On Fri, Oct 5, 2012 at 6:20 PM, Paul Libbrecht <[email protected]> wrote:
> The story evolved down here.
>
> I have crafted an extra observer that listens to notifications and checks if
> the values are the same when in event and one second later in a spawned
> thread. They're not.
>
> The code is copied below, it is inspired from the nice tutorial about
> observation.
>
> Since about 36h, the observation listener below has reported 967 saves. From
> them, 145 indicate the warning at the end of this code.
Couldn't it be that you did several saves very quickly so when you
received the remote event the database was changed again already ?
>
> This warning indicates that the title, number of a objects of a particular
> class (where we observed the bug first), or version differ:
> - when pulled from the source of the event (XWikiDocument or
> LazyXWikiDocument)
> - or when pulled one second later with xwiki.getXWiki().getDocument().
>
> However, and that's the crusty bit.
> Somehow, the attempt to reproduce the bug have almost all failed since that
> time as well.
> (no systematic way to reproduce the bug has been found, neither has there
> been a page that stayed different between the two nodes). We're on hold but
> this is a rather good surprise!
>
> Paul
>
>
>>> It was the request of previous versions which has failed.
>>>
>>> All that seems quite curriki specific in there is a simple listener, using
>>> the old-style-notification, which analyzes the document and indexes it and
>>> maybe "related" documents (for example reindexes the user-document so as to
>>> display the count of contributions, or reindexes all of the resources of
>>> the user if the user has changed his name...). The IndexUpdater of the
>>> LucenePlugin does not seem to care for this (but then, it doesn't seem to
>>> measure differences).
>> OK will try with 50 and see what I get. Not sure how this could be
>> related unless it makes the LazyXWikiDocument fail to get the document
>> from the database for some weird reason.
>
>
> // {{groovy}}
> // This page should be Util.TryObservation
> //
> import org.xwiki.observation.*
> import org.xwiki.observation.event.*
> import com.xpn.xwiki.web.*
> import com.xpn.xwiki.*
> import org.xwiki.bridge.event.DocumentUpdatedEvent
> import com.xpn.xwiki.doc.XWikiDocument
> import org.apache.commons.logging.Log
> import org.apache.commons.logging.LogFactory
> import com.xpn.xwiki.util.AbstractXWikiRunnable
> import org.xwiki.observation.remote.RemoteObservationManagerContext
>
> class TryObservation implements EventListener
> {
>
>
> static final Log LOG =
> LogFactory.getLog("groovyPages.Sandbox.TryObservation");
> boolean DEBUG = LOG.isDebugEnabled();
>
> XWiki xwiki
> XWikiContext xcontext
>
> TryObservation(xwiki, xcontext)
> {
> this.xwiki = xwiki
> this.xcontext = xcontext
> }
>
> String getName()
> {
> // The unique name of this event listener
> return "Changes-Version-Checker"
> }
>
> List<Event> getEvents()
> {
> // The list of events this listener listens to
> return Arrays.asList(new DocumentUpdatedEvent())
> }
>
> // Called by the Observation Manager when an event matches the list of
> events returned
> // by getEvents()
> void onEvent(Event event, Object source, Object data)
> {
> XWikiDocument xdoc = source;
> LOG.warn("Received event: " + event + ", source: " + source);
> LOG.warn("Title of changed document " + xdoc.getTitle())
> LOG.warn("Version of changed document " + xdoc.getVersion())
> int count = 0;
> List o = xdoc.getObjects("CurrikiCode.SubAssetClass");
> if(o!=null) count = o.size()
> LOG.warn("Number of children: " + count);
>
> LOG.warn("Is remote? " +
> Utils.getComponent(RemoteObservationManagerContext.class).isRemoteState());
>
> Thread obs = new Thread(new DelayedObserver(xwiki, xcontext,
> xdoc.getFullName(), xdoc.getTitle(), xdoc.getVersion(), count),"delayed obs");
> obs.start();
> LOG.warn("started obs " + obs);
> // Prevent infinite recursion since in this example we log to wiki
> page which
> // triggers a document change... :)
> /* if (source.fullName != "Sandbox.TryObservation") {
> def document = xwiki.getDocument("Sandbox.TryObservation")
> document.setContent("${document.getContent()}\n${source.fullName}
> has changed")
> document.save("Logging event", true)
> } */
> }
>
> public static class DelayedObserver extends AbstractXWikiRunnable {
>
> public DelayedObserver(XWiki xwiki, XWikiContext context, String
> fullName, String inEventTitle, String inEventVersion, int inEventCount) {
> super(XWikiContext.EXECUTIONCONTEXT_KEY, context.clone());
> LOG.warn("(delayed) delayed observer initting. ")
> this.xwiki = xwiki;
> this.fullName = fullName;
> this.context = context;
> this.inEventTitle = inEventTitle;
> this.inEventVersion = inEventVersion;
> this.inEventCount = inEventCount;
> }
>
> private XWiki xwiki;
> private XWikiContext context;
> private String fullName, inEventTitle, inEventVersion;
> private int inEventCount;
>
> public void runInternal() {
> try {
> Thread.currentThread().setName("delayed observer " +
> fullName);
> LOG.warn("(delayed) delayed observer starting. ")
> Thread.sleep(1000);
> XWikiDocument doc = xwiki.getDocument(fullName, context);
> LOG.warn("(delayed) Title of changed document " +
> doc.getTitle())
> LOG.warn("(delayed) Version of changed document " +
> doc.getVersion())
> int count = 0;
> List o = doc.getObjects("CurrikiCode.SubAssetClass");
> if(o!=null) count = o.size()
> LOG.warn("(delayed) Number of children: " + count);
> LOG.warn("(delayed) Is remote? " +
> Utils.getComponent(RemoteObservationManagerContext.class).isRemoteState());
> if(!(inEventVersion==doc.getVersion() &&
> inEventTitle==doc.getTitle() && count == inEventCount)) {
> LOG.error("(delayed) WARNING: inEvent and and delayed do
> not match!!");
> }
> } catch (Exception ex) {
> LOG.warn("Exception at the delayed bit: "+ ex, ex);
> }
> }
> }
>
> }
>
> // Register against the Observation Manager
>
> def observation = Utils.getComponent(ObservationManager.class)
> observation.removeListener("Changes-Version-Checker")
> def listener = new TryObservation(xwiki.getXWiki(), xcontext.getContext())
> observation.addListener(listener)
>
> // {{/groovy}}
> _______________________________________________
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> http://lists.xwiki.org/mailman/listinfo/devs
--
Thomas Mortagne
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