Re: pg_dump quietly ignore missing tables - is it bug?

On Fri, Mar 13, 2015 at 10:01 AM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
wrote:

>
>
> 2015-03-13 17:39 GMT+01:00 Robert Haas <robertmhaas(at)gmail(dot)com>:
>
>> On Fri, Mar 13, 2015 at 11:26 AM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
>> wrote:
>> > we found possible bug in pg_dump. It raise a error only when all
>> specified
>> > tables doesn't exists. When it find any table, then ignore missing
>> other.
>> >
>> > /usr/local/pgsql/bin/pg_dump -t Foo -t omega -s postgres > /dev/null;
>> echo
>> > $?
>> >
>> > foo doesn't exists - it creates broken backup due missing "Foo" table
>> >
>> > [pavel(at)localhost include]$ /usr/local/pgsql/bin/pg_dump -t Foo -t
>> omegaa -s
>> > postgres > /dev/null; echo $?
>> > pg_dump: No matching tables were found
>> > 1
>> >
>> > Is it ok? I am thinking, so it is potentially dangerous. Any explicitly
>> > specified table should to exists.
>>
>> Keep in mind that the argument to -t is a pattern, not just a table
>> name. I'm not sure how much that affects the calculus here, but it's
>> something to think about.
>>
>
> yes, it has a sense, although now, I am don't think so it was a good idea.
> There should be some difference between table name and table pattern.
>
>
​There is...a single table name is simply expressed as a pattern without
any wildcards. The issue here is that pg_dump doesn't require that every
instance of -t find one (or more, if a wildcard is present) entries only
that at least one entry is found among all of the patterns specified by -t​.

I'll voice my agreement that each of the -t specifications should find at
least one table in order for the dump as a whole to succeed; though
depending on presented use cases for the current behavior I could see
allowing the command writer to specify a more lenient interpretation by
specifying something like --allow-missing-tables.

Command line switch formats don't really allow you to write "-t?​" to mean
"I want these table(s) if present", do they? I guess the input itself
could be interpreted that way though; a leading "?" is not a valid wildcard
and double-quotes would be required for it to be a valid table name.

David J.