Computer Engineering - Data Bases 2

Full exam

Databases 2 - exam - February 5, 2025 -Dur. 2h S. Comai, P. Fraternali, D. Martinenghi A. Concurrency control (11 points) Consider a distributed system with three nodes (A, B, C) with the following wait-for conditions: NODE A:E B→ t 4; t 4→ t 7; t 7→ t 5; t 5→ E C NODE B:E C→ t 1; t 1→ t 3; t 3→ t 2; t 3→ t 4; t 4→ E A NODE C:E A→ t 5; t 5→ t 6; t 6→ t 8; t 6→ t 1; t 1→ E B Apply the Obermarck algorithm and determine if a deadlock is detected, under the two following conventions:(1)A node X transmits to a downstream node Y the arct j→ t iif j>i. (4 points) (2)A node X transmits to a downstream node Y the arct j→ t iif j