CHAPTER
10
Storage and File Structure
Practice Exercises
10.1
Answer: This arrangement has the problem that Pi and B4i 3 are on the
same disk. So if that disk fails, reconstruction of B4i 3 is not possible, since
data and parity are both lost.
10.2
Answer
CHAPTER
13
Query Optimization
Practice Exercises
13.1
Show that the following equivalences hold. Explain how you can apply
them to improve the efciency of certain queries:
a.
E 1 1 ( E 2 E 3 ) = ( E 1 1 E 2 E 1 1 E 3 ).
b.
( AG F ( E ) =
c.
( E1 1 E2) =
A
CHAPTER
12
Query Processing
Practice Exercises
12.1
Assume (for simplicity in this exercise) that only one tuple ts in a block
and memory holds at most 3 blocks. Show the runs created on each pass
of the sort-merge algorithm, when applied to sort the foll
CHAPTER
11
Indexing and Hashing
Practice Exercises
11.1
Answer: Reasons for not keeping indices on every attribute include:
Every index requires additional
CPU time and disk I/O overhead
during inserts and deletions.
Indices on non-primary keys might ha
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1
CHAPTER
Introduction
Practice Exercises
1.1
What are the three main purposes of an operating system?
Answer:
The three main puropses are:
To provide an environment for a computer user to execute programs
on computer hardware in a