RE: Conflict handling for COPY FROM

Hello Surafel,

I'm very interested in this patch.
Although I'm a beginner,I would like to participate in the development of PostgreSQL.

1. I want to suggest new output format.
In my opinion, it's kind to display description of output and add "line number" and "error" to output.
For example,

error lines

line number | first | second | third | error
------------+-------+--------+-------+------------
1 | 1 | 10 | 0.5 | UNIQUE
2 | 2 | 42 | 0.1 | CHECK
3 | 3 | NULL | 0 | NOT NULL
(3 rows)

Although only unique or exclusion constraint violation returned back to the caller currently,
I think that column "error" will be useful when it becomes possible to handle other types of errors(check, not-null and so on).

If you assume that users re-execute COPY FROM with the output lines as input, these columns are obstacles.
Therefore I think that this output format should be displayed only when we set new option(for example ERROR_VERBOSE) like "COPY FROM ... ERROR_VERBOSE;".

2. I have a question about copy meta-command.
When I executed copy meta-command, output wasn't displayed.
Does it correspond to copy meta-command?

Regards

--
Asaba Takanori