How to skip loading one column?

slawek · **Joined:** Wed Aug 10, 2005 8:54 am **Posts:** 10

here is situation:
I have class (ex. Document) that contains String property (ex. content) and ofcourse many other properties. Problem is that this string property may contain veeery big object.
I dont need "content of the document" while loading list of all documents, but i need it only when loading details of selected document.

How to prevent hibernate from loading specific columns (in criteria api)?
Its importand to me bacause of perfomance - giant memory usage while loading whole list.

batmat · **Posted:** Sun Jan 14, 2007 3:50 pm

Did you try projecting only the columns you need?

slawek · **Joined:** Wed Aug 10, 2005 8:54 am **Posts:** 10

i have tried this in mapping:
<property
name="titleAndContent"
formula="concat(title, content)"
type="java.lang.String"
lazy="true"
/>

or this in DAO:
crit.setFetchMode("titleAndContent", FetchMode.SELECT);

but unfaortunatelly data if fetched, therefore result list consumes lots of memory:/

what am i doing wrong?

batmat · **Posted:** Sun Apr 15, 2007 2:11 pm

Did you verify you activated the bytecode instrumentation as you ought to?

roger_rf · **Posted:** Sun Apr 15, 2007 7:51 pm

Hi slawek,
How are you performing your query? Are you using the Criteria API, or HQL? After seeing batmat's comment, I think a possible solution may be to create a special construtor for your Document class where the [titleAndContent] property is not initialized, and use that constructor in an HQL query projecting only the columns that you need. See the sixth example in Section 14.6 of the reference documentation:

http://www.hibernate.org/hib_docs/v3/re ... ryhql.html

Cheers,
Roger

slawek · **Joined:** Wed Aug 10, 2005 8:54 am **Posts:** 10

batmat wrote:

Did you verify you activated the bytecode instrumentation as you ought to?

hmm i'm quite confused...

what is 'bytecode instrumentation' and what do You mean by 'activating' this?

You say that i ought to do this, but to be honest i have never heard about that in 2 years of hibernate developing - maybe im just stupid ignorant;PPP

slawek · **Joined:** Wed Aug 10, 2005 8:54 am **Posts:** 10

roger_rf wrote:

Hi slawek,
How are you performing your query? Are you using the Criteria API, or HQL? After seeing batmat's comment, I think a possible solution may be to create a special construtor for your Document class where the [titleAndContent] property is not initialized, and use that constructor in an HQL query projecting only the columns that you need.

Unfortunatelly i'm using Criteria API.
For me its better solution because i have complicated criteria conditions (many if statements) so criteria code just looks better than concatenation of dozens of strings.

Somme time ago i tried to use my own constructor... it worked well when constructor attributters were simple (Integer, String, ect.) but i needed to fetch somme Sets - i couldnt make it to work when constructor had Set perameter:/

but question remains:
why 'lazy = true' in my mapping or 'setFetchMode' in criteria doesnt work? Is it even possible to lazy load String collumn? Or mayby this works only for associated Objects that are mapped?

batmat · **Posted:** Mon Apr 16, 2007 4:30 am

slawek wrote:

what is 'bytecode instrumentation' and what do You mean by 'activating' this?

You say that i ought to do this, but to be honest i have never heard about that in 2 years of hibernate developing - maybe im just stupid ignorant;PPP

Maybe just read the documentation :) :
http://www.hibernate.org/hib_docs/v3/re ... n-property

Quote:

lazy (optional - defaults to false): Specifies that this property should be fetched lazily when the instance variable is first accessed (requires build-time bytecode instrumentation).

Using lazy="true" on a property is not the same as on a class relationship.

slawek · **Joined:** Wed Aug 10, 2005 8:54 am **Posts:** 10

thanks a lot batmat for being so lenient for me:)

i have instrumented my classes, but something is wrong:/
my app keep throwing LazyInitException in places where everything was OK before instrumentation...

maping:

Code:

<many-to-one
        name="qmsdocumenttype"
        class="org.quamasoft.common.model.Qmsdocumenttype"
        not-null="true"
    >
        <column name="QMSDocumentTypeID" />
</many-to-one>

criteria api:

Code:

crit.setFetchMode("qmsdocumenttype", FetchMode.JOIN);

as i said: it worked before Instrumentalization and after it filed is not fetched cause i get LazyInitException:/

batmat · **Posted:** Tue Apr 17, 2007 10:39 am

Please show the stacktrace.

slawek · **Joined:** Wed Aug 10, 2005 8:54 am **Posts:** 10

it's full stacktrace from console:

