What is a deadlock in the context of concurrency control?
- A state where a database is locked for maintenance
- A state where a transaction is unable to acquire the necessary locks to proceed
- A state where transactions are executed in parallel without conflicts
- A state where two or more transactions are waiting indefinitely for each other to release locks
A deadlock occurs when two or more transactions are waiting indefinitely for each other to release locks, leading to a situation where none of the transactions can proceed. Deadlocks must be resolved to allow the system to continue processing transactions.
In Git, a "conflict" occurs when the changes in two branches are _______.
- Identical
- Incompatible
- Independent
- Synchronized
In Git, a "conflict" occurs when the changes in two branches are Incompatible. This happens when Git can't automatically merge changes due to conflicting modifications in the same lines of code. Resolving conflicts is necessary before completing the merge or rebase.
What is the key difference between hot and cold backups in backup strategies?
- Cold backups are less reliable
- Cold backups require the system to be offline
- Hot backups are slower than cold backups
- Hot backups are taken while the system is running
The key difference between hot and cold backups lies in the system's operational state during the backup process. Hot backups are taken while the system is running, ensuring continuous availability, while cold backups require the system to be offline, providing a consistent state but causing downtime.
Which JavaScript framework is widely used for building scalable and maintainable web applications, featuring two-way data binding?
- Angular
- Ember.js
- React
- Vue.js
Angular is a JavaScript framework known for building scalable and maintainable web applications. It features two-way data binding, allowing automatic synchronization of data between the model and the view.
Google Cloud Platform's _______ service provides managed NoSQL databases.
- Cloud SQL
- Cloud Spanner
- Cloud Storage
- Firestore
Google Cloud Platform's Firestore service provides managed NoSQL databases. Firestore is a flexible, scalable, and serverless document database that supports real-time updates and seamless integration with other Google Cloud services.
_______ testing involves checking the code for potential security vulnerabilities.
- Integration
- Penetration
- Security
- Unit
Penetration testing involves checking the code for potential security vulnerabilities. It is a proactive approach to identifying and addressing security issues in software applications.
What is the purpose of a data structure?
- Controlling access to a database
- Executing instructions in a computer program
- Organizing and managing data efficiently
- Representing colors in digital images
The purpose of a data structure is to organize and manage data efficiently. It involves storing, retrieving, and manipulating data in a way that facilitates effective algorithms and operations.
What status code is returned by a RESTful API to indicate a successful request?
- 200 OK
- 201 Created
- 404 Not Found
- 500 Internal Server Error
The status code returned by a RESTful API to indicate a successful request is 200 OK. This status code indicates that the request was successful, and the server has fulfilled the client's request.
A company needs to handle large volumes of semi-structured data. Which type of database would you recommend, and why?
- Both SQL and NoSQL
- It depends on the specific requirements
- NoSQL
- SQL
When dealing with large volumes of semi-structured data, a NoSQL database is recommended. NoSQL databases can handle flexible schema designs, making them suitable for semi-structured data like JSON or XML.
Your company's database is experiencing slow query performance during peak usage hours. How would you troubleshoot and optimize the queries to maintain optimal performance levels?
- Analyze query logs and execution times, Identify and resolve blocking queries, Optimize database indexes, Consider query caching
- Backup and restore the entire database, Optimize only the most frequently used queries, Ignore query logs, Add more indexes without analysis
- Disable query caching, Increase server memory, Use NoSQL instead of SQL, Optimize the network configuration
- Reboot the database server, Purge all old records, Increase the database security, Change the database schema
Troubleshooting slow query performance involves analyzing query logs, execution times, and identifying/resolving blocking queries. Optimizing indexes and considering query caching are effective strategies to maintain optimal performance during peak hours.