Function AddRelcacheInvalidationMessage

src/backend/utils/cache/inval.c:417–442

* Add a relcache inval entry */

 * Add a relcache inval entry
 */
static void
AddRelcacheInvalidationMessage(InvalidationListHeader *hdr,
							   Oid dbId, Oid relId)
{
	SharedInvalidationMessage msg;

	/*
	 * Don't add a duplicate item. We assume dbId need not be checked because
	 * it will never change. InvalidOid for relId means all relations so we
	 * don't need to add individual ones when it is present.
	 */
	ProcessMessageList(hdr->rclist,
					   if (msg->rc.id == SHAREDINVALRELCACHE_ID &&
						   (msg->rc.relId == relId ||
							msg->rc.relId == InvalidOid))
					   return);

	/* OK, add the item */
	msg.rc.id = SHAREDINVALRELCACHE_ID;
	msg.rc.dbId = dbId;
	msg.rc.relId = relId;
	/* check AddCatcacheInvalidationMessage() for an explanation */
	VALGRIND_MAKE_MEM_DEFINED(&msg, sizeof(msg));

	AddInvalidationMessage(&hdr->rclist, &msg);
}

/*
 * Add a snapshot inval entry