On 24 October 2011 18:55, Leszek Gawron <[email protected]> wrote:
> Hello,
>
> @Jasha: advising a user to limit the amount of data usually does not work.
> :)
You can tell the user his search query has a result of 25000 items but I
guess he doesn't want them all in 1 screen. Postprocessing that amount of
items can be tried but many have failed before...
>
>
> On 2011-10-24 18:29, Paul Joseph wrote:
>
>> Actually the real reason is that the user is using a query that required
>> crafting to return 25K results. He is seeking to show the system "does
>> not scale."
>>
>> Actually I am using in my XML template, a cocoon flowscript repeater
>> widget that does paging. But this is well after the Java logic has
>> built the large array of results (the array results and the vector
>> secureResults below)
>>
>
> I suspect what might be the problem:
>
> 1. Are your continuations session bound? They are not by default - even
> though you set a short session expiry time most of the data is still held by
> continuations which are being expired with totally different mechanism.
> Container bound continuations are useful in only one case: you build a
> session-less site. For "session" exprience ALWAYS use
> session-bound-continuations.
>
> 2. Your flowscript continuation probably holds the ENTIRE rowset and will
> hold it until it expires (and all children expire). You are not supposed to
> put heavyweight object into your continuation.
>
> Your solutions are:
>
> a. use a generator instead of flowscript. Implementing own generator is
> actually dead easy. Style your data with XSLT.
>
> b. make flowscript "forget" the data after the report has been rendered.
> You probably regenerate your rowset with each request anyway.
>
> This one is actually also easy. This is an example of my production code:
>
> /* TEMPLATE
>> var config = {
>> defaultOrderBy: "name",
>> defaultDirection: "asc",
>> valueListProvider: cocoon.getComponent( "valueListBeanName"
>> ),
>> filterModelName: "filterModel",
>> viewName: "viewName",
>> errorRedirect: "/",
>> rowSelectionReturns: false,
>> bizData: bizData,
>> selections: selections,
>> formHandler: function ( action, bizData ) {
>> },
>> rowHandler: function( id, action, bizData ) {
>> }
>> }
>> */
>> function sortedFilteredView( config ) {
>> var defaultMaxResults = new Integer( 100 );
>> var modelName = ( config.filterModelName != undefined ) ?
>> config.filterModelName : config.viewName;
>> var form = new Form( "cocoon:/form-def/" + modelName );
>> //form.createBinding("cocoon:/**form-bind/" +
>> config.filterModelName );
>>
>> form.locale = determineLocale();
>> var model = form.getModel();
>>
>> var bizData = ( config.bizData != undefined ) ? config.bizData :
>> new java.util.HashMap();
>> model.orderBy = config.defaultOrderBy;
>> model.direction = ( config.defaultDirection != undefined ) ?
>> config.defaultDirection : "asc";
>> model.maxResults = ( config.maxResults != undefined ) ?
>> config.maxResults : defaultMaxResults;
>>
>> if ( config.formInitializer != undefined ) {
>> config.formInitializer( model );
>> }
>>
>> model.skipResults = new Integer( 0 );
>> while ( true ) {
>> model.pageNo = new java.lang.Integer( model.skipResults /
>> model.maxResults + 1 );
>> var filterContext = Packages.org.apache.cocoon.**
>> forms.util.**ContainerWidgetAsMap( form.form );
>> var items = config.valueListProvider.**generateResults(
>> filterContext, bizData );
>>
>> var totalItemCount = config.valueListProvider.**countEntries(
>> filterContext, bizData );
>> var pageCount = new java.lang.Integer( java.lang.Math.ceil(
>> totalItemCount / model.maxResults ) );
>> var firstPage = ( model.skipResults == 0 );
>> var lastPage = ( model.skipResults + model.maxResults >=
>> totalItemCount );
>>
>> form.showForm( "form/" + config.viewName,
>> { items : items,
>> orderBy :
>> model.orderBy,
