It is faster to build mosaic dataset (MD) locally and then copy it to AWS RDS. ArcGIS Pro allows copying MD through GUI.
Step-by-step guide
- Connect to local folder from Catalog pane
- Right click on local MD and select Copy.
- Select AWS RDS connection.
- Right click and select Paste.
See https://pro.arcgis.com/en/pro-app/tool-reference/data-management/copy.htm to learn copy using arcpy.
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