On a certain database, the evaluator was spending 17 seconds on a single
iteration, which is usually a bad sign.
Looking more closely, we find the following culprit:
```
(621s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i1#fb44303q after 17.8s:
79429084 ~0% {3} r1 = JOIN `TypeTrackingImpl::TypeTracker.start/0#dispred#f8047cd1` WITH `DataFlowPublic::Node.asExpr/0#dispred#2845197a` CARTESIAN PRODUCT OUTPUT Rhs.0, Lhs.0 't', Rhs.1
59018875 ~7% {3} | JOIN WITH LocalSources::LocalSourceNode#2491029a ON FIRST 1 OUTPUT Lhs.2, Lhs.1 't', Lhs.0 'result'
7929 ~1% {3} | JOIN WITH `PoorMansFunctionResolution::lastDecoratorCall/1#152a5a8f_10#join_rhs` ON FIRST 1 OUTPUT Lhs.1 't', Rhs.1 'func', Lhs.2 'result'
277654 ~5% {3} r2 = JOIN `TypeTrackingImpl::TypeTracker.start/0#dispred#f8047cd1` WITH `Function::Function.getDefinition/0#dispred#6279b12c` CARTESIAN PRODUCT OUTPUT Rhs.0, Lhs.0 't', Rhs.1
{3} | AND NOT `project#Function::Function.getADecorator/0#dispred#119184e3`(FIRST 1)
269725 ~0% {3} | SCAN OUTPUT In.2, In.1 't', In.0 'func'
270268 ~0% {3} | JOIN WITH `DataFlowPublic::Node.asExpr/0#dispred#2845197a_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1 'result', Lhs.1 't', Lhs.2 'func'
270268 ~7% {3} | JOIN WITH LocalSources::LocalSourceNode#2491029a ON FIRST 1 OUTPUT Lhs.1 't', Lhs.2 'func', Lhs.0 'result'
278197 ~5% {3} r3 = r1 UNION r2
return r3
```
This is clearly silly. We're creating a type tracker start spot for
_every expression_, and only then filtering them down to just final
decorator calls.
To fix this, I simply pushed the `.asExpr` into `lastDecoratorCall` and
made that `pragma[nomagic]`.
This resulted in a much more reasonable iteration:
```
(585s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i1#62ade299 after 2.1s:
61252093 ~0% {2} r1 = JOIN `TypeTrackingImpl::TypeTracker.start/0#dispred#f8047cd1` WITH LocalSources::LocalSourceNode#2491029a CARTESIAN PRODUCT OUTPUT Rhs.0, Lhs.0 't'
7929 ~3% {3} | JOIN WITH `PoorMansFunctionResolution::lastDecoratorCall/1#152a5a8f_10#join_rhs` ON FIRST 1 OUTPUT Lhs.1 't', Rhs.1 'func', Lhs.0 'result'
277654 ~5% {3} r2 = JOIN `TypeTrackingImpl::TypeTracker.start/0#dispred#f8047cd1` WITH `Function::Function.getDefinition/0#dispred#6279b12c` CARTESIAN PRODUCT OUTPUT Rhs.0, Lhs.0 't', Rhs.1
{3} | AND NOT `project#Function::Function.getADecorator/0#dispred#119184e3`(FIRST 1)
269725 ~0% {3} | SCAN OUTPUT In.2, In.1 't', In.0 'func'
270268 ~0% {3} | JOIN WITH `DataFlowPublic::Node.asExpr/0#dispred#2845197a_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1 'result', Lhs.1 't', Lhs.2 'func'
270268 ~5% {3} | JOIN WITH LocalSources::LocalSourceNode#2491029a ON FIRST 1 OUTPUT Lhs.1 't', Lhs.2 'func', Lhs.0 'result'
278197 ~5% {3} r3 = r1 UNION r2
return r3
```
That's better, but can we do better still? Ideally, we'll join with
`lastDecoratorCall` _first_, and only then consider `LocalSourceNode`s.
Time to add some pragmas:
```
(6s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i1#049abau6 after 51ms:
247936 ~0% {3} r1 = SCAN TypeTrackingImpl::Cached::MkTypeTracker#ff50e2d8 OUTPUT In.1, In.0, In.2 't'
2 ~0% {3} | JOIN WITH `num#Option::Option<TypeTrackingImpl::TypeTrackingInput::Content>::TNone#364b4b8a` ON FIRST 1 OUTPUT Lhs.1, Lhs.2 't', _
{2} | REWRITE WITH Tmp.2 := false, TEST InOut.0 = Tmp.2 KEEPING 2
1 ~0% {1} | SCAN OUTPUT In.1 't'
7929 ~0% {3} r2 = JOIN r1 WITH `PoorMansFunctionResolution::lastDecoratorCall/1#152a5a8f` CARTESIAN PRODUCT OUTPUT Rhs.1 'result', Lhs.0 't', Rhs.0
7929 ~3% {3} | JOIN WITH LocalSources::LocalSourceNode#2491029a ON FIRST 1 OUTPUT Lhs.1 't', Lhs.2 'func', Lhs.0 'result'
277654 ~5% {3} r3 = JOIN r1 WITH `Function::Function.getDefinition/0#dispred#6279b12c` CARTESIAN PRODUCT OUTPUT Rhs.0, Lhs.0 't', Rhs.1
{3} | AND NOT `project#Function::Function.getADecorator/0#dispred#119184e3`(FIRST 1)
269725 ~0% {3} | SCAN OUTPUT In.2, In.1 't', In.0 'func'
270268 ~0% {3} | JOIN WITH `DataFlowPublic::Node.asExpr/0#dispred#2845197a#fb_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1 'result', Lhs.1 't', Lhs.2 'func'
270268 ~5% {3} | JOIN WITH LocalSources::LocalSourceNode#2491029a ON FIRST 1 OUTPUT Lhs.1 't', Lhs.2 'func', Lhs.0 'result'
278197 ~5% {3} r4 = r2 UNION r3
return r4
```
Perfect! (Here, the optimiser has for some reason decided to inline
`t.start()`, but this is not important.)
Iteration timings before:
```
(621s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i1#fb44303q after 17.8s:
(623s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i2#fb44303q after 1.9s:
(628s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i3#fb44303q after 5.2s:
(629s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i4#fb44303q after 696ms:
(629s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i5#fb44303q after 238ms:
(630s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i6#fb44303q after 401ms:
(630s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i7#fb44303q after 6ms:
(630s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i8#fb44303q after 3ms:
(630s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i9#fb44303q after 1ms:
(630s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i10#fb44303q after 525ms:
(631s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/1#c7f86fe2#fb/2@6a2459s7 after 518ms:
(631s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/1#c7f86fe2#fb_10#join_rhs/2@eab64fk2 after 42ms:
```
And after:
```
(585s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i1#62ade299 after 2.1s:
(585s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i2#62ade299 after 331ms:
(590s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i3#62ade299 after 4.8s:
(592s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i4#62ade299 after 1.9s:
(593s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i5#62ade299 after 504ms:
(593s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i6#62ade299 after 312ms:
(593s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i7#62ade299 after 6ms:
(593s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i8#62ade299 after 2ms:
(593s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i9#62ade299 after 1ms:
(593s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i10#62ade299 after 489ms:
(594s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/1#c7f86fe2#fb/2@7cac46aj after 522ms:
(594s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/1#c7f86fe2#fb_10#join_rhs/2@a15a372e after 41ms:
```
(Curiously, in the "before" run it appeared to run that tracker _twice_,
with the same performance characteristics the second time around. This
is not present in the "after" version.)
And finally with the pragma:
```
(596s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i1#7ef50eer after 636ms:
(596s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i2#7ef50eer after 180ms:
(598s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i3#7ef50eer after 1.9s:
(604s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i4#7ef50eer after 6.2s:
(606s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i5#7ef50eer after 1.4s:
(607s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i6#7ef50eer after 1.7s:
(607s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i7#7ef50eer after 55ms:
(607s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i8#7ef50eer after 8ms:
(607s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i9#7ef50eer after 2ms:
(608s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i10#7ef50eer after 619ms:
(609s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/1#c7f86fe2#fb/2@4cb536id after 566ms:
(609s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/1#c7f86fe2#fb_10#join_rhs/2@f0664dnr after 56ms:
(714s) Tuple counts for m#PoorMansFunctionResolution::poorMansFunctionTracker/1#c7f86fe2#fb/1@fe47420j after 14ms:
(718s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i1#769227t3 after 369ms:
(719s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i2#769227t3 after 623ms:
(724s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i3#769227t3 after 5.3s:
(727s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i4#769227t3 after 2.8s:
(727s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i5#769227t3 after 289ms:
(727s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i6#769227t3 after 285ms:
(727s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i7#769227t3 after 7ms:
(727s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i8#769227t3 after 3ms:
(727s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i9#769227t3 after 1ms:
(728s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01/3@i10#769227t3 after 672ms:
(731s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/2#75430e01_201#join_rhs/3@cacd816f after 2.5s:
(732s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/1#c7f86fe2#fb/2@14c0cfsk after 80ms:
(732s) Tuple counts for PoorMansFunctionResolution::poorMansFunctionTracker/1#c7f86fe2#fb_10#join_rhs/2@fc0f040d after 0ms:
```
Note the double evaluation again. This will need to be investigated
further.
The "most expensive predicates" report had the following line on a
certain database:
```
1m15s | 11 | 37s @ 4 | ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0@12bb4xdo
```
Investigating further revealed the following bad joins
```
(388s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i4#b2325xoe after 36.5s:
0 ~0% {2} r1 = JOIN `ImportResolution::ImportResolution::sys_modules_module_with_name/1#134529bf#prev_delta` WITH `ImportResolution::ImportResolution::getReferenceToModuleName/1#bc5da225` ON FIRST 1 OUTPUT Rhs.1 'result', Lhs.1 'm'
74884348 ~0% {3} r2 = JOIN `ImportResolution::ImportResolution::getModuleReference/1#28368ea4#prev_delta` WITH `ImportResolution::ImportResolution::potential_module_export/2#19340171` ON FIRST 1 OUTPUT Lhs.1, Rhs.1, Lhs.0
5221604 ~0% {3} | JOIN WITH `Attributes::AttrRef.accesses/2#dispred#31929f12_120#join_rhs` ON FIRST 2 OUTPUT Rhs.2 'result', Lhs.2, Lhs.1
5219926 ~2% {3} | JOIN WITH Attributes::AttrRead#class#f6c3f431 ON FIRST 1 OUTPUT Lhs.1, Lhs.2, Lhs.0 'result'
5300880 ~1% {2} | JOIN WITH `ImportResolution::ImportResolution::module_export/3#f2fc6a2a` ON FIRST 2 OUTPUT Rhs.2, Lhs.2 'result'
42211 ~5% {2} | JOIN WITH `ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0#prev` ON FIRST 1 OUTPUT Lhs.1 'result', Rhs.1 'm'
957042 ~4% {3} r3 = JOIN `ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0#prev_delta` WITH `ImportResolution::ImportResolution::module_export/3#f2fc6a2a_201#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Rhs.2, Lhs.1 'm'
957035 ~0% {3} | JOIN WITH `ImportResolution::ImportResolution::potential_module_export/2#19340171` ON FIRST 2 OUTPUT Lhs.1, Lhs.2 'm', Lhs.0
236753257 ~1% {4} | JOIN WITH `Attributes::AttrRef.accesses/2#dispred#31929f12_201#join_rhs` ON FIRST 1 OUTPUT Rhs.1 'result', Lhs.1 'm', Lhs.2, Rhs.2
199557145 ~2% {4} | JOIN WITH Attributes::AttrRead#class#f6c3f431 ON FIRST 1 OUTPUT Lhs.2, Lhs.3, Lhs.1 'm', Lhs.0 'result'
1 ~0% {2} | JOIN WITH `ImportResolution::ImportResolution::getModuleReference/1#28368ea4#prev` ON FIRST 2 OUTPUT Lhs.3 'result', Lhs.2 'm'
15199013 ~1951% {2} r4 = JOIN `ImportResolution::ImportResolution::getModuleReference/1#28368ea4#prev_delta` WITH `Module::Module.getPackageName/0#dispred#bb0c3872` ON FIRST 1 OUTPUT Lhs.1, Rhs.1
14707604 ~2136% {3} | JOIN WITH `Attributes::AttrRef.accesses/2#dispred#31929f12_102#join_rhs` ON FIRST 1 OUTPUT Rhs.1 'result', Lhs.1, Rhs.2
14623588 ~2190% {4} r5 = JOIN r4 WITH Attributes::AttrRead#class#f6c3f431 ON FIRST 1 OUTPUT _, Lhs.0 'result', Lhs.1, Lhs.2
14623588 ~2058% {2} | REWRITE WITH Tmp.0 := ".", Out.0 := (In.2 ++ Tmp.0 ++ In.3) KEEPING 2
14623588 ~2139% {5} r6 = JOIN r4 WITH Attributes::AttrRead#class#f6c3f431 ON FIRST 1 OUTPUT _, Lhs.0 'result', Lhs.1, Lhs.2, _
14623588 ~2092% {2} | REWRITE WITH Tmp.0 := ".", Tmp.0 := (In.2 ++ Tmp.0 ++ In.3), Tmp.4 := ".__init__", Out.0 := (Tmp.0 ++ Tmp.4) KEEPING 2
29247176 ~2099% {2} r7 = r5 UNION r6
199786001 ~6922% {2} | JOIN WITH `Module::isPreferredModuleForName/2#5fb427f9_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.1 'result'
199756923 ~7024% {2} | JOIN WITH `Module::Module.getFile/0#dispred#53eb9b1b_10#join_rhs` ON FIRST 1 OUTPUT Lhs.1 'result', Rhs.1 'm'
199799135 ~6954% {2} r8 = r1 UNION r2 UNION r3 UNION r7
199793992 ~6954% {2} | AND NOT `ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0#prev`(FIRST 2)
return r8
```
Clearly, waiting to joining with `getModuleReference` last is not
healthy. To fix this, I opted to simply create a helper predicate for
the `accesses` construct.
After this change, here are the iteration timings
```
(327s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i1#74f41yqa after 1.2s:
(327s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i1#8a053ys7 after 1.3s:
(327s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i2#74f41yqa after 20ms:
(327s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i2#8a053ys7 after 20ms:
(337s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i4#74f41yqa after 8.5s:
(341s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i4#8a053ys7 after 3.2s:
(346s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i5#74f41yqa after 7.2s:
(349s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i6#74f41yqa after 3ms:
(352s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i5#8a053ys7 after 10s:
(352s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i8#74f41yqa after 37ms:
(352s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i9#74f41yqa after 0ms:
(352s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i10#74f41yqa after 0ms:
(352s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i11#74f41yqa after 1ms:
(352s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i12#74f41yqa after 1ms:
(353s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i6#8a053ys7 after 1ms:
(354s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i8#8a053ys7 after 7ms:
(354s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i9#8a053ys7 after 0ms:
(354s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i10#8a053ys7 after 0ms:
(354s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i11#8a053ys7 after 0ms:
(354s) Tuple counts for ImportResolution::ImportResolution::getImmediateModuleReference/1#3553e6c0#reorder_1_0/2@i12#8a053ys7 after 0ms:
```
And the helper predicate itself is also quick to evaluate:
```
(327s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i1#74f41xqa after 0ms:
(327s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i1#8a053xs7 after 0ms:
(329s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i3#74f41xqa after 99ms:
(337s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i3#8a053xs7 after 98ms:
(338s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i4#74f41xqa after 679ms:
(341s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i4#8a053xs7 after 400ms:
(346s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i5#74f41xqa after 1ms:
(349s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i6#74f41xqa after 22ms:
(352s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i5#8a053xs7 after 1ms:
(352s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i7#74f41xqa after 1.4s:
(352s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i8#74f41xqa after 8ms:
(352s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i9#74f41xqa after 0ms:
(352s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i10#74f41xqa after 1ms:
(352s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i11#74f41xqa after 1ms:
(352s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i12#74f41xqa after 1ms:
(353s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i13#74f41xqa after 806ms:
(353s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i6#8a053xs7 after 7ms:
(354s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i7#8a053xs7 after 870ms:
(354s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i8#8a053xs7 after 2ms:
(354s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i9#8a053xs7 after 0ms:
(354s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i10#8a053xs7 after 0ms:
(354s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i11#8a053xs7 after 0ms:
(354s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i12#8a053xs7 after 0ms:
(354s) Tuple counts for ImportResolution::ImportResolution::module_reference_accesses/3#8f45b418#reorder_1_2_0/3@i13#8a053xs7 after 276ms:
```
(I note that we appear to be evaluating this code twice, which is a bit
worrying. I'll leave that investigaton for later.)
A case of bad magic. Rather than evaluating separately whether a class
has a method of some name, the compiler opted to magick in the fact
that this was done as part of the `findFunctionAccordingToMro`
predicate. Hilarity ensued.
However, _we_ know that magic really isn't needed in this case (the
number of results is bounded by `Class.getAMethod` since methods have
only a single name), so by factoring it out into a helper predicate, we
can help the join-orderer along.
