Performance Tuning - Question 068.

Which two conditions are necessary for free space in a block to be coalesced automatically? (Choose two.)

A . Free space is not coalesced automatically; it must be done manually.

B . Free space is coalesced automatically on instance startup.

C. An INSERT or UPDATE statement attempts to update a block that has enough free space.

D. The free space in the block is fragmented such that no new rows can fit into contiguous free space.

E . A DELETE statement is issued, and there are noncontiguous rows below the PCTFREE mark.

Explanation:

Answer C and D: Free space within a data block is not coalesced manually, ; it is not coalesced automatically when rows are deleted, or when the instance starts up. Free space within a block is coalesced when there is enough free space (when the block is on the free list), an INSERT or UPDATE occurs, and the free space within the block is fragmented such that the INSERT or UPDATE cannot occur in the block unless coalescing occurs.