SAP HANA interview questions

SAP HANA Scheduling using Windows Scheduler And HDBSQL:
HDBSQL the command line interface helps SAP HANA system interact with SAP HANA database. As SAP HANA adds new features, it si important to note that SAP HANA has a scheduler missing now. This prevents us from scheduling routine batch jobs at DB level.However, it is possible to schedule at windows level using OS scheduler and SAP HANA HDBSQL command-line tool

SAP HANA DB Users:

If an user wants to work with SAP HANA DB he needs a user accoutn with a set of privileges to work on SAP HANADB

What is a role?

Role is the set of privileges

Why is a role important in SAP HANA DB?

Every user who gets created and works with SAP HANA DB will be grnated a role which internally carries set of privileges

This is a clear demarcation of level of access a user gets and actions a user can perform at SAP HANA DB

What happens when SAP HANA DB is installed?

As a part of default SAP HANA installation some standard user like SYSTEM which is the user account used for day-to-day activities gets created. SYSTEM user account is also important as this is account that created DB users and offer them privilege to perform tasks at SAP HANA DB level

In addition to standard SYSTEM users, some DB technical accounts that perform database technicalities like statistics collection, SYs operation are also created. Some of these accounts include SYS, _SYS_STATISTICS. Note that we cannot log onto SAP HANA DB using these accounts

SAP HANA Operating System User Overview

Users who wish o work with SAP HANA DB need a user account at DB level. During SAP HANA install SYSTEM account the DB account gets created that helps in other user account creation and administration

At OS level an user account adm called the OS system administrator gets created. This account controls SAP HANA system files and file structures at OS level. This user doesnt exist at DB. In short this is system administrator account from OS context

What is significance of OS admin form SAP HANA studio perspective?

This user credentials are neede dto perform DB start/stop, recovery of DB and such DB admin tasks from sAP HANA studio interface. The first step (i.e) to start a SAP HANA system requires adm OS administrator credentials

SAP HANA Backup File Location:

As with any system SAP HANA system needs to be backed up. The backup destination of SAP HANA is smae as common software system $DIR_INSTANCE/backup/data

This is default backup destination and it is possible to change the backup destination using global.ini parameter basepath_databackup

It is also possible to make changes using SAP HANA studio configuration tab. Choose file global.ini->persistence, make changes

SAP HANA Project Orange:

On November 7th, 2011 SAP released its much awaited in-memory database originally names as Project Orange but later rebranded as SAP HANA. Hence both names represent same. As per SAP project orange is huge and it is  a project that will likely replace all the vendor databases including oracle, sql server , db2 and migrate entire SAP infrastructure onto its DB

It is good practice to always work on latest version of SAP HANA studio. We can check for updates manually on a regular basis.We cna also configure SAP HANA studio to check for updates automatically

We can configure automated updates download form site (same as simple microsoft updates)



How to specify the update site details?

In SAP HANA studio specify the update site details using following navigation

Window->Preferences->Install/Update->Available Software Sites

Choose Add option and specify name of update repository and its location there



SAP HANA studio manual updates:

It is possible to apply manual updates as follows :

From Main menu choose, Help->Check For Updates -- Teh SAP HANA studio software checks specified site for latest updates

If you see an update look at the instructions, follow instruction and install updates



SAP HANA Studio Manual And Automated Updates - SAP HANA Studio automated updates :

We cna configure SAP HANA studio to check for updates automatically and get an alert on new update if one exists

From Main menu choose -> windows->Preferences->Install/Update->Automatic Updates

Specify update settings to get automated update availability alert

SAP Offers ERP Migration From DB to HANA:

Recently SAP announced that business suite is in ramp-up for HANA. ERP migration (i.e) BW migration from current RDBMS database to HANA is going to be risk free as per SAP

SAP recommends a dual delivery setup wherein we first migrateERP RDBMS to HANA, test the migrated systems, verify migration, move end users to BW on HANA system

