binder: plan not optimal for count(*) with filter #559
Conversation
Signed-off-by: xiaoyong-z <a997647204@gmail.com>
src/logical_planner/select.rs
Outdated
| @@ -140,7 +141,7 @@ impl LogicalPlaner { | |||
| *ref_id, | |||
| column_ids.to_vec(), | |||
| column_descs.to_vec(), | |||
| with_row_handler, | |||
| is_delete || (with_row_handler && column_ids.is_empty()), | |||
There was a problem hiding this comment.
And is the with_row_handler parameter still needed? Can we derive it directly here?
BTW, I think it is not enough to only handle it here in planner. Maybe in optimizer instead, as mentioned in #503.
There was a problem hiding this comment.
Well, the "is_delete" flag indicates whether the plan is from a delete statement.
For "delete" statement, always set with_row_handler to be true as "is delete" flag is true for "delete" statement.
For "select" statement, the "is_delete" flag is false, and then we need to further check if the with_row_handler is true and column_ids is empty. Here i use the && insteand of || is to ensure that when we already have some column scans, we don't need the row_handler, the picture following points out this problem.
There was a problem hiding this comment.
I think for "delete" statement, it is not needed. For "select" statement, may be it is still needed?
And is the
with_row_handlerparameter still needed? Can we derive it directly here?
For this bug in the #482, I think handle it in the planner is enough? In #503, i didn't see how to handle this part in optimizer, can you give me more insights?
BTW, I think it is not enough to only handle it here in planner. Maybe in optimizer instead, as mentioned in #503.
There was a problem hiding this comment.
I'm wondering why planner still needs to compute with_row_handler when it is a given parameter? Does it mean that the argument is wrong?
It may look better if it is either completely computed here or simply passed as argument.
There was a problem hiding this comment.
Now the computation of with_row_handler is only in plan_select function.
Signed-off-by: xiaoyong-z <a997647204@gmail.com>
Signed-off-by: xiaoyong-z a997647204@gmail.com
close #482
For select statement, set with_row_handler to be true when "with_row_handler = true" and "column_ids.is_empty()".
For delete statement, always set with_row_handler to be true.