如何在回滚之前显示消息？

Question

我想测试交易

begin;
delete from A;
delete from B where B.A in (select guid from A);
rollback;

并查看有多少记录会被删除。但在 pgadmin 中我只看到

ROLLBACK
Query returned successfully in 906 msec.

要设置什么才能查看此事务将删除两个表中的多少条记录？