Operating System
📌 Java environment:
java -version
# (on MacOS)
# java version "21.0.4" 2024-07-16 LTS
# Java(TM) SE Runtime Environment (build 21.0.4+8-LTS-274)
# Java HotSpot(TM) 64-Bit Server VM (build 21.0.4+8-LTS-274, mixed mode, sharing)
# (on OSU coelinux)
# openjdk version "20.0.2" 2023-07-18
# OpenJDK Runtime Environment (build 20.0.2+9-78)
# OpenJDK 64-Bit Server VM (build 20.0.2+9-78, mixed mode, sharing)-
- myAnswer
- Reference1: https://medium.com/@reetesh043/java-wait-notify-and-notifyall-methods-3d3b511bd3ae
- Reference2: https://stackoverflow.com/questions/5887709/getting-random-numbers-in-java
- Reference3: https://wangwilly.github.io/willywangkaa/2018/07/10/Operating-System-Process-Synchronization/
- Reference4: https://wangwilly.github.io/willywangkaa/2018/08/04/Operating-System-Process-Synchronization-2/
- Reference5: https://www.geeksforgeeks.org/static-variables-in-java-with-examples/
-
Lab 1
- Execute:
./scripts/runLab1.sh Database - Debug:
DEBUG=true ./scripts/debugLab1.sh Database
- Execute:
./scripts/runLab1.sh Database1 ./testcases/lab1/db1_test1.txt
./scripts/runLab1.sh Database2 ./testcases/lab1/db2_test1.txtTest case format:
Read
<TxId> R <RowId>
Write
<TxId> W <RowId> <Value>
Prompt: Since all rows are known before executing a transaction, you should be able to avoid the deadlock problem.
- ❌ Deadlock Detection: Regularly check for cycles in the resource allocation graph and abort transactions to break deadlocks.
- 🚧 Deadlock Prevention: Ensure that the system will never enter a deadlock state.
- Hold and Wait: Require processes to request all resources at once and prevent them from requesting additional resources while holding resources.
- (For 2-phase locking) Lock all resources before starting the transaction by ordering the resources and requesting them in order.
- Implement the history of operations in the database.
- Compute the serialization graph of the transactions from the history.
- Enumerate all possible serial schedules.
- Use flow algorithms to find a serial schedule from the serialization graph.