Hi,
I am trying to use OJB to manage experiment data, and have started
with a naive approach where each experiment is a nested collection
eventually ending with variable/value pairs. Storing data works well,
and retrieving it using getCollectionByQuery() works eventually, but
is taking much longer than it should.
When retrieving an experiment object, OJB invokes BasePrefetcher's
prefetchRelationship(), which makes a bunch of JDBC calls via
getCollectionByQuery(), which seems to return all the data OJB needs
to reconstruct the object. This takes about 10 seconds for my test
experiment (1000 runs, 25 observations each). prefetchRelationship()
then invokes associateBatched(), and stays there for another 20
minutes with no further debug output, mainly creating Identity
objects.
I'm wondering whether I've set up my schema in a way that's grossly
inefficient for OJB. (I've appended part of the repository.xml file
below.) I've thought about adding a reference from Value back to
Level, or using explicit PKs instead of anonymous ones, but haven't
tried either yet.
FWIW, I'm using OJB 1.0.rc5 with the PB interface against a MySQL
database (3.0.9-stable driver).
many thanks for any ideas,
-j
Jason Woodard
[EMAIL PROTECTED]
<!-- Definitions for sim.harness.store.Level -->
<class-descriptor
class="sim.harness.store.Level"
table="LEVEL"
>
<field-descriptor
name="id"
column="ID"
jdbc-type="INTEGER"
primarykey="true"
autoincrement="true"
access="anonymous"
/>
<!-- foreign key for parent collection -->
<field-descriptor
name="seriesId"
column="SERIES"
jdbc-type="INTEGER"
access="anonymous"
/>
<field-descriptor
name="variableId"
column="VARIABLE"
jdbc-type="INTEGER"
access="anonymous"
/>
<reference-descriptor
name="variable"
class-ref="sim.harness.store.Variable"
auto-update="true"
auto-delete="true"
>
<foreignkey field-ref="variableId"/>
</reference-descriptor>
<field-descriptor
name="valueId"
column="VALUE"
jdbc-type="INTEGER"
access="anonymous"
/>
<reference-descriptor
name="value"
class-ref="sim.harness.store.Value"
auto-update="true"
auto-delete="true"
>
<foreignkey field-ref="valueId"/>
</reference-descriptor>
</class-descriptor>
<!-- Definitions for sim.harness.store.Variable -->
<class-descriptor
class="sim.harness.store.Variable"
table="VARIABLE"
>
<field-descriptor
name="id"
column="ID"
jdbc-type="INTEGER"
primarykey="true"
autoincrement="true"
access="anonymous"
/>
<field-descriptor
name="name"
column="NAME"
jdbc-type="VARCHAR"
/>
</class-descriptor>
<!-- Definitions for sim.harness.store.Value -->
<class-descriptor
class="sim.harness.store.Value"
>
<extent-class class-ref="sim.harness.store.AbstractValue"/>
</class-descriptor>
<!-- Definitions for sim.harness.store.AbstractValue -->
<class-descriptor
class="sim.harness.store.AbstractValue"
>
<extent-class class-ref="sim.harness.store.IntValue"/>
<extent-class class-ref="sim.harness.store.DoubleValue"/>
<extent-class class-ref="sim.harness.store.BooleanValue"/>
<extent-class class-ref="sim.harness.store.StringValue"/>
</class-descriptor>
<!-- Definitions for sim.harness.store.DoubleValue -->
<class-descriptor
class="sim.harness.store.DoubleValue"
table="DBL_VALUE"
>
<field-descriptor
name="id"
column="ID"
jdbc-type="INTEGER"
primarykey="true"
autoincrement="true"
access="anonymous"
/>
<field-descriptor
name="value"
column="VALUE"
jdbc-type="DOUBLE"
/>
</class-descriptor>
<!-- etc. for other Value types -->
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