CODEWITHSUNDEEP
sqljpaeclipselink
mik
mik

Reputation: 1575

jpa setMaxResults extra query

I'm using eclipse persistence jpa with OracleDriver and I can't get why it shows some extra queries in logs. Example:

Query q = em.createQuery("SELECT v FROM Vehicle v")
                .setFirstResult(0)
                .setMaxResults(1);

List<Vehicle> list = q.getResultList();

What I see in eclipselink logs is:

Execute query ReadAllQuery(referenceClass=Vehicle sql="SELECT ID, ... FROM VEHICLE")

[EL Fine]: 2012-05-18 11:03:28.076--ServerSession(763807850)--Connection(340360448)--Thread(Thread[main,5,main])

    --SELECT * FROM (SELECT /*+ FIRST_ROWS */ a.*, ROWNUM rnum  FROM (SELECT ID AS a1,  .... FROM VEHICLE) a WHERE ROWNUM <= ?) WHERE rnum > ?
                bind => [1, 0]

So, the first query really scares me. Does it really queries all the records from the table, even if I use setMaxResults?

Upvotes: 1

Views: 2961

Answers (1)

perissf
perissf

Reputation: 16273

No, it doesn't read all the records. The query sent to the db connector is the second one.

Upvotes: 1

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