SAP Basis Learnings

AS Java Cluster Architecture An AS Java cluster consists of several types of instances, each one of which has an instance number and can be started,  stopped and monitored separately. They are 1.          Central services instance The central services instance consists of a Message Service and Enqueue Service . They are responsible for lock  administration, message exchange and load balancing within the Java cluster. 2.         One or more Java instances A Java instance consists of an Internet Communication Manager (ICM) and one or several server processes . The ICM  handles requests coming from clients and dispatches them to the available server processes , which actually process the requests. 3.         Database The database stores system and application data. There is one central database. It is also possible to have several  application databases. Minimum AS Java Cluster Installation: Large AS Java Cluster Installation: Java Instance: A Java instance is a unit in t

  The architecture of SAP HANA has several components working together. The   main component of the entire SAP HANA architecture is the Index server   which stores and processes all the data. All the other components or engines such as Name server Relational database engine OLAP engine, etc., are linked to the index server and work with it. We will learn about all the architectural components and services in detail in this tutorial. When a user is working on SAP HANA, it is interacting with the client application. A session between the client application and the data source (which is SAP HANA in-memory database) is established which connects the two. The Session and Transaction Manager handle the session initiation and management. Once, the client is connected with the database, queries and data are launched in languages such as  SQL  and SQLScript.  SQLScript is the scripting language of SAP HANA Database . SAP HANA also supports applications and programs developed in the  R language

  Row Vs Column store : The SAP HANA database supports two types of table: store data either 1) column-wise (column tables) 2) row-wise (row tables). SAP HANA is optimized for column storage and this is the default table type. Conceptually, a database table is a two dimensional data structure with cells organized in rows and columns. Computer memory however is organized as a linear sequence. For storing a table in linear memory, two options can be chosen as shown below. A row store stores a sequence of records that contains the fields of one row in the table. In a column store, the entries of a column are stored in contiguous memory locations. Storage Type When to Use Column store Calculations are typically executed on individual or a small number of columns. The table is searched based on the values of a few columns. The table has a large number of columns . The table has a large number of rows and columnar operations are required (aggregate, scan, and so on ) High compression rates c