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Java: Improve several join-orders#20088

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aschackmull merged 3 commits intogithub:mainfromaschackmull:java/joinorders1

Jul 18, 2025

Merged

Java: Improve several join-orders#20088

aschackmull merged 3 commits intogithub:mainfromaschackmull:java/joinorders1

Jul 18, 2025

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aschackmull commentedJul 18, 2025

These were all identified by the join-order badness metric and relate to the mass inclusion of quality queries (see#19799 (comment))

Commit 1: ForGenerics::hasParameterSubstitution the join after the delta is much improved if we join on both columns at the same time.
Before:

Pipeline standard for Generics::hasParameterSubstitution/6#69ef8058@fa8a3w37 was evaluated in 4 iterations totaling 37ms (delta sizes total: 14069).          22988  ~2%    {4} r1 = SCAN `Generics::hasSubstitution/4#141198e9#prev_delta` OUTPUT In.1, In.0, In.2, In.3        3849584  ~0%    {5}    | JOIN WITH `Generics::ParameterizedType.getTypeArgument/1#dispred#1493bd8f_201#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Rhs.2        3849584  ~0%    {6}    | JOIN WITH `Generics::ParameterizedType.getGenericType/0#dispred#d00cd684` ON FIRST 1 OUTPUT Lhs.0, Lhs.1, Lhs.2, Lhs.3, Lhs.4, Rhs.1        6164397  ~3%    {7}    | JOIN WITH `Generics::unificationTargets/2#f62be8b8_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.4, Lhs.1, Lhs.2, Lhs.3, Lhs.0, Lhs.5          14148  ~0%    {5}    | JOIN WITH `Generics::ParameterizedType.getTypeArgument/1#dispred#1493bd8f` ON FIRST 3 OUTPUT Lhs.0, Lhs.3, Lhs.4, Lhs.5, Lhs.6          14093  ~4%    {6}    | JOIN WITH `Generics::ParameterizedType.getGenericType/0#dispred#d00cd684` ON FIRST 1 OUTPUT Rhs.1, Lhs.0, Lhs.4, Lhs.3, Lhs.1, Lhs.2          14069  ~4%    {6}    | AND NOT `Generics::hasParameterSubstitution/6#69ef8058#prev`(FIRST 6)                        return r1

After:

Pipeline standard for Generics::hasParameterSubstitution/6#69ef8058@942b1w00 was evaluated in 4 iterations totaling 1ms (delta sizes total: 14068).        14101  ~0%    {4} r1 = JOIN `Generics::hasSubstitution/4#141198e9#prev_delta` WITH `project#Generics::unificationTargetsParameterized/5#fbd9d89b_2301#join_rhs` ON FIRST 2 OUTPUT Rhs.2, Lhs.2, Lhs.3, Rhs.3        14092  ~6%    {5}    | JOIN WITH `Generics::ParameterizedType.getGenericType/0#dispred#d00cd684` ON FIRST 1 OUTPUT Lhs.3, Lhs.1, Lhs.2, Lhs.0, Rhs.1        14092  ~4%    {6}    | JOIN WITH `Generics::ParameterizedType.getGenericType/0#dispred#d00cd684` ON FIRST 1 OUTPUT Lhs.4, Lhs.3, Rhs.1, Lhs.0, Lhs.1, Lhs.2        14068  ~4%    {6}    | AND NOT `Generics::hasParameterSubstitution/6#69ef8058#prev`(FIRST 6)                      return r1

Commit 2:getSourceDeclaration and the TC ofgetASourceSuperType commute, and switching them yields a much better join order in these two cases.
Before:

[2025-07-18 10:53:27] Evaluated non-recursive predicate ContainsTypeMismatch::MismatchedContainerAccess#ac8b7648@88b9e2nn in 34ms (size: 1350).Evaluated relational algebra for predicate ContainsTypeMismatch::MismatchedContainerAccess#ac8b7648@88b9e2nn with tuple counts:           3699   ~3%    {6} r1 = JOIN `_#Expr::Call.getCallee/0#dispred#3c1718adMerge_#Expr::Call.getCallee/0#dispred#3c1718adMerge_10#join__#shared` WITH `Expr::Call.getCallee/0#dispred#3c1718ad` ON FIRST 1 OUTPUT Lhs.4, Lhs.1, Lhs.2, Lhs.3, Lhs.0, Rhs.1           3699   ~0%    {6}    | JOIN WITH `Member::Member.getDeclaringType/0#dispred#6084de84` ON FIRST 1 OUTPUT Lhs.5, Lhs.3, Lhs.1, Lhs.2, Lhs.4, Rhs.1           3699   ~2%    {5}    | JOIN WITH `Member::Callable.getParameter/1#dispred#58097e89` ON FIRST 2 OUTPUT Rhs.2, Lhs.2, Lhs.3, Lhs.4, Lhs.5           3699   ~6%    {5}    | JOIN WITH `Variable::Parameter.getType/0#dispred#bfa3c0f9` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.4           3486   ~1%    {4}    | JOIN WITH JDK::TypeObject#5026c17b ON FIRST 1 OUTPUT Lhs.1, Lhs.2, Lhs.3, Lhs.4                                3486   ~3%    {3} r2 = JOIN r1 WITH `#Type::RefType.hasQualifiedName/2#dispred#459e386fMerge_120#join_rhs` ON FIRST 2 OUTPUT Lhs.3, Rhs.2, Lhs.2            730   ~0%    {1}    | JOIN WITH `Type::RefType.getSourceDeclaration/0#dispred#770ab75c` ON FIRST 2 OUTPUT Lhs.2                                3486   ~0%    {3} r3 = JOIN r1 WITH `#Type::RefType.hasQualifiedName/2#dispred#459e386fMerge_120#join_rhs` ON FIRST 2 OUTPUT Rhs.2, Lhs.2, Lhs.3        6544767   ~0%    {3}    | JOIN WITH `#Type::RefType.getSourceDeclaration/0#dispred#770ab75cMerge_10#join_rhs` ON FIRST 1 OUTPUT Lhs.2, Rhs.1, Lhs.1           1348   ~0%    {1}    | JOIN WITH `doublyBoundedFastTC:#Type::RefType.getASourceSupertype/0#dispred#418e5974Merge:_##Type::RefType.getASourceSupertype/0#dispred#418e5974MergePlus#bf#sourceBound#2#2#3#2#3#2#3_##Type__#higher_order_body:##Type::RefType.getASourceSupertype/0#dispred#418e5974MergePlus#bf#sinkBound#3` ON FIRST 2 OUTPUT Lhs.2                                2078  ~52%    {1} r4 = r2 UNION r3                         return r4

After:

[2025-07-18 10:58:28] Evaluated non-recursive predicate ContainsTypeMismatch::MismatchedContainerAccess#ac8b7648@79993c9t in 0ms (size: 1350).Evaluated relational algebra for predicate ContainsTypeMismatch::MismatchedContainerAccess#ac8b7648@79993c9t with tuple counts:        3699   ~3%    {6} r1 = JOIN `_#Expr::Call.getCallee/0#dispred#3c1718adMerge_#Expr::Call.getCallee/0#dispred#3c1718adMerge_10#join__#shared` WITH `Expr::Call.getCallee/0#dispred#3c1718ad` ON FIRST 1 OUTPUT Lhs.4, Lhs.1, Lhs.2, Lhs.3, Lhs.0, Rhs.1        3699   ~0%    {6}    | JOIN WITH `Member::Member.getDeclaringType/0#dispred#6084de84` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.4, Lhs.5        3699   ~0%    {6}    | JOIN WITH `Type::RefType.getSourceDeclaration/0#dispred#770ab75c` ON FIRST 1 OUTPUT Lhs.5, Lhs.3, Lhs.1, Lhs.2, Lhs.4, Rhs.1        3699   ~4%    {5}    | JOIN WITH `Member::Callable.getParameter/1#dispred#58097e89` ON FIRST 2 OUTPUT Rhs.2, Lhs.2, Lhs.3, Lhs.4, Lhs.5        3699   ~1%    {5}    | JOIN WITH `Variable::Parameter.getType/0#dispred#bfa3c0f9` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.4                          3486   ~0%    {4} r2 = JOIN r1 WITH JDK::TypeObject#5026c17b ON FIRST 1 OUTPUT Lhs.4, Lhs.1, Lhs.2, Lhs.3         730   ~0%    {1}    | JOIN WITH `Type::RefType.hasQualifiedName/2#dispred#459e386f` ON FIRST 3 OUTPUT Lhs.3                          3486   ~5%    {4} r3 = JOIN r1 WITH JDK::TypeObject#5026c17b ON FIRST 1 OUTPUT Lhs.1, Lhs.2, Lhs.3, Lhs.4        3486   ~0%    {3}    | JOIN WITH `#Type::RefType.hasQualifiedName/2#dispred#459e386fMerge_120#join_rhs` ON FIRST 2 OUTPUT Lhs.3, Rhs.2, Lhs.2         620   ~0%    {1}    | JOIN WITH `doublyBoundedFastTC:#Type::RefType.getASourceSupertype/0#dispred#418e5974Merge:_##Type::RefType.getASourceSupertype/0#dispred#418e5974MergePlus#bf#sinkBound#4#2#3#2#2#3#2#2#3_##Ty__#higher_order_body:##Type::RefType.getASourceSupertype/0#dispred#418e5974MergePlus#bf#sinkBound#3` ON FIRST 2 OUTPUT Lhs.2                          1350   ~0%    {1} r4 = r2 UNION r3                      return r4

Before:

[2025-07-18 10:58:29] Evaluated non-recursive predicate ContainsTypeMismatch::MismatchedContainerAccess.getReceiverElementType/1#dispred#217c793b@ea461e9b in 28ms (size: 1350).Evaluated relational algebra for predicate ContainsTypeMismatch::MismatchedContainerAccess.getReceiverElementType/1#dispred#217c793b@ea461e9b with tuple counts:             13   ~0%    {5} r1 = CONSTANT(string, string, string, int, int)["contains(java.lang.Object)","java.util","Collection",0,0;...]          20968   ~0%    {5}    | JOIN WITH `#Member::Callable.getSignature/0#dispred#6167942cMerge_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.4           3699   ~0%    {5}    | JOIN WITH `#Expr::Call.getCallee/0#dispred#3c1718adMerge_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.4           2765   ~0%    {5}    | JOIN WITH ContainsTypeMismatch::MismatchedContainerAccess#ac8b7648 ON FIRST 1 OUTPUT Lhs.0, Lhs.1, Lhs.2, Lhs.3, Lhs.4           2765   ~0%    {6}    | JOIN WITH `Expr::Call.getCallee/0#dispred#3c1718ad` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.4, Lhs.0           2765   ~1%    {6}    | JOIN WITH `Member::Member.getDeclaringType/0#dispred#6084de84` ON FIRST 1 OUTPUT Lhs.1, Lhs.2, Lhs.3, Lhs.4, Lhs.5, Rhs.1                                2765   ~0%    {5} r2 = JOIN r1 WITH `#Type::RefType.hasQualifiedName/2#dispred#459e386fMerge_120#join_rhs` ON FIRST 2 OUTPUT Lhs.5, Rhs.2, Lhs.2, Lhs.3, Lhs.4            730   ~0%    {5}    | JOIN WITH `Type::RefType.getSourceDeclaration/0#dispred#770ab75c` ON FIRST 2 OUTPUT Lhs.0, Lhs.1, Lhs.2, Lhs.3, Lhs.4                                2765   ~0%    {5} r3 = JOIN r1 WITH `#Type::RefType.hasQualifiedName/2#dispred#459e386fMerge_120#join_rhs` ON FIRST 2 OUTPUT Rhs.2, Lhs.2, Lhs.3, Lhs.4, Lhs.5        5073554   ~1%    {6}    | JOIN WITH `#Type::RefType.getSourceDeclaration/0#dispred#770ab75cMerge_10#join_rhs` ON FIRST 1 OUTPUT Lhs.4, Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.0           1348   ~0%    {5}    | JOIN WITH `doublyBoundedFastTC:#Type::RefType.getASourceSupertype/0#dispred#418e5974Merge:_##Type::RefType.getASourceSupertype/0#dispred#418e5974MergePlus#bf#sourceBound#4#2#2#3#2#2#2#4_##Ty__#higher_order_body:##Type::RefType.getASourceSupertype/0#dispred#418e5974MergePlus#bf#sinkBound#4#3` ON FIRST 2 OUTPUT Lhs.0, Lhs.5, Lhs.2, Lhs.3, Lhs.4                                2078  ~54%    {5} r4 = r2 UNION r3           2078  ~52%    {3}    | JOIN WITH `Collections::indirectlyInstantiates/4#e3fb5c16` ON FIRST 3 OUTPUT Lhs.4, Lhs.3, Rhs.3                         return r4

After:

[2025-07-18 11:03:59] Evaluated non-recursive predicate ContainsTypeMismatch::MismatchedContainerAccess.getReceiverElementType/1#dispred#217c793b@f927a29q in 2ms (size: 1350).Evaluated relational algebra for predicate ContainsTypeMismatch::MismatchedContainerAccess.getReceiverElementType/1#dispred#217c793b@f927a29q with tuple counts:           13   ~0%    {5} r1 = CONSTANT(string, string, string, int, int)["contains(java.lang.Object)","java.util","Collection",0,0;...]        20968   ~0%    {5}    | JOIN WITH `#Member::Callable.getSignature/0#dispred#6167942cMerge_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.4         3699   ~0%    {5}    | JOIN WITH `#Expr::Call.getCallee/0#dispred#3c1718adMerge_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.4         2765   ~0%    {5}    | JOIN WITH ContainsTypeMismatch::MismatchedContainerAccess#ac8b7648 ON FIRST 1 OUTPUT Lhs.0, Lhs.1, Lhs.2, Lhs.3, Lhs.4         2765   ~0%    {6}    | JOIN WITH `Expr::Call.getCallee/0#dispred#3c1718ad` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.4, Lhs.0         2765   ~0%    {6}    | JOIN WITH `Member::Member.getDeclaringType/0#dispred#6084de84` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.4, Lhs.5                            2765   ~0%    {7} r2 = JOIN r1 WITH `Type::RefType.getSourceDeclaration/0#dispred#770ab75c` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.2, Lhs.3, Lhs.4, Lhs.5, Lhs.0          730   ~0%    {5}    | JOIN WITH `Type::RefType.hasQualifiedName/2#dispred#459e386f` ON FIRST 3 OUTPUT Lhs.6, Lhs.0, Lhs.3, Lhs.4, Lhs.5                            2765   ~0%    {7} r3 = JOIN r1 WITH `Type::RefType.getSourceDeclaration/0#dispred#770ab75c` ON FIRST 1 OUTPUT Lhs.1, Lhs.2, Lhs.3, Lhs.4, Lhs.5, Lhs.0, Rhs.1         2765   ~0%    {6}    | JOIN WITH `#Type::RefType.hasQualifiedName/2#dispred#459e386fMerge_120#join_rhs` ON FIRST 2 OUTPUT Lhs.6, Rhs.2, Lhs.2, Lhs.3, Lhs.4, Lhs.5          620   ~0%    {5}    | JOIN WITH `doublyBoundedFastTC:#Type::RefType.getASourceSupertype/0#dispred#418e5974Merge:_##Type::RefType.getASourceSupertype/0#dispred#418e5974MergePlus#bf#sinkBound#4#3#2#2#3#2#2#3_##Type__#higher_order_body#1:##Type::RefType.getASourceSupertype/0#dispred#418e5974MergePlus#bf#sinkBound#4#6` ON FIRST 2 OUTPUT Lhs.5, Lhs.1, Lhs.2, Lhs.3, Lhs.4                            1350   ~0%    {5} r4 = r2 UNION r3         1350   ~0%    {3}    | JOIN WITH `Collections::indirectlyInstantiates/4#e3fb5c16` ON FIRST 3 OUTPUT Lhs.4, Lhs.3, Rhs.3                       return r4

Commit 3: The inlinedhaveIntersection really needs both arguments bound in order to perform properly - hence why it's inlined. With a bindingset and inline_late we can actually ensure this.
Before:

[2025-07-18 11:07:43] Evaluated non-recursive predicate ConfusingOverloading::potentiallyConfusingTypesRefTypes/2#df374734#bb@e60feekv in 12ms (size: 319).Evaluated relational algebra for predicate ConfusingOverloading::potentiallyConfusingTypesRefTypes/2#df374734#bb@e60feekv with tuple counts:          24440  ~0%    {1} r1 = JOIN `project##Variable::Parameter.getType/0#dispred#bfa3c0f9Merge` WITH Type::RefType#d8df7f7d ON FIRST 1 OUTPUT Lhs.0            830  ~0%    {2}    | JOIN WITH `ConfusingOverloading::paramTypePair/2#9f9a834c_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.0            790  ~0%    {2}    | JOIN WITH Type::RefType#d8df7f7d ON FIRST 1 OUTPUT Lhs.0, Lhs.1            752  ~0%    {2}    | AND NOT `ConfusingOverloading::potentiallyConfusingTypesSimple/2#9c414149`(FIRST 2)            752  ~0%    {2}    | JOIN WITH `project##Variable::Parameter.getType/0#dispred#bfa3c0f9Merge` ON FIRST 1 OUTPUT Lhs.0, Lhs.1            752  ~0%    {3}    | JOIN WITH `cached_Type::erase/1#afa87d84` ON FIRST 1 OUTPUT Rhs.1, Lhs.1, Lhs.0        1863914  ~0%    {3}    | JOIN WITH `Type::erasedHaveIntersection/2#a066b803` ON FIRST 1 OUTPUT Lhs.1, Rhs.1, Lhs.2            319  ~0%    {2}    | JOIN WITH `cached_Type::erase/1#afa87d84` ON FIRST 2 OUTPUT Lhs.2, Lhs.0                        return r1

After (now inlined intopotentiallyConfusingTypes):

[2025-07-18 11:14:37] Evaluated non-recursive predicate ConfusingOverloading::potentiallyConfusingTypes/2#2ca3f84a#bb@fb4163j4 in 1ms (size: 109).Evaluated relational algebra for predicate ConfusingOverloading::potentiallyConfusingTypes/2#2ca3f84a#bb@fb4163j4 with tuple counts:           43     ~0%    {2} r1 = SCAN `ConfusingOverloading::potentiallyConfusingTypesSimple/2#9c414149` OUTPUT In.1, In.0           43     ~0%    {2}    | JOIN WITH `project##Variable::Parameter.getType/0#dispred#bfa3c0f9Merge` ON FIRST 1 OUTPUT Lhs.1, Lhs.0           43     ~0%    {2}    | JOIN WITH `project##Variable::Parameter.getType/0#dispred#bfa3c0f9Merge` ON FIRST 1 OUTPUT Lhs.0, Lhs.1                                              {2} r2 = REWRITE `ConfusingOverloading::paramTypePair/2#9f9a834c` WITH TEST InOut.0 = InOut.1           39     ~1%    {1}    | SCAN OUTPUT In.0           39     ~1%    {1}    | STREAM DEDUP           39     ~1%    {1}    | JOIN WITH `project##Variable::Parameter.getType/0#dispred#bfa3c0f9Merge` ON FIRST 1 OUTPUT Lhs.0           34     ~0%    {1}    | JOIN WITH Type::RefType#d8df7f7d ON FIRST 1 OUTPUT Lhs.0           34     ~1%    {2}    | JOIN WITH `cached_Type::erase/1#afa87d84` ON FIRST 1 OUTPUT Lhs.0, Rhs.1           34     ~1%    {3}    | JOIN WITH `cached_Type::erase/1#afa87d84` ON FIRST 1 OUTPUT Lhs.1, Rhs.1, Lhs.0           34     ~1%    {2}    | JOIN WITH `Type::erasedHaveIntersection/2#a066b803` ON FIRST 2 OUTPUT Lhs.2, Lhs.2                         {2}    | AND NOT `ConfusingOverloading::potentiallyConfusingTypesSimple/2#9c414149`(FIRST 2)            0     ~0%    {2}    | SCAN OUTPUT In.0, In.0                               869     ~0%    {2} r3 = SCAN `ConfusingOverloading::paramTypePair/2#9f9a834c` OUTPUT In.1, In.0          869     ~0%    {2}    | JOIN WITH `project##Variable::Parameter.getType/0#dispred#bfa3c0f9Merge` ON FIRST 1 OUTPUT Lhs.1, Lhs.0          805     ~0%    {2}    | JOIN WITH Type::RefType#d8df7f7d ON FIRST 1 OUTPUT Lhs.1, Lhs.0          790     ~0%    {2}    | JOIN WITH Type::RefType#d8df7f7d ON FIRST 1 OUTPUT Lhs.1, Lhs.0          790     ~0%    {3}    | JOIN WITH `cached_Type::erase/1#afa87d84` ON FIRST 1 OUTPUT Lhs.1, Lhs.0, Rhs.1          790     ~0%    {4}    | JOIN WITH `cached_Type::erase/1#afa87d84` ON FIRST 1 OUTPUT Lhs.2, Rhs.1, Lhs.0, Lhs.1                               357     ~0%    {2} r4 = JOIN r3 WITH `Type::erasedHaveIntersection/2#a066b803` ON FIRST 2 OUTPUT Lhs.2, Lhs.3           46     ~2%    {2}    | JOIN WITH `#ConfusingOverloading::hasSubtypeOrInstantiation/2#6e757869Plus#bf` ON FIRST 2 OUTPUT Lhs.1, Lhs.0           12     ~0%    {2}    | AND NOT `ConfusingOverloading::potentiallyConfusingTypesSimple/2#9c414149`(FIRST 2)           12     ~0%    {2}    | JOIN WITH `project##Variable::Parameter.getType/0#dispred#bfa3c0f9Merge` ON FIRST 1 OUTPUT Lhs.0, Lhs.1                               357     ~0%    {2} r5 = JOIN r3 WITH `Type::erasedHaveIntersection/2#a066b803` ON FIRST 2 OUTPUT Lhs.3, Lhs.2                                46     ~0%    {2} r6 = JOIN r5 WITH `#ConfusingOverloading::hasSubtypeOrInstantiation/2#6e757869Plus#bf` ON FIRST 2 OUTPUT Lhs.0, Lhs.1           12     ~0%    {2}    | AND NOT `ConfusingOverloading::potentiallyConfusingTypesSimple/2#9c414149`(FIRST 2)           12     ~0%    {2}    | JOIN WITH `project##Variable::Parameter.getType/0#dispred#bfa3c0f9Merge` ON FIRST 1 OUTPUT Lhs.0, Lhs.1                               319     ~0%    {2} r7 = r5 AND NOT `ConfusingOverloading::potentiallyConfusingTypesSimple/2#9c414149`(FIRST 2)          319     ~0%    {2}    | JOIN WITH `project##Variable::Parameter.getType/0#dispred#bfa3c0f9Merge` ON FIRST 1 OUTPUT Lhs.0, Lhs.1        74981     ~7%    {3}    | JOIN WITH `#ConfusingOverloading::hasSubtypeOrInstantiation/2#6e757869Plus#bf` ON FIRST 1 OUTPUT Lhs.1, Rhs.1, Lhs.0         1622  ~2354%    {2}    | JOIN WITH `#ConfusingOverloading::hasSubtypeOrInstantiation/2#6e757869Plus#bf` ON FIRST 2 OUTPUT Lhs.2, Lhs.0                              1689  ~1440%    {2} r8 = r1 UNION r2 UNION r4 UNION r6 UNION r7                         return r8

