While Appian and the integration technically support 1 GB file uploads, handling such large files during interactive sessions can negatively impact application performance, user experience, and resource utilization.
A better approach is to request that the business allow these files to be uploaded asynchronously (e.g., overnight batch process), by temporarily storing them (e.g., in a staging table or folder) and processing them when system load is lower. This makes the process more performant and reliable without straining Appian or the external system.

Appian provides an out-of-the-box pre-built connected system for SharePoint, allowing you to integrate file uploads to SharePoint with a guided experience for configuration-making this the best way to fulfill the requirement.

Configure SAML for single sign-on (SSO).
The bearer-assertion flow relies on an existing SAML SSO configuration so Appian can issue a signed SAML assertion on behalf of the signed-in user.
Register the connection in the third-party system.
You must register (or "trust") Appian's client/certificate with the external system so it will accept the SAML assertion and issue an OAuth 2.0 access-token for the user.

The service account must be granted access to the web API, typically via group management, to allow authenticated calls.
The service account must be a user in the Service Accounts group to be used for authentication in integrations such as web APIs.

Applying appropriate filters and indices in both Appian and the database ensures that only relevant data is retrieved and the database query runs efficiently, improving overall query performance.