2007-04-18 11:06:25,265 [http-8080-Processor23] ERROR org.hibernate.LazyInitializationException - session is not connected
org.hibernate.LazyInitializationException: session is not connected
at org.hibernate.intercept.FieldInterceptor.intercept(FieldInterceptor.java:70)
at org.hibernate.intercept.FieldInterceptor.readObject(FieldInterceptor.java:130)
at org.quamasoft.common.model.Qmsdocument.$cglib_read_qmsdocumenttype(Qmsdocument.java)
at org.quamasoft.common.model.Qmsdocument.getQmsdocumenttype(Qmsdocument.java:362)
at org.quamasoft.common.utils.DocumentUtils.generateTicket(DocumentUtils.java:49)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentRow.<init>(DocumentRow.java:97)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.loadDocuments(DocumentsBean.java:361)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.showDocuments(DocumentsBean.java:269)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.showDocumentsCommon(DocumentsBean.java:209)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.showDocumentsManual(DocumentsBean.java:160)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.myfaces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:129)
at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:63)
at javax.faces.component.UICommand.broadcast(UICommand.java:106)
at javax.faces.component.UIViewRoot._broadcastForPhase(UIViewRoot.java:94)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:168)
at org.apache.myfaces.lifecycle.LifecycleImpl.invokeApplication(LifecycleImpl.java:343)
at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:86)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:137)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:144)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.quamasoft.server.filters.LicensedActionServletFilter.doFilter(LicensedActionServletFilter.java:86)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.uhc.filters.JsfAuthenticationFilter.doFilter(JsfAuthenticationFilter.java:49)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.uhc.filters.SessionFilter.doFilter(SessionFilter.java:88)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.quamasoft.server.filters.ServletContextFilter.doFilter(ServletContextFilter.java:42)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Unknown Source)
StandardWrapperValve[Faces Servlet]: Servlet.service() for servlet Faces Servlet threw exception
javax.faces.FacesException: Error calling action method of component with id MainMenuForm:d1
at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:74)
at javax.faces.component.UICommand.broadcast(UICommand.java:106)
at javax.faces.component.UIViewRoot._broadcastForPhase(UIViewRoot.java:94)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:168)
at org.apache.myfaces.lifecycle.LifecycleImpl.invokeApplication(LifecycleImpl.java:343)
at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:86)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:137)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:144)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.quamasoft.server.filters.LicensedActionServletFilter.doFilter(LicensedActionServletFilter.java:86)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.uhc.filters.JsfAuthenticationFilter.doFilter(JsfAuthenticationFilter.java:49)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.uhc.filters.SessionFilter.doFilter(SessionFilter.java:88)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.quamasoft.server.filters.ServletContextFilter.doFilter(ServletContextFilter.java:42)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Unknown Source)
Caused by: javax.faces.el.EvaluationException: Exception while invoking expression #{documentsBean.showDocumentsManual}
at org.apache.myfaces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:153)
at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:63)
... 45 more
Caused by: org.hibernate.LazyInitializationException: session is not connected
at org.hibernate.intercept.FieldInterceptor.intercept(FieldInterceptor.java:70)
at org.hibernate.intercept.FieldInterceptor.readObject(FieldInterceptor.java:130)
at org.quamasoft.common.model.Qmsdocument.$cglib_read_qmsdocumenttype(Qmsdocument.java)
at org.quamasoft.common.model.Qmsdocument.getQmsdocumenttype(Qmsdocument.java:362)
at org.quamasoft.common.utils.DocumentUtils.generateTicket(DocumentUtils.java:49)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentRow.<init>(DocumentRow.java:97)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.loadDocuments(DocumentsBean.java:361)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.showDocuments(DocumentsBean.java:269)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.showDocumentsCommon(DocumentsBean.java:209)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.showDocumentsManual(DocumentsBean.java:160)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.myfaces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:129)
... 46 more

javax.faces.FacesException: Error calling action method of component with id MainMenuForm:d1
at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:74)
at javax.faces.component.UICommand.broadcast(UICommand.java:106)
at javax.faces.component.UIViewRoot._broadcastForPhase(UIViewRoot.java:94)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:168)
at org.apache.myfaces.lifecycle.LifecycleImpl.invokeApplication(LifecycleImpl.java:343)
at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:86)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:137)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:144)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.quamasoft.server.filters.LicensedActionServletFilter.doFilter(LicensedActionServletFilter.java:86)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.uhc.filters.JsfAuthenticationFilter.doFilter(JsfAuthenticationFilter.java:49)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.uhc.filters.SessionFilter.doFilter(SessionFilter.java:88)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.quamasoft.server.filters.ServletContextFilter.doFilter(ServletContextFilter.java:42)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Unknown Source)
Caused by: javax.faces.el.EvaluationException: Exception while invoking expression #{documentsBean.showDocumentsManual}
at org.apache.myfaces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:153)
at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:63)
... 45 more
Caused by: org.hibernate.LazyInitializationException: session is not connected
at org.hibernate.intercept.FieldInterceptor.intercept(FieldInterceptor.java:70)
at org.hibernate.intercept.FieldInterceptor.readObject(FieldInterceptor.java:130)
at org.quamasoft.common.model.Qmsdocument.$cglib_read_qmsdocumenttype(Qmsdocument.java)
at org.quamasoft.common.model.Qmsdocument.getQmsdocumenttype(Qmsdocument.java:362)
at org.quamasoft.common.utils.DocumentUtils.generateTicket(DocumentUtils.java:49)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentRow.<init>(DocumentRow.java:97)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.loadDocuments(DocumentsBean.java:361)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.showDocuments(DocumentsBean.java:269)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.showDocumentsCommon(DocumentsBean.java:209)
at org.quamasoft.client.jsf.managedbeans.backingbeans.documents.DocumentsBean.showDocumentsManual(DocumentsBean.java:160)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.myfaces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:129)
... 46 more