aschackmull added3 commits

July 18, 2025 11:45

Java: Allow 2-column join on delta to improve join-order.

1273252

Java: getSourceDeclaration() and getASourceSupertype*() commute and t…

7883124

…his yields much better join-order.

Java: Improve join-order by properly annotating haveIntersection.

d9f47bd

CopilotAI review requested due to automatic review settings

July 18, 2025 09:56

aschackmull added the no-change-note-requiredThis PR does not need a change note label

Jul 18, 2025

aschackmull requested a review froma team as acode owner

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Pull Request Overview

This pull request optimizes join-order performance in Java CodeQL queries by refactoring several predicates to improve query execution efficiency. The changes were identified through join-order badness metrics and focus on reducing intermediate result set sizes during query evaluation.

Key changes include:

Restructuring generic type parameter substitution logic to join on multiple columns simultaneously
Reordering type declaration and supertype traversal operations for better join selectivity
Adding binding constraints and inline pragmas to ensure proper predicate evaluation order

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
java/ql/src/Likely Bugs/Collections/ContainsTypeMismatch.ql	Reorders getSourceDeclaration() and getASourceSupertype*() calls to improve join performance
java/ql/lib/semmle/code/java/Type.qll	Adds binding constraints and inline_late pragmas to haveIntersection predicate with helper predicate
java/ql/lib/semmle/code/java/Generics.qll	Extracts unificationTargetsParameterized predicate and refactors hasParameterSubstitution to join on multiple columns

Comments suppressed due to low confidence (1)

java/ql/lib/semmle/code/java/Type.qll:1275

[nitpick] The predicate name 'erasedHaveIntersectionFilter' is unclear about its purpose. Consider renaming to 'erasedHaveIntersectionBound' or 'erasedHaveIntersectionConstrained' to better reflect that it's a binding-constrained wrapper around erasedHaveIntersection.

private predicate erasedHaveIntersectionFilter(RefType t1, RefType t2) {

michaelnebel approved these changes

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Looks plausible to me!

owen-mc approved these changes

Jul 18, 2025

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aschackmull commentedJul 18, 2025

Dca looks good.

aschackmull merged commitd64a936 intogithub:main

Jul 18, 2025

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aschackmull deleted the java/joinorders1 branch

July 18, 2025 12:54

aschackmull mentioned this pull request

Jul 18, 2025

Java: Improve more join-orders#20092

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Java: Improve several join-orders#20088

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