daijinara
said 9 months ago
on
Private Chat Groups
:
Isn't it counter performative to index the role attribute, since it contains small number of possible values?
The common data structure of index is a balanced-tree with leaf node as linked list, which only supports fast lookup when variety of the values is huge. Otherwise, all the redundant values will be stored in a linked list which is not quite different from scanning the whole table, and sometimes it would be even slower if it needs to fetch the rows one by one from the table.
If you can share me your thoughts why indexing is better, I will greatly appreciate it.
The common data structure of index is a balanced-tree with leaf node as linked list, which only supports fast lookup when variety of the values is huge. Otherwise, all the redundant values will be stored in a linked list which is not quite different from scanning the whole table, and sometimes it would be even slower if it needs to fetch the rows one by one from the table.
If you can share me your thoughts why indexing is better, I will greatly appreciate it.