RethinkDB 2.2.0 发布，分布式数据库

渡人自渡

12月12日北京OSC源创会 —— 开源技术的年终盛典 »  
　　RethinkDB 2.2.0 发布，此版本引入了 atomic changefeeds，包含从数据库到 changefeed 结果的现有值，可以原子转换到流更新。
　　Atomic changefeeds 使得动态构建实时应用更简单：用户可以使用单个代码路径来填充应用的初始数据，并且继续接收实时数据更新。这大大提升了系统的性能，改进了系统伸缩性，提升 RethinkDB 集群大小。
　　详细改进请看发行说明。
兼容性
　　RethinkDB 1.16 以上版本可以自动迁移，但是升级之前需要备份好数据。
　　如果是 RethinkDB 1.14.x 或者 1.15.x 升级，需要先迁移二级索引：

• 　　安装 RethinkDB 2.0.5.
  
• 　　更新 RethinkDB Python 驱动 (sudo pip install 'rethinkdb<2.1.0').
  
• 　　重建索引： rethinkdb index-rebuild.
  

　　RethinkDB 1.13 及以下版本，用户需要手动使用： rethinkdb dump 升级

API 不兼容改进

• 　　Changefeeds on .orderBy.limit as well as .get queries previously providedinitial results by default. You now need to include the optional argumentincludeInitial: true to .changes to achieve the same behavior.
  
• 　　The deprecated protocol buffer driver protocol is no longer supported. The newer JSONprotocol is now the only supported driver protocol. Older drivers using the deprecatedprotocol no longer work with RethinkDB 2.2.0. See the drivers list forup-to-date drivers.
  
  
  
  • 　　If you're using Java, please note that at the time of writing, existing communitydrivers have not been updated to use the newer JSON protocol. However, anofficial Java driver is in active development and will be availablesoon.
    
  
  
• 　　Certain argument errors that used to throw ReqlDriverError exceptions now throwReqlCompileError exceptions. See #4669 for a full list of changes.
  

支持的版本
　　RethinkDB 2.2.0 提供 Ubuntu 15.10 (Wily Werewolf) 和 CentOS 7 官方包，不再提供 Ubuntu 10.04 (Lucid Lynx) 包。

新特性

• 　　Added full support for atomic changefeeds through the include_initial optarg (#3579)
  
• 　　Added a values command to obtain the values of an object as an array (#2945)
  
• 　　Added a conn.server command to identify the server for a given connection (#3934)
  
• 　　Extended r.uuid to accept a string and work as a hash function (#4636)
  

改进

• 　　Server
  
  
  
  • 　　Improved the scalability of range queries on sharded tables (#4343)
    
  • 　　Improved the performance of between queries on secondary indexes (#4862)
    
  • 　　Reduced the memory overhead for large data sets (#1951)
    
  • 　　Redesigned the internal representation of queries to improve efficiency (#4601)
    
  • 　　Removed the deprecated protocol buffer driver protocol (#4601)
    
  • 　　Improved the construction of secondary indexes to make them resumable and to reducetheir impact on any production workload (#4959)
    
  • 　　Improved the performance when using getAll with a secondary index in some edge cases(#4948)
    
  • 　　Removed the limit of 1024 concurrent changefeeds on a single connection (#4732)
    
  • 　　Implemented automatically growing coroutine stacks to avoid stack overflows (#4462)
    
  • 　　Optimized the deserialization of network messages to avoid an extra copy (#3734)
    
  • 　　Added a raft_leader field to a table's status to expose its current Raft leader(#4902)
    
  • 　　Made the handling of invalid lines in the 'logs' system table more robust (#4929)
    
  
  
• 　　ReQL
  
  
  
  • 　　indexStatus now exposes the secondary index function (#3231)
    
  • 　　Added an optarg called changefeed_queue_size to specify how many changes the servershould buffer on a changefeed before generating an error (#3607)
    
  • 　　Extended branch to accept an arbitrary number of conditions and values (#3199)
    
  • 　　Strings can now contain null characters (except in primary keys) (#3163)
    
  • 　　Streams can now be coerced directly to an object (#2802)
    
  • 　　Made coerceTo('BOOL') consistent with branch (#3133)
    
  • 　　Changefeeds on filter and map queries involving geospatial terms are now allowed(#4063)
    
  • 　　Extended or and and to accept zero arguments (#4132)
    
  
  
• 　　Web UI
  
  
  
  • 　　The Data Explorer now allows executing only parts of a query be selecting them (#4814)
    
  
  
• 　　All drivers
  
  
  
  • 　　Improved the consistency of ReQL error types by throwing ReqlCompileError ratherthan ReqlDriverError for certain errors (#4669)
    
  
  
• 　　JavaScript driver
  
  
  
  • 　　Added an eachAsync method on cursors that behaves like each but also returns apromise (#4784)
    
  
  
• 　　Python driver
  
  
  
  • 　　Implemented an API to override the default JSON encoder and decoder (#4825, #4818)
    
  
  

Bug 修复

• 　　Server
  
  
  
  • 　　Fixed a segmentation fault that could happen when disconnecting a server whilehaving open changefeeds (#4972)
    
  • 　　Updated the description of the --server-name parameter in rethinkdb --help (#4739)
    
  • 　　Fixed a crash with the message &quot;Guarantee failed: [ts->tv_nsec >= 0 &&ts->tv_nsec < (1000LL * (1000LL * 1000LL))] &quot; (#4931)
    
  • 　　Fixed a problem where backfill jobs didn't get removed from the 'jobs' table (#4923)
    
  • 　　Fixed a memory corruption that could trigger a segmentation fault duringgetIntersecting queries (#4937)
    
  • 　　Fixed an issue that could stop data files from RethinkDB 1.13 from migrating properly(#4991)
    
  • 　　Fixed a &quot;Guarantee failed: [pair.second] key for entry_t already exists&quot; crash whenrapidly reconnecting servers (#4968)
    
  • 　　Fixed an &quot;Uncaught exception of type interrupted_exc_t&quot; crash (#4977)
    
  • 　　Added a check to catch r.minval and r.maxval values when writing to the'_debug_scratch' system table (#4032)
    
  
  
• 　　ReQL
  
  
  
  • 　　Fixed the error message that's generated when passing in a function with the wrongarity (#4189)
    
  • 　　Fixed a regression that caused r.asc(&quot;test&quot;) to not fail as it should (#4951)
    
  
  
• 　　JavaScript driver
  
  
  
  • 　　Object keys in toString are now properly quoted (#4997)
    
  
  

　　下载：https://github.com/rethinkdb/rethinkdb/archive/v2.2.0.zip

　　RethinkDB 设计用来存储 JSON 文档的分布式数据库，可通过简单操作实现多机分布式存储。支持表的联合和分组查询。