100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Previously searched by you
Previously searched by you
logo
HW4 Solution University of Michigan EECS 484 $7.99   Add to cart
Quickly navigate to
Preview
  2.  
  3. EECS 484 Database Mgt Syst
  4.  
  5. EECS 484 Database Mgt Syst

Exam (elaborations)

HW4 Solution University of Michigan EECS 484
 78 views  1 purchase
  • Course
  • EECS 484 Database Mgt Syst
  • Institution
  • EECS 484 Database Mgt Syst

Question 1 (20 points) 1.1) (6 points) Block Nested Loops Join (A) Reads = |R| + |S| * ceil(|R|/(B-2)) = 5,000 + 15,000 * ceil(5,000/(800-2)) = 110,000 (B) Writes = 0 (no writes are required for nested loops joins) 1.2) (7 points) Grace Hash Join (A) Reads in Partition phase = |R| + |S| = 20...

[Show more]

Preview 1 out of 3  pages

Document information

  • March 30, 2023
  • 3
  • 2022/2023
  • Exam (elaborations)
  • Questions & answers

Subjects

  • hw4 solution university of michigan eecs 484
  • question 1 20 points 11 6 points block nested loops join a reads |r| |s| ceil|r|b 2 5
  • 000 15
  • 000 ceil5
  • 000800 2 110
  • 000 b

Written for

  • EECS 484 Database Mgt Syst
All documents for this subject (3)

Seller

avatar-seller
ExamsConnoisseur

Reviews received

Content preview

Question 1​ (20 points)

1.1) (6 points)
Block Nested Loops Join
(A) Reads = |R| + |S| * ceil(|R|/(B-2)) = 5,000 + 15,000 * ceil(5,000/(800-2)) = 110,000
(B) Writes = 0 (no writes are required for nested loops joins)

1.2) (7 points)
Grace Hash Join
(A) Reads in Partition phase = |R| + |S| = 20,000
Reads in Probe phase = |R| + |S| = 20,000
Total reads = 2 * (|R| + |S|) = 40,000
(B) Total writes = |R| + |S| = 20,000

1.3) (7 points)
BNJ = 110,000 * 1 [reads; no writes] = 110,000
GHJ = 40,000 * 1 [reads] + 20,000 * X [writes]
From BNJ = GHJ → 110,000 = 40,000 + 20,000 * 3.5,
we get X = 3.5
So we should choose BNJ if X > 3.5, but GHJ if X < 3.5

Question 2​ (20 points)

2.1) (4 points) B - 1 buckets

2.2) (4 points) Recursively apply hash-based projection technique to further split the buckets with
different hash functions until no more partition overflow.

2.3) (4 points) (B - 1)^2 buckets

2.4) (4 points) Accelerate the record matching in memory or reduce CPU cost of record matching.

2.5) (4 points) No. In the probing phase, using the same hash function will assign each data record into
the same bucket. No speeding up for join in the probing phase is obtained by using the same hash
function.

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller ExamsConnoisseur. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for $7.99. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

79223 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 14 years now

Start selling
$7.99  1x  sold
  • (0)
  Add to cart