Hello,
Recently, I turned on the show_sql and started observing this behavior. I would like to confirm whether this is supposed to happen and curious to know how to optimize it. Currently, I am facing severe deadlock issues.

I need to resolve this ASAP and I greatly appreciate your time and help.

I have typical bidirectional one-to-many with the many-valued end as the inverse end. Let me explain this using a simple example. Entity A has one-to-many with Entity B which then has one-to-many with Entity C. I am doing the following

session.load(Entity C, entity_id)

What I am noticing is that Hibernate is executing the following sql.

select Entity C (expected)
select Entity B (unexpected)
select Entity A (unexpected)
select <other children of Entity A> (highly unexpected)
select <other children of Entity B> (highly unexpected)
....
....

I am curious to know why it is doing a select on the ancestors. Is this is expected? I am asking because I was under the impression that only Entity C would be used and it not happening the way I thought. This is causing DEADLOCK issues to me as it happens to acquire locks on ALL entities preventing legitimate access to the ancestors from the other threads. I would like to add that the database that we use is a single-user database (quadcap.com) that does table-locking instead of row-locking for all queries.

Madhan.

Since you have shown none of the relevant information listed in the huge red message when you post, the answer is a guess at best. Next time read before posting!

Anyway, looks like you have not enabled proxies, so please refer to the Hibernate documentation. Read it from beginning to end.

Just execute transactions serialy on singe user database(in synchronized block).

Thanks for your instant response. I apologize. I have included the missing pieces. I am trying to use the proxies in the meantime.

Hibernate version: 2.1.1

<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

Mapping 1
------------
<hibernate-mapping>
<class
name="DirectorImpl"
table="DIRECTORS"
dynamic-update="true"
dynamic-insert="false"
>

<id
name="id"
column="DIRECTORS_ID"
type="int"
unsaved-value="any"
>
<generator class="assigned">
</generator>
</id>

<many-to-one
name="parent"
class="CEOImpl"
cascade="none"
outer-join="auto"
update="true"
insert="true"
column="CEOS_ID"
not-null="true"
/>

<bag
name="children"
table="MANAGERS"
lazy="false"
inverse="true"
cascade="all"
>
<key
column="DIRECTORS_ID"
/>
<one-to-many
class="ManagerImpl"
/>
</bag>

</class>
</hibernate-mapping>

Mapping 2:
-------------
<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>
<class
name="ManagerImpl"
table="MANAGERS"
dynamic-update="true"
dynamic-insert="false"
>

<id
name="id"
column="MANAGERS_ID"
type="int"
unsaved-value="any"
>
<generator class="assigned">
</generator>
</id>

<many-to-one
name="parent"
class="DirectorImpl"
cascade="none"
outer-join="auto"
update="true"
insert="true"
column="DIRECTORS_ID"
not-null="true"
/>

<bag
name="children1"
table="ASSISTANTS"
lazy="false"
inverse="true"
cascade="all"
>

<key
column="MANAGERS_ID"
/>

<one-to-many
class="AssistantImpl"
/>
</bag>

<bag
name="children"
table="EMPLOYEES"
lazy="false"
inverse="true"
cascade="all"
>

<key
column="MANAGERS_ID"
/>

<one-to-many
class="EmployeeImpl"
/>
</bag>

</class>
</hibernate-mapping>

Mapping 3:
------------
<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>
<class
name="EmployeeImpl"
table="EMPLOYEES"
dynamic-update="true"
dynamic-insert="false"
>

<id
name="id"
column="EMPLOYEES_ID"
type="int"
unsaved-value="any"
>
<generator class="assigned">
</generator>
</id>

<many-to-one
name="parent"
class="ManagerImpl"
cascade="none"
outer-join="auto"
update="true"
insert="true"
column="MANAGERS_ID"
not-null="true"
/>

<many-to-one
name="parent1"
class="AsistantImpl"
cascade="none"
outer-join="auto"
update="true"
insert="true"
column="ASISTANTS_ID"
not-null="false"
/>

</class>
</hibernate-mapping>

Mapping 4:
-------------
<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>
<class
name="AssistantImpl"
table="ASSISTANTS"
dynamic-update="true"
dynamic-insert="false"
>

<id
name="id"
column="ASSISTANTS_ID"
type="int"
unsaved-value="any"
>
<generator class="assigned">
</generator>
</id>

<many-to-one
name="parent"
class="ManagerImpl"
cascade="none"
outer-join="auto"
update="true"
insert="true"
column="MANAGERS_ID"
not-null="true"
/>

<bag
name="children"
table="EMPLOYEES"
lazy="false"
inverse="true"
cascade="all"
>

<key
column="ASSISTANTS_ID"
/>

<one-to-many
class="EmployeeImpl"
/>
</bag>

</class>
</hibernate-mapping>

------------------------------------------------------------------------------
I find it difficult to show the code between openSession() and close() as they are scattered all around. Essentially, what I am doing is instantiating the all the entities involved (and add them to appripriate collections) and then do a store() on the top level entity and commit all the changes. Then, close the session and open a new session and call

session.load(EmployeeImpl.class, new Integer(1005));

-------------------------------------------------------------------------------
This is the partial output on the console:
<EXPECTED> Hibernate: select employeeimp0_.EMPLOYEES_ID as EMPLOYEES1_0_, employeeimp0_.active as active0_, emplo
<UNEXPECTED> Hibernate: select manag0_.MANAGERS_ID as MANAGERS_ID0_, manager0_.DIRECTORS_ID as DIRECTORS_ID0_, c
<UNEXPECTED> Hibernate: select directorimpl0_.DIRECTORS_ID as DIRECTORS_ID0_, directorimpl0_.CEOS_ID as CEO_2_

------------------------------------------------------------------------------
Database: Quadcap 3.2

If you want lazy loading for a "one side", you need to proxy that class. For an explanation why this is so, please take a look at http://www.hibernate.org/162.html