Partition pruning.
also: time-based partitioning · date partitioning · partition eliminationSplitting tables by a column (usually date) so a query's filter lets the engine skip every partition it can't need.
the two-minute refresher
- Daily partitions + WHERE date in January = read 31 partitions, skip 334.
- Choose granularity by query pattern; aim for about 100 MB to 1 GB per partition.
- Hash partitions on user_id make single-user queries read one partition.
- Queries that don't filter on the partition column get no benefit.