Lately I faced the following problem - what is faster: manual load or mview refresh. I would not tell - while mview refresh is a direct copy from a source to a destination, the manual load offers full control over the whole process, so we may additionally cut it according to our needs. There is one obstacle though in this particular issue - the final result should be an mview, we may refresh incrementally.
I was not sure if this is possible to run a fast refresh without initial complete refresh - if it would be impossible then the whole concept with the manual load would be useless regarding the circumstances. And during the standard Google search I hit
this article.
In summary it proofs the thing is really fairly easy. I played a little with it and it seems the refresh is really a dumb machanism in this case (which works in our favour). In short it does not check when one initially loaded the pre-built table or which change was last or any SCN or whatever the implementers thought of. It simply assumes a user knows what he/she does, which approach is one of my favorite ones. Thus assuming one have a source table with a primary key defined, a pre-built table initially loaded with (some) data shaped according to one's needs, a mview log on the source table and a mview defined on top of the pre-built table the call to refresh the materialized view looks into the mlog, collects operations stored there and applies them to the destination mview without worrying about the integrity of the data - exactly what I tried to achieve.
