Enhancement/pattern expression

[czpmango]

What type of PR is this?

• bug
• feature
• enhancement

Description:

This pr is optimized for the case of pattern expression as a predicate. In this case, the runtime doesn't actually have to construct the path. The principle is similar to sql semi apply related optimization.

Compared to previous implementations, this pr has three main optimization points:

• The runtime does not construct paths to pattern predicate(overhead of Project(pathBuild expression)).
• Avoid the overhead of RollUpJoin, which is likely to have high cpu overhead(hash build and probe)and the large table being constructed will also have high memory overhead.
• Avoid the overhead of Filter executor.

For example:
Query statement: MATCH (v:player)-->(n) where (v)-[:like]->() and size((v)-[:serve]-())>2 and v.age>3 and not (v)-[:teammate]-(n) RETURN id(v)
Old plan:

Optimized plan:

Special notes for your reviewer

I will fix some FIXMEs related to handling of expression later. Expression visitor needs to cover all expressions, and currently supports only simple expressions.

Checklist:

Tests:

• Unit test(positive and negative cases)
• Function test
• Performance test
• N/A

Affects:

• Documentation affected (Please add the label if documentation needs to be modified.)
• Incompatibility (If it breaks the compatibility, please describe it and add the label.）
• If it's needed to cherry-pick (If cherry-pick to some branches is required, please label the destination version(s).)
• Performance impacted: Consumes more CPU/Memory

Release notes:

Optimize the implementation of pattern predicate.

[jievince]

Well done!

[czpmango]

We should add PushFilterDownRollUpApply and PushFilterDownPatternApply rules.

[codecov-commenter]

Codecov Report

Base: 76.76% // Head: 76.79% // Increases project coverage by +0.03% 🎉

Coverage data is based on head (8ca99eb) compared to base (8842efb).
Patch coverage: 83.39% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4916      +/-   ##
==========================================
+ Coverage   76.76%   76.79%   +0.03%     
==========================================
  Files        1101     1103       +2     
  Lines       81180    81425     +245     
==========================================
+ Hits        62317    62533     +216     
- Misses      18863    18892      +29     

Impacted Files	Coverage Δ
src/graph/context/ast/CypherAstContext.h	100.00% <ø> (ø)
src/graph/optimizer/rule/RemoveNoopProjectRule.cpp	93.61% <ø> (ø)
src/graph/planner/plan/PlanNode.h	89.42% <ø> (ø)
src/graph/util/ExpressionUtils.h	100.00% <ø> (ø)
src/graph/planner/plan/Query.cpp	66.91% <30.43%> (-1.28%)	⬇️
src/graph/executor/query/PatternApplyExecutor.cpp	82.79% <82.79%> (ø)
src/graph/validator/MatchValidator.cpp	89.06% <84.93%> (-0.49%)	⬇️
src/graph/util/ExpressionUtils.cpp	94.27% <94.11%> (-0.01%)	⬇️
src/graph/executor/Executor.cpp	79.75% <100.00%> (+0.09%)	⬆️
src/graph/executor/query/PatternApplyExecutor.h	100.00% <100.00%> (ø)
... and 39 more

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[Shylock-Hg]

Please add test.

[czpmango]

Please add test.

This pr can be considered as an optimization or refactoring, and all the statement behavior is guaranteed by previous tests related to pattern expression.
If the test case coverage is not complete, it will be evaluated and completed in the future planning.

[yixinglu]

Now we don't hurry to tuning the LDBC according to the PR, you could transform the implementation to the optimizer rule.

[czpmango]

Now we don't hurry to tuning the LDBC according to the PR, you could transform the implementation to the optimizer rule.

IMHO, implementing this in the optimizer is not necessarily better.
#4916 (comment)

[Sophie-Xie]

Pls don‘t merge, wait for @yixinglu .

[yixinglu]

Need some tck cases

[czpmango]

Need some tck cases

As it says here: #4916 (comment)