Hi All!
I’m new in openJPA, and didn’t manage to get over the problem with simple
select statement for one object after a few days of investigation. Please
help!
For simple select from one object, OpenJPA ( same strategy for 1.0, 1.2.1,
2.0 ) fist generates right query to retrieve all rows and fields, and then
start generating query per object by primary key.
Code :
StringBuffer queryBuf = new StringBuffer("SELECT a FROM Account AS a
WHERE a.date = :date ");
PersistenceProviderImpl impl = new PersistenceProviderImpl();
OpenJPAEntityManagerFactory fac =
impl.createEntityManagerFactory("MainPersistence", System.getProperties());
OpenJPAEntityManager man = fac.createEntityManager();
Query query = man.createQuery(queryBuf.toString());
query.setParameter("date", reportDate);
List res = query.getResultList();
LOG TRACE
[7/14/09 16:57:50:475 MSD] R 266 MainPersistence TRACE openjpa.Runtime -
Query "SELECT a FROM Account AS a WHERE a.date = :date " is cached as target
query "null"
[7/14/09 16:57:50:475 MSD] R 266 MainPersistence TRACE openjpa.Query -
Executing query: [SELECT a FROM Account AS a WHERE a.date = :date] with
parameters: {date=java.util.GregorianCalendar[]}
[7/14/09 16:57:50:475 MSD] R 266 MainPersistence TRACE openjpa.jdbc.SQL
- <t 1495423266, conn 1329090360> executing prepstmnt 1388597956 SELECT
t0.id, t0.version, t0.cur_code, t0.acc_date, t0.mask, t0.acc_name,
t0.acc_seq, t0.value FROM ACCOUNT t0 WHERE (t0.acc_date = ?)
[params=(Timestamp) 2009-07-03 00:00:00.0]
[7/14/09 16:57:50:553 MSD] R 344 MainPersistence TRACE openjpa.jdbc.SQL -
<t 1495423266, conn 1329090360> [78 ms] spent
[7/14/09 16:57:50:553 MSD] R 344 MainPersistence TRACE openjpa.jdbc.SQL -
<t 1495423266, conn 1329090360> executing prepstmnt 139855958 SELECT
t0.mask, t0.acc_name, t0.acc_seq, t0.value FROM ACCOUNT t0 WHERE t0.id = ?
[params=(long) 328]
[7/14/09 16:57:50:631 MSD] R 422 MainPersistence TRACE [WebContainer : 2]
openjpa.jdbc.SQL - <t 1495423266, conn 1329090360> [78 ms] spent
[7/14/09 16:57:50:631 MSD] R 422 MainPersistence TRACE [WebContainer : 2]
openjpa.jdbc.SQL - <t 1495423266, conn 1329090360> executing prepstmnt
646850190 SELECT t0.mask, t0.acc_name, t0.acc_seq, t0.value FROM ACCOUNT t0
WHERE t0.id = ? [params=(long) 329]
[7/14/09 16:57:50:709 MSD] R 500 MainPersistence TRACE [WebContainer : 2]
openjpa.jdbc.SQL - <t 1495423266, conn 1329090360> [78 ms] spent
[7/14/09 16:57:50:709 MSD] R 500 MainPersistence TRACE [WebContainer : 2]
openjpa.jdbc.SQL - <t 1495423266, conn 1329090360> executing prepstmnt
2146074602 SELECT t0.mask, t0.acc_name, t0.acc_seq, t0.value FROM ACCOUNT t0
WHERE t0.id = ? [params=(long) 330]
[7/14/09 16:57:50:787 MSD] R 578 MainPersistence TRACE [WebContainer : 2]
openjpa.jdbc.SQL - <t 1495423266, conn 1329090360> [78 ms] spent
………………………………..
I need just list of detached objects to show it in grid. As it’s seen from
log trace above, first query is enough to return all necessary objects and
fields.
Why OpenJPA makes select per object after that? In this case simple code
above works 37 seconds for retrieving 440 rows, since same jdbc select and
wrap works 1.5 sec. I’ve tried different query hints and a few openjpa
versions, but with no result.
--
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