Question

我遇到了一个关于OCA考试的问题，问题是：

Select the true statments about space managemnt:

a. Segment creation in oracle database 12c is deffered for all tables. There are no exeptions.
b. All UNUSABLE indexes and index partitions are created without a segment.
c. Shrinking segments space is a nonresumable operation.
d. You can set thresholds by tablespace.

Answer (according to oracle book): b, d

我无法理解为什么第三点（收缩段空间是不可恢复的操作）不是答案。取决于oracle docs https://docs.oracle.com/cd/B28359_01/server.111/b28310/schema002.htm#ADMIN11582

The resumable operation are:

-Queries
SELECT statements that run out of temporary space (for sort areas) are candidates for resumable execution. When using OCI, the calls OCIStmtExecute() and OCIStmtFetch() are candidates.

-DML
INSERT, UPDATE, and DELETE statements are candidates. The interface used to execute them does not matter; it can be OCI, SQLJ, PL/SQL, or another interface. Also, INSERT INTO...SELECT from external tables can be resumable.

-Import/Export
As for SQL*Loader, a command line parameter controls whether statements are resumable after recoverable errors.

-DDL
The following statements are candidates for resumable execution:

CREATE TABLE ... AS SELECT
CREATE INDEX
ALTER INDEX ... REBUILD
ALTER TABLE ... MOVE PARTITION
ALTER TABLE ... SPLIT PARTITION
ALTER INDEX ... REBUILD PARTITION
ALTER INDEX ... SPLIT PARTITION
CREATE MATERIALIZED VIEW
CREATE MATERIALIZED VIEW LOG

有人可以解释一下为什么情况就是这样。

感谢。

Answer 1

取决于@BarbarosÖzhan的研究，以及“OCA：Oracle数据库12c管理员认证助理学习指南......由Biju Thomas撰写”一书“1101”答案编号“14”，听起来如下：

ALTER TABLE ... SHRINK SPACE不会创建任何新的范围，也不会恢复。

这表明，OCA考试问题的答案是错误的。

缩小的段空间是不可恢复的操作？

1 个答案: