Re: concurrent access to LRS
) org.apache.myfaces.component.html.ext.HtmlDataTableHack.setRowIndex (HtmlDataTableHack.java:243) org.apache.myfaces.component.html.ext.HtmlDataTable.setRowIndex (HtmlDataTable.java:263) org.apache.myfaces.shared_tomahawk.renderkit.html.HtmlTableRendererB as e.encodeInnerHtml(HtmlTableRendererBase.java:257) org.apache.myfaces.shared_tomahawk.renderkit.html.HtmlTableRendererB as e.encodeChildren(HtmlTableRendererBase.java:134) org.apache.myfaces.renderkit.html.ext.HtmlTableRenderer.encodeChildr en (HtmlTableRenderer.java:187) javax.faces.component.UIComponentBase.encodeChildren (UIComponentBase.java:828) javax.faces.component.UIComponent.encodeAll(UIComponent.java:883) javax.faces.component.UIComponent.encodeAll(UIComponent.java:889) com.sun.facelets.FaceletViewHandler.renderView (FaceletViewHandler.java:578) Cheers, Roger -- View this message in context: http://www.nabble.com/concurrent- access-to-LRS-tf2811717.html#a7846241 Sent from the open-jpa-dev mailing list archive at Nabble.com. -- View this message in context: http://www.nabble.com/concurrent- access-to-LRS-tf2811717.html#a7846763 Sent from the open-jpa-dev mailing list archive at Nabble.com. -- View this message in context: http://www.nabble.com/concurrent-access-to-LRS-tf2811717.html#a7849597 Sent from the open-jpa-dev mailing list archive at Nabble.com.
concurrent access to LRS
Now that I have an em which lives for longer than one request (as per my previous thread) I have noticed some concurrency issues accessing the large result set. Since my app uses frames, there are occasions when two frames will be refreshed at the same time. When this occurs, and the both try to iterate the LRS I will frequently get either a NullPointerException or NoSuchElementException (result list is closed). Loading the frames one by one works fine. I've tried to the following with no avail: * Adding openjpa.Multithreaded=true * Synchronizing the LRS' getter method * Removing connection pooling (i.e. use openjpa's datasource) * Using mysql instead of postgresql * Disabling the query cache * Disabling the data cache As you can see, I'm a bit stuck. Any suggestions welcome. The NullPointerException stacktrace is: java.lang.NullPointerException org.apache.openjpa.jdbc.kernel.SelectResultObjectProvider.next(SelectResultObjectProvider.java:96) org.apache.openjpa.lib.rop.WindowResultList.getInternal(WindowResultList.java:126) org.apache.openjpa.lib.rop.AbstractNonSequentialResultList.get(AbstractNonSequentialResultList.java:69) org.apache.openjpa.kernel.DelegatingResultList.get(DelegatingResultList.java:241) javax.faces.model.ListDataModel.getRowData(ListDataModel.java:141) javax.faces.model.ListDataModel.setRowIndex(ListDataModel.java:175) javax.faces.model.ListDataModel.setWrappedData(ListDataModel.java:209) javax.faces.model.ListDataModel.init(ListDataModel.java:68) org.apache.myfaces.component.html.ext.HtmlDataTableHack.createDataModel(HtmlDataTableHack.java:448) org.apache.myfaces.component.html.ext.HtmlDataTable.createDataModel(HtmlDataTable.java:847) org.apache.myfaces.component.html.ext.HtmlDataTableHack.getDataModel(HtmlDataTableHack.java:414) org.apache.myfaces.component.html.ext.HtmlDataTable.getDataModel(HtmlDataTable.java:839) org.apache.myfaces.component.html.ext.HtmlDataTableHack.getRowCount(HtmlDataTableHack.java:87) org.apache.myfaces.shared_tomahawk.renderkit.html.HtmlTableRendererBase.encodeInnerHtml(HtmlTableRendererBase.java:226) org.apache.myfaces.shared_tomahawk.renderkit.html.HtmlTableRendererBase.encodeChildren(HtmlTableRendererBase.java:134) org.apache.myfaces.renderkit.html.ext.HtmlTableRenderer.encodeChildren(HtmlTableRenderer.java:187) javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:828) javax.faces.component.UIComponent.encodeAll(UIComponent.java:883) javax.faces.component.UIComponent.encodeAll(UIComponent.java:889) com.sun.facelets.FaceletViewHandler.renderView(FaceletViewHandler.java:578) and