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4 Layers of AWS Architecture a Quick Answer

I have collected real interview questions on AWS key architecture components. Those are S3, EC2, SQS, and SimpleDB. AWS is one of the most popular skills in the area of Cloud computing. Many companies are recruiting software developers to work on cloud computing.

AWS Key Architecture Components AWS is the top cloud platform. The knowledge of this helpful to learn other cloud platforms. Below are the questions asked in interviews recently.
What are the components involved in AWS?Amazon S3.With this, one can retrieve the key information which is occupied in creating cloud structural design, and the amount of produced information also can be stored in this component that is the consequence of the key specified.Amazon EC2. Helpful to run a large distributed system on the Hadoop cluster. Automatic parallelization and job scheduling can be achieved by this component.Amazon SQS. This component acts as a mediator between different controllers. Also worn for cushioning requirements those are obt…

SAP HANA In-memory Real Usage

Below are the list of questions on SAP HANA In-memory. That explains the real usage.

1. What is in-memory computing?

A1) In-memory computing is a technology that allows the processing of massive quantities of data in main memory to provide immediate results from analysis and transaction. 

The data that is processed is ideally real-time data (that is, data that is available for processing or analysis immediately after it is created).

2. How in-memory computing works?

A2) Keep data in main memory to speed up data access. Minimize data movement by using the columnar storage concept, compression, and performing calculations at the database level. 

Divide and conquer. Use the multi-core architecture of modern processors and multi-processor servers (or even scale out into a distributed landscape) to grow beyond what can be supplied by a single server.

3. What is the benefit of keeping data in memory?

A3) Data accessing from main memory is much faster than accessing data from Disk.

4. If data is in memory(i.e RAM), what will happen in loss of Power?
  • In database technology, atomicity, consistency, isolation, and durability (ACID) is the following set of requirements that ensures that database transactions are processed reliably:
    • A transaction must be atomic. If part of a transaction fails, the entire transaction must fail and leave the database state unchanged.
    • The consistency of a database must be preserved by the transactions that it performs.
    • Isolation ensures that no transaction interferes with another transaction.
    • Durability means that after a transaction is committed, it remains committed. Although the first three requirements are not affected by the in-memory concept, durability is a requirement that cannot be met by storing data in main memory alone. Main memory is volatile storage. It loses its content when it is out of electrical power. To make data persistent, it must be on non-volatile storage, such as HDDs, solid-state drives (SSDs), or flash devices.

5. How SAP HANA will store data in non-volatile storage?

A5) The storage that is used by a database to store data (in this case, main memory) is divided into pages. When a transaction changes data, the corresponding pages are marked and written to non-volatile storage in regular intervals. 

In addition, a database log captures all changes that are made by transactions. Each committed transaction generates a log entry that is written to non-volatile storage, which ensures that all transactions are permanent.

6. How SAP HANA minimizes data movement?

A6) Although today's memory capacities allow keeping enormous amounts of data in-memory, compressing the data in-memory is still preferable. 

The goal is to compress data in a way that does not use up the performance that is gained while still minimizing data movement from RAM to the processor.

Related: SAP Hana Best Selected Interview Questions (Part 2 of 3)

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