What are the approaches for refreshing materialized views in Oracle, when underlying tables are updated often?
If you can, use fast refresh instead of complete refresh - it will save you a lot of compute time. you'll have to create materialized view logs on the source tables, but if you run the refreshes frequently you will keep them small and only have to deal with the incremental updates. If you're using 12.2 you can also use "real-time" materialized views, as illustrated here: https://www.youtube.com/watch?v=k5nhZfyPHdY