4 ms·
A sequential scan could also be faster if the join selectivity is poor. As an extreme example say if every id in event_type appeared in prop_keys for a given ap
by yipenghuang 9y ago
A sequential scan could also be faster if the join selectivity is poor. As an extreme example say if every id in event_type appeared in prop_keys for a given app. So scanning the index repeatedly would be a waste of time since you would have to scan the table anyway.
- brianwawok 9y agoWhich is the point of stats, right? To know when it's better to use an index vs just read the whole table because you need 50%+ of it anyway.