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🟢 Approval recommended
The four narrowly scoped optimization annotations preserve analysis logic and introduce no identified blocking issues.
No open issues 🎉
What changed in this PR
Opts selected C++ analysis predicates out of dynamic join ordering to avoid poor evaluation plans when that feature is enabled. Existing analysis logic and default behavior remain unchanged.
Changes:
- Add
no_dynamic_join_orderto lower- and upper-bound calculations and the value-number bound constructor. - Apply the same annotation to local expression-flow traversal.
| File | Description |
|---|---|
cpp/ql/lib/semmle/code/cpp/rangeanalysis/SimpleRangeAnalysis.qll |
Disable dynamic join ordering for lower- and upper-bound implementations. |
cpp/ql/lib/semmle/code/cpp/rangeanalysis/new/internal/semantic/analysis/Bound.qll |
Disable dynamic join ordering for TBoundValueNumber. |
cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowUtil.qll |
Disable dynamic join ordering for localExprFlowStepImpl. |
Review effort: Max
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We are working on a new dynamic join orderer for CodeQL that join orders predicates at evaluation-time using run-time cardinality information instead of relying on a statically chosen join order decided at compilation-time. At the moment a couple of CPP predicates are join ordered badly by the dynamic join orderer. This PR disables dynamic join ordering for the affected predicates.
Dynamic join ordering is still disabled by default during compilation and evaluation and the
no_dynamic_join_orderpragma has no effect on compilation when dynamic join ordering is not explicitly enabled during compilation.