Principles Of Distributed Database Systems Exercise Solutions May 2026

Official exercise solutions for Principles of Distributed Database Systems

• Completeness: Every assignment belongs to a project. Since the set of projects $PROJ_1 \cup PROJ_2$ covers all projects, every assignment tuple will find a match.
• Disjointness: Assuming a project exists at only one site, an assignment belongs to exactly one project, thus appearing in only one fragment.

She flipped to Chapter 9: Global Commit Protocols. Exercise 9.4 read: Completeness: Every assignment belongs to a project

• Compute $R' = R \ltimes S$.
• Let's assume selectivity is 10% (only 100 tuples of $R$ match $S$).
• $R'$ size = $100 \text tuples \times 100 \text bytes = 10,000 \text bytes$.

A distributed database system is a collection of multiple databases that are connected through a network, allowing users to access and share data across different locations. The main goals of a distributed database system are: She flipped to Chapter 9: Global Commit Protocols

Step 1 (Detect): Run a distributed diff on the write-ahead logs of all 23 nodes. Find the anomaly: transaction #A442. 000 \text bytes$.

In distributed exercises, you'll often encounter the Centralized 2PL vs. Distributed 2PL debate.

Comparison:

Solution: We construct the Local Wait-For Graphs (LWFG) and combine them into a Global Wait-For Graph (GWFG).