Enormous response times to simple queries

Question

Dear Forum
I am using TopLink via JPA in a Spring(V2) environment – using for tests the “org.springframework.orm.jpa.LocalEntityManagerFactoryBean”.
There are 2700 Location objects stored in memory which have one Many-to-one relationship and a lot of one-to-many to not yet existing objects defined as lazy.
I defined a query "findLocationByCode" (“SELECT DISTINCT l FROM Location l WHERE l.code = :code ") which takes normally about 30 ms!
When I use that a creating a very complicated object with about 1000 dependent objects then that query may take up to 30 sec(!!!). Inspecting the database there is no relevant activity and it seems that the time is mainly wasted within TopLink (cache?).
I use Oracle 10g 10.2.0 Enterprise edition, I have 2GB notebook ("Intel Pentium 1.7GHz) with Windows XP Professional, SP 2.
TopLink: 2.0-b41-beta2 (03/30/2007)
In the following I append a snapshot of the persistence.xml and the annotations of Location and LocClass classes.
Y.s.
Wolfgang
TopLink settings in persistence.xml
<property name="toplink.sessions-xml"
     value="META-INF/sessions.xml" />
<property name="toplink.session-name" value="solver" />
<property name="toplink.cache.type.default" value="HardWeak" />
<property name="toplink.cache.size.default" value="15000"/>
<property name="toplink.cache.type" value="NONE" />
<property name="toplink.refresh" value="true"/>
<property name="oracle.orm.throw.exceptions" value="false" />
<property name="toplink.weaving" value="true" />
<property name="toplink.jdbc.bind-parameters" value="true" />
<property name="toplink.jdbc.native-sql" value="true" />
<property name="toplink.jdbc.batch-writing"
     value="BUFFERED" />
<property name="toplink.jdbc.cache-statements.size"
     value="100" />
<property name="toplink.jdbc.read-connections.max"
     value="10" />
<property name="toplink.jdbc.read-connections.min"
     value="2" />
<property name="toplink.jdbc.read-connections.shared"
     value="true" />
<property name="toplink.jdbc.write-connections.max"
     value="4" />
<property name="toplink.jdbc.write-connections.min"
     value="4" />
<property name="toplink.logging.level" value="SEVERE" />
<property name="toplink.logging.timestamp" value="true" />
<property name="toplink.logging.thread" value="true" />
<property name="toplink.logging.session" value="true" />
<property name="toplink.logging.exceptions" value="true" />
<property name="toplink.logging.file"
Location Class
@Entity
@Table(name = "LOCATION")
@NamedQuery(
name="findLocationByCode",
query="SELECT DISTINCT l FROM Location l WHERE l.code = :code "
public class Location implements ILocation {
     // persistent part
     // primary key field
     @Id
     @GeneratedValue
     @Column(name = "LOC_ID")
     transient
     private Long id;
     @Id
     @Column(name = "LOC_CODE", nullable = false)
     private String code;
     @Column(name = "LOC_NAME", nullable = true)
     private String name;
     @ManyToOne(cascade = CascadeType.ALL)
     @JoinColumn(name = "LOC_CLASS_ID")
     private LocClass locClass;
     @Column(name = "LOC_GPSX", nullable = true)
     private Float gpsX;
     @Column(name = "LOC_GPSY", nullable = true)
     private Float gpsY;
     @Column(name = "LOC_GRX", nullable = true)
     private Float grX;
     @Column(name = "LOC_GRY", nullable = true)
     private Float grY;
     @Column(name = "LOC_LOCAL_RADIO", nullable = true)
     private String localRadio;
     @OneToMany(mappedBy = "fromLoc", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
     private Set<Connection> fromConnections = new HashSet();
     @OneToMany(mappedBy = "toLoc", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
     private Set<Connection> toConnections = new HashSet();
     @OneToMany(mappedBy = "location", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
     private Set<ViewLoc> viewLocs = new HashSet();
     @OneToMany(mappedBy = "location", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
     private Set<Entry> entries = new HashSet();
LocClass Class
@Entity
@Table(name = "LOCCLASS")
@NamedQuery(
name="findLocClassByCode",
query="SELECT DISTINCT lc FROM LocClass lc WHERE lc.code = :code"
public class LocClass implements ILocClass{
//persistent part
// primary key field
@Id
@GeneratedValue
@Column(name = "LC_ID")
transient     
private Long id;
@Id
@Column(name = "LC_CODE", nullable=false)
public String code;
@Column(name = "LC_NAME", nullable=false)
public String name;
@Column(name = "LC_DIS_NAME", nullable=false)
public Boolean displayLocName;
@Column(name = "LC_D_LINE_MODE", nullable=false)
public Integer displayLineMode;
@Column(name = "LC_D_RUNTIME")
public Boolean displayRuntime;
@Column(name = "LC_SWITCH_POSS")
public Boolean switchPossibility;

Answer 1

Hello Wolfgang,
You mention your notebook has 2gs but not how much memory or heap space the JVM is configured to use (or how much it is actually using). If you haven't tuned the JVM, this could be once cause of the slowdown.
I do not see anything wrong with your entities - assuming the LOC_CLASS_ID field is a string type anyway. One thing to try is to mark the Many-to-one relationship as lazy, or bring it in using fetch join with the location query ie:
SELECT DISTINCT l FROM Location l join fetch l.locClass WHERE l.code = :code
Best Regards,
Chris