(N+1)queries problem on entity browser screens

Support
1

I am trying to optimize the performance of my application, and I observed that on browse screens Jmix is creating queries to load related entities to my browse entity even when I don´t specify the references to these relations in the fetch plan nor in the screen interface.

For example: I have an entity Document that has a composition to DocVersion linked by the reference Document::docDovs. When I load the browser screen for Document, I see one query for DocVersion from each instance of Document on the screen page. Please see below:

2026-08-12 15:51:07.506 DEBUG 17976 — [nio-8080-exec-5] eclipselink.logging.sql                  : <t 348672877, conn 1013861459> SELECT ID AS a1, DOC_CODE AS a2, DOC_TITLE AS a3, DOC_TYPE AS a4, VERSION AS a5, DOC_ACT_ID AS a6, DOC_PRO_ID AS a7 FROM DOCUMENT LIMIT ?, ?
bind => [0, 50]

2026-08-12 15:51:07.511 DEBUG 17976 — [nio-8080-exec-5] eclipselink.logging.sql                  : <t 348672877, conn 1006824356> SELECT ID, DOV_CREATION_DATE, DOV_DESCR, DOV_FILE_CHANGE_DATE, DOV_FILE_REF, DOV_ID, DOV_LAST_CHANGE_DATE, DOV_LCS, DOV_UPLOADED, VERSION, DOV_DOC_ID, DOV_APPR_CYCLE_EVT_ID FROM DOC_VERSION WHERE (DOV_DOC_ID = ?) ORDER BY DOV_ID ASC
bind => [03da7f6457524884cbc90a773cabeba0]

2026-08-12 15:51:07.519 DEBUG 17976 — [nio-8080-exec-5] eclipselink.logging.sql                  : <t 348672877, conn 2137240691> SELECT ID, DOV_CREATION_DATE, DOV_DESCR, DOV_FILE_CHANGE_DATE, DOV_FILE_REF, DOV_ID, DOV_LAST_CHANGE_DATE, DOV_LCS, DOV_UPLOADED, VERSION, DOV_DOC_ID, DOV_APPR_CYCLE_EVT_ID FROM DOC_VERSION WHERE (DOV_DOC_ID = ?) ORDER BY DOV_ID ASC
bind => [05100c5fe372f9b4373c5645a27310d1]

.

.

.

I figured out that the method Document::getDovDocs is called from within Jmix infrastructure, which seems to be causing the lazy loading of all related DocVersion instances. Please see the stack dump below:

java.lang.Exception: Stack trace
at java.base/java.lang.Thread.dumpStack(Thread.java:1391)
at com.calidus.pdcs.entity.documents.Document.getDocDovs(Document.java:102)
at io.jmix.core.entity.BaseEntityEntry.getAttributeValue(BaseEntityEntry.java:85)
at io.jmix.core.entity.EntityValues.getValue(EntityValues.java:100)
at io.jmix.data.impl.EntityAttributesEraserImpl.traverseEntities(EntityAttributesEraserImpl.java:137)
at io.jmix.data.impl.EntityAttributesEraserImpl.collectErasingReferences(EntityAttributesEraserImpl.java:55)
at io.jmix.data.impl.DataStoreInMemoryCrudListener.entityLoading(DataStoreInMemoryCrudListener.java:104)
at io.jmix.core.datastore.DataStoreEntityLoadingEvent.sendTo(DataStoreEntityLoadingEvent.java:85)
at io.jmix.core.datastore.AbstractDataStore.fireEvent(AbstractDataStore.java:353)
at io.jmix.core.datastore.AbstractDataStore.loadList(AbstractDataStore.java:132)
at io.jmix.core.impl.UnconstrainedDataManagerImpl.loadList(UnconstrainedDataManagerImpl.java:112)
at io.jmix.ui.model.impl.CollectionLoaderImpl._load(CollectionLoaderImpl.java:121)
at io.jmix.ui.model.impl.CollectionLoaderImpl.load(CollectionLoaderImpl.java:101)
at io.jmix.ui.component.dataloadcoordinator.OnFrameOwnerEventLoadTrigger.load(OnFrameOwnerEventLoadTrigger.java:48)
at io.jmix.ui.component.dataloadcoordinator.OnFrameOwnerEventLoadTrigger.lambda$new$0(OnFrameOwnerEventLoadTrigger.java:39)
at io.jmix.core.common.event.EventHub.publish(EventHub.java:170)
at io.jmix.ui.screen.Screen.fireEvent(Screen.java:150)
at io.jmix.ui.screen.UiControllerUtils.fireEvent(UiControllerUtils.java:58)
at io.jmix.ui.sys.ScreensImpl.fireScreenBeforeShowEvent(ScreensImpl.java:1364)
at io.jmix.ui.sys.ScreensImpl.show(ScreensImpl.java:357)
at io.jmix.ui.sys.ScreensImpl.showFromNavigation(ScreensImpl.java:452)
at io.jmix.ui.menu.MenuItemCommands$ScreenCommand.run(MenuItemCommands.java:193)
at io.jmix.ui.menu.SideMenuBuilder$MenuCommandExecutor.accept(SideMenuBuilder.java:272)
at io.jmix.ui.menu.SideMenuBuilder$MenuCommandExecutor.accept(SideMenuBuilder.java:257)
.

.

.

How can I avoid that?

Thanks in advance.

Ramiro.

