[OptRule] Collapse continuous Project plan node #1282
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czpmango
added
ready-for-testing
| | 7 | Project | 6 | | | ||
| | 6 | Project | 5 | | |
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could these projects not be collapsed ?
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In order to avoid multiple calculations of the expression($-._path referenced twice in the following project node), this situation was disabled.
| # | ||
| # This source code is licensed under Apache 2.0 License, | ||
| # attached with Common Clause Condition 1.0, found in the LICENSES directory. | ||
| Feature: Push Filter down LeftJoin rule |
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Please fix the feature name.
| namespace nebula { | ||
| namespace opt { | ||
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| class CollapseProjectRule final : public OptRule { |
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Emmm, a pattern is always not enough to understand the details, so we better add some comment for the opt rule.
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How about the case that the result of collapsed Project may be used by other operator? |
Is this not checked in |
That seems only check whether data flow same with control flow |
Merge consecutive project plan nodes to avoid memory replication, and this may benefit column pruning in some cases.
example: match (v:player) with v, v.age/10 as age, v.name as name, abs(v.age) as abs return age-1 as res
old plan:
...->Project(v,age,name,abs)->Project(res)plan applying this rule:
...->Project(res)(res=v.age/10-1)