I've got a GAE app which uses JDO to manage a single persistent class.
Memcache not used. Every time a new instance of the app starts up, I see
3524 data store read operations added to my quota usage. That number
happens to be the number of rows in the persistent table, currently. So it
seems that JDO is reading through the entire table upon startup. I've done
thorough logging and testing to confirm that my own app code is not doing
this -- my code only does queries thatl read at most 1-12 rows at a time,
and the effect on quota usage for an already started instance matches my
expectations. It's only when GAE starts a new instance that I see the huge
increment to data store read ops.
Because usage of my app varies up and down through a typical day, GAE
starts new instances frequently (which come and go). So this 3500+ hit to
quota each time easily exceeds 50K total a day, so this is costing me $.
Questions: why in the world does JDO need to read through the entire table
upon startup, and is there any way to prevent it?
Below is the log output at startup from JDO.
Thanks very much in advance for any advice anybody provides.
1. 2013-11-21 13:45:01.543
2.
org.datanucleus.plugin.NonManagedPluginRegistry resolveConstraints: Bundle
"org.datanucleus.jpa" has an optional dependency to "org.datanucleus.enhancer"
but it cannot be resolved
3. I2013-11-21 13:45:01.543
org.datanucleus.plugin.NonManagedPluginRegistry resolveConstraints: Bundle
"org.datanucleus" has an optional dependency to "org.eclipse.equinox.registry"
but it cannot be resolved
4. I2013-11-21 13:45:01.544
org.datanucleus.plugin.NonManagedPluginRegistry resolveConstraints: Bundle
"org.datanucleus" has an optional dependency to "org.eclipse.core.runtime" but
it cannot be resolved
5. I2013-11-21 13:45:02.237
org.datanucleus.PersistenceConfiguration setProperty: Property
datanucleus.rdbms.sql.allowAllSQLStatements unknown - will be ignored
6. I2013-11-21 13:45:02.244
org.datanucleus.PersistenceConfiguration setProperty: Property
datanucleus.rdbms.stringDefaultLength unknown - will be ignored
7. I2013-11-21 13:45:02.263
org.datanucleus.PersistenceConfiguration setProperty: Property
datanucleus.appengine.autoCreateDatastoreTxns unknown - will be ignored
8. I2013-11-21 13:45:02.268
org.datanucleus.ObjectManagerFactoryImpl logConfiguration: =================
Persistence Configuration ===============
9. I2013-11-21 13:45:02.270
org.datanucleus.ObjectManagerFactoryImpl logConfiguration: DataNucleus
Persistence Factory - Vendor: "DataNucleus" Version: "1.1.5"
10. I2013-11-21 13:45:02.271
org.datanucleus.ObjectManagerFactoryImpl logConfiguration: DataNucleus
Persistence Factory initialised for datastore URL="appengine" driver=""
userName=""
11. I2013-11-21 13:45:02.271
org.datanucleus.ObjectManagerFactoryImpl logConfiguration:
===========================================================
12. I2013-11-21 13:45:02.839
org.datanucleus.PersistenceConfiguration setProperty: Property
datanucleus.query.cached unknown - will be ignored
13. I2013-11-21 13:45:03.840
org.datanucleus.jdo.metadata.JDOMetaDataManager <init>: Registering listener
for metadata initialisation
14. I2013-11-21 13:45:04.692
org.datanucleus.jdo.metadata.JDOAnnotationReader processClassAnnotations:
Class "net.traub.tagxlate.server.dao.gae.GaeGcpRuleRecord" has been specified
with JDO annotations so using those.
15. I2013-11-21 13:45:04.851
org.datanucleus.store.appengine.MetaDataValidator validate: Performing
appengine-specific metadata validation for
net.traub.tagxlate.server.dao.gae.GaeGcpRuleRecord
16. I2013-11-21 13:45:04.851
org.datanucleus.store.appengine.MetaDataValidator validate: Finished
performing appengine-specific metadata validation for
net.traub.tagxlate.server.dao.gae.GaeGcpRuleRecord
17. I2013-11-21 13:45:04.936
org.datanucleus.store.StoreDataManager registerStoreData: Managing
Persistence of Class : net.traub.tagxlate.server.dao.gae.GaeGcpRuleRecord
[Table : <class name="GaeGcpRuleRecord"
identity-type="application"
objectid-class="javax.jdo.identity.LongIdentity"
persistence-modifier="persistence-capable"
>
[details omitted here to save space] </class>
, InheritanceStrategy : new-table]
18. I2013-11-21 13:45:05.034
org.datanucleus.store.StoreDataManager registerStoreData: Managing
Persistence of Class : net.traub.tagxlate.server.dao.gae.GaeGcpRuleRecord
[Table : <class name="GaeGcpRuleRecord"
identity-type="application"
objectid-class="javax.jdo.identity.LongIdentity"
persistence-modifier="persistence-capable"
>
<inheritance strategy="new-table">
</inheritance>
[details omitted here to save space] </class>
, InheritanceStrategy : new-table]
19. I2013-11-21 13:45:06.235
org.datanucleus.jdo.metadata.JDOMetaDataManager$MetaDataRegisterClassListener
registerClass: Listener found initialisation for persistable class
net.traub.tagxlate.server.dao.gae.GaeGcpRuleRecord
20. W2013-11-21 13:45:07.758
com.google.appengine.api.datastore.QueryResultsSourceImpl
logChunkSizeWarning: This query does not have a chunk size set in FetchOptions
and has returned over 1000 results. If result sets of this size are common for
this query, consider setting a chunk size to improve performance.
To disable this warning set the following system property in
appengine-web.xml (the value of the property doesn't matter):
'appengine.datastore.disableChunkSizeWarning'
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