Function CachedPlanIsSimplyValid

src/backend/utils/cache/plancache.c:1531–1568

* CachedPlanIsSimplyValid: quick check for plan still being valid * * This function must not be used unless CachedPlanAllowsSimpleValidityCheck * previously said it was OK. * * If the plan is valid, and "owner" is not NULL, record a refcount on * the plan in that resowner before returning. It is caller's responsibility * to be sure that a refcount is held on any plan that's being actively

 * advisable to also save plan->generation and verify that that still matches.
 */
bool
CachedPlanIsSimplyValid(CachedPlanSource *plansource, CachedPlan *plan,
						ResourceOwner owner)
{
	/*
	 * Careful here: since the caller doesn't necessarily hold a refcount on
	 * the plan to start with, it's possible that "plan" is a dangling
	 * pointer.  Don't dereference it until we've verified that it still
	 * matches the plansource's gplan (which is either valid or NULL).
	 */
	Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);

	/*
	 * Has cache invalidation fired on this plan?  We can check this right
	 * away since there are no locks that we'd need to acquire first.  Note
	 * that here we *do* check plansource->is_valid, so as to force plan
	 * rebuild if that's become false.
	 */
	if (!plansource->is_valid || plan != plansource->gplan || !plan->is_valid)
		return false;

	Assert(plan->magic == CACHEDPLAN_MAGIC);

	/* Is the search_path still the same as when we made it? */
	Assert(plansource->search_path != NULL);
	if (!OverrideSearchPathMatchesCurrent(plansource->search_path))
		return false;

	/* It's still good.  Bump refcount if requested. */
	if (owner)
	{
		ResourceOwnerEnlargePlanCacheRefs(owner);
		plan->refcount++;
		ResourceOwnerRememberPlanCacheRef(owner, plan);
	}

	return true;
}

/*
 * CachedPlanSetParentContext: move a CachedPlanSource to a new memory context