Given:
R = 10,000 tuples, S = 50,000 tuples. Hash function partitions data into 10 buckets. Each site sends its bucket to a single join site. Network cost = 1 per tuple. Local join cost negligible.
Question: Compute total network cost.
Solution:
If hash partitioning already aligned with join site:
Each tuple of R and S sent exactly once to join site → cost = 10,000 + 50,000 = 60,000.
If data is initially distributed across sites and must be repartitioned:
Better is to perform parallel hash join: each site joins locally on its own bucket after exchanging only needed buckets (cost = same total data volume). So 60,000 is correct.
Problem:
Social media app: user profile update (need immediate consistency across all followers’ caches) vs. “like” counter (can be eventually consistent). Which replication strategy for each?
Solution:
Answer:
Profile update → eager replication (strong consistency). Like counter → lazy replication (eventual consistency).
Exercises often present a schedule of operations across sites and ask: Is this schedule serializable under 2PL (Two-Phase Locking) or T/O (Timestamp Ordering)? Given: R = 10,000 tuples, S = 50,000 tuples
Given:
Three fragments F1, F2, F3; two sites S1, S2.
Read frequencies (per second):
Question: Find an allocation minimizing total cost.
Solution:
Cost for a fragment at site j = sum over all sites i of (read_freq(i,j)*remote_read_cost + update_freq(i,j)*remote_update_cost).
For F1:
For F2: symmetric cost 100 if at S1 or S2 → either site is optimal.
For F3:
Solving exercises in Distributed Database Systems requires a shift in perspective from local optimization to global system coordination. Better is to perform parallel hash join: each
Official exercise solutions for the textbook "Principles of Distributed Database Systems" by M. Tamer Özsu and Patrick Valduriez are primarily reserved for instructors who teach courses using the book. However, select resources and examples of specific solutions are available through academic platforms and institutional sites. Official Instructor Resources
Access to the full, authorized solution manual is typically restricted to educators to maintain the integrity of student assessments:
Official Book Site: The Principles of Distributed Database Systems site notes that solutions are only available to verified instructors.
Requesting Access: If you are an instructor, you can often request these materials directly from the publisher or through the University of Waterloo CS faculty portal. Publicly Accessible Solution Samples
For students looking for practice or specific problem breakdowns, some chapters and problems have been shared online:
Fragmentation Exercise (Ch 3): A detailed solution for Primary Horizontal Fragmentation (Exercise 3.2) is available, illustrating how to derive minterm predicates for distributed design.
Technical Summaries: Platforms like GitHub host community-generated study notes that summarize key principles like CSMA/CD, network topologies (Bus, Star, Ring, Mesh), and data distribution strategies. Problem: Social media app: user profile update (need
Assignment Banks: Academic sites like Scribd and Course Hero often host student-uploaded assignments and partial solution sets covering query processing and concurrency control. Key Concepts Covered in Exercises
Most solutions focus on the following foundational distributed principles:
Fragmentation & Allocation: Dividing relations into horizontal or vertical fragments and placing them across nodes.
Transparency: Exercises often ask to define or apply levels of transparency (location, fragmentation, replication).
Distributed Transactions: Implementation of ACID properties (Atomicity, Consistency, Isolation, Durability) across multiple sites.
Concurrency Control: Managing simultaneous data access using distributed locking or timestamp ordering.
Query Optimization: Calculating the cost of moving data versus local processing for global queries.
Are you working on a specific chapter or exercise number from the book that you need help with? Principles of Distributed Database Systems, Third Edition