Before
```
(377s) Starting to evaluate predicate _DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3#prev_DataFlowDispatch::getNextClassInMro/1#__#shared/3@i6#L3#f893bw2h (iteration 6)
(377s) Tuple counts for _DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3#prev_DataFlowDispatch::getNextClassInMro/1#__#shared/3@i6#L3#f893bw2h after 16ms:
33363 ~0% {2} r1 = SCAN `DataFlowDispatch::getNextClassInMro/1#e1ee596a#prev_delta` OUTPUT In.1, In.0 'arg1'
159696 ~4% {3} | JOIN WITH `DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3#prev` ON FIRST 1 OUTPUT Rhs.1 'arg0', Lhs.1 'arg1', Rhs.2 'arg2'
return r1
(377s) Starting to evaluate predicate _Class::Class.getAMethod/0#dispred#66416e47_Function::Function.getName/0#dispred#033700ef_10#join_rh__#antijoin_rhs/3@i6#L4#f893bw2h (iteration 6)
(382s) Tuple counts for _Class::Class.getAMethod/0#dispred#66416e47_Function::Function.getName/0#dispred#033700ef_10#join_rh__#antijoin_rhs/3@i6#L4#f893bw2h after 4.4s:
1770825904 ~4% {4} r1 = JOIN `_DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3#prev_DataFlowDispatch::getNextClassInMro/1#__#shared` WITH `Function::Function.getName/0#dispred#033700ef_10#join_rhs` ON FIRST 1 OUTPUT Lhs.1 'arg0', Rhs.1, Lhs.0 'arg1', Lhs.2 'arg2'
34558 ~3% {3} | JOIN WITH `Class::Class.getAMethod/0#dispred#66416e47` ON FIRST 2 OUTPUT Lhs.0 'arg0', Lhs.2 'arg1', Lhs.3 'arg2'
return r1
...
(382s) Starting to evaluate predicate DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3/3@i6#f893b1xh (iteration 6)
(382s) - DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3_delta has 125138 rows (order for disjuncts: delta=<standard>).
(382s) Tuple counts for DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3/3@i6#f893b1xh after 12ms:
33363 ~0% {2} r1 = SCAN `DataFlowDispatch::getNextClassInMro/1#e1ee596a#prev_delta` OUTPUT In.1, In.0 'cls'
159696 ~0% {3} | JOIN WITH `DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3#prev` ON FIRST 1 OUTPUT Lhs.1 'cls', Rhs.1 'name', Rhs.2 'result'
125138 ~1% {3} | AND NOT `_Class::Class.getAMethod/0#dispred#66416e47_Function::Function.getName/0#dispred#033700ef_10#join_rh__#antijoin_rhs`(FIRST 3)
0 ~0% {3} r2 = JOIN `DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3#prev_delta` WITH `DataFlowDispatch::getNextClassInMro/1#e1ee596a#reorder_1_0#prev` ON FIRST 1 OUTPUT Lhs.1 'name', Lhs.2 'result', Rhs.1 'cls'
{3} | AND NOT `_Class::Class.getAMethod/0#dispred#66416e47_DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3#__#antijoin_rhs`(FIRST 3)
0 ~0% {3} | SCAN OUTPUT In.2 'cls', In.0 'name', In.1 'result'
125138 ~1% {3} r3 = r1 UNION r2
125138 ~1% {3} | AND NOT `DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3#prev`(FIRST 3)
return r3
```
And now
```
(18s) Tuple counts for DataFlowDispatch::class_has_method/2#0d2ae9c0/2@ff66c1lr after 18ms:
202279 ~1% {2} r1 = JOIN `Class::Class.getAMethod/0#dispred#66416e47_10#join_rhs` WITH `Function::Function.getName/0#dispred#033700ef` ON FIRST 1 OUTPUT Lhs.1 'cls', Rhs.1 'name'
return r1
...
(490s) Tuple counts for DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3/3@i6#48b6c1xi after 54ms:
0 ~0% {3} r1 = JOIN `DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3#prev_delta` WITH `DataFlowDispatch::getNextClassInMro/1#e1ee596a#reorder_1_0#prev` ON FIRST 1 OUTPUT Rhs.1 'cls', Lhs.1 'name', Lhs.2 'result'
0 ~0% {3} | AND NOT `DataFlowDispatch::class_has_method/2#0d2ae9c0`(FIRST 2)
33363 ~0% {2} r2 = SCAN `DataFlowDispatch::getNextClassInMro/1#e1ee596a#prev_delta` OUTPUT In.1, In.0 'cls'
159696 ~0% {3} | JOIN WITH `DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3#prev` ON FIRST 1 OUTPUT Lhs.1 'cls', Rhs.1 'name', Rhs.2 'result'
125138 ~1% {3} | AND NOT `DataFlowDispatch::class_has_method/2#0d2ae9c0`(FIRST 2)
125138 ~1% {3} r3 = r1 UNION r2
125138 ~1% {3} | AND NOT `DataFlowDispatch::findFunctionAccordingToMro/2#a610c0a3#prev`(FIRST 3)
return r3
```
