166.View the Exhibit and examine the setting for a table. Which statement is true about the PCTFR
2016-08-07 18:03
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166.View the Exhibit and examine the setting for a table.
Which statement is true about the PCTFREE setting for the table?
A.It sets the minimum percentage of a data block to be reserved to contain chained rows from other blocks.
B.It sets the minimum percentage of a data block to be reserved as free space before the server prevents inserts into the block.
C.It sets the minimum percentage of a data block to be reserved to contain the bitmap used to maintain the free block information.
D.It sets the minimum percentage of a block that can be used for row data plus overhead before new rows are added to the block.
答案:B
解析:
PCTFREE 指的是为一个块保留的空间百分比,也就是什么情况下可以insert,保留它的目的其实是为了给update保留空间,防止发生行迁移
A:错误,不是为了行链接
B:正确
C:错误,不是为了位图
D:错误
Which statement is true about the PCTFREE setting for the table?
A.It sets the minimum percentage of a data block to be reserved to contain chained rows from other blocks.
B.It sets the minimum percentage of a data block to be reserved as free space before the server prevents inserts into the block.
C.It sets the minimum percentage of a data block to be reserved to contain the bitmap used to maintain the free block information.
D.It sets the minimum percentage of a block that can be used for row data plus overhead before new rows are added to the block.
答案:B
解析:
PCTFREE 指的是为一个块保留的空间百分比,也就是什么情况下可以insert,保留它的目的其实是为了给update保留空间,防止发生行迁移
A:错误,不是为了行链接
B:正确
C:错误,不是为了位图
D:错误
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