Yii2模式扫描ALL_OBJECTS而不扫描USER_OBJECTS？

Question

为什么Yii2使用ALL_OBJECTS扫描架构，然后通过OWNER =“owner_name”进行筛选，而不是只扫描USER_OBJECTS？

由于某些原因，扫描ALL_OBJECTS时执行查询需要很长的执行时间（45秒），查询USER_OBJECTS时需要大约2秒。 （生产环境）

SELECT 
    A.COLUMN_NAME, 
    A.DATA_TYPE, 
    A.DATA_PRECISION, 
    A.DATA_SCALE, 
    A.DATA_LENGTH, 
    A.NULLABLE, 
    A.DATA_DEFAULT, 
    COM.COMMENTS AS COLUMN_COMMENT 
FROM ALL_TAB_COLUMNS A 
    INNER JOIN ALL_OBJECTS B ON B.OWNER = A.OWNER AND LTRIM(B.OBJECT_NAME) = LTRIM(A.TABLE_NAME) 
    LEFT JOIN ALL_COL_COMMENTS COM ON (A.OWNER = COM.OWNER AND A.TABLE_NAME = COM.TABLE_NAME AND A.COLUMN_NAME = COM.COLUMN_NAME) 
WHERE 
    A.OWNER = 'owner_name' 
    AND B.OBJECT_TYPE IN ('TABLE', 'VIEW', 'MATERIALIZED VIEW') 
    AND B.OBJECT_NAME = 'object_name' 
ORDER BY A.COLUMN_ID 

由于

Answer 1

有访问ALL_*视图/同义词和USER_*视图/同义词之间的差。

ALL_OBJECTS描述了当前可用的所有对象，而USER_OBJECTS仅列出了属于当前用户的对象。