Slow query via PersistenceBroker

[Oleg Lebedev <ol...@waterford.org>]

Hi all.
 
I just barely started using OJB and have a problem with performance.
I was following "The Persistence Broker API" tutorial and tried to
retrieve a single record from the database table which contains about
150 rows. It takes 1500ms to execute this query and get the result back!
 
I am using SQL Server and the query takes a couple of milliseconds when
executed directly from the database.
 
In the code below it takes 800ms to allocate the broker and 600ms to
execute the query.
Why is it so slow and what's the best way to avoid such delays?
 
Thanks.
 
Oleg
 
CODE:

public static Objective findObjectiveById(int id) {

System.out.println("findObjectiveById(" + id + ")");
long start = System.currentTimeMillis();
Objective result = null;
PersistenceBroker broker = null;

try { 
broker = PersistenceBrokerFactory.defaultPersistenceBroker();
System.out.println("Allocated broker in " + (System.currentTimeMillis()
- start) + "ms.");
start = System.currentTimeMillis();

// For small datasets use Collection as shown below.
Criteria crit = new Criteria();
crit.addEqualTo("objid", new Integer(id));
QueryByCriteria query = QueryFactory.newQuery(Objective.class, crit);

System.out.println("Created query in " + (System.currentTimeMillis() -
start) + "ms.");
start = System.currentTimeMillis();

try {
// ask the broker to retrieve a Collection
Collection results = broker.getCollectionByQuery(query);

System.out.println("Executed query in " + (System.currentTimeMillis() -
start) + "ms.");
start = System.currentTimeMillis();

// print the results
Iterator iter = results.iterator();
if (iter.hasNext()) {
result = (Objective)iter.next();
}

System.out.println("Obtained result in " + (System.currentTimeMillis() -
start) + "ms.");
start = System.currentTimeMillis();

} catch (Throwable t) {
t.printStackTrace();
}

} catch (Throwable t) {
t.printStackTrace();

} finally {
if (broker != null) broker.close(); 
System.out.println("DONE executing findObjectiveById.");
}

return result;

} 
  
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Re: Slow query via PersistenceBroker

[Andy Malakov <an...@transdecisions.com>]

Hello Oleg,

OJB needs some time perform one-time initialization (load all library classes, initialize metadata registry, etc). 
Execute your test method several times  to warm up OJB and JVM before measuring it performance.

----- Original Message ----- 
From: "Oleg Lebedev" <ol...@waterford.org>
To: <oj...@db.apache.org>
Sent: Friday, February 13, 2004 6:04 PM
Subject: Slow query via PersistenceBroker


Hi all.
 
I just barely started using OJB and have a problem with performance.
I was following "The Persistence Broker API" tutorial and tried to
retrieve a single record from the database table which contains about
150 rows. It takes 1500ms to execute this query and get the result back!
 
I am using SQL Server and the query takes a couple of milliseconds when
executed directly from the database.
 
In the code below it takes 800ms to allocate the broker and 600ms to
execute the query.
Why is it so slow and what's the best way to avoid such delays?
 
Thanks.
 
Oleg
 
CODE:

public static Objective findObjectiveById(int id) {

System.out.println("findObjectiveById(" + id + ")");
long start = System.currentTimeMillis();
Objective result = null;
PersistenceBroker broker = null;

try { 
broker = PersistenceBrokerFactory.defaultPersistenceBroker();
System.out.println("Allocated broker in " + (System.currentTimeMillis()
- start) + "ms.");
start = System.currentTimeMillis();

// For small datasets use Collection as shown below.
Criteria crit = new Criteria();
crit.addEqualTo("objid", new Integer(id));
QueryByCriteria query = QueryFactory.newQuery(Objective.class, crit);

System.out.println("Created query in " + (System.currentTimeMillis() -
start) + "ms.");
start = System.currentTimeMillis();

try {
// ask the broker to retrieve a Collection
Collection results = broker.getCollectionByQuery(query);

System.out.println("Executed query in " + (System.currentTimeMillis() -
start) + "ms.");
start = System.currentTimeMillis();

// print the results
Iterator iter = results.iterator();
if (iter.hasNext()) {
result = (Objective)iter.next();
}

System.out.println("Obtained result in " + (System.currentTimeMillis() -
start) + "ms.");
start = System.currentTimeMillis();

} catch (Throwable t) {
t.printStackTrace();
}

} catch (Throwable t) {
t.printStackTrace();

} finally {
if (broker != null) broker.close(); 
System.out.println("DONE executing findObjectiveById.");
}

return result;

} 
  
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