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forum_thread

Slow searching with two indexes

I'm running queries on a large database (tens of millions of objects), and I'm running into a performance problem using two indexes.  An entity I'm querying has two indexed fields - one is the primary key (id) and so is different for each object, and the other is an object reference that only has a few tens of different values.   When I query by just the primary key, it's (of course) extremely fast, but when I also query using the other key, queries can take minutes. #1 2016-11-15 12:01 I'm running queries on a large database (tens of millions of objects), and I'm running into a performance ...

 
api-jpa

getResultList()

Execute a SELECT query and return the query results as an untyped List.(Method of javax.persistence.Query)

 
api-jdo

javax.jdo.annotations.Query

Annotation for a named query.(Annotation of JDO)

 
issue

Issue with DISTINCT Select

It is getting more and more frustrating :( We've introduced distinct select instead of regular selection in our code (no changes else) and suddenly receive invalid identifiers in queries exceptions in various queries. Here's the stacktrace: ... Implicit variables that are generated as a result of path navigation (e.g. x.a.b ). Only explicit ... than on tuple, e.g. if (1,2a) and (1,2b) are both result tuples - only 1 is returned. How should it be ordered as 2a.lastName or ...

 
manual

JPA Query API

Describes the API that JPA provides for running queries against the database.... interface should be used mainly when the query result type is unknown or when a query returns polymorphic results and the lowest known common denominator of all the result objects is Object . When a more specific result type is expected ...

 
forum_thread

Caching/Paging Questions...

Greetings ObjectDB team, All below questions assume a very large database (~1,000,000,000 objects): Q1: Two queries with a big overlap between their result sets. If I query the first set and hold the results in memory somehow, would that speed up the execution of the second query since many of its result objects already created and reside in memory ?... Q1: Two queries with a big overlap between their result sets. If I query the first set and hold the results in memory somehow, ... up the execution of the second query since many of its result objects already created and reside in memory ? Q2: Do I need to ...

 
forum_thread

Explorer in 2.3

First, the new Explorer in ObjectDB is fantastic! This is exactly what we've needed - an easy way to do ad-hoc JPQL queries and navigate through the results and even make small changes to primitive data and Strings. After playing with it for a while, here is a list of additional features I'd love to have: 1. Export of selected data: a. Simple - Select a range of cells or a column header and copy text to the clipboard or save to a file (csv, html, etc..). (There appear to be copy menu options, but I cannot get them to work.) ... Viewing all the objects of a class without a query and max result limit is not a common feature in database viewers. Any idea how this can ... that are opened while navigating the results. My initial result might have only a few records, but they may contain collections ...

 
release

2.6.6

... in queries. Fixed a bug in ordering query result by an expression that is used in IN operator. Fixed a ... ( issue #249 ). Improved title of query result windows in the Explorer. Changed the Enhancer to return ...

 
manual

Logical Operators in JPQL and Criteria API

Explains how to use AND, OR and NOT in JPQL queries.... operand is NULL and the other operand is FALSE the result is FALSE , because one FALSE operand is sufficient for a FALSE result. If one operand is NULL and the other operand is either TRUE or ...

 
api-jpa

javax.persistence.SqlResultSetMapping

Specifies the mapping of the result of a native SQL query.(Annotation of JPA)