Re: Misleading error message in logical decoding for binary plugins
| От | Michael Paquier |
|---|---|
| Тема | Re: Misleading error message in logical decoding for binary plugins |
| Дата | |
| Msg-id | CAB7nPqR2rdF1sLZVVW4fptPuo6UOE3=Q3GjCcQTCU8TwkeViqQ@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Misleading error message in logical decoding for binary plugins (Andres Freund <andres@2ndquadrant.com>) |
| Ответы |
Re: Misleading error message in logical decoding for
binary plugins
|
| Список | pgsql-hackers |
On Fri, Aug 29, 2014 at 10:48 PM, Andres Freund <andres@2ndquadrant.com> wrote:
Sounds fine for me. I am sure that native English speakers will come up as well with additional suggestions.On 2014-08-29 22:42:46 +0900, Michael Paquier wrote:I don't like the new message much. It's imo even more misleading than
> Hi all,
>
> Using a plugin producing binary output, I came across this error:
> =# select data from pg_logical_slot_peek_changes('foo', NULL, NULL);
> ERROR: 0A000: output plugin cannot produce binary output
> LOCATION: pg_logical_slot_get_changes_guts, logicalfuncs.c:404
>
> Shouldn't the error message be here something like "binary output plugin
> cannot produce textual output"? The plugin used in my case produces binary
> output, but what is requested from it with pg_logical_slot_peek_changes is
> textual output.
the old message. How about
"output plugin produces binary output but the sink only accepts textual data"?
Btw, I am having a hard time understanding in which case OUTPUT_PLUGIN_BINARY_OUTPUT is actually useful. Looking at the code it is only a subset of what OUTPUT_PLUGIN_TEXTUAL_OUTPUT can do as textual can generate both binary and textual output, while binary can only generate binary output. The only code path where a flag OUTPUT_PLUGIN_* is used is in this code path for this very specific error message. On top of that, a logical receiver receives data in textual form even if the decoder is marked as binary when getting a message with PQgetCopyData.
Perhaps I am missing something... But in this case I think that the documentation should have a more detailed explanation about the output format options. Currently only the option value is mentioned, and there is nothing about what they actually do. This is error-prone for the user.
Regards,
--
Michael
Michael
В списке pgsql-hackers по дате отправления: