About Persistence Context

forum_thread

Listing large number of complicated objects with paging.

Hi, For last few hours I was working on a problem with bad performance and memory problems with such a simple query: select prod from Product prod order by prod.id ASC Right now I have 55541 'Product' (attached to this post) entities in database and I'm trying to speed listing them with paging. The problem is, that running code that looks like this: ... javax. jdo . annotations . *; import javax. persistence . *;   public class F294 { public ... Use ctrl + right click to open the browser context menu in the editing area (e.g. for using a browser spell ...

 
issue

Exception in thread "ODB-StoreHandler-5094" java.lang.NullPointerException

Hi, ... Are transactions failing and receiving a a JPA Persistence exception?  Is there any risk of database corruption or data ... Use ctrl + right click to open the browser context menu in the editing area (e.g. for using a browser spell ...

 
forum_thread

find repeated records by JPQL

Hi, I know a single command in MySQL can find repeated records: Select * from TTT t where id in (select id from TTT s group id having count(id)>1) I dont know how to do this using JPQL, but I use query from 430,000 records and put them into hashmap, finally it cost one hour and failed: ... "main" [ ObjectDB 2.2.9_03 ] javax. persistence . PersistenceException Failed to read the value of field ... Use ctrl + right click to open the browser context menu in the editing area (e.g. for using a browser spell ...

 
forum_thread

Fetching Collections Puzzle

I am working on a project where I need to travel through a massive graph of objects. One of the main entity is the Node which is shown below. class Node { Node parent List<Node> children Node rightSibling Node leftSibling int rank } I have the following issues/doubts ... root Node. I have been looking for an optimum persistence solution for my project for quite some time now. I have tried every ... Use ctrl + right click to open the browser context menu in the editing area (e.g. for using a browser spell ...

 
forum_thread

Query problem after transaction commit

I have a machine running the objectdb server and the client on another machine connect to it. The client program can connect to the server and query to get all the records. However, after transaction.begin ... persist(p) .. commit of a new object, my client program can no longer retrieve the old records but only the latest stored record. I tried to run database explorer on the server machine and able to see all the records including the new stored record.... Use ctrl + right click to open the browser context menu in the editing area (e.g. for using a browser spell ...

 
forum_thread

internal object DB locking in an embedded multi threaded application

Hi, we are using Embeded objectDB 2.4.4_06 in a highly multithreaded concurrent manner and we have noticed a performance problem in our application that seems to be attributed to ObjectDb's internal locking. When profiling our app in JVisualVm we notice a large number of threads are blocked and when doing a threaddump we notice that they are all blocked in the same place: ... Use ctrl + right click to open the browser context menu in the editing area (e.g. for using a browser spell ...

 
forum_thread

lockfiles in client/server mode

i have an objectdb server running on localhost as user "objectdb", spawned like so: java -server -cp /usr/local/share/objectdb/objectdb.jar: com.objectdb.Server -conf /etc/objectdb/objectdb.conf start it has naturally created and taken ownership of /tmp/ObjectDB. ... machine where the objectdb server has done it. a persistence unit is defined in src/main/webapp/META-INF/persistence.xml with a ... Use ctrl + right click to open the browser context menu in the editing area (e.g. for using a browser spell ...

 
forum_thread

Optimization Question

One of our uses for your ObjectDB software is in maintaining the current state of a large number of data objects called tracks. These tracks change very frequently over time (every 10-15 seconds is not unreasonable), but they are also very large complex data structures so it's extremely difficult to identify exactly what fields have changed from one update to the next. Currently the following sequence executes when a track update comes in: - If it’s a new track simply add it to the database.... Use ctrl + right click to open the browser context menu in the editing area (e.g. for using a browser spell ...

 
forum_thread

Failed to commit transaction: Attempt to commit a rollback only transaction

Anyone know what this means?? Suddenly cropped up.   Failed to commit transaction: Attempt to commit a rollback only transaction (error 613) at com.objectdb.jpa.EMImpl.commit(EMImpl.java:271) at javax.jdo.Transaction$commit.call(Unknown Source) ... Use ctrl + right click to open the browser context menu in the editing area (e.g. for using a browser spell ...

 
issue

NoResultException: No matching results for a unique query

I am very often getting a "com.objectdb.o._NoResultException: No matching results for a unique query" when modifying my already persisted entities within a transaction. I cannot replicate it however because it happens infrequently. The weird thing is that the entity nevertheless gets comitted perfectly right and all data is correctly written so I have no clue what's going on!?? Here's the stacktrace (copy+paste from debug output): ... Use ctrl + right click to open the browser context menu in the editing area (e.g. for using a browser spell ...