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List:       jboss-user
Subject:    Re: [JBoss-user] Performance issue while adding to a EJB 2.0 relation - JBoss version: 3.0.2
From:       Stephen Coy <steve () whitesmiths ! com ! au>
Date:       2002-09-30 3:12:41
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I don't think you are missing anything. Please see  [  
jboss-Patches-608221 ] Unidirectional CMR performance patch.

This patch works for us, but Dain says he has found a better way to fix  
it which is in Branch_3_2 as of Friday or  thereabouts.

No need to dig deeper, I've been down there already :-)

Steve Coy

On Monday, September 30, 2002, at 11:08  AM, bobby abraham wrote:

>
> Recently while creating several tens of thousands of entities I  
> noticed a general increase in the time taken to add an entity.  The  
> time is roughly proportional to the number of rows in the table.
>
> The offending code, less the comments and logging, looks as follows :
>
> AttributeLocal attribute =  
> attributeHome.findByNameAndType(attributeData.getName(), "ld");
> AttributeInstanceLocal attributeInstance =  
> attributeInstanceHome.create(attributeInstanceData);
> attributeInstance.setAttribute(attribute);
> parcel.getAttributeInstances().add(attributeInstance);
>
> The relationships involved are
> Attribute (1) <- (M) AttributeInstance [ via foreign key on the  
> attributeinstance table called attribute_id]
> Parcel (1) -> (M) AttributeInstance [ via a link table ]
>
> Now the jboss server log included below shows the sql query "SELECT  
> AttributeInstance_id FROM ATTRIBUTEINSTANCE WHERE (attribute_id=?)".  
> In this case it takes 210 ms but this time is proportional to the  
> number of attributeinstances already related to this attribute.  This  
> query does in fact typically return thousands of rows.
>
> I can see no good reason for this select to be executed at all - or  
> have I missed something ?
>
> 2002-09-27 16:32:02,360 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCFindByPrimaryKeyQuery.Sequence.find 
> ByPrimaryKey] Executing SQL: SELECT name FROM SEQUENCE WHERE name=?
> 2002-09-27 16:32:02,370 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCLoadEntityCommand.Sequence]  
> Executing SQL: SELECT nextVal FROM SEQUENCE WHERE (name=?)
> 2002-09-27 16:32:02,370 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCLoadEntityCommand.Sequence]  
> Executing SQL: SELECT nextVal FROM SEQUENCE WHERE (name=?)
> 2002-09-27 16:32:02,380 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreEntityCommand.Sequence]  
> Executing SQL: UPDATE SEQUENCE SET nextVal=? WHERE name=?
> 2002-09-27 16:32:02,380 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreEntityCommand.Sequence] Rows  
> affected = 1
> 2002-09-27 16:32:02,380 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCCreateEntityCommand.AttributeInstan 
> ce] Create: pk=80936
> 2002-09-27 16:32:02,380 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCCreateEntityCommand.AttributeInstan 
> ce] Executing SQL: SELECT COUNT(*) FROM ATTRIBUTEINSTANCE WHERE  
> AttributeInstance_id=?
> 2002-09-27 16:32:02,380 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCCreateEntityCommand.AttributeInstan 
> ce] Executing SQL: INSERT INTO ATTRIBUTEINSTANCE  
> (AttributeInstance_id, value, deprecated, userstamp, timestamp,  
> attribute_id) VALUES (?, ?, ?, ?, ?, ?)
> 2002-09-27 16:32:02,390 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCCreateEntityCommand.AttributeInstan 
> ce] Rows affected = 1
> 2002-09-27 16:32:02,390 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCLoadEntityCommand.Attribute]  
> Executing SQL: SELECT type, unit, data_type, description, name,  
> deprecated, userstamp, timestamp FROM ATTRIBUTE WHERE (attribute_id=?)
> 2002-09-27 16:32:02,390 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCLoadRelationCommand.Attribute]  
> Executing SQL: SELECT AttributeInstance_id FROM ATTRIBUTEINSTANCE  
> WHERE (attribute_id=?)
> 2002-09-27 16:32:02,600 INFO  [STDOUT] LOAD--2 attribute instance add  
> 240 milliseconds
> 2002-09-27 16:32:02,600 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreEntityCommand.AttributeInstanc 
> e] Executing SQL: UPDATE ATTRIBUTEINSTANCE SET attribute_id=? WHERE  
> AttributeInstance_id=?
> 2002-09-27 16:32:02,600 DEBUG  
> [org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreEntityCommand.AttributeInstanc 
> e] Rows affected = 1
>
>
> I'm happy to dig deeper into this problem but am hoping that someone  
> can give me a few pointers as to what might be going on here.



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