psql's \copy incompatible with :variables

Josh Berkus wrote:

Summary: \copy interprets psql's :variables as literal strings

Tested On: 8.4.4, 9.0.4

Severity: Annoyance

Steps to Reproduce:

psql

\set filename 'test.csv'

\copy pg_class to :filename with csv

\q

ls

:filename

Note that psql variables work perfectly fine with COPY. It's just \copy
which seems to be misbehaving.

The problem is that none of the backslash commands interpret variables:

test=> \set x '''y'''
test=> select :x;
?column?
----------
y
(1 row)

test=> \d :y
Did not find any relation named ":y".

Should they?

--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +

Bruce Momjian <bruce@momjian.us> writes:

Josh Berkus wrote:

Note that psql variables work perfectly fine with COPY. It's just \copy
which seems to be misbehaving.

The problem is that none of the backslash commands interpret variables:

Nonsense.

regression=# \set foo bar
regression=# \d foo
Did not find any relation named "foo".
regression=# \d :foo
Did not find any relation named "bar".

\copy is different because it uses OT_WHOLE_LINE mode to read the
argument, and that doesn't expand :variable references. I'd be a bit
leery of changing that.

regards, tom lane

Tom Lane wrote:

Bruce Momjian <bruce@momjian.us> writes:

Josh Berkus wrote:

Note that psql variables work perfectly fine with COPY. It's just \copy
which seems to be misbehaving.

The problem is that none of the backslash commands interpret variables:

Nonsense.

regression=# \set foo bar
regression=# \d foo
Did not find any relation named "foo".
regression=# \d :foo
Did not find any relation named "bar".

\copy is different because it uses OT_WHOLE_LINE mode to read the
argument, and that doesn't expand :variable references. I'd be a bit
leery of changing that.

Oh, I see. My tests were wrong. Thanks.

--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +

\copy is different because it uses OT_WHOLE_LINE mode to read the
argument, and that doesn't expand :variable references. I'd be a bit
leery of changing that.

So, doc warning then?

--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com

Josh Berkus wrote:

\copy is different because it uses OT_WHOLE_LINE mode to read the
argument, and that doesn't expand :variable references. I'd be a bit
leery of changing that.

So, doc warning then?

I don't think enough people have hit this problem to warrant that.

--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +