Spring JPA + Hibernate Search : How update the Search Index(Lucene) only?

Question

I use Spring JPA + Hibernate Search to implement persistant and search in my application.

I have models like this

public class FeatureMeta {

    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long id;

    @Column(unique=true)
    private String uri;

    @Column
    @Field
    private String name;

    @Field
    @Column
    private String businessDesc;

    @Field
    @Column
    private String logicalDesc;

    .
    .


    @Field
    @Column(insertable=false,updatable=false)
    private Long totalDownloads;

    .
    .

}

To give the idea about this class, "FeatureMeta" maintains meta-data information which updates very rarely.

However the field "totalDownloads" is constantly changing whenever user download information about this "feature". Basically "totalDownloads" is not part of the meta-data but I had to put this field in the model because I need to show the "totalDownloads" in the search result of "feature search".

I use same JPA Repository which updates both MySQL and Lucene index.

My question is ; Is it possible to only update the "totalDownloads" in the Lucene Index but not the entity in MySQL whenever change is done to the "totalDownloads" field ?

Answer 1

You'll have to use the @Transient annotation to mark that you don't want this attribute part of your database model.

@Field
@Transient
private Long totalDownloads;

Making the field transient also means it won't be loaded from the database (completely ignored by Hibernate ORM, but not by Hibernate Search); if that's not what you intended you could add an additional field: map one to Hibernate ORM and the other indexed with Hibernate Search and annotated with @Transient. In this case you'll have to make the setter update both fields.

You will likely need to change this configuration property too:

hibernate.search.enable_dirty_check = false

as Hibernate Search will otherwise not generate any change in the Lucene index, in case the entity has no other changes.