当设置RESULT_CACHE_MAX_SIZE参数并且重启过database后，Query Result Cache 还是被禁用的。

来源于：

Query Result Cache is disabled After Setting RESULT_CACHE_MAX_SIZE And Restarting The Database (文档 ID 460581.1)

适用于：

Oracle Server - Standard Edition - Version: 11.1.0.6 to 11.1.0.6

This problem can occur on any platform.

症状：

The RESULT_CACHE_MAX_SIZE parameter is zero after the restart although it was set to a non zero value in the spfile. The Query Result Cache feature is disabled when the parameter is set to 0.

原因：

This is happening on Standard Edition installations. The Query Result Cache feature is available in Oracle Enterprise Edition only.

查询结果缓存是Oracle database 企业版的特性

解决方案：

Install Oracle Enterprise Edition if this feature is needed.