Questions about upgrading Informix

This topic provides short answers to some frequently asked questions about upgrading to the new version of Informix®.

What can I do to avoid problems when upgrading to the new version of Informix?

Plan for upgrading to the new version and complete all crucial steps. To avoid problems when upgrading to a new version of Informix:

  1. Read the Release Notes® and Machine Notes before you begin upgrading the database server.
  2. Follow the guidelines in the Preparing for migration and Migrating to Informix Version 12.10 topics in the IBM Informix Migration Guide.
Important: Do not cut corners to try to save time. Not doing adequate planning can cause problems later.

What data should I collect when upgrading to a new version of Informix?

Before you upgrade to a newer version of Informix, gather diagnostic information, especially if you have large, complex applications. Diagnostic information is useful to verify database server behavior after upgrading. This information is also useful if you need help from IBM® Software Support.

For information about the data that you should collect, see the Preparing for migration and Pre-migration checklist of diagnostic information topics. Also, see the following IBM Technote on collecting data when upgrading:

http://www.ibm.com/support/docview.wss?uid=swg21266298&myns=swgimgmt&mynp=OCSSGU8G&mync=R

Must I remove in-place alter operations before upgrading or reverting between product versions?

Removing outstanding in-place alter operations is not required before upgrading, but it is a best practice.

If you upgraded, ran in-place alter operations in the new version, and must revert, you must ensure that the outstanding in-place alter operations are resolved. If the reversion process lists all of the tables that have outstanding in-place alter operations if reversion does not complete successfully. You must resolve in-place alter operations on each of the tables in the list before you can revert to the older database server.

For more information, see Resolve outstanding in-place alter operations.

Can I upgrade HDR clusters without downtime?

You can upgrade a high-availability cluster online by following one of several approaches for transforming the primary server and one of the secondary servers, either the remote standalone (RS) secondary server or the HDR secondary server, to form a pair of Enterprise Replication (ER) servers. ER supports this transformation because it allows replication between heterogeneous server versions.

For more information, see the IBM developerWorks® article on rolling upgrades (http://www.ibm.com/developerworks/data/library/techarticle/dm-1012rollingupgrade/index.html) or your IBM Informix Migration Guide.

Must I use the new onconfig.std file after upgrading?

Each version of the database server includes a new onconfig.std file. The file contains new configuration parameters and might contain new default values for some existing configuration parameters. In addition, some configuration parameters used with earlier versions of the database server might not be used with the new version.

After upgrading, use the new onconfig.std file. You can customize it as necessary to match the configuration of the prior version of your database. Do not use the old onconfig.std file with the new version of the server.

For information about the new and changed configuration parameters in each new release, see Configuration parameter changes by version.

What should I do if my queries are slower after an upgrade?

If your queries are slower after an upgrade, find out what changed that affects your configuration and adjust your configuration and queries as necessary. For details, see Tune the new version for performance and adjust queries.

Parent topic: Frequently asked questions (FAQs) about IBM Informix 14.10