SAP HANA migration is a full database migration and hence all the users in current RDBMS of BW will be migrated to SAP HANA

All users/roles in BW application are initially defined using ERP application layer. Hence after migration there will be a simple role change for users of SAP HANA datamodeling studio in HANA datamart

SAP HANA HDBSQL Options:

HDBSQL is the command line interface that can be used to query information on DB and DB objects. This cna be used in interactive, non-interactive mode. Following are some common options that come with HDBSQL

-i - This is DB instance ID. it is usally possible to make use of windows services panel to get to know detials on DB instance

-u - This is useraccoutn using which we try to log into DB. Note that user account must exist at DB

-p - This is password for DB user

-U - this is credential from user store

-z - This sets autocommit mode off

-saml-assertion - Used file to provide SAML assertion

-r - This option supresses usage of prepared statements

-n - this is hostname of machine on which DB is installed and port number

SAP HANA Analytics Foundation For SAP Business Suite:

SPA HANA analytics foundation for SAP Business suite popularly called SHAF was released on December 2012

It provides infrastructure to enable data from SAP business suite to be used by SAP HANA for analytic processing

This provides views in SAP HANA for reporting on data that persisted in SAP HANA table format from SAP business suite of products without any data transfer form original tables in suite

This helps business users analyze data and make business decisions.

Technical implemnetation is using SAP HANA integrated studio that makes reporting possible from SAP business suite

To put it simple SHAF is the reporting tool to generate business report from SAP business suite of products

SAP HANA system Properties Brief Overview:

In any system its properties are usually stored in a common file called as configuration file. Say in case of oracle DB it is init.ora (or) spfile.ora

In case of a PHP system it si php.ini

similar to that SAP HANA system stores its configuration properties in a system file. The properties of SAP HANA system are defined as part of different configuration parameters in this file

Parameters of same category are bundled and categorized in this configuration file



How can we change the properties of SAP HANA system?

As with all other systems, an user wiht administrative privilege INIFILE ADMIN will be able to make changes to the properties in the file

1) In SAP HANA studio administration editor, choose Configuration tab - This gives us list of all configuration files

2) Choos eand expand the particular configuraiton file we want to change - This lists all the sections of that particular configuration file

3) Expand the section of interest - Choose parameter we wish to change. By default these parameters will have some value set in place

4) Choose Change in context menu of configuraiton parameter. This pops Change Configuration Value dialog box

5) Enter new value

6) While entering new value if these changes are confined to specific hosts, we need to choose the Hosts area of Change Configuration value dialog box, choose specific hosts and enter host specific values

Thus it is possible to change value and have its scope across systems,hosts. If specified hosts specific value takes precedence over systemwide value



Some parameters can't be changed at host level and they show disabled icon in Hosts area of Change Configuraiton value dialog



Does the change in parameter value require system restart?

simple answer is No. If needed relevant components of system are restarted on it own

SAP HANA System Schema:

System schema are database schemas that get created in SAP HANA database. As these are not realtime users we cannot make use of these accounts to log into database

Following is the list of SAP HANA System schema

1)_SYS_BI

2) _SYS_BIC - This contains details on column views, metadata

3) _SYS_REORG

4) _SYS_REPO - This is repsitory owner

5) _SYS_STATISTICS - Schema used for statistics collection at DB. Performance of a system depends on statistics and it needs to be uptodate for optimal system performance

SAP HANA Studio An Introduction Usage Overview:

SAP HANA studio is a java application that is supported on top of eclipse platform. It is a all in one tool that is being used by administrators, developers, project managers as it ahs lots of features to be used by many different people in an organization

1) SAP HANA studio tool has provision to start, stop, monitor the system, perform configuration, create modeled views, stored procedures etc

2) It connects to SAP HANA DB using sql (JDBC internally)

3) SAP HANA DB acts as repository to store modeled views, stored procedures and such artifacts



Who can make use of SAP HANA studio?