the NoSuchElementException: java.util.NoSuchElementException: The result list has been closed. org.apache.openjpa.lib.rop.AbstractResultList.assertOpen(AbstractResultList.java:91) org.apache.openjpa.lib.rop.WindowResultList.size(WindowResultList.java:81) org.apache.openjpa.kernel.DelegatingResultList.size(DelegatingResultList.java:133) javax.faces.model.ListDataModel.isRowAvailable(ListDataModel.java:99) javax.faces.model.ListDataModel.setRowIndex(ListDataModel.java:174) org.apache.myfaces.component.html.ext.HtmlDataTableHack.setRowIndex(HtmlDataTableHack.java:243) org.apache.myfaces.component.html.ext.HtmlDataTable.setRowIndex(HtmlDataTable.java:263) org.apache.myfaces.shared_tomahawk.renderkit.html.HtmlTableRendererBase.encodeInnerHtml(HtmlTableRendererBase.java:257) org.apache.myfaces.shared_tomahawk.renderkit.html.HtmlTableRendererBase.encodeChildren(HtmlTableRendererBase.java:134) org.apache.myfaces.renderkit.html.ext.HtmlTableRenderer.encodeChildren(HtmlTableRenderer.java:187) javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:828) javax.faces.component.UIComponent.encodeAll(UIComponent.java:883) javax.faces.component.UIComponent.encodeAll(UIComponent.java:889) com.sun.facelets.FaceletViewHandler.renderView(FaceletViewHandler.java:578) Cheers, Roger -- View this message in context: http://www.nabble.com/concurrent-access-to-LRS-tf2811717.html#a7846241 Sent from the open-jpa-dev mailing list archive at Nabble.com.
Re: concurrent access to LRS
Roger- Was a transaction committed or rolled back between the two requests? Many databases and/or JDBC drivers do not allow a result set cursor to span multiple transactions, which might be the cause of this error (which, admittedly, we are not handling as gracefully as we could be). On Dec 12, 2006, at 6:26 PM, roger.keays wrote: Now that I have an em which lives for longer than one request (as per my previous thread) I have noticed some concurrency issues accessing the large result set. Since my app uses frames, there are occasions when two frames will be refreshed at the same time. When this occurs, and the both try to iterate the LRS I will frequently get either a NullPointerException or NoSuchElementException (result list is closed). Loading the frames one by one works fine. I've tried to the following with no avail: * Adding openjpa.Multithreaded=true * Synchronizing the LRS' getter method * Removing connection pooling (i.e. use openjpa's datasource) * Using mysql instead of postgresql * Disabling the query cache * Disabling the data cache As you can see, I'm a bit stuck. Any suggestions welcome. The NullPointerException stacktrace is: java.lang.NullPointerException org.apache.openjpa.jdbc.kernel.SelectResultObjectProvider.next (SelectResultObjectProvider.java:96) org.apache.openjpa.lib.rop.WindowResultList.getInternal (WindowResultList.java:126) org.apache.openjpa.lib.rop.AbstractNonSequentialResultList.get (AbstractNonSequentialResultList.java:69) org.apache.openjpa.kernel.DelegatingResultList.get (DelegatingResultList.java:241) javax.faces.model.ListDataModel.getRowData(ListDataModel.java:141) javax.faces.model.ListDataModel.setRowIndex(ListDataModel.java:175) javax.faces.model.ListDataModel.setWrappedData(ListDataModel.java: 209) javax.faces.model.ListDataModel.init(ListDataModel.java:68) org.apache.myfaces.component.html.ext.HtmlDataTableHack.createDataMode l(HtmlDataTableHack.java:448) org.apache.myfaces.component.html.ext.HtmlDataTable.createDataModel (HtmlDataTable.java:847) org.apache.myfaces.component.html.ext.HtmlDataTableHack.getDataModel (HtmlDataTableHack.java:414) org.apache.myfaces.component.html.ext.HtmlDataTable.getDataModel (HtmlDataTable.java:839) org.apache.myfaces.component.html.ext.HtmlDataTableHack.getRowCount (HtmlDataTableHack.java:87) org.apache.myfaces.shared_tomahawk.renderkit.html.HtmlTableRendererBas e.encodeInnerHtml(HtmlTableRendererBase.java:226) org.apache.myfaces.shared_tomahawk.renderkit.html.HtmlTableRendererBas e.encodeChildren(HtmlTableRendererBase.java:134) org.apache.myfaces.renderkit.html.ext.HtmlTableRenderer.encodeChildren (HtmlTableRenderer.java:187) javax.faces.component.UIComponentBase.encodeChildren (UIComponentBase.java:828) javax.faces.component.UIComponent.encodeAll(UIComponent.java:883) javax.faces.component.UIComponent.encodeAll(UIComponent.java:889) com.sun.facelets.FaceletViewHandler.renderView (FaceletViewHandler.java:578) and the NoSuchElementException: java.util.NoSuchElementException: The result list has been closed. org.apache.openjpa.lib.rop.AbstractResultList.assertOpen (AbstractResultList.java:91) org.apache.openjpa.lib.rop.WindowResultList.size (WindowResultList.java:81) org.apache.openjpa.kernel.DelegatingResultList.size (DelegatingResultList.java:133) javax.faces.model.ListDataModel.isRowAvailable(ListDataModel.java:99) javax.faces.model.ListDataModel.setRowIndex(ListDataModel.java:174) org.apache.myfaces.component.html.ext.HtmlDataTableHack.setRowIndex (HtmlDataTableHack.java:243) org.apache.myfaces.component.html.ext.HtmlDataTable.setRowIndex (HtmlDataTable.java:263) org.apache.myfaces.shared_tomahawk.renderkit.html.HtmlTableRendererBas e.encodeInnerHtml(HtmlTableRendererBase.java:257) org.apache.myfaces.shared_tomahawk.renderkit.html.HtmlTableRendererBas e.encodeChildren(HtmlTableRendererBase.java:134) org.apache.myfaces.renderkit.html.ext.HtmlTableRenderer.encodeChildren (HtmlTableRenderer.java:187) javax.faces.component.UIComponentBase.encodeChildren (UIComponentBase.java:828) javax.faces.component.UIComponent.encodeAll(UIComponent.java:883) javax.faces.component.UIComponent.encodeAll(UIComponent.java:889) com.sun.facelets.FaceletViewHandler.renderView (FaceletViewHandler.java:578) Cheers, Roger -- View this message in context: http://www.nabble.com/concurrent- access-to-LRS-tf2811717.html#a7846241 Sent from the open-jpa-dev mailing list archive at Nabble.com.
Re: concurrent access to LRS
(UIComponent.java:883) javax.faces.component.UIComponent.encodeAll(UIComponent.java:889) com.sun.facelets.FaceletViewHandler.renderView (FaceletViewHandler.java:578) Cheers, Roger -- View this message in context: http://www.nabble.com/concurrent- access-to-LRS-tf2811717.html#a7846241 Sent from the open-jpa-dev mailing list archive at Nabble.com. -- View this message in context: http://www.nabble.com/concurrent-access-to-LRS-tf2811717.html#a7846763 Sent from the open-jpa-dev mailing list archive at Nabble.com.
Re: concurrent access to LRS
) org.apache.myfaces.renderkit.html.ext.HtmlTableRenderer.encodeChildr en (HtmlTableRenderer.java:187) javax.faces.component.UIComponentBase.encodeChildren (UIComponentBase.java:828) javax.faces.component.UIComponent.encodeAll(UIComponent.java:883) javax.faces.component.UIComponent.encodeAll(UIComponent.java:889) com.sun.facelets.FaceletViewHandler.renderView (FaceletViewHandler.java:578) Cheers, Roger -- View this message in context: http://www.nabble.com/concurrent- access-to-LRS-tf2811717.html#a7846241 Sent from the open-jpa-dev mailing list archive at Nabble.com. -- View this message in context: http://www.nabble.com/concurrent- access-to-LRS-tf2811717.html#a7846763 Sent from the open-jpa-dev mailing list archive at Nabble.com.
