WiredTiger 3.0.0 发布，MongoDB 存储引擎

MongoDB 存储引擎已发布 WiredTiger 3.0.0 版本，新版本移除了对 wtstats 的支持、修改了日志文件格式以记录先前的 LSN 记录，此外还包含很多其他的 bug 修复和变更。

详细更新如下：

• WT-3039 Change the log file format to record a previous LSN record
• WT-3181 Add support for application defined transaction IDs via a mechanism called timestamps.
• WT-3310 Add support to WT_SESSION::alter to change table log setting
• WT-3389 Restructure page split code to hold a split generation for the entire operation.
• WT-3406 Fix a bug in reconciliation so that it ignores concurrent updates.
• WT-3418 Fix a block manager race in tree close/open
• WT-3435 Improvements to the cache overflow mechanism aka lookaside
• WT-3437 Improvements to auto tuning of number of eviction workers
• WT-3440 Add a log record when starting a checkpoint.
• WT-3461 Avoid hangs when system clocks move backwards by using CLOCK_MONOTONIC for pthread_cond_timedwait if possible.
• WT-3490 Fix a bug in WT_CURSOR.modify unaligned size_t access.
• WT-3495 Fix a bug so we don’t ftruncate if log cursors are open
• WT-3497 Improve logging message when hitting the configured session limits
• WT-3537 Split pages in memory when nothing can be written
• WT-3556 Remove wtstats support
• WT-3681 Change recovery so that it doesn’t truncate the last log file
• WT-3683 Allow eviction of clean pages with history when cache is stuck
• WT-3710 Get a page-level lock to ensure page splits are single threaded
• WT-3752 Allow trimming of obsolete modify updates.

查看 JIRA 更新日志以了解全部更新列表：https://jira.mongodb.org/projects/WT/versions/18401

有关 api 和行为更改的详细信息，请参阅升级文档，点此查看完整更新日志。

源码下载：

• wiredtiger-3.0.0.tar.bz2
• Source code (zip)
• Source code (tar.gz)

转自 http://www.oschina.net/news/92425/wiredtiger-3-0-0-released