About concurrency
Locking in JPA
Explains how to use optimistic locking and pessimistic locking in JPA. JPA 2 supports both optimistic locking and pessimistic locking . Locking is essential to avoid update collisions resulting from simultaneous updates to the same data by two concurrent users. Locking in ObjectDB (and in JPA) is always at the da ...
JPA Entity Fields
Explains how to define and use primary keys in JPA, including composite and embedded primary keys. Fields of persistable user defined classes (entity classes, embeddable classes and mapped superclasses) can be classified into the following five groups: Transient fields Persistent fields Inverse (Mapped By ...
ArrayIndexOutOfBoundsException at com.objectdb.o.ALS.c(ALS.java:89)
Hi all, I have created a packet grabber using JNetPcap. It creates a scala actor (java thread) for every packet grabbed which connect to an OpenDB database to add or update relevant entry's. Everything works fine until packets arrive with a time difference in the order of microseconds. Every scala actor opens a connection to the database, does what it needs to do, and then closes the connection. Something like: #1 2011-05-11 08:24 Hi all, I have created a packet grabber using JNetPcap. It creates a scala actor (java thread) for every ...
Optimistic locking failure
Optimistic locking failure: I am using a Semaphore to force this execution of concurrents transactions T1 and T2 that cause parallel updates to A/B but it does not throw an OptimisticLockException and roll back. #1 2012-04-30 16:02 Optimistic locking failure: I am using a Semaphore to force this execution of concurrents transactions T1 ...
Many connections possible? and will it makes problem in future?
Hello , we are currently making new instant messenger but we were planing to use some security addons and privileges on access some of the fields on java side. My questions is about : 1-) Can objectdb server handle 200.000+ connections at the same time concurrently ? Does it have queue and cache ? 2-) Can we give privileges to users , for example some users can only read some fields and some just can write java fields. Some users only allowed insert ability. #1 2012-03-17 12:46 My questions is about : 1-) Can objectdb server handle 200.000+ connections at the same time concurrently ...
2.2.6
Release date: 2011-06-02 Download (5.13 MB) Binary: objectdb-2.2.6.zip You should start by following a tutorial or reading the manual ...
2.2.5
Release date: 2011-05-20 Download (5.1 MB) Binary: objectdb-2.2.5.zip You should start by following a tutorial or reading the manual ...
use of Singleton into tomcat
hi all. i would write a class singleton that encapsulate the entitymanagerFACTORY into it.(the entitymanagerFactory IS A property of the only instance of class singleton. (the class singleton is not a Ejb!!!!!!!!!). into tomcat it not possible use ejbs............. i have to manage the concurrency for the operations on db............... with a method static i can get the only instance of singleton for manage all operation on database. I get a instance of it into multiple servlet. ... use ejbs............. i have to manage the concurrency for the operations on db............... with a method ...
2.2.7
Release date: 2011-06-14 Download (5.13 MB) Binary: objectdb-2.2.7.zip You should start by following a tutorial or reading the manual ...
2.2.8
Release date: 2011-07-03 Download (5.14 MB) Binary: objectdb-2.2.8.zip You should start by following a tutorial or reading the manual ...
