Installation und Upgrade > Installations- und Konfigurationshandbuch - Vorhandene Installation aktualisieren > Updating an Existing Installation > Preparing Your System for the Update > Capture Non-modeled Indexes
  
Capture Non-modeled Indexes
If you have manually added non-modeled indexes to your database, they are dropped during the update. You are instructed to manually recreate them later to complete your update.
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If this situation applies to your setup, you MUST complete the following. Failure to do so causes your manually added non-modeled indexes to be dropped.
1. Fully document any non-modeled indexes that you have created for performance or other reasons. Since the database schema from PTC might have changed between releases, you must test that the objects you are going to create are defined correctly and are still needed in the context of the new release.
2. Create or locate SQL schema definition scripts to recreate the indexes. These need to be executed later.
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• The list of indexes that have been dropped are available in the Upgrade Database Schema Report, that is created when you run the Update Tool.
• The custom sequences are listed in the Obsolete Sequences section of the Upgrade Database Schema Report along with obsolete PTC sequences.