>> direction:
>> model.direction,
>> maxResults:
>> model.maxResults,
>> pageNumber:
>> model.pageNo,
>> pageCount:
>> pageCount,
>> firstPage:
>> firstPage,
>> lastPage :
>> lastPage,
>> viewConfig: config,
>> startIndex:
>> ((model.pageNo - 1) * model.maxResults + 1),
>> bizData : bizData,
>> selections:
>> config.selections },
>> function() {
>> delete
>> items;
>> }
>> );
>>
>> if ( form.submitId == "finish" ) { //search
>> model.skipResults = new Integer( 0 );
>> } else if ( form.submitId == "cancel" ) {
>> return null;
>> } else if ( form.submitId == "next" ) {
>> model.skipResults = new Integer( model.skipResults
>> + model.maxResults );
>> } else if ( form.submitId == "prev" ) {
>> model.skipResults = new Integer( model.skipResults
>> - model.maxResults );
>> if ( model.skipResults < 0 )
>> model.skipResults = new Integer( 0 );
>> } else if ( form.submitId == "first" ) {
>> model.skipResults = new Integer( 0 );
>> } else if ( form.submitId == "last" ) {
>> model.skipResults = new java.lang.Integer( (
>> java.lang.Math.ceil( totalItemCount / model.maxResults ) - 1 ) *
>> model.maxResults );
>> } else if ( form.submitId == "changePage" ) {
>> if ( model.pageNo != null ) {
>> var skipCount = ( model.pageNo - 1 ) *
>> model.maxResults;
>> if ( skipCount < totalItemCount )
>> model.skipResults = new
>> Integer( skipCount );
>> else
>> model.skipResults = new
>> java.lang.Integer( ( java.lang.Math.ceil( totalItemCount / model.maxResults
>> ) - 1 ) * model.maxResults );
>> if ( skipCount < 0 )
>> model.skipResults = new
>> Integer( 0 );
>> }
>> } else if ( form.submitId == "changeMaxResults" ) {
>> model.skipResults = new Integer( 0 );
>> } else if ( form.submitId != null ) {
>> if ( form.submitId == "selectRow" &&
>> config.rowSelectionReturns == true )
>> return model.rowId;
>> if ( config.rowHandler != undefined && model.rowId
>> != null )
>> config.rowHandler( model.rowId,
>> form.submitId, bizData );
>> if ( config.formHandler != undefined && model.rowId
>> == null )
>> config.formHandler( form.submitId, bizData
>> );
>> }
>> if ( model.maxResults <= 0 )
>> model.maxResults = defaultMaxResults;
>> model.rowId = null;
>> }
>> }
>>
>
> The code is responsible for showing a pageable sortable filterable rowset.
>
> The most important part is :
>
> var items = config.valueListProvider.**generateResults( filterContext,
> bizData );
>
> This object is VERY heavy (it might any row count you might like).
>
> The next important thing is after rendering this object is deleted:
>
> form.showForm( "form/" + config.viewName,
>> { items : items,
>> orderBy :
>> model.orderBy,
>> direction:
>> model.direction,
>> maxResults:
>> model.maxResults,
>> pageNumber:
>> model.pageNo,
>> pageCount:
>> pageCount,
>> firstPage:
>> firstPage,
>> lastPage :
>> lastPage,
>> viewConfig: config,
>> startIndex:
>> ((model.pageNo - 1) * model.maxResults + 1),
>> bizData : bizData,
>> selections:
>> config.selections },
>> function() {
>> delete
>> items;
>> }
>> );
>>
>
> There is a parameter for cocoon.sendPageAndWait which is not widely known:
> a cleanup function.
>
> http://cocoon.apache.org/2.1/**userdocs/flow/api.html#cocoon<http://cocoon.apache.org/2.1/userdocs/flow/api.html#cocoon>
>
> So your code has to look something like that:
>
> var report = generateYourHorriblyBigReport(**);
>
> cocoon.sendPageAndWait( "myreport.html",
> { report: report },
> function() {
> delete report;
> }
> );
>
>
>
> I advice you to use some kind of profiler. Money spent on YourProfiler
> might be one of best spent dollars. You can:
>
> - make a memory snapshot
> - do your request
> - make a subsequent memory snapshot
> - compare both snapshots: there should be NO significant memory
> consumption difference.
>
> HTH
>
> lg
>
> --
> Leszek Gawron http://lgawron.posterous.com
>
>
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