Module volatility 

SQL function volatility and expression rewrite safety over catalog metadata.

Volatility is a semantic property, not merely an optimizer hint. A VOLATILE call may not be duplicated, elided, moved to a different join level, or hidden behind a statement-local view cache. Keep the decision in one place so the view, CTE, predicate-pushdown, column-pruning, and DPccp paths cannot drift apart.

Traits

VolatilityCatalog

Metadata needed to classify SQL expressions without invoking a routine or reading a row.

Functions

expr_contains_volatile_function

function_binding_is_volatile

function_volatility

Resolve the volatility of the implementation that can run for name.

function_volatility_with_binding

query_contains_volatile_function

Inspect a complete query, including transitive view dependencies.

select_contains_volatile_function

The block’s own subquery plans are inspected separately by the query-level walk, so subquery references here are not conservatively volatile.

unified_plan_contains_volatile_function

Whether scalar optimizer rewrites or DPccp join enumeration must be kept away from a plan. rewrite_scalar_expressions is exhaustive over query, mutation, CTE, prepared/explained, and expression-plan children.