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In memory processing for ObjectDB

Hi there ! We are building a platform for trades processing where we want to keep our processing speeds very high. We like ObjectDb because its simplicity and the performance benchmarks, but to take it to next level really we wanted to check whether is there any In memory mode available for ObjectDB where recovery is possible, something like prevalyer etc. ... Query program cache Query results cache ObjectDB Support ObjectDB - ...


GROUP BY and HAVING clauses

Explains how to use the GROUP BY and HAVING clauses in a JPA/JPQL query. The GROUP BY clause enables grouping of query results. A JPQL query with a GROUP BY clause returns properties of generated ... expressions that are used to form groups over the query results. See JavaDoc Reference Page... ( c. get ... expressions that are used to form groups over the query results. See JavaDoc Reference Page... method takes a variable ...



Execute a SELECT query that returns a single untyped result.(Method of javax.persistence.Query)


Query Parameters in JPA

Explains how to use parameters (named parameters and ordinal parameters) in JPA queries.... with different parameter values to retrieve different results. Running the same query multiple times with different parameter values ... } The WHERE clause reduces the query results to Country objects whose name field value is equal to :name , ...


ObjectDB Object Database Features

ObjectDB provides a rich set of features, many of them as the result of supporting the JPA and JDO APIs. ObjectDB provides a rich set of features. Many features are implemented as part of ObjectDB's support of the JPA JPA Reference (JavaDoc) Java/JPA API Reference (based on the JPA 3 JavaDoc) See JavaDoc Reference Page... an ...


Memory leak with OutOfMemoryError exception

Hi, I'm new to using object databases. Currently I'm experience the following error: ... , symbol ) ;   List<DailyEntry> results = q. getResultList ( ) ;   em. close ( ) ;   return results ; } The method above is called from: for ...


Join performance in Objectdb

select count(e) from Meta e, ImageNet i, Page p where e.idImage=i.id and e.idPage=p.id; So simple a command cause me half an hour and is running now! Each table has about 160K records. What formula can predict the time for such counting? TIA ... to repeat this with the following test but could get your results. Can you change this test to demonstrate the execution time ...


JQL-Update Queries fails with activated L2-Cache

When using JQL-Update Queries it is basically not working without calling entityManager.clear() after a transaction commit. When the clear() method isn't called the entityManager will never return a container the updated Entities. Scenario 1: Disabled L2 Cache, updating elements using UPDATE-Query and fetching Entities afterwards from database. Expected result: Getting changed Entities from database - Actual result: No changes are visble. Bug Version: Priority: Critical Status: Closed Replies: 1 Type:  Bug ...


Retrieve data of all entity classes in a single query

I have in an objectdb file 10 Entity Classes with some data in each (Athlete, Trainer, Stadium etc) This is the code I use to retrieve all Managed Types and data for the Athlete class ... ; // I want to avoid this List<Athlete> results = query. getResultList ( ) ; for ( Athlete result : results ) { System. out . println ( ...


g when using SIZE in combination with date lower parameter

Hello, I have 2 entity types, which I want to query, ParserJob and Tag. Unfortunately there seems to be a bug if I use the lower date select: SELECT j.jobId, SIZE(j.tags) FROM ParserJob j WHERE j.dateCreated < :date This returns a SIZE(j.tags) of 0 Tags, but the only existing ParserJob has 1 Tag. If I run the query: SELECT j.jobId, SIZE(j.tags) FROM ParserJob j WHERE j.dateCreated >= :date I get the correct result (1 Tag). ... the Tester.main(), both queries should return the same results. I use the latest ObjectDB 2.7.2_05 on Windows 10 but the bug also ... that the query that returns 0 should actually return no results as there are no matching jobs in the database? ...