Preparing for migration

Preparing for migration includes gathering information about and backing up your data, so that you can reinstall the previous version of the server and restore your data if you have a migration problem. Preparing for migration is crucial for successful migration.

Before you begin

  • Ensure that licensing is completed before running HCL Informix. For more information, see HCL Informix Licensing.
  • If you use Enterprise Replication, you must first prepare your replication environment for migration. For more information, see Enterprise Replication and Upgrading.
  • If you are upgrading from Informix® Version 9.21 or earlier versions and you have columns for smart large objects (BLOB data types) that were defined with a default value of an empty string, you must redefine the columns to have NULL as the default value.
  • If you are upgrading from Informix® Version 7.3, you must drop all stored procedures that have embedded CREATE TRIGGER statements, CREATE TABLE statements with fragmentation expressions, ALTER TABLE or CREATE TABLE statements with constraint expressions, and nested CREATE PROCEDURE statements. After migrating to the current database server, you must recreate all stored procedures that were dropped.
  • If you are migrating from Informix® 7.31, the number of columns of the VARCHAR or NVARCHAR data type per table for Version 11.50 or later versions has been reduced from 231 to 195, within a row size of 32762 bytes and based on a page size of 2K on UNIX™ or Linux™. The same 195-column restriction also applies to BYTE and TEXT columns.

    On platforms where the page size is 4K (Windows™ and AIX®), the limit for the number of columns limit is approximately 450 columns.

About this task

Procedure

Review and complete all tasks that apply:

  1. Reviewing changes in Informix product functionality.
  2. Checking and configuring available space.
  3. Configuring for recovery of restore point data in case an upgrade fails.
  4. Renaming user-defined routines (UDRs) that have the following names: CHARINDEX() , LEFT(), RIGHT(), INSTR(), DEGREES(), RADIANS(), REVERSE(), SUBSTRING_INDEX(), LEN(), and SPACE().
    These names are reserved for built-in SQL string manipulation functions.
  5. Adjusting settings:
    1. If you use UNICODE, ensure that the GL_USEGLU environment variable on the source server is set to the same value as the GL_USEGLU environment variable on the target server.
    2. If the source version of the database server contains the IFX_EXTEND_ROLE configuration parameter, which controls authorization to register DataBlade® modules or external UDRs, disable the parameter by setting it to 0 (off).
  6. Saving copies of the current configuration files.
  7. Saving a copy of the storage manager sm_versions file.
  8. Preparing 12.10 BSON columns with DATE fields for upgrade.
  9. Resolving outstanding in-place alter operations.
  10. Closing all transactions and shutting down the source database server.
  11. Initiating fast recovery to verify that no open transactions exist.
  12. Verifying the integrity of the data.
  13. Verifying that the database server is in quiescent mode.
  14. Making a final backup of the source database server.
    Important: Complete the previous step in case you have to revert to the source database server.
  15. Verifying that the source database server is offline.

What to do next

If you use high-availability clusters, you must complete additional preparations. See High-availability cluster migration.