Multiple psql -c / -f options
IMHO the current behavior is broken:
decibel@decina:[17:46]~/pgsql/HEAD/i$bin/psql -c 'select 1' -c 'select 2'
?column?
----------
2
(1 row)
I would expect psql to either run both commands or throw an error.
What I'd personally prefer is that psql execute -c and -f (and arguably -v) in the order they're encountered, within the same session. I realize you can get the same behavior by creating a .sql file, but for simple needs that's sometimes more hassle than it's worth.
If we don't want to support that, we should throw an error if we encounter more than one -c|-f. Not doing so allows for subtle, silent breakage.
Related to this, there's a bunch of other options that should only be allowed once (ie: -d).
BTW, why do we special-case -? and -V at the top of main?
if (argc > 1)
{
if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
{
usage();
exit(EXIT_SUCCESS);
}
if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
{
showVersion();
exit(EXIT_SUCCESS);
}
}
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Jim C. Nasby, Data Architect jim@nasby.net
512.569.9461 (cell) http://jim.nasby.net
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IMHO the current behavior is broken:
decibel@decina:[17:46]~/pgsql/HEAD/i$bin/psql -c 'select 1' -c 'select 2'
?column?
----------
2
(1 row)
Another try with one -c but with similar results:
sh> psql -c "SELECT 1; SELECT 'hello';"
?column?
----------
hello
(1 row)
sh> psql -V
psql (PostgreSQL) 9.3.1
--
Fabien.
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On 10/18/2013 02:19 AM, Fabien COELHO wrote:
IMHO the current behavior is broken:
decibel@decina:[17:46]~/pgsql/HEAD/i$bin/psql -c 'select 1' -c
'select 2'
?column?
----------
2
(1 row)Another try with one -c but with similar results:
sh> psql -c "SELECT 1; SELECT 'hello';"
?column?
----------
hello
(1 row)sh> psql -V
psql (PostgreSQL) 9.3.1
It's not broken. All this behaviour is documented fairly explicitly. See
<http://www.postgresql.org/docs/current/static/app-psql.html> For
example, regarding Fabio's example, which is actually very different
from Jim's, the docs say: "only the result of the last SQL command is
returned."
If you want to argue that it should be enhanced, then do. But it's
acting as designed and as documented.
I suspect changing this might actually have more wrinkles that you
imagine, but I could be wrong.
Incidentally, both of you could probably achieve what you apparently
want with:
echo 'some sql here' | psql
cheers
andrew
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On 10/18/13 8:39 AM, Andrew Dunstan wrote:
On 10/18/2013 02:19 AM, Fabien COELHO wrote:
IMHO the current behavior is broken:
decibel@decina:[17:46]~/pgsql/HEAD/i$bin/psql -c 'select 1' -c 'select 2'
?column?
----------
2
(1 row)Another try with one -c but with similar results:
sh> psql -c "SELECT 1; SELECT 'hello';"
?column?
----------
hello
(1 row)sh> psql -V
psql (PostgreSQL) 9.3.1It's not broken. All this behaviour is documented fairly explicitly. See <http://www.postgresql.org/docs/current/static/app-psql.html> For example, regarding Fabio's example, which is actually very different from Jim's, the docs say: "only the result of the last SQL command is returned."
If you want to argue that it should be enhanced, then do. But it's acting as designed and as documented.
Perhaps "broken" was a bad choice of words. :)
Even if the owner's manual for your car says "You must manually lock the doors before you can start the engine" that doesn't mean it's good behavior. ;)
There's actually additional problems with compound statements. For example, EXECUTE 'CREATE TABLE foo(...); ALTER TABLE foo ...;' doesn't work (at least last I checked). I ass-u-me that there's some fundamental issue to fixing that, so I haven't even looked into it.
When it comes to multiple command-line options, ISTM that current behavior fails the "least surprise" test miserably by simply ignoring some options:
psql --cluster 9.1/us-cnuapp_b -d cnuapp_prod -c 'CREATE TEMP VIEW t AS SELECT 1' -c 'SELECT * FROM t'
ERROR: relation "t" does not exist
LINE 1: SELECT * FROM t
I've never run across any other command-line tool that does that, and I don't think we should either.
I suspect changing this might actually have more wrinkles that you imagine, but I could be wrong.
The only one I've thought of is some users might actually be depending on existing behavior...
Incidentally, both of you could probably achieve what you apparently want with:
echo 'some sql here' | psql
True... while I personally think it'd be nice to actually support multiple -c/-f options it's not all that hard to work around that being missing.
What does concern me is that we're intentionally ignoring requests the user has made of psql. We should either fulfill the requests or throw an error.
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Jim C. Nasby, Data Architect jim@nasby.net
512.569.9461 (cell) http://jim.nasby.net
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