Even if I set @OneToOne(fetch=FetchType.LAZY) and run "SELECT h FROM
Hotel h" it runs hundreds of queries. I tried switching the JPA
provider to Hibernate and it does the same, or worse. It seems to be
n*n queries now.
Ryan de Laplante wrote:
> Hi,
>
> I'm using GlassFish V2 and am trying to run a JPQL query, but am
> having the n+1 problem where it should be running a single query, but
> it is running a query for every single result. The JOIN FETCH feature
> is supposed to fix that, and it does in a way. The generated SQL
> changes to include all fields from both tables to make it possible to
> build all entities using a single query. The problem is that this
> query is still being run for every single result.
>
> I have two entities: Hotel and HotelSettings. Both entities have an
> id field called hotelCode which happen to have the same value in both
> tables. Hotel has the following relationship:
>
> @OneToOne
> @JoinColumn(name="SiteCode", insertable=false, updatable=false)
> private HotelSettings settings;
>
> The HotelSettings entity doesn't know about the Hotel entity. The
> JPQL query looks like this:
>
> SELECT h FROM Hotel h LEFT JOIN FETCH h.settings
>
>
> Any ideas? Is this a TopLink Essentials bug?
>
>
> Thanks,
> Ryan
>
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