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Posted to github@arrow.apache.org by GitBox <gi...@apache.org> on 2022/11/29 10:04:12 UTC
[GitHub] [arrow-datafusion] liukun4515 commented on a diff in pull request #4411: optimize limit push for join case
liukun4515 commented on code in PR #4411:
URL: https://github.com/apache/arrow-datafusion/pull/4411#discussion_r1034542438
##########
datafusion/optimizer/src/limit_push_down.rs:
##########
@@ -192,6 +196,18 @@ impl OptimizerRule for LimitPushDown {
LogicalPlan::Join(join) => {
let limit = fetch + skip;
let new_join = match join.join_type {
+ JoinType::Left | JoinType::Right | JoinType::Full
+ if is_no_join_condition(join) =>
+ {
+ // push left and right
+ push_down_join(join, Some(limit), Some(limit))
+ }
+ JoinType::LeftSemi | JoinType::LeftAnti
+ if is_no_join_condition(join) =>
+ {
+ // push left
+ push_down_join(join, Some(limit), None)
+ }
JoinType::Left => push_down_join(join, Some(limit), None),
JoinType::Right => push_down_join(join, None, Some(limit)),
Review Comment:
> remove these
```
JoinType::Left | JoinType::Right | JoinType::Full
if is_no_join_condition(join) =>
```
the `on condition` is empty, the rule can be applied, but if the `on condition` is not empty,
```
JoinType::Left => push_down_join(join, Some(limit), None),
JoinType::Right => push_down_join(join, None, Some(limit)),
```
can be applied.
cc @jackwener
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