Oracle In_memory 中是否需要创建index
对in_memory中存储的数据,不需要手工介入创建Index,每个IMCU header自动创建和管理索引。
官方完整描述如下:
Every IMCU header automatically creates and manages In-Memory Storage Indexes (IM storage indexes) for its CUs. An IM storage index stores the minimum and maximum for all columns within the IMCU.
For example, sales
is populated in the IM column store. Every IMCU for this table has all columns. The sales.prod_id
column is stored in a separate CU within every IMCU. The IMCU header has the minimum and maximum values of each prod_id
CU (and every other CU).
To eliminate unnecessary scans, the database can perform IMCU pruning based on SQL filter predicates. The database scans only the IMCUs that satisfy the query predicate, as shown in the WHERE prod_id > 14 AND prod_id < 29
example in the following graphic.
该案例暂时没有网友评论
✖
案例意见反馈
亲~登录后才可以操作哦!
确定你的邮箱还未认证,请认证邮箱或绑定手机后进行当前操作