Function execute_dml_stmt

contrib/postgres_fdw/postgres_fdw.c:4550–4599

* Execute a direct UPDATE/DELETE statement. */

 * Execute a direct UPDATE/DELETE statement.
 */
static void
execute_dml_stmt(ForeignScanState *node)
{
	PgFdwDirectModifyState *dmstate = (PgFdwDirectModifyState *) node->fdw_state;
	ExprContext *econtext = node->ss.ps.ps_ExprContext;
	int			numParams = dmstate->numParams;
	const char **values = dmstate->param_values;

	/* First, process a pending asynchronous request, if any. */
	if (dmstate->conn_state->pendingAreq)
		process_pending_request(dmstate->conn_state->pendingAreq);

	/*
	 * Construct array of query parameter values in text format.
	 */
	if (numParams > 0)
		process_query_params(econtext,
							 dmstate->param_flinfo,
							 dmstate->param_exprs,
							 values);

	/*
	 * Notice that we pass NULL for paramTypes, thus forcing the remote server
	 * to infer types for all parameters.  Since we explicitly cast every
	 * parameter (see deparse.c), the "inference" is trivial and will produce
	 * the desired result.  This allows us to avoid assuming that the remote
	 * server has the same OIDs we do for the parameters' types.
	 */
	if (!PQsendQueryParams(dmstate->conn, dmstate->query, numParams,
						   NULL, values, NULL, NULL, 0))
		pgfdw_report_error(ERROR, NULL, dmstate->conn, false, dmstate->query);

	/*
	 * Get the result, and check for success.
	 *
	 * We don't use a PG_TRY block here, so be careful not to throw error
	 * without releasing the PGresult.
	 */
	dmstate->result = pgfdw_get_result(dmstate->conn, dmstate->query);
	if (PQresultStatus(dmstate->result) !=
		(dmstate->has_returning ? PGRES_TUPLES_OK : PGRES_COMMAND_OK))
		pgfdw_report_error(ERROR, dmstate->result, dmstate->conn, true,
						   dmstate->query);

	/* Get the number of rows affected. */
	if (dmstate->has_returning)
		dmstate->num_tuples = PQntuples(dmstate->result);
	else
		dmstate->num_tuples = atoi(PQcmdTuples(dmstate->result));
}

/*
 * Get the result of a RETURNING clause.