Based on its features and functionality it cna be used by range of personnel in an organization including



1) SAP HANA Admins

2) DBA's

3) Dat aModeler

4) SAP HANA Developer

5) Lifecycle managers (usually ALM personnel)

SAP HANA _SYS_REPO User:

SAP HANA has some technical database users that usually cant be used for logging into database. Instead they support various technicalities of SAP HANA database. One such user is _SYS_STATISTICS, _SYS_REPO etc.

_SYS_REPO is teh SAP HANA technical database user that is used by SAP HANA repository.

SAP HANA repository consists of design time versions of many different objects such as analytic views,calculation views, procedures, analytic privileges, roles. The owner of all objects in repository and activated runtime version is _SYS_REPO user

How is query analysed in SAP HANA database?

Query analysis in any database starts with query plan. SAP HANA DB is no different.We can generate explain plan for query under investigation in SQL console and use this to determine next steps

Enter the query in SLQ console and in context menu choose EXPLAIN PLAN. this is for explain plan for single query.To generate multiple explain plans for many different queries we enter many SQL's seperated by semicolon

EXPLAIN PLAN is displayed in Result tab

Are plan explanations stored at DB level?

Yes, SQL EXPLAIn PLAN explanations are stored at explain_plan_table view of SYS schema. This cna be used for later examination

SAP HANA HDBSQL Overview:

Just as the case with all software systems SAP HANA comes with its own flavour of command line execution using HDBSQL.We can execute sql commands, DB procedures, query information on DB and DB objects using HDBSQL component of SAP HANA software. We can access databases on both local systems and remote computers

How do I start using HDBSQL?

Execute hdbsql [options] to call hdbsql

Note that hdbsql cna be used in both interactive and non-interactive mode to query informaiton on DB and DB objects

We can also import command from a file and execute it in backend using HDBSQL

SAP BW on SAP HANA :

This is a common terminology usd among SAP datawarehousing professionals these days. It is simple SAP BW netweaver datawarehouse that is hosted and runs on in-memory appliance software SAP HANA. SAP supports migration of existing BW RDBMS to SAP HANAand it provider faster output than regular dataabses like ORacle,SQL Server

It is possible to migrate data from existingERP (SAP BW) to SAP HANA using dual delivery model. Themigration is a full DB migration and involves some changes in SAP HANA datamart roles after migration

SAP BW on HANA Sizing :

It is important to have capacity planning of SAP BW on SAP HANA and sizing involves following considerations

1) RAM Sizing - Get details on full data footprint - This involves memory sizing for column store data , memory sizing for row store data, memory sizing for runtime objects, data load, query execution

2) CPU sizing

3) Disk Sizing



Capacity planning involves personnel who will be working on this technical infrastructure. We can also make use of an ABAP script that helps us get sizign details

The sizing report /SDF/HANA_BW_SIZING is a easy to deploy script that considers user defined future growth and has many parametrs and is independent of source databasecompression

SAP HANA Database Backup Methods & Tools :

It is possible to perform SAP HANA database backup using different tools and methods



1) SAP HANA studio - This eclipse framework offers a way to perform SAP HANA backup. This requires OS <sid>adm privilege to proceed further without any issues

2) SQL commands

3) Batch mode - This is set of commands in a file run usually as batch script

 What is SAP's Business Framework?

SAP's Business Framework is a product oriented architecture framework from SAP.This framework enables simple configuration and connection management of all business processes.This provides hardware and platform independence of components and help them function in an integrated fashion.This framework enables easy addition and removal of applications into existing enterprise software without interrupting day-to-day activities of business.Applications included in this framework communicate using ALE (Application Link Enabling). protocol.



Data is transferred between the applications included in this framework using SAP-certified BAPI interfaces.



The applications can be SAP Products such as SAP Business Information Warehouse (BW), Advanced Planner and Optimizer(APO) or non-SAP products.



Applications such as a company's existing self-service intranet applications can be integrated into this framework.



For connecting third-party applications into this framework they must be SAP certified.



A good example of an application integrated in the SAP's Business Framework is R/3 System.