Exam 1z0-062 topic 1 question 309 discussion

Actual exam question from Oracle's 1z0-062

Question #: 309
Topic #: 1

You create a locally managed tablespace ORDERS_TBS with automatic segment management.
You then create the table DAILY_ORDS_LST in the ORDERS_TBS tablespace using the command.
CREATE TABLE daily_ords_1st(ordno NUMBER, ord_date DATE) PCTFREE 20;
How does the PCTFREE storage parameter influence data storage for this table?

A. It allows only 80% of space to be occupied in all data blocks of this table.
B. It minimizes row chaining during row insertion.
C. It minimizes row migration during existing row data updation.
D. It automatically coalesces free space of a data block when it reaches 20% of available space.

Show Suggested Answer

Suggested Answer: A 🗳️

by Dule123 at Oct. 1, 2020, 12:32 p.m.

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Dule123

Highly Voted 4 years, 8 months ago

Answer is C

upvoted 11 times

yosiw96816

4 years, 5 months ago

upvoted 2 times

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jackymak

3 years, 2 months ago

I agree that is C now. PCTFREE will not limited the data block usage below 80%. It will move to next data block when it reach 80% used. I mean you can make the data block usage exceed 80% by update the row, so it is not A. However, It reserve 20% for the updated which make a cushion for row migration.

upvoted 1 times

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DANG257315

Highly Voted 4 years, 5 months ago

Answer A: The PCTFREE parameter sets the minimum percentage of a data block to be reserved as free space for possible updates to rows that already exist in that block. https://docs.oracle.com/cd/B19306_01/server.102/b14220/logical.htm

upvoted 5 times

katetel

3 years, 9 months ago

so, the question is 'PCTFREE storage parameter influence'. a is correct

upvoted 1 times

katetel

3 years, 9 months ago

sorry, the answer is c, yosiw96816 is right

upvoted 2 times

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Ray520

Most Recent 3 years ago

Selected Answer: C

The PCTFREE SQL parameter sets the minimum percentage of a data block reserved as free space for updates to existing rows. PCTFREE is important for preventing row migration and avoiding wasted space. While the percentage of free space cannot be less than PCTFREE, the amount of free space can be greater. For example, setting PCTFREE to 20% prevents the total amount of free space from dropping to 5% of the block, but allows 50% of the block to be free. option A is not entirely correct as during DML operations, the free space is used for the transaction, so technically, 80% only full is not always right.

upvoted 1 times

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Ray520

3 years ago

The PCTFREE SQL parameter sets the minimum percentage of a data block reserved as free space for updates to existing rows. PCTFREE is important for preventing row migration and avoiding wasted space.

upvoted 1 times

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NorwayOracle

3 years, 1 month ago

Selected Answer: C

The PCTFREE storage parameter specifies the percentage of each data block that is to be kept free for future updates that might expand the rows stored in that block. This parameter also can be used to control the number of rows that reside in a block.

upvoted 1 times

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