3 ms·
It's not just column order. Sometimes the columns you select affect performance of the query.
by 0xFACEFEED 8y ago
It's not just column order. Sometimes the columns you select affect performance of the query.
- deleted 8y ago[deleted]
- deleted 8y ago[deleted]
- greenleafjacob 8y agoMore precisely, if you only select indexed columns you can read only from the index rather than read from index then read the rest of columns from table. Usually the indices are entirely in memory as well, so it's buttery smooth, whereas a read from the table will probably require a disk read.