ygf11 opened a new pull request, #5156:
URL: https://github.com/apache/arrow-datafusion/pull/5156
# Which issue does this PR close?
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Closes #5022.
# Rationale for this change
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For the nested loop join, the algorithm will be like:
```
for out-row in outer-table
for inner-row in inner-table
check-join
```
We can see, the inner table will be visited many time.
In the current implemetion of `NestedLoopJoin`, the relationship between
`inner/outer table` and `left/right table` is not fixed, it is decided by the
required distribution:
* For (UnspecifiedDistribution, SinglePartition), right is the inner table
side.
* For (SinglePartition, UnspecifiedDistribution), left table is the inner
table side.
If the table is the inner side, we should add `OnceFut` for it. There are
two reasons:
* It is better to cache the result of a physical plan that has to be
executed many times.
* Some physical plan can not be executed many time, like `RepartitionExec`.
The `NestedLoopJoinExec` always add `OnceFut` for the left table now, it is
not correct, some queries(#5022) will panic.
# What changes are included in this PR?
1. Add `OnceFut` for the inner table side of nested loop join.
3. Remove redundant usage of `bitmap`, Left/LeftAnti/LeftSemi does not need
the bitmap.
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# Are these changes tested?
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# Are there any user-facing changes?
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