Partitioning

Concepts: paPartitioning

What They Want to Hear 'I partition by the column that appears most often in WHERE clauses, usually date. Partition pruning lets the engine skip all other date folders entirely. A query for one day reads 1/365th of the data.' Then immediately add the pitfall: 'The risk is over-partitioning. Too many partitions create thousands of tiny files, which is actually slower than no partitioning at all because of per-file overhead.'