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A database can and will also scan an index and not even touch the table if the index has all the data it requires. I haven't tried it, but the idea of creating
by jdmichal 6y ago
A database can and will also scan an index and not even touch the table if the index has all the data it requires. I haven't tried it, but the idea of creating an index with just the data necessary for aggregation isn't far fetched.
https://www.postgresql.org/docs/12/indexes-index-only-scans.html https://www.postgresql.org/docs/12/indexes-index-only-scans....
- brudgers 6y agoIn a sense storing column values in an index is how row based databases convert to column based. Do that for all the columns and you are logically close. Execution is another matter.
- deleted 6y ago[deleted]