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SAP DB, SAP's Open Source RDBMS: Free, Scalable Database Management

by Jurg Hoffmeister | SAPinsider

October 1, 2001

by Jurg Hoffmeister, SAP Labs Berlin, SAP AG SAPinsider - 2001 (Volume 2), October (Issue 4)
 

Look beneath the covers of your R/3 systems, the SAP Knowledge Warehouse, or SAP's CRM, B2B, and SCM solutions, and there you will find the SAP DB relational database management system. It serves not only as an RDBMS, but also as liveCache in the SAP APO Supply Chain Management solution, as a database option for Requisite's BugsEye search engine in SAP Business- to-Business Procurement, and as the Content Server and Content Server Cache in the SAP Knowledge Warehouse.

     While SAP DB is not a household word, I suspect it soon will be. This proven, powerful, reliable, and scalable database management system (DBMS) is now available, free-of-charge and free-of-license-fee, as an open-source database management system. So, in addition to being used in SAP solutions, you can now use SAP DB for your non-SAP systems as well.

     As of October 2000, SAP DB was made available to system administrators and developers, as a professional relational database system. The latest release, SAP DB 7.3, has been available since April 2001. You can get it, along with source code and documentation, on the SAP web site at www.sapdb.org or order the free CD-ROM version from SAP.

     When compared to proprietary databases, SAP DB's open model promotes a more streamlined DBMS. As a portable system, it is designed to provide all of the standard functionality required, but without the unnecessary "features" and complexity that often burden proprietary systems - and in fact can actually inhibit manageability and performance.

     Although the reduced DBMS complexity of SAP DB is intended to promote greater ease of use and reduce demand on system resources, that's not to say that SAP DB is a bare-bones database management system - just the opposite. System administrators will also find:

  • Automated design decisions, exception handling, and database maintenance
  • An easy-to-use interface (DBMGUI)
  • An innovative approach that combines full, standard SQL database functionality combined with object management system features

     What's more, the latest version introduces new browser-based frontend tools. And with SAP DB, there are also no reorganization requirements, because there is no fragmentation of secondary storage structures.1

     But the most important benefits are the low cost of ownership and the ability to use a single database management system across all your applications - not just SAP. And with the program and source code freely available, SAP's own Basis development team and the entire Open Source community will be involved in continually enhancing SAP DB.

Automatic Management and Reorganization Features

With SAP DB's automatic memory management features, administrators do not waste time constantly monitoring the size of tables or reorganizing the database. Instead, steps that would normally be checked manually are now performed automatically.

     For example, if database recovery is necessary, a precise proposal for reconstructing the system is generated from the backup logs. The user is notified automatically about this proposal when choosing to recover the database. Then the administrating user simply confirms the proposal, and the system executes it. (The only other manual operation is inserting or changing tapes or other media!) Of course, the user also can decide to follow other possible recovery paths by selecting incremental backup instead of logs. Point-in-time recovery is supported as well.

     The database can be scaled easily using its own process and thread management (internal tasking) functions and is suitable for both large and small database configurations, regardless of number of users.

SAP DB Features at a Glance

In 1997, SAP procured the technology (last developed by SQL Datenbanksysteme GmbH, a subsidiary of Software AG) in an effort to develop the product further and to ensure support for customers who ran SAP solutions on ADABAS D. Since 1997, these features have been added to SAP DB:

  • Optimized checkpoint handling
  • Parallel create index
  • Parallel backup and restore
  • Online backup without impact on overall performance
  • Assisted restore process
  • Optimized locking and logging
  • Improved handling of “log full” or “database full”
  • Reduced converter cache size (this cache now needs factor 10 less memory)
  • Improved monitoring and diagnostics
  • 64-bit Unix platforms
  • Linux as additional platform, as of Release 7.2
  • NT-based database tools, as of Release 7.2
  • Unicode support (UTF-16), as of Release 7.3
  • New browser-based database tools with Release 7.

DBMGUI: SAP DB's Easy-to-Use Interface

The SAP DB interface makes management easy. With the special graphic user interface (DBMGUI), shown in Figure 1, it is possible to manage multiple SAP DB installations from a single workstation or screen.

Figure 1 The DBMGUI User Interface for SAP DB

     From the Database Manager, the user has an at-a-glance overview of the database A73, along with specific user-selected information. The top right window offers an overview of the current state of each of the registered databases with a few key supervision areas: data size, log size, and major hit ratios. In the window below, which displays the selection path and the database name (Info-Data-A73), you can view information you have selected through the menus to the left, which offer various specialized areas of supervision and maintenance. In this example, the administrator is looking for information about the data devspaces for database A73.

SAP DB's Optimal Approach: Both OMS and RDBMS

Another differentiator is SAP DB's hybrid approach: SAP DB is designed as both an object management system (OMS) and a relational database management system (RDBMS). This hybrid database system and the functional "intersections" that result - such as "SQL class" and "OMS class" - make it possible to access either OMS data or SQL data through C++ application coding.

