Re: POC, WIP: OR-clause support for indexes
| От | Marcos Pegoraro |
|---|---|
| Тема | Re: POC, WIP: OR-clause support for indexes |
| Дата | |
| Msg-id | CAB-JLwb7NQHUdrc9_coV+kKGYF7hBb+XktY6TkYj4aejCqF9DQ@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: POC, WIP: OR-clause support for indexes (Alena Rybakina <a.rybakina@postgrespro.ru>) |
| Ответы |
Re: POC, WIP: OR-clause support for indexes
|
| Список | pgsql-hackers |
I agree with your idea and try to implement it and will soon attach a patch with a solution.
Additionally, if those OR constants repeat you'll see ...
If all constants are the same value, fine
explain select * from x where ((ID = 1) OR (ID = 1) OR (ID = 1));
Index Only Scan using x_id on x (cost=0.42..4.44 rows=1 width=4)
Index Cond: (id = 1)
Index Cond: (id = 1)
if all values are almost the same, ops
explain select * from x where ((ID = 1) OR (ID = 1) OR (ID = 1) OR (ID = 2));
Bitmap Heap Scan on x (cost=17.73..33.45 rows=4 width=4)
Recheck Cond: ((id = 1) OR (id = 1) OR (id = 1) OR (id = 2))
-> BitmapOr (cost=17.73..17.73 rows=4 width=0)
-> Bitmap Index Scan on x_id (cost=0.00..4.43 rows=1 width=0)
Index Cond: (id = 1)
-> Bitmap Index Scan on x_id (cost=0.00..4.43 rows=1 width=0)
Index Cond: (id = 1)
-> Bitmap Index Scan on x_id (cost=0.00..4.43 rows=1 width=0)
Index Cond: (id = 1)
-> Bitmap Index Scan on x_id (cost=0.00..4.43 rows=1 width=0)
Index Cond: (id = 2)
Recheck Cond: ((id = 1) OR (id = 1) OR (id = 1) OR (id = 2))
-> BitmapOr (cost=17.73..17.73 rows=4 width=0)
-> Bitmap Index Scan on x_id (cost=0.00..4.43 rows=1 width=0)
Index Cond: (id = 1)
-> Bitmap Index Scan on x_id (cost=0.00..4.43 rows=1 width=0)
Index Cond: (id = 1)
-> Bitmap Index Scan on x_id (cost=0.00..4.43 rows=1 width=0)
Index Cond: (id = 1)
-> Bitmap Index Scan on x_id (cost=0.00..4.43 rows=1 width=0)
Index Cond: (id = 2)
thanks
Marcos
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