About memory

manual

SELECT clause (JPQL / Criteria API)

Explains how to use the SELECT clause and projections in a JPA/JPQL query.... lightweight, they are built faster and they consume less memory. SELECT DISTINCT Queries that use projection may return ...

 
manual

Database Management Settings

Explains settings and performance tuning of the ObjectDB Java object database for JPA/JDO.... attribute is a hint that specifies the the amount of memory that is used for caching pages of the database file. The ...

 
manual

Index Definition

Describes how to define indexes in JPA entity classes and explains how indexes are used in JPQL queries.... that ObjectDB maintains in the file system rather than in memory. The keys of the BTree are all the unique values in the indexed field ...

 
manual

FROM clause (JPQL / Criteria API)

Explains how to use the FROM clause and JOIN expressions in a JPA/JPQL query.... illusion that all the database objects are available in memory for navigation. But this feature could also cause performance problems. ...

 
forum_thread

One transaction or two?

If I have a large number of objects to delete and then add to a PersistenceManager is it more efficient to do everything in one transaction or two? Currently my code looks like this: ... On the hand such a solution is expected to consume more memory. Since you are asking about add/remove operations rather than ...

 
issue

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

Hi, ... may be some impact over time (but not necessaraly) on memory consumption and socket usage, but this could be negligible. ...

 
manual

Obtaining a JPA Database Connection

Shows how to use Java/JPA to connect to the ObjectDB Object Database.... . Database updates are collected and managed in memory and applied to the database when the transaction is committed: em. ...

 
issue

com.objectdb.o.InternalException

No idea what happened.  A simple getResultList() opearation. DB table affected size is ~ 26000 records, physical DB file size is ~ 8.5MB Thanks for any help ! Leon log file: ------------------------------------------------------------------------------------------------------------------------ [2016-07-13 19:58:12 #1 store] Database '/home/gsi/wdsync/db/Media_wdsync.odb' is opened by 12659@server ... this specific query? Yes. I suspect a JVM memory shortage problem as I'm running in an embedded system (ODROID-C1) ...

 
forum_thread

Exception when dataset bigger than treshold

I was working on reporting service for my application and found a problem with datasets bigger than treshold set in objectdb.conf.   ... 96M "fixes" the problem - with 96MB can run this query in memory, so no temp files. Doctor works fine with low treshold values ...

 
manual

[ODB1] Chapter 7 - JDOQL Queries

Explains how to use JDOQL, the Java/JDO Query Language.... an Extent . It is useful for filtering a collection in memory, and for requerying the result of a previous JDOQL query. A ...