根据metalink文档<ANNOUNCEMENT: Deprecating the cursor_sharing = ‘SIMILAR’ setting [ID 1169017.1]>在11g中将逐渐废弃cursor_sharing参数的SIMILAR选项，原因是在今后的版本中Exact和Force选项可以满足游标共享的需求了，使用SIMILAR选项可能引发额外的version_count过多或cursor pin s on X等待事件。
| We recommend that customers discontinue setting cursor_sharing = SIMILAR due to the many problematic situations customers have experienced using it. The ability to set this will be removed in |
本文转自maclean_007 51CTO博客，原文链接:http://blog.51cto.com/maclean/1277836
