How do I re-segment a projection in Vertica?

Question

I've run analyze_workload on some of my tables in production, and one suggestion for some tables is to re-segment certain projections. The output tells me that re-segmenting the projection would have a low impact.

One slight problem. I can't find anything in the documentation about to go about doing this. Is there a way to do this besides creating new projections and deleting the old ones? That doesn't sound like low impact, so I would assume so.

Thanks for any help in advance.

Answer 1

Is there a way to do this besides creating new projections and deleting the old ones?

I think that's what resegmenting means. The projection refresh process is on some background processing pool, whose priority can be tuned somewhat.

Personally, I often choose to create a new table with the new projection design, copy data into it, and swap. This is of course more intense, but I have more control of when it happens, and I have better gut sense of how long it'll take.