Hi!
I wrote a simple JPQL query a little optimized for speed:
final Query q = em.createQuery("SELECT DISTINCT session FROM InboundEventSession session JOIN FETCH session.events ");
q.setMaxResults(10000);
final long start = System.currentTimeMillis();
final List<InboundEventSession> sessions = q.getResultList();
final long stop = System.currentTimeMillis();
LOG.info("Loaded sessions: " + sessions.size() + " Time: " + ((stop - start) / 1000));
This fragment takes [b]460 seconds.[/b]
I switch toplink essentials logging to FINE and used the generated query in SQuirreL (btw, the generated query looks quite fine):
SELECT DISTINCT t0.ID, t0.COMPARISONSESSION, t0.PROJECTID, t0.STATE, t0.CID, t0.VERSION, t0.TSTAMP, t1.ID, t1.VALUE, t1.PID, t1.VERSION, t1.TSTAMP, t1.EVENTTYPE, t1.INBOUNDEVENTSESSION_ID, t1.PARENTEVENT_ID FROM core_InboundSession t0, core_BusinessEvent t1 WHERE (t1.INBOUNDEVENTSESSION_ID = t0.ID)
Query 1 of 1 elapsed time (seconds) - Total: 5.206, SQL query: [b]1.772[/b], Building output: 3.434
Why is the JPQL Query [b]260 times slower[/b]?
What can I do to speed it up?
Thanks
ste'confused'han
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