In ETL for data warehousing, what does the term “load and index” typically mean in the context of preparing warehouse tables for analytics?

Introduction / Context:
Once data is extracted and transformed, it must be loaded into target tables and optimized for query performance. The phrase “load and index” captures this final stage of ETL/ELT processes.

Given Data / Assumptions:

• Warehouse tables (fact and dimensions) need data and performance structures.
• Indexes (or clustering/sort keys in columnar systems) improve query speed.
• Quality steps may occur pre- or post-load, but are distinct from “load and index.”

Concept / Approach:
“Load and index” means bulk loading data into the warehouse tables followed by creating or refreshing indexes/statistics to optimize access paths for BI queries. In some platforms, indexing may be deferred until after loading for efficiency.

Step-by-Step Solution:

Verification / Alternative check:
Many DBMS bulk-load guides recommend disabling/rebuilding indexes around loads for speed, which aligns with this interpretation.

Why Other Options Are Wrong:

• A: rejection is not the purpose here.
• C/D: quality upgrades are cleansing steps, not “load and index.”

Common Pitfalls:
Assuming indexing refers only to B-tree creation; cost-based stats and columnar sort/encode steps also fall under performance preparation.

Final Answer:
A process to load the data in the data warehouse and to create the necessary indexes