Jmix version: 1.7.3
Jmix Studio Plugin Version: 2.6.4-243
IntelliJ version: IntelliJ IDEA 2024.3.7.1 (Community Edition)

3

I forgot to explain the fetch plan used here. This screen is a fragment that uses a collection provided by its host screen, as below:

Host screen:

<data>
    <collection id="documentsDc"
                class="com.calidus.pdcs.entity.documents.Document"
                fetchPlan="document-browsing-fetch-plan">
        <loader id="documentsDl">
            <query>
                <![CDATA[select doc from Document doc]]>
            </query>
        </loader>
    </collection>
</data>

Fragment:

<data>
    <collection id="documentsDc"
                class="com.calidus.pdcs.entity.documents.Document"
                provided="true">
    </collection>
</data>

Finally, the fetch plan is:

<fetchPlan entity="Document" name="document-browsing-fetch-plan" extends="_base">
</fetchPlan>

As one can see, I do not specify any references to be eagerly loaded via the fetch plan. My objective is that all related entities are loaded lazily, but that is not what is happening.

4

Hi Ramiro,
Please provide the source code of the Document.dovDocs attribute with all annotations.

Regards,
Konstantin

6

Here is my Document entity, Konstantin. The property is Document.docDovs (the document versions for a document):

package com.calidus.pdcs.entity.documents;

import com.calidus.pdcs.entity.activities.Activity;
import com.calidus.pdcs.entity.products.Product;
import io.jmix.core.DeletePolicy;
import io.jmix.core.entity.annotation.CaseConversion;
import io.jmix.core.entity.annotation.JmixGeneratedValue;
import io.jmix.core.entity.annotation.OnDeleteInverse;
import io.jmix.core.metamodel.annotation.Comment;
import io.jmix.core.metamodel.annotation.Composition;
import io.jmix.core.metamodel.annotation.InstanceName;
import io.jmix.core.metamodel.annotation.JmixEntity;

import javax.persistence.*;
import javax.validation.constraints.NotNull;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

@JmixEntity
@Table(name = "DOCUMENT", indexes = {
        @Index(name = "IDX_DOCUMENT_DOC_PRO", columnList = "DOC_PRO_ID"),
        @Index(name = "IDX_DOCUMENT_DOC_ACT", columnList = "DOC_ACT_ID")
}, uniqueConstraints = {
        @UniqueConstraint(name = "IDX_DOCUMENT_UNQ_DOC_CODE", columnNames = {"DOC_CODE"})
})
@Entity
public class Document {
    @JmixGeneratedValue
    @Column(name = "ID", nullable = false)
    @Id
    private UUID id;

    @Comment("Product related to this document")
    @OnDeleteInverse(DeletePolicy.DENY)
    @JoinColumn(name = "DOC_PRO_ID")
    @ManyToOne(fetch = FetchType.LAZY)
    private Product docPro;

    @Column(name = "VERSION", nullable = false)
    @Version
    private Integer version;

    @Comment("Type of document.")
    @Column(name = "DOC_TYPE", nullable = false)
    @NotNull
    private Integer docType;

    @Comment("User defined code (identification) for document.")
    @CaseConversion
    @Column(name = "DOC_CODE", nullable = false, length = 50)
    @NotNull
    @InstanceName
    private String docCode;

    @Comment("Document title.")
    @Lob
    @Column(name = "DOC_TITLE", nullable = false)
    @NotNull
    private String docTitle;

    @Comment("All document versions existing for this document.")
    @Composition
    @OrderBy("dovId")
    @OneToMany(mappedBy = "dovDoc", cascade = CascadeType.REMOVE)
    private List<DocVersion> docDovs = new ArrayList<>();

    @Comment("Related activity")
    @OnDeleteInverse(DeletePolicy.DENY)
    @JoinColumn(name = "DOC_ACT_ID")
    @ManyToOne(fetch = FetchType.LAZY)
    private Activity docAct;

    public Activity getDocAct() {
        return docAct;
    }

    public void setDocAct(Activity docAct) {
        this.docAct = docAct;
    }

    public Product getDocPro() {
        return docPro;
    }

    public void setDocPro(Product docPro) {
        this.docPro = docPro;
    }

    public List<DocVersion> getDocDovs() {
        return docDovs;
    }
    public void setDocDovs(List<DocVersion> docDovs) {
        this.docDovs = docDovs;
    }

    public String getDocCode() {
        return docCode;
    }

    public void setDocCode(String docCode) {
        this.docCode = docCode;
    }

    public String getDocTitle() {
        return docTitle;
    }

    public void setDocTitle(String docTitle) {
        this.docTitle = docTitle;
    }

    public DocType getDocType() {
        return docType == null ? null : DocType.fromId(docType);
    }

    public void setDocType(DocType docType) {
        this.docType = docType == null ? null : docType.getId();
    }

    public Integer getVersion() {
        return version;
    }

    public void setVersion(Integer version) {
        this.version = version;
    }

    public UUID getId() {
        return id;
    }

    public void setId(UUID id) {
        this.id = id;
    }

}
7

Remove new ArrayList<>() initialization from the field, or replace it with io.jmix.data.impl.lazyloading.NotInstantiatedList. See Entities :: Jmix Documentation.

If it doesn’t help, attach also the DocVersion source code.

Regards,
Konstantin

8

It solved the problem, Konstantin!

Now all queries for DocVersion have disappeared.

I would have struggled a lot to find the solution without your help. Thanks a lot!

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