Re: PG 15 (and to a smaller degree 14) regression due to ExprEvalStep size

I wrote:
> Andres Freund <andres@anarazel.de> writes:
>> Maybe it's worth sticking a StaticAssert() for the struct size
>> somewhere.

> Indeed.  I thought we had one already.

>> I'm a bit wary about that being too noisy, there are some machines with
>> odd alignment requirements. Perhaps worth restricting the assertion to
>> x86-64 + armv8 or such?

> I'd put it in first and only reconsider if it shows unfixable problems.

Now that we've got the sizeof(ExprEvalStep) under control, shouldn't
we do the attached?

            regards, tom lane

diff --git a/src/include/executor/execExpr.h b/src/include/executor/execExpr.h
index 86e1ac1e65..06c3adc0a1 100644
--- a/src/include/executor/execExpr.h
+++ b/src/include/executor/execExpr.h
@@ -669,6 +669,10 @@ typedef struct ExprEvalStep
     }            d;
 } ExprEvalStep;
 
+/* Enforce the size rule given in the comment above */
+StaticAssertDecl(sizeof(ExprEvalStep) <= 64,
+                 "size of ExprEvalStep exceeds 64 bytes");
+
 
 /* Non-inline data for container operations */
 typedef struct SubscriptingRefState