Function SPI_register_trigger_data

src/backend/executor/spi.c:3627–3668

* Register the transient relations from 'tdata' using this SPI connection. * This should be called by PL implementations' trigger handlers after * connecting, in order to make transition tables visible to any queries run * in this connection. */

 * in this connection.
 */
int
SPI_register_trigger_data(TriggerData *tdata)
{
	if (tdata == NULL)
		return SPI_ERROR_ARGUMENT;

	if (tdata->tg_newtable)
	{
		EphemeralNamedRelation enr =
		palloc(sizeof(EphemeralNamedRelationData));
		int			rc;

		enr->md.name = tdata->tg_trigger->tgnewtable;
		enr->md.reliddesc = tdata->tg_relation->rd_id;
		enr->md.tupdesc = NULL;
		enr->md.enrtype = ENR_NAMED_TUPLESTORE;
		enr->md.enrtuples = tuplestore_tuple_count(tdata->tg_newtable);
		enr->reldata = tdata->tg_newtable;
		rc = SPI_register_relation(enr);
		if (rc != SPI_OK_REL_REGISTER)
			return rc;
	}

	if (tdata->tg_oldtable)
	{
		EphemeralNamedRelation enr =
		palloc(sizeof(EphemeralNamedRelationData));
		int			rc;

		enr->md.name = tdata->tg_trigger->tgoldtable;
		enr->md.reliddesc = tdata->tg_relation->rd_id;
		enr->md.tupdesc = NULL;
		enr->md.enrtype = ENR_NAMED_TUPLESTORE;
		enr->md.enrtuples = tuplestore_tuple_count(tdata->tg_oldtable);
		enr->reldata = tdata->tg_oldtable;
		rc = SPI_register_relation(enr);
		if (rc != SPI_OK_REL_REGISTER)
			return rc;
	}

	return SPI_OK_TD_REGISTER;
}