Gurjeet Singh escribió: > Interesting to note that SELECT * FROM table_with_zero_cols does not > complain of anything. > > postgres=# select * from test1; > -- > (0 rows) > > This I believe result of the fact that we allow user to drop all columns of > a table. > > On a side note, Postgres allows me to do this (which I don't think is a bug > or useless): I inserted some rows into a table, and then dropped the > columns. The resulting table has no columns, but live rows. > > postgres=# select * from test_0_col_table ; > -- > (200000 rows)
Yeah. alvherre=# create table foo (); CREATE TABLE alvherre=# insert into foo default values; INSERT 0 1 alvherre=# insert into foo default values; INSERT 0 1 alvherre=# insert into foo default values; INSERT 0 1 alvherre=# insert into foo default values; INSERT 0 1 alvherre=# insert into foo select * from foo; INSERT 0 4 alvherre=# insert into foo select * from foo; INSERT 0 8 alvherre=# insert into foo select * from foo; INSERT 0 16 alvherre=# insert into foo select * from foo; INSERT 0 32 alvherre=# insert into foo select * from foo; INSERT 0 64 alvherre=# select count(*) from foo; count ------- 128 (1 fila) alvherre=# select * from foo; -- (128 filas) If you examine the ctid system column you can even see that those empty rows consume some storage space. -- Álvaro Herrera http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
