SAP HANA

SAP HANA 基础架构简介（二）

IndexServer–Connection 和Session 管理

为Clients 创建和管理sessions and connections
一旦a session 创建clients 用SQL statements 与index server通讯
- Analytical applications may also use the multidimensional query language MDX (MultiDimensionaleXpressions)
Connection ID in trace file entries: [11097]{421970}[117779] 2013-05-21 15:03:15.318517 e CalcEngine

IndexServer–Transaction Manager

[11097]{421970}[117779] 2013-05-21 15:03:15.318517 e CalcEngine

Index Server –Repository

通过Repository REST API通信
- Request and response consist of a document in JavaScript Object Notation (JSON) and not HTTP
- Repository REST access is tunneled through the SQL layer via SQL procedure REPOSITORY_REST
remote access 通过REST 接口打开和关闭transaction
维护~ 30 (Column Store) tables in schema _SYS_REPO object 信息, e.g.:
- ACTIVE_OBJECT
- INACTIVE_OBJECT
用object ID (OID) and version定义一个Object
Repository object 有命名和种类(e.g. table, procedure, view, web content, JavaScript for XSEngine,…)

Index Server –Authorization Manager

确保授权用户只能操作它们被授予权限的作业
For each SQL statement type (e.g. SELECT, UPDATE, EXECUTE) a corresponding privilege exists that the executing user needs to have
- Additionally, objects in the database (e.g. tables, views, stored procedures) have an owner, that can access the objects and grant privileges on them
Scenario: The SQL Processor or CalcEngine executes a query where a certain table, view or stored procedure is accessed
- Then the SQL Processor or CalcEnginewill call the Authorization Manager to check whether the required privilege has been granted to the current user

Index Server –Metadata Manager

Metadata of all objects 存储在Catalog中
- Metadata Manager manages the catalog
- Catalog is stored in Row Store tables
在多节点系统中the metadata 共享在所有服务器上
- The master nodes Index Server acts as a metadata master
- The metadata managers on the slave nodes retrieve the metadata from the metadata master and store it in a local cache as read-only copies

Index Server –SQL Processor

SQL Processor 接收incoming SQL requests
执行data manipulation statements
Forwards…
- data definition statements to the Metadata Manager
- transaction control statements to the Transaction Manager
- planning commands to the planning engine
SQL Processor and Calculation Engine 都包含optimizer
- To execute these plans, the SQL Processor and Calculation Engine invoke the row store or column store

Index Server –Planning Engine

允许数据库层面执行planningoperations
- e.g. Create a new version of a data set as a copy of an existing one while applying filters and transformations
Uses case is mainly financial planning
- Example: Planning data for a new year is created as a copy of the data from the previous year
Implements planning commands that are used by integrated planning in SAP NetWeaverBusiness Warehouse
- Typically these planning commands 在 the ABAP application server执行
- 使用planning engine 可以在HANA database 层面更有效

Index Server –Calculation Engine

Orchestrates OLAP Engine and Join Engine
事项商务逻辑
- e.g. currency conversion
Users create in the modeler a Calc. Plan to define data sources (e.g. tables, views, other Calc. Scenarios, everything the Column Store supports) as inputs and different operations (Join, aggregation, projection) for data manipulation
- Stored Procedures are realized as Calc. Models
- Calc. Models≡ Calc. Scenarios
To execute SELECT on a Calc. Scenario, a Calc. View is created that points to the Calc. Scenario
- Modeler does this when a scenario is activated
Calc. Views 存储在 the Catalog
Calc. Scenarios 存储在 Repository
- Stored in JavaScript Object Notation (JSON)
重要的 Monitors:
- SYS.M_CE_CALCSCENARIOS
- SYS.M_CE_CALCVIEW_DEPENDENCIES
  - Shows what views point to what Calc. Scenarios
  - Multiple entries per Calc. Scenario are possible

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