     To enable SAP DB to operate efficiently in a complex data model with a relatively large volume of data, SAP added a main-memory-focused object management system to SAP DB back with Release 7.1. This addition made it possible to store C++ data structures (pointer structures, such as trees or networks) and enabled several users to navigate to those structures and change them at the same time. The result is increased speed, up to at least 50 times higher than if SQL tables had been used for modeling and navigation (and in some cases, it takes less than 10 microseconds to navigate to an object). Using this approach, SAP DB offers potential for special database technology when operated in conjunction with SAP applications, which means that it can be optimized for certain requirements.

     SAP's liveCache is an example of the potential of SAP DB's dual approach (see Figure 2).

Figure 2 SAP DB: A Hybrid Database Management System Supporting Object Management Sustem (OMS) and SQL Approaches

     liveCache is an instance of the SAP DB designed specifically to handle planning problems with vast amounts of data, first applied in modules in SAP's Supply Chain Management solution. SAP designed it for extremely fast, data-intensive functions to leverage very large, main-memory (64-bit) hardware architecture. liveCache is an instance of SAP DB that is started only as one specific instance type. Objects in liveCache are managed by means of transactions and can, if required, be stored as persistent objects, depending on the application.

     Figure 2 highlights some of the benefits of this approach. The ABAP application layer with its database interface resides on the application server, and communicates with liveCache through TCP/IP to exchange packets. liveCache allows functional packages of an application to be defined as C++ methods of a COM object. Those objects must be available on the liveCache server as libraries (DLL). Their methods are made available to the liveCache through a registration process, and afterward can be called as database procedures. The libraries are linked to the liveCache kernel at runtime and are executed directly in the liveCache address space.

     Because liveCache is based on SAP DB's hybrid technology, access to data is provided in one of two ways:

  • Instances of C++ classes (OMS Class) or their data elements respectively can be read from the database (OMS Basis) to the address space of the method, or vice versa (i.e., elements can be written to the database).
  • SQL commands to access relational schemas (SQL Basis) can be transmitted to the database as a method of the SQL C++ Class (SQL Class).

SAP DB Technical Guidelines

Binary versions of SAP DB are available for these operating systems:

  • Linux
  • Solaris
  • IBM AIX
  • HP-UX
  • Compaq Tru64
  • Windows NT

Database interfaces supported include ODBC (3.5.1), JDBC (2.0), and a connection to script languages such as Perl, Phython, and PHP. Windows-based tools such as Database Manager and SQL Studio are used for administration and database SQL access, and are accompanied by the browser-based variants Web DBM and Web SQL.

     All SAP DB source code will be released in accordance with GNU Public License (GPL, LGPL) regulations. For Linux users, SAP DB will be made available through software distributors, including SuSE. All subsequent versions of the SAP DB will also be made available in real time to the open source community during the development phase.

Download, Development, and Support

To obtain your own copy of SAP DB, you can either download it from www.sapdb.org or order the CD-ROM version. (The current CD, material number 50048324, contains SAP DB 7.3 and is available free of charge.)

     For more information on SAP DB and ordering the CD version, or to download packages directly, visit www.sapdb.org. This site provides a wide range of information, software downloads (with the option of setting up a model database using a script), documentation, and programming examples.

     Information is also available from the two mailing lists set up by SAP:

     SAP DB can be used in SAP applications without incurring license fees. When SAP DB is used in conjunction with SAP applications, support is provided by SAP's regular support infrastructure.

     Customers who wish to use SAP DB "outside" of an SAP solution can receive support from a range of software vendors and application service providers (ASPs) who have many years' experience with SAP DB and its predecessors. For users of SAP DB outside of SAP applications, free online support is available through the sapdb-general mailing list. (This is regarded more as a self-help option, but can also be used to report problems.)

     Advanced customers, software vendors, and ASPs can receive high-level, comprehensive support by setting up a customer competence center for SAP DB and purchasing a Premier Support Contract from SAP. This contract offers full access to the SAP service and support landscape, such as the OSS Online Service System and SAP Service Marketplace customer access. For those organizations that already run SAP solutions on SAP DB, the Premier Support Contract fee will be reduced by the value of the customer's current SAP DB maintenance fee.

     No matter whether you're a developer interested in open source database management program, or an SAP customer looking for a single database system to support your SAP and non-SAP programs alike, SAP DB provides a freely available, scalable, tested relational database management system to meet your needs.


Jürg Hoffmeister is a product manager for SAP DB in the SAP Labs Berlin. He is also in charge of software production and development support. He has been working on the database since 1985 and has extensive experience in database integration and database development.


1 For a full list of SAP DB features, see "SAP DB Features at a Glance" above.

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