Skip to main content

Top SAP HANA Iot must read Interview Questions (1 of 3)

The below are the list of awesome interview questions asked for SAP Hana interviews. Across the globe the below are the basic questions people are asking.
Q.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.

SAP hana interview questions
Image courtesy|Stockphotos.io
4) If data is in memory(i.e RAM), what will happen in loss of Power?
A4) 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)

Comments

Popular posts from this blog

Four Tableau products a quick review and explanation

I want to share you what are the Products most popular.

Total four products. Read the details below.

Tableau desktop-(Business analytics anyone can use) - Tableau  Desktop  is  based  on  breakthrough technology  from  Stanford  University  that  lets  you drag & drop to analyze data. You can connect to  data in a few clicks, then visualize and create interactive dashboards with a few more.

We’ve done years of research to build a system that supports people’s natural  ability  to  think visually. Shift fluidly between views, following your natural train of thought. You’re not stuck in wizards or bogged down writing scripts. You just create beautiful, rich data visualizations.  It's so easy to use that any Excel user can learn it. Get more results for less effort. And it’s 10 –100x faster than existing solutions.

Tableau server
Tableau  Server  is  a  business  intelligence  application  that  provides  browser-based  analytics anyone can use. It’s a rapid-fire alternative to th…

The Sqoop in Hadoop story to process structural data

Why Sqoop you need while working on Hadoop-The Sqoop and its primary reason is to import data from structural data sources such as Oracle/DB2 into HDFS(also called Hadoop file system).
To our readers, I have collected a good video from Edureka which helps you to understand the functionality of Sqoop.

The comparison between Sqoop and Flume

The Sqoop the word came from SQL+Hadoop Sqoop word came from SQL+HADOOP=SQOOP. And Sqoop is a data transfer tool. The main use of Sqoop is to import and export the large amount of data from RDBMS to HDFS and vice versa. List of basic Sqoop commands Codegen- It helps to generate code to interact with database records.Create-hive-table- It helps to Import a table definition into a hiveEval- It helps to evaluateSQL statement and display the resultsExport-It helps to export an HDFS directory into a database tableHelp- It helps to list the available commandsImport- It helps to import a table from a database to HDFSImport-all-tables- It helps to import tables …

Different Types Of Payment Cards

The Credit Card (Shopping): The purpose o this card is to buy any item withing the limit prescribed by banks to cardholder. These cards can have both Magnetic stripe and Chip cards. 
Now a days all banks are issuing credit cards with CHIP and PIN. After entering the PIN by cardholder, then transaction starts for further processing.

The debit (ATM, Cash) card is a relatively new method of payment. It is different from a credit card because the debit cardholder pays with the money available in their bank account, which is debited immediately in real time. A debit card seems to be more dangerous compared to a credit card because the debit card is directly linked to the bank checking account and usually allows ATM cash withdrawals.

On the other hand, it is more protected by the required two-factor authentication (PIN number plus card itself). The real dangerous element of many branded debit cards is that they can be processed as credit cards, without entering the PIN.

The Gift card
is simila…