Installation and Upgrade > Upgrade Guide > The Windchill Upgrade Procedure > Capture Non-modeled Indexes
  
Capture Non-modeled Indexes
If you have manually added non-modeled indexes to your database, the non-modeled indexes are dropped during the upgrade. You are instructed to manually recreate the non-modeled indexes later to complete your upgrade. For more information see Recreate Non-modeled Indexes.
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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.
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.
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 are dropped are available in the Upgrade Database Schema Report, that is created when you run the Windchill Upgrade Manager.
The custom sequences are listed in the Obsolete Sequences section of the Upgrade Database Schema Report along with obsolete PTC sequences.