Does Vertica DBD takes Inner Queries into account while configuring Projections?

Question

I created COMPREHENSIVE design using a list of 80-85 Queries. Most of them are too big , like 300 - 400 lines each . And most of the Queries has a lot of inner Queries . My Query is that does DBD takes into account the inner Queries too for Projection creation, AS most of the inner Query 's Explain plan does seem to suggest it.

Answer 1

It does take into account queries with joins, in the sense that it tries to look for a common key. After DBD is finished with the design, it's always a good idea to review the design before deploying.

The best way to optimize for joins is by using primary & foreign keys, and possibly pre-join projections.

Another approach is to look at your actual schema design as the goal should be to have joins to perform locally. You may want to replicate smaller tables or have a single, very large table replicated. This will still allow joins to happen locally.

Some articles which may help in optimizing joins:

• Join Operator Overview
• Pre-join Projections Overview