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🟢 Approval recommended
The narrowly scoped optimizer annotation leaves predicate logic unchanged and has no identified blocking issues.
No open issues 🎉
What changed in this PR
This PR disables dynamic join ordering for Java’s compile-time constant-expression predicate to avoid a poor runtime join order.
Changes:
- Adds
pragma[no_dynamic_join_order]toCompileTimeConstantExpr()without changing predicate logic or compilation when dynamic join ordering is disabled.
| File | Description |
|---|---|
java/ql/lib/semmle/code/java/Expr.qll |
Disables dynamic join ordering for the constant-expression characteristic predicate. |
Review effort: Max
aschackmull
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aschackmull
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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 Java predicate is join ordered badly by the dynamic join orderer. This PR disables dynamic join ordering for the affected predicate.
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.