i'm using jpa and eclipselink. it says version 2.0.2.v20100323-r6872 for eclipselink. it's an SE application, small. local persistence unit. i am using a postgres database. i have some code
the wakes up once per second and does a jpa query on a table. it's polling to see whether some fields on a given record change. but when i update a
field in sql, it keeps showing
the same value each time i query it. and this is after waiting, creating a new entitymanager, and giving a query hint. when i query
the table
from sql or python, i can see
the changed
field. but
from within my jpa query, once i've read
the value, it never changes in later executions of
the query -- even though
the entity manager has been recreated. i've tried telling it to not look in
the cache. but it seems to ignore that. very puzzling, can you help please?
here is
the method. i call this once every 3 seconds.
the tgt.getTrlDlrs() println shows me i get
the same value for this
field on every call of
the method ("value won't change"). even if i change
the field in
the database. when i query
the record
from outside java, i see
the change right away. also, if i stop
the java program and restart it, i see
the new value printed out immediately:
public void exitChk(EntityManagerFactory emf, Main_1 mn){
// this will be a list of
the trade close targets that are active
List<Pairs01Tradeclosetgt> mn_res = new ArrayList<Pairs01Tradeclosetgt>();
//this is a list of
the place number in
the array list above
//of positions to close
ArrayList<Integer> idxsToCl = new ArrayList<Integer>();
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
em.clear();
String qryTxt =
"SELECT p
FROM Pairs01Tradeclosetgt p WHERE p.isClosed = :isClosed AND p.isFilled = :isFilled";
Query qMn = em.createQuery(qryTxt);
qMn.setHint(QueryHints.CACHE_USAGE, CacheUsage.DoNotCheckCache);
qMn.setParameter("isClosed", false);
qMn.setParameter("isFilled", true);
mn_res = (List<Pairs01Tradeclosetgt>) qMn.getResultList();
// are there any trade close targets we need to check for closing?
if (mn_res!=null){
//if yes, see whether they've hit their target
for (int i=0;i<mn_res.size();i++){
Pairs01Tradeclosetgt tgt = new Pairs01Tradeclosetgt();
tgt = mn_res.get(i);
System.out.println("value won't change:" + tgt.getTrlDlrs());
here is my entity class (partial):
@Entity
@Table(name = "pairs01_tradeclosetgt", catalog = "blah", schema = "public")
@NamedQueries({
@NamedQuery(name = "Pairs01Tradeclosetgt.findAll", query = "SELECT p
FROM Pairs01Tradeclosetgt p"),
@NamedQuery(name = "Pairs01Tradeclosetgt.findByClseRatio", query = "SELECT p
FROM Pairs01Tradeclosetgt p WHERE p.clseRatio = :clseRatio")})
public class Pairs01Tradeclosetgt implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@Basic(optional = false)
@Column(name = "id")
@SequenceGenerator(name="pairs01_tradeclosetgt_id_seq", allocationSize=1)
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator = "pairs01_tradeclosetgt_id_seq")
private Integer id;
and my persitence unit:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
<persistence-unit name="testpu" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<class>mourv02.Pairs01Quotes</class>
<class>mourv02.Pairs01Pair</class>
<class>mourv02.Pairs01Trderrs</class>
<class>mourv02.Pairs01Tradereq</class>
<class>mourv02.Pairs01Tradeclosetgt</class>
<class>mourv02.Pairs01Orderstatus</class>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:postgresql://192.168.1.80:5432/blah"/>
<property name="javax.persistence.jdbc.password" value="secret"/>
<property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver"/>
<property name="javax.persistence.jdbc.user" value="noone"/>
</properties>
</persistence-unit>
</persistence>
