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We still need partitions and indexes, and I will continue to commute by train even when…

We still need indexes, and I will continue to commute by train even when self-driving cars become reality…

When the Autonomous Data Warehouse Cloud Service had been announced, Oracle came with this surprising idea that we do not need to create Indexes, Partitions and Materialized views for our analytic queries. It was even blocked in ADW and recently released but not recommended. Automatic indexing is for ATP and the message for ADW is: you don’t need indexes for your analytic queries.

In my opinion, and even with the best performance in non-index access, we will still need index range scans. And even when it is not the fastest access path. Because the fastest response time is not the first performance criteria for the end-user.

Full Table Scan vs. Index access

Here is a diagram I used to explain the cost of Full Table Scan vs. Index Access, depending on the number of rows to return.