Principles Of Distributed Database Systems Exercise Solutions Portable < VERIFIED ✦ >
Site 1 (R) Site 2 (S) │ │ │ ─── 1. Send Project(R, A) [1,000 bytes] ─────> │ │ │ Reduce S to S' │ │ using Projection │ <── 2. Send Reduced S' [200,000 bytes] ─────── │ ▼ ▼ Project attribute from relation at Site 1, and send it to Site 2.
Upon restart, coordinator sends COMMIT to P3 (if decision logged). If no decision logged and some participant already committed (via unilateral decision), P3 must commit → but this violates 2PC’s blocking property? Actually, 2PC can block if coordinator crashes without decision. That’s why 3PC is non-blocking.
Reconstruction Formula: R=R1∪R2∪R3Reconstruction Formula: cap R equals cap R sub 1 union cap R sub 2 union cap R sub 3 If a data item occurs in fragment Ricap R sub i , it must not appear in any other fragment Rjcap R sub j
A global deadlock detector aggregates local graphs into a single unified view. By superimposing the edges of all LWFGs, we construct the GWFG: Site 1 (R) Site 2 (S) │ │ │ ─── 1
One of the first challenges in a distributed environment is deciding how to split data (fragmentation) and where to put it (allocation). Horizontal vs. Vertical Fragmentation
LWFG (Site 2): T1→T2LWFG (Site 2): cap T sub 1 right arrow cap T sub 2 Global Wait-For Graph (GWFG)
This article serves as a guide to solving these critical exercises, breaking down key chapters, key concepts, and providing practical approaches to exercise solutions. 1. Introduction to Distributed Database Concepts Actually, 2PC can block if coordinator crashes without
Strategy B (Semi-join) reduces network traffic from 400,000 bytes to 88,000 bytes, making it the optimal choice. 3. Distributed Concurrency Control Distributed Deadlock Detection
Horizontal partitioning divides a relation into tuples based on specific predicates.
: Draw a timeline. For T/O, always compare the transaction’s timestamp with the Read-TS and Write-TS of the data item. For 2PL, check lock compatibility matrices and ensure no lock release before the end of the transaction. By superimposing the edges of all LWFGs, we
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?
The lowest level. The user must specify both the exact fragment and the precise physical location/local DBMS syntax to access the data.
"Can a system be CA (Consistent and Available) during a network partition?"
This ensures that the transaction is executed atomically and consistently across both nodes.
Search GitHub for "Özsu Valduriez solutions." Several graduate students have uploaded their worked-out LaTeX solutions for the 3rd and 4th editions. Publisher Resources: