Artifacts customization

Under certain circumstances, it might be beneficial to alter the generated database artifacts to improve performance. In general, there are two approaches that can be taken: iterative improvement and ad-hoc improvement

Iterative table space mapping improvement

The number of tables that are created by the Schema Generator depends (among other facts) on the complexity of the Business Measures-Modell. Thus it is initially difficult to determine how to optimally assign those tables to the table spaces. The following simple approach can help you to incrementally improve your table to table space mapping, as defined by the table space configuration file. For more information about database planning, refer to Preparation of database artifacts deployment. To improve table to table space mapping, you have to perform the following tasks:
  1. Run the Schema Generator using the default or any other customized table space configuration file.
  2. Extract the generated artifacts into a temporary directory and identify the number and type of tables that will be created in the database. For each Business Measures-Modell, tables of the following types will be created:
    • Context and activity: Exist only in the State and Runtime databases and are accessed by the server and dashboards.
    • CD: Exists only in the State and Runtime databases. CD Tables usually contain a few more columns than there associated context or activity tables. The size of a particular CD table depends heavily on the number of transactions against its corresponding context or activity table, the ratio of update to insert transactions, and how often the associated apply component of a data movement service reads the transactions from the CD table and inserts them into a corresponding CCD table, and how often the CD table entries are pruned by the associated source life cycle component.
    • CCD: Exists only in the Runtime and Historical databases. A CCD table has the exact same structure as its corresponding CD table, and largely depends upon the same factors to determine its size. The one difference is that instead of being read by a apply component the transactions are read by an ETL component and entries are pruned by a target life cycle component.
    • RM Internal Tables: Exists only in the Runtime and Historical databases. These tables use pages with a maximum size of 4 KB.
    • Fact and Dimension: Exist only in the Historical database.
  3. Modify the table space configuration file so that it contains:
    • A mapping for each table type
    • Multiple table type to table space mappings if a large number of tables would otherwise be assigned to the same table space
    Anmerkung:
    • Do not specify table-space declarations for table types that will not be created in a database because those table spaces will not be used.
    • Metrics map to table columns. The more metrics you define, the larger a table will be and the larger the page size that will be needed for its table space.
  4. Create those table spaces (and buffer pools) before deploying the generated artifacts: The Schema Generator does not validate whether the table spaces declared in the configuration file exist because no database connection has been established. However, deployment will fail if the table spaces do not exist.
  5. Re-Run the Schema Generation using the optimized table space configuration file.
    Anmerkung: Change the configuration file name in the Schema Generator administrative console configuration if you created a new table space configuration file.

Ad-hoc improvements

You can modify the generated artifacts by changing the following: In general, changes allowed do not alter the fundamental table schema or structure.
When you change the generated scripts, consider the following limitations:
Wichtig: The changes made to the generated database artifacts are not taken into consideration the next time schema generation is performed for the same Business Measures-Modell. For example, a user alters the generated artifacts for a Business Measures-Modell "Finance Model" prior to deploying them. Subsequently the user alters the Business Measures-Modell and regenerates all artifacts. In this case the user will have to modify the newly generated artifacts again because Schema Generator does not know about the modification made to the previously generated artifacts.
Anmerkung:
  • The artifacts deployment requires Java version 1.4.2 or higher.
  • The Java bin directory should be added to the system path before executing the replication scripts.

Copyright IBM Corporation 2005, 2006. Alle Rechte vorbehalten.