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Allocation of Temporary Segments for Temporary Tables and Indexes (28)

原创 数据库开发技术 作者:tsinglee 时间:2007-09-14 15:58:39 0 删除 编辑

Oracle allocates segments for a temporary table when the first INSERT into that table is issued.
(This can be an internal insert operation issued by CREATE TABLE AS SELECT.) The first
INSERT into a temporary table allocates the segments for the table and its indexes,
creates the root page for the indexes, and allocates any LOB segments.
Segments for a temporary table are allocated in a temporary tablespace of the user
who created the temporary table.
Oracle drops segments for a transaction-specific temporary table at the end of the
transaction and drops segments for a session-specific temporary table at the end of the
session. If other transactions or sessions share the use of that temporary table, the
segments containing their data remain in the table.

1. 临时表在第一次insert into(ctas)时 , Oracle给分配临时段
2. 当事务结束时 , Oracle drops segments for a transaction-specific temporary table.
3. 当会话结束时 , Oracle drops segments for a session-specific temporary table.
4. 有其他事务或者会话共享临时表时 , 临时段依然保留着数据.

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