Re: Why scan all columns when we select distinct c1?

Thanks for the explanation. Tom Lane 于2024年1月14日周日 23:46写道： > Ron Johnson writes: > > On Sun, Jan 14, 2024 at 6:18 AM Yongtao Huang > > wrote: > >> gpadmin=# create table t1 (c1 int, c2 text); > >> CREATE TABLE > >> gpadmin=# explain (costs off, verbo

Why scan all columns when we select distinct c1?

16.01? If `select distinct c1`, scan the column `c1` is enough, like PG 9.4. Related GPDB issue link: https://github.com/greenplum-db/gpdb/issues/15266 Reporter: David Kimura and Yongtao Huang