3. in-memory 相关的视图
v$im_segments , v$im_user_segments
SELECT v.owner, v.segment_name name, v.populate_status status FROM v$im_segments;
4. 如何将objects设置 In-Memory Column Store
我们熟悉的 *_TABLES 视图(比如dba_tables)增加了三个字段:
INMEMORY_PRIORITY, INMEMORY_DISTRIBUTE, and INMEMORY_COMPRESSION
SELECT table_name, cache, inmemory_priority,
inmemory_distribute,inmemory_compression FROM user_tables;
如果查询出来cache字段的值为Y, 那么表示他们被cache在buffer cache中了,但是还没有
被标识为 In-Memory Column Store , 我们可以用如下语句更改:
ALTER TABLE lineorder INMEMORY;
5. INMEMORY_PRIORITY 参数
默认情况下值为NONE, 表示第一次访问这个table的时候,oracle会将这个表放入内存。当然也可以
设置优先级,设置后,数据库开启时,就会按照优先级从HIGH到LOW队列立刻populates the In-Memory
Column Store 。
如果使用alter命令修改这个参数为非默认值,那么DDL操作直到 population 完成才会返回结束。
Alternatively, the priority level can be set, which queues the population of the table
into the In-Memory Column Store immediately. The queue is drained from HIGH to LOW
priority. This is also referred to as “at startup” as Oracle populates the In-Memory
Column Store using this priority queue each time the database starts. If the priority
is set to a non-default value during an alter command then the DDL won’t return until
the population has completed.
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