OCP-1Z0-052-V8.02-166题

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.

Answer: B

答案解析：

默认的PCTFREE 为10%，意味着在一个数据块里至少有10%的空闲空间，如果插入的数据或者更新的数据让数据块的空闲空间少于10%，则会插入或更新到另一个数据块里。

PCTFREE integer

Specify a whole number representing the percentage of space in each data block of the database object reserved for future updates to rows of the object. The value ofPCTFREE must be a value from 0 to 99. A value of 0 means that the entire block can be filled by inserts of new rows. The default value is 10.This value reserves 10% of each block for updates to existing rows and allows inserts of new rows to fill a maximum of 90% of each block.