DataTable: LazyDataModel.load gets invoked multiple times when datatable is lazy and has headerRow #11452

coderoth · 2024-02-16T20:19:44Z

Describe the bug

DataTable component invokes LazyDataModel::load multiple times (one for each item in the current page of the datatable) when the datatable is lazy and has a headerRow.

Please, check the attached zip that reproduces the problem and shows one workaround to the issue.
To execute the reproducer:

mvn jetty:run

And open the following page in the browser

http://localhost:8080/primefaces-test

primefaces-test.zip

Reproducer

The ProblematicLazyDataModel::load method below will be executed multiple times (one for each returned item in the pagination). With datatable configured with rows=5, this is the server output (showing that querying a real database would result in 5 queries being executed with weird pagination parameters):

ProblematicLazyDataModel.load(first=0, size=5) executed in the fake database
ProblematicLazyDataModel.load(first=0, size=1) executed in the fake database
ProblematicLazyDataModel.load(first=1, size=2) executed in the fake database
ProblematicLazyDataModel.load(first=2, size=3) executed in the fake database
ProblematicLazyDataModel.load(first=3, size=4) executed in the fake database

Please, check provided uploaded primefaces-test.zip for a working and complete example.

Sample xhtml:

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"
        xmlns:h="http://xmlns.jcp.org/jsf/html"
        xmlns:f="http://xmlns.jcp.org/jsf/core"
        xmlns:pt="http://xmlns.jcp.org/jsf/passthrough"
        xmlns:jsf="http://xmlns.jcp.org/jsf"
        xmlns:ui="http://xmlns.jcp.org/jsf/facelets"
        xmlns:p="http://primefaces.org/ui">

    <h:head>
        <title>PrimeFaces Test</title>
        <h:outputScript name="test.js" />
        <h:outputStylesheet name="test.css" />
    </h:head>
    <h:body>

        <h1>Problem</h1>

                <p:dataTable value="#{problematicLazyDataModel}" var="obj"
                                         lazy="true" paginator="true"
                                         paginatorPosition="bottom" rows="5">

                        <p:headerRow field="artist" expandable="false">
                                <p:column colspan="3">#{obj.artist}</p:column>
                        </p:headerRow>

                        <p:column headerText="ID">
                                <h:outputText value="#{obj.id}" />
                        </p:column>

                        <p:column headerText="Song">
                                <h:outputText value="#{obj.name}" />
                        </p:column>

                        <p:column headerText="Released">
                                <h:outputText value="#{obj.released}" />
                        </p:column>

                </p:dataTable>

    </h:body>
</html>

Sample problematic datamodel:

package org.primefaces.test;

import java.util.List;
import java.util.Map;

import javax.faces.view.ViewScoped;
import javax.inject.Named;

import org.primefaces.model.FilterMeta;
import org.primefaces.model.LazyDataModel;
import org.primefaces.model.SortMeta;

@Named
@ViewScoped
public class ProblematicLazyDataModel extends LazyDataModel<TestObject> {

        private static final long serialVersionUID = 1L;

        @Override
        public int count(Map<String, FilterMeta> filterBy) {
                return FakeDB.count();
        }

        @Override
        public List<TestObject> load(int first, int pageSize, Map<String, SortMeta> sortBy, Map<String, FilterMeta> filterBy) {
                System.out.println(String.format("%s.load(first=%d, size=%d) executed in the fake database", this.getClass().getSimpleName(), first, pageSize));
                return FakeDB.find(first, pageSize);
        }

}

Expected behavior

DataTable should invoke the LazyDataModel::load method once, like que WorkaroundLazyDataModel example below.
The output:

WorkaroundLazyDataModel.load(first=0, size=5) executed in the fake database

WorkaroundLazyDataModel code, with overriden getRowData method (the workaround):

package org.primefaces.test;

import java.util.List;
import java.util.Map;

import javax.faces.view.ViewScoped;
import javax.inject.Named;

import org.primefaces.model.FilterMeta;
import org.primefaces.model.LazyDataModel;
import org.primefaces.model.SortMeta;

@Named
@ViewScoped
public class WorkaroundLazyDataModel extends LazyDataModel<TestObject> {

        private static final long serialVersionUID = 1L;

        @Override
        public int count(Map<String, FilterMeta> filterBy) {
                return FakeDB.count();
        }

        @Override
        public List<TestObject> load(int first, int pageSize, Map<String, SortMeta> sortBy, Map<String, FilterMeta> filterBy) {
                System.out.println(String.format("%s.load(first=%d, size=%d) executed in the fake database", this.getClass().getSimpleName(), first, pageSize));
                return FakeDB.find(first, pageSize);
        }

        /*
         * WORKAROUND
         *
         * */
        @Override
        public TestObject getRowData(int rowIndex, Map<String, SortMeta> sortBy, Map<String, FilterMeta> filterBy) {

                if (rowIndex < 0 || getPageSize() == 0) {
                        return null;
                }

                int pageRowIndex = (rowIndex % getPageSize());
                List<TestObject> wrappedData = getWrappedData();
                if (wrappedData != null && wrappedData.size() > pageRowIndex) {
                        return wrappedData.get(pageRowIndex);
                }

