Apache Solr 4.0 Alpha 发布

   <p><a href="/misc/goto?guid=4958186452675297062" target="_blank">Solr</a>是一个高性能，采用Java5开发，基于Lucene的全文搜索服务器。文档通过Http利用XML加到一个搜索集合中。查询该集合也是通过 http收到一个XML/JSON响应来实现。它的主要特性包括：高效、灵活的缓存功能，垂直搜索功能，高亮显示搜索结果，通过索引复制来提高可用性，提 供一套强大Data Schema来定义字段，类型和设置文本分析，提供基于Web的管理界面等。<br /> <br /> Apache Solr 4.0 Alpha 发布了，该版本主要是对应 Lucene 4.0 alpha 发布而发布，详细改进记录：</p>    <pre>3 July 2012, Apache Solr™ 4.0-alpha available  The Lucene PMC is pleased to announce the release of Apache Solr 4.0-alpha.    Solr is the popular, blazing fast, open source NoSQL search platform from  the Apache Lucene project. Its major features include powerful full-text  search, hit highlighting, faceted search, dynamic clustering, database  integration, rich document (e.g., Word, PDF) handling, and geospatial search.  Solr is highly scalable, providing fault tolerant distributed search  and indexing,  and powers the search and navigation features of many of the world's  largest internet sites.    Solr 4.0-alpha is available for immediate download at:     http://lucene.apache.org/solr/mirrors-solr-latest-redir.html?ver=4.0a    See the CHANGES.txt file included with the release for a full list of  details.    Solr 4.0-alpha Release Highlights:    The largest set of features goes by the development code-name “Solr  Cloud” and involves bringing easy scalability to Solr.  See  http://wiki.apache.org/solr/SolrCloud for more details.   * Distributed indexing designed from the ground up for near real-time  (NRT) and NoSQL features such as realtime-get, optimistic locking, and  durable updates.   * High availability with no single points of failure.   * Apache Zookeeper integration for distributed coordination and  cluster metadata and configuration storage.   * Immunity to split-brain issues due to Zookeeper's Paxos distributed  consensus protocols.   * Updates sent to any node in the cluster and are automatically  forwarded to the correct shard and replicated to multiple nodes for  redundancy.   * Queries sent to any node automatically perform a full distributed  search across the cluster with load balancing and fail-over.    Solr 4.0-alpha includes more NoSQL features for those using Solr as a  primary data store:   * Update durability – A transaction log ensures that even uncommitted  documents are never lost.   * Real-time Get – The ability to quickly retrieve the latest version  of a document, without the need to commit or open a new searcher   * Versioning and Optimistic Locking – combined with real-time get,  this allows read-update-write functionality that ensures no  conflicting changes were made concurrently by other clients.   * Atomic updates -  the ability to add, remove, change, and increment  fields of an existing document without having to send in the complete  document again.    There are many other features coming in Solr 4, such as   * Pivot Faceting – Multi-level or hierarchical faceting where the top  constraints for one field are found for each top constraint of a  different field.   * Pseudo-fields – The ability to alias fields, or to add metadata  along with returned documents, such as function query values and  results of spatial distance calculations.   * A spell checker implementation that can work directly from the main  index instead of creating a sidecar index.   * Pseudo-Join functionality – The ability to select a set of  documents based on their relationship to a second set of documents.   * Function query enhancements including conditional function queries  and relevancy functions.   * New update processors to facilitate modifying documents prior to indexing.   * A brand new web admin interface, including support for SolrCloud.    This is an alpha release for early adopters. The guarantee for this  alpha release is that the index  format will be the 4.0 index format, supported through the 5.x series  of Lucene/Solr, unless there  is a critical bug (e.g. that would cause index corruption) that would  prevent this.    Please report any feedback to the mailing lists  (http://lucene.apache.org/solr/discussion.html)    Happy searching,    Lucene/Solr developers</pre>    <p></p>    <p> </p>