Storage and File Structure
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.
Show that the following equivalences hold. Explain how you can apply
them to improve the efciency of certain queries:
E 1 1 ( E 2 E 3 ) = ( E 1 1 E 2 E 1 1 E 3 ).
( AG F ( E ) =
( E1 1 E2) =
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
Indexing and Hashing
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
What are the three main purposes of an operating system?
The three main puropses are:
To provide an environment for a computer user to execute programs
on computer hardware in a