Clinical notes and addenda are limited to 5000 characters as they are stored as a details node which has a 5000 character limit.
investigated increasing the length of the act_details value column to support this for all acts, but there is a performance hit in doing so. The length can be doubled to 10000 characters for a minor performance reduction, but beyond that it starts getting expensive.
To support large notes, instead use:
a details node for notes <= 5000 characters
a document for notes > 5000 characters
Note that this is not as flexible as the solution outlined in https://openvpms.org/project/large-text-documents in that documents will need to be loaded in order to search them. This is because blob fields cannot be searched via the query API.
This will require a change to templates that print patient history, including:
Insurance Claim Medical Records.jrxml
It will also require a change to reports that search patient history:
Patient History Search.jrxml