.user.client.ui.RootPanel;
>
> > > > > > > /**
> > > > > > > * Entry point classes define <code>onModuleLoad()</code>.
> > > > > > > */
> > > > > > > public class TestApplication01 implements EntryPoint {
>
> > > > > > > /**
> > > > > > > * This is the entry point method.
> > > > > > > */
> > > > > > > public void onModuleLoad() {
> > > > > > > RootPanel.get("container").add( new MainPanel() );
> > > > > > > }
>
> > > > > > > private class MainPanel extends DecoratorPanel{
>
> > > > > > > private HorizontalSplitPanel hsp;
> > > > > > > private HTMLPanel lPanel;
> > > > > > > private HTMLPanel rPanel;
> > > > > > > private DecoratedTabPanel tabPanel;
> > > > > > > int rightPanelCount = 0;
>
> > > > > > > public MainPanel(){
> > > > > > > hsp = new HorizontalSplitPanel();
> > > > > > > hsp.setSplitPosition("25%");
> > > > > > > hsp.setSize("800px", "400px");
> > > > > > > lPanel = new HTMLPanel("<div id=\"reloadButton\"/>");
>
> > > > > > > rPanel = new HTMLPanel("<div id=\"right-panel-contents\"/>");
> > > > > > > Button reloadButton = new ReloadButton(this);
> > > > > > > reloadButton.setVisible(true);
> > > > > > > lPanel.add( reloadButton, "reloadButton" );
> > > > > > > hsp.setLeftWidget(lPanel);
> > > > > > > hsp.setRightWidget(rPanel);
> > > > > > > this.add( hsp );
> > > > > > > reloadRight();
> > > > > > > }
>
> > > > > > > char[] chars = new char[] {' ',' ',' ', ' ', ' ',
> > > > > > > 'a','b','c','d','e','f','g','h','i','j','k','l','m',
> > > > > > > 'n','o','p','q','r','s','t','u','v','w','x','y','z' };
>
> > > > > > > private String getSomeText(int length){
> > > > > > > StringBuffer sb = new StringBuffer(length);
> > > > > > > for ( int i=0; i<length; ++i ){
>
> > > > > > > sb.append( chars[ (int)Math.round(Math.random()*(chars.length-1)) ]);
> > > > > > > if ( i>0 && i % 60 == 0 )
> > > > > > > sb.append("<br>");
> > > > > > > }
> > > > > > > return sb.toString();
> > > > > > > }
>
> > > > > > > protected void reloadRight(){
> > > > > > > ++rightPanelCount;
> > > > > > > rPanel.clear();
>
> > > > > > > tabPanel = new DecoratedTabPanel();
> > > > > > > tabPanel.setWidth("400px");
> > > > > > > tabPanel.setAnimationEnabled(true);
>
> > > > > > >
>
> ...
>
> read more »
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