10+ Amazon MX Player Interview Questions and Answers

To delete 95,000 records with limited local memory, use batch processing and delete in chunks.

• Use batch processing to delete records in chunks

• Delete records in descending order of their IDs to avoid index fragmentation

• Commit the transaction after deleting each batch to avoid long-running transactions

• Consider archiving the deleted records instead of permanently deleting them

Wait for completion of all threads and join them into a single thread.

• Use join() method to wait for completion of each thread.

• Create a new thread and call start() method to start the execution of all threads.

• Use sleep() method to pause the execution of the current thread until all threads complete their execution.

Merge sort algorithm can be used to sort the balls in each basket and then merge the sorted baskets.

• Apply merge sort algorithm to sort the balls in each basket

• Merge the sorted baskets to get the final sorted order

• Use recursion to implement merge sort

• Time complexity of merge sort is O(nlogn)

Program in C to implement a function 'sum' that performs integer addition, float addition, and string concatenation based on the input arguments.

• Define the function 'sum' with two arguments of type 'void *'.

• Use 'if-else' statements to check the data type of the arguments.

• Perform integer addition if both arguments are of type 'int'.

• Perform float addition if both arguments are of type 'float'.

• Concatenate the strings if both arguments are of type 'char *'.

• Return the result of th...read more

Multithreading is the ability of a CPU to execute multiple threads concurrently. A process is an instance of a program in execution.

• Multithreading allows multiple threads to run concurrently within a single process.

• Threads share the same memory space and resources of the process they belong to.

• Processes are independent of each other and have their own memory space and resources.

• Threads are lightweight compared to processes and have less overhead.

• Examples of multithreading inc...read more

SQL query for creating tables

• Use CREATE TABLE statement

• Specify table name and column names with data types

• Add constraints like primary key, foreign key, etc.

• Example: CREATE TABLE customers (id INT PRIMARY KEY, name VARCHAR(50), email VARCHAR(50))

Mutual Exclusion is a technique to ensure that only one process at a time can access a shared resource.

• It prevents race conditions and ensures data consistency.

• It can be implemented using locks, semaphores, or monitors.

• Examples include critical sections in multi-threaded programs and database transactions.

• It can lead to performance issues if not implemented efficiently.

Nested tables are tables within tables, used to organize and store complex data structures.

• Nested tables are commonly used in databases to store arrays of data within a single row of a table.

• They can also be used in programming languages to create multidimensional arrays.

• Accessing data within a nested table requires using multiple levels of indexing.

• Nested tables can improve data organization and simplify complex data structures.

Semaphore is a synchronization object used to control access to a shared resource.

• Semaphore is used to limit the number of threads accessing a shared resource.

• It can be used to implement critical sections and avoid race conditions.

• Semaphore can be binary or counting, depending on the number of resources available.

• Examples of semaphore in programming languages include Java's Semaphore class and Python's threading.Semaphore.

Views are virtual tables that display data from one or more tables in a database.

• Views are created using SELECT statements.

• They can be used to simplify complex queries.

• They can also be used to restrict access to sensitive data.

• Views do not store data themselves, but rather display data from underlying tables.

• Changes made to the underlying tables are reflected in the view.

Postfix expression can be evaluated using a stack data structure.

• Create an empty stack

• Scan the expression from left to right

• If the scanned character is an operand, push it onto the stack

• If the scanned character is an operator, pop two operands from the stack, perform the operation and push the result back

• Repeat until the end of the expression

• The final result is the top of the stack

Three weaknesses include lack of experience in a specific technology, difficulty with time management, and tendency to overthink solutions.

• Lack of experience in a specific technology (e.g. not familiar with a certain programming language or framework)

• Difficulty with time management (e.g. struggling to prioritize tasks effectively)

• Tendency to overthink solutions (e.g. spending too much time analyzing a problem before taking action)

To increase sales on eBay website, I would focus on improving product listings, optimizing search results, and leveraging social media.

• Improve product listings with high-quality images, detailed descriptions, and competitive pricing

• Optimize search results by using relevant keywords and tags, and offering free shipping and returns

• Leverage social media by promoting products on Facebook, Instagram, and Twitter, and engaging with customers through comments and messages

I would quarantine the damaged product, document the issue, and notify the appropriate personnel.

• Quarantine the damaged product to prevent it from being used or shipped

• Document the issue by taking photos, writing a report, and recording details such as product ID and location

• Notify the appropriate personnel such as the production team, quality control manager, and supplier

• Investigate the root cause of the damage to prevent future occurrences

Scaling a system involves increasing its capacity to handle more load or users.

• Identify bottlenecks and optimize them

• Use load balancing to distribute traffic evenly

• Implement caching to reduce database load

• Horizontal scaling by adding more servers

• Vertical scaling by upgrading hardware