Function SPI_is_cursor_plan

src/backend/executor/spi.c:1962–1992

* Returns true if the plan contains exactly one command * and that command returns tuples to the caller (eg, SELECT or * INSERT ... RETURNING, but not SELECT ... INTO). In essence, * the result indicates if the command can be used with SPI_cursor_open * * Parameters * plan: A plan previously prepared using SPI_prepare */

 *	  plan: A plan previously prepared using SPI_prepare
 */
bool
SPI_is_cursor_plan(SPIPlanPtr plan)
{
	CachedPlanSource *plansource;

	if (plan == NULL || plan->magic != _SPI_PLAN_MAGIC)
	{
		SPI_result = SPI_ERROR_ARGUMENT;
		return false;
	}

	if (list_length(plan->plancache_list) != 1)
	{
		SPI_result = 0;
		return false;			/* not exactly 1 pre-rewrite command */
	}
	plansource = (CachedPlanSource *) linitial(plan->plancache_list);

	/*
	 * We used to force revalidation of the cached plan here, but that seems
	 * unnecessary: invalidation could mean a change in the rowtype of the
	 * tuples returned by a plan, but not whether it returns tuples at all.
	 */
	SPI_result = 0;

	/* Does it return tuples? */
	if (plansource->resultDesc)
		return true;

	return false;
}

/*
 * SPI_plan_is_valid --- test whether a SPI plan is currently valid