Environment Assessment

The outcome of your environment assessment will influence which migration strategy you eventually choose. Therefore, make sure that your migration team has a detailed understanding of the current setup very early in the process. This also helps in identifying possible challenges at an early stage.

We recommend that you also document objects that you do not need to migrate because you will no longer use them in Exasol, since this information can be useful as a reference to be used in later stages or for troubleshooting purposes.

The following section lists the major things you should consider documenting.

Data Objects

Document all the data objects that you want to migrate. For example:

  • Databases

    • Which databases must be migrated? A database in Teradata will map to a schema in Exasol.

  • Schemas

    • Which schemas must be migrated?

  • Tables

    • Check for data types where you cannot do a one-to-one mapping with Exasol, such as BLOB types.

    • To get an overview of all the data types used and the possible challenges, run the query in Appendix A: Data Type Mapping.

  • Views

  • Functions

    • User-Defined Functions can be either translated to Exasol’s PL/SQL style functions or rewritten using Exasol’s UDF framework.

    • To get an overview of all functions, run the query in Appendix C: Overview of Teradata Functions.

  • Stored procedures

  • Macros

    • Macros can be converted to Exasol LUA scripts.

  • Triggers

    • Triggers are not supported in Exasol.

  • Indexes

    • You do not have to migrate any indexes, as Exasol creates indexes automatically on the fly.

ETL Processes

Document all the ETL Processes in your Teradata warehouse, such as:

  • Data integration / ETL / scheduling tools
  • Handwritten procedures for ETL / ELT processing
  • Data sources
    • Files
    • Databases
    • Applications
  • For each data source document:
    • Security (for example, required users/roles)
    • Connectivity
    • Loading frequency and loading window
    • Network bandwidth
  • Loading SLAs

BI Tools and Other Applications

Document all applications used by your current Teradata data warehouse, such as:

  • BI tools
  • SQL editors
  • Data science applications (for example, integration with R and Python)
  • Other applications that access data from the data warehouse

Check the connectivity for all of your existing tools to Exasol (see Ecosystem Overview). If none of the tools are supported, look for alternatives. For example, you can use DBVisualizer or DBeaver as an alternative to Teradata Studio.

Database Security

Document all the security requirements currently implemented in Teradata that must be migrated to Exasol, such as:

  • Encryption of data at rest and in motion

  • Users/roles and their privileges

    To get an overview of the users and roles, run the query in Appendix E: Overview of Users and Roles

  • Are users authenticated via LDAP or Active Directory?

  • Do you have row or column level security implemented?

  • Auditing capabilities

Database Environments

Document all your existing environments and consider them for your migration plan. For example: 

  • Production environment
  • Pre-production / QA environment
  • Development environment

Database Operations

For your general migration planning, consider the following operational aspects and include them in your migration plan:

  • General SLA requirements
  • Document the current backup strategy
  • Document the current disaster recovery strategy
  • Document your enterprise monitoring tools