A telecom keeps a customers table with 400 million rows. Plan A splits the table so customers from different regions sit in separate partitions. Plan B moves rarely used, very wide attachment columns into a companion table keyed by the same customer ID. Which statement correctly names these two approaches?
Show answer and explanation
Answer: D
Horizontal partitioning divides a table by rows, so Plan A places different subsets of customers into separate partitions or shards. Vertical partitioning divides a table by columns, so Plan B separates infrequently used wide columns into a companion table linked by the key. Horizontal partitioning usually targets scale, while vertical partitioning often improves storage layout and access patterns.
Why the other options are wrong
- A. The labels are reversed. Row-based splits are horizontal and column-based splits are vertical, so this option swaps both definitions.
- B. Vertical partitioning does not have to distribute data across servers. Splitting columns into separate structures on one server is a common use.
- C. Table size does not decide the partitioning direction. Either approach can apply to any table, depending on whether rows or columns are being separated.