                // couldnt load from cache, trying the old way
                return super.getRowData(rowIndex, sortBy, filterBy);
        }

}

PrimeFaces edition

Community

PrimeFaces version

13.0.5

Theme

No response

JSF implementation

Mojarra

JSF version

2.3.21

Java version

1.8.0_361

Browser(s)

No response

The text was updated successfully, but these errors were encountered:

melloware · 2024-02-16T20:30:15Z

It was introduced by this ticket: #9077 cc @sebsoftware

Looking at the source code it seems this was intentional with a comment in the DataTableRenderer.isInSameGroup method:

        // in case of a lazy DataTable, the LazyDataModel currently only loads rows inside the current page; we need a small hack here
        // 1) get the rowData manually for the next row
        // 2) put it into request-scope
        // 3) invoke the groupBy ValueExpression
        if (table.isLazy()) {
            Object nextRowData = table.getLazyDataModel().getRowData(nextRowIndex, table.getActiveSortMeta(), table.getActiveFilterMeta());
            if (nextRowData == null) {
                return false;
            }

            nextGroupByData = ComponentUtils.executeInRequestScope(context, table.getVar(), nextRowData, () -> groupByVE.getValue(elContext));
        }

…tiple times when datatable is lazy and has headerRow

Rapster · 2024-02-18T21:23:36Z

Indeed, that extra call is not needed when no summaryRow present

#11457) * Fix #11452 - DataTable: LazyDataModel.load gets invoked multiple times when datatable is lazy and has headerRow * Fix and rename LazyDataModel#getRowData into LazyDataModel#loadOne to avoid confusion * Update 14_0_0.md * Update LazyDataModel.java * Update DataTableRenderer.java * Update 14_0_0.md * Update DataTableRenderer.java * Update LazyDataModel.java --------- Co-authored-by: Melloware <mellowaredev@gmail.com>

…ked multiple times

…le times (#11461)

coderoth · 2024-02-19T16:09:45Z

Wow, thanks for the fix!

melloware · 2024-02-19T16:10:20Z

13.0.6 is in Maven Central if you want to try it @coderoth

coderoth added ‼️ needs-triage Issue needs triaging 🐞 defect Bug...Something isn't working labels Feb 16, 2024

melloware removed the ‼️ needs-triage Issue needs triaging label Feb 16, 2024

melloware added the discussion Item needs to be discussed by core devs label Feb 16, 2024

Rapster self-assigned this Feb 18, 2024

Rapster added a commit to Rapster/primefaces that referenced this issue Feb 18, 2024

Fix primefaces#11452 - DataTable: LazyDataModel.load gets invoked mul…

b2b2437

…tiple times when datatable is lazy and has headerRow

melloware mentioned this issue Feb 18, 2024

Fix #11452 - DataTable: LazyDataModel.load gets invoked multiple time… #11457

Merged

melloware added this to the 13.0.6 milestone Feb 18, 2024

melloware removed the discussion Item needs to be discussed by core devs label Feb 18, 2024

melloware added ⚡ performance Performance related issue or enhancement and removed 🐞 defect Bug...Something isn't working labels Feb 19, 2024

melloware closed this as completed in #11457 Feb 19, 2024

melloware added a commit to melloware/primefaces that referenced this issue Feb 19, 2024

Fix primefaces#11452 - 13.0.6 DataTable: LazyDataModel.load gets invo…

6d0f054

…ked multiple times

melloware mentioned this issue Feb 19, 2024

Fix #11452 - 13.0.6 DataTable: LazyDataModel.load gets invoked multip… #11461

Merged

melloware added a commit that referenced this issue Feb 19, 2024

Fix #11452 - 13.0.6 DataTable: LazyDataModel.load gets invoked multip…

4f3be01

…le times (#11461)

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

DataTable: LazyDataModel.load gets invoked multiple times when datatable is lazy and has headerRow #11452

DataTable: LazyDataModel.load gets invoked multiple times when datatable is lazy and has headerRow #11452

coderoth commented Feb 16, 2024

melloware commented Feb 16, 2024 •

edited

Loading

Rapster commented Feb 18, 2024

coderoth commented Feb 19, 2024

melloware commented Feb 19, 2024

DataTable: LazyDataModel.load gets invoked multiple times when datatable is lazy and has headerRow #11452

DataTable: LazyDataModel.load gets invoked multiple times when datatable is lazy and has headerRow #11452

Comments

coderoth commented Feb 16, 2024

Describe the bug

Reproducer

Expected behavior

PrimeFaces edition

PrimeFaces version

Theme

JSF implementation

JSF version

Java version

Browser(s)

melloware commented Feb 16, 2024 • edited Loading

Rapster commented Feb 18, 2024

coderoth commented Feb 19, 2024

melloware commented Feb 19, 2024

melloware commented Feb 16, 2024 •

edited

Loading