Function get_stmt_mcontext

src/pl/plpgsql/src/pl_exec.c:1505–1516

* Create a memory context for statement-lifespan variables, if we don't * have one already. It will be a child of stmt_mcontext_parent, which is * either the function's main context or a pushed-down outer stmt_mcontext. */

 * either the function's main context or a pushed-down outer stmt_mcontext.
 */
static MemoryContext
get_stmt_mcontext(PLpgSQL_execstate *estate)
{
	if (estate->stmt_mcontext == NULL)
	{
		estate->stmt_mcontext =
			AllocSetContextCreate(estate->stmt_mcontext_parent,
								  "PLpgSQL per-statement data",
								  ALLOCSET_DEFAULT_SIZES);
	}
	return estate->stmt_mcontext;
}

/*
 * Push down the current stmt_mcontext so that called statements won't use it.