ECLIPSELINK DOCUMENTATION PDF

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EclipseLink is an advanced, object- persistence and persistence, supporting the JPA (Java Persistence API) specification and a native API. Refer to the EclipseLink Documentation Center. Please see the EclipseLink Solutions Guide and Understanding EclipseLink ( Concepts Search the EclipseLink JPA documentation wiki.

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While the chapter provides common performance tuning considerations and related documentation resources, it is not meant to be comprehensive list of areas to tune. This chapter introduces EclipseLink.

By using the object cache, queries that access the data source can avoid the cost of building the objects and their relationships if the object is already present. The EclipseLink properties specify the settings for database read and write operations and logging.

In addition to the object cache in EclipseLink, EclipseLink also supports a query cache: You can also force queries to go to the database dicumentation disableHits. Basic example illustrating how a table can easily be exposed as a web service using default CRUD operations.

Java Persistence, a wiki-based “open book” about JPA 2.

The query cache is distinct from the object cache. Other Resources For more information, see: If you want to use proprietary features, you’ll have to learn things about the underlying persistence engine. Unless refresh has been set on the query, the cached objects can be returned without being refreshed from the database. Doug Clarke eclipselin 6. Introduction to EclipseLink Queries at http: Optimistic All users have read access to the data.

EclipseLink Documentation | The Eclipse Foundation

You can specify whether a given query runs against the in-memory cache, the database, or both. Typically, these properties can be used when the entire result set of a query returning a large number of rows is not needed. Stack Overflow works best with JavaScript enabled. The many advanced mappings enable developers to handle the complex XML structures without having to mirror the schema in their Java class model.

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In this case you should also use optimistic locking, which automatically refresh stale objects when a locking error occurs.

You may also consider using optimized loading with LoadGroups which allows a query to force instantiation of relationships. If you are reading objects, increasing the fetch size to can significantly reduce the time required to fetch the query’s results.

Other Downloads Previous releases, milestones, nightlies, Note that this tool is intended for use with single-threaded finite use cases. For the best performance of selects, where batch odcumentation is not supported, a join is recommended Lazy loading Without lazy loading on, when EclipseLink retrieves a persistent object, it retrieves all of the dependent objects to which it refers.

And, joining works on queries that not work with batch fetching. JPA Extensions Reference 2. The posted link about Expressions is an example.

Not Used Use for frequently executed non-primary key queries with infrequently changing result sets. For example, when a user scans the result set a page at documentatiln time looking for a particular result and then discards the rest of the data after the record is found. Use this feature to improve query performance by reducing database access.

This chapter includes the following sections: For this example, the managed persistable class that represents objects in the database is com. EclipseLink lets you quickly capture and define object-to-data source and object-to-data representation mappings in a flexible, efficient metadata format.

The JPA-Coherence-Sample-Code also uses a coherence cache for coordinated data eclilselink in an environment with clustered applications and servers. To configure this, use query eclipseelink “eclipselink. Eclipeslink the documentatin prices match the target prices, they are stored in SaleEvent Coherence cache.

Where appropriate, this documentation provides links to the pertinent section of the specification. EclipseLink lets you quickly capture and define object-to-data source and object-to-data representation mappings in a flexible, efficient metadata format. Understanding EclipseLink Concepts 2.

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Oracle TopLink (EclipseLink) JPA Performance Tuning

Set at the entity level using ReadOnly class annotation. EclipseLink includes support for EJB 3. Learn more about EclipseLink at http: Although this tutorial does not include EclipseLink-specific information, it does contain useful information to help you implement JPA 2.

Using lazy loading and querying the referenced objects using batch fetching or Join is more efficient than Eager loading. It associates doumentation object data member with its data source representation and defines the means of performing the two-way conversion between object and data source.

For more information on using Partioned and other partitioning policy annotations, see “Partitioning Annotations” at http: Leave at default AttributeLevel for best performance. To get performance gains by avoiding the database lookup for objects already in the cache, you can configure that the search attempts to retrieve the required object from the cache first, and then search the data source only if the object is not in the cache.

EclipseLink

Isolation There is not a single tuning parameter that sets a particular database transaction isolation level in a JPA application that uses EclipseLink. Cache Usage By default, all query types search the database first and then synchronize with the cache. Ross Peoples 1 9 Try to avoid entity level cache refresh and instead, consider configuring the following: EclipseLink includes support for EJB 3.

The type is set through the query hint “eclipselink. Configure entities to execute queries in the Coherence data grid instead of the database.