Re: COPY is not working

On 5/3/2010 10:51 PM, Tom Lane wrote:
> Jan Wieck <JanWieck@Yahoo.com> writes:
>> On 4/30/2010 1:56 AM, Jaime Casanova wrote:
>>> ah! this is because COPY doesn't follow inherited tables... should it?
> 
>> The TRUNCATE command's behavior was changed in that regard. What 
>> TRUNCATE did in 8.3 is now TRUNCATE ONLY in 8.4. I don't see a reason 
>> why COPY should not follow suit.
> 
> How about "because it's inappropriate for dump/reload, which is the main
> use-case for COPY"?  In any case it'd be weird for COPY FROM and COPY TO
> to behave differently on this point, but I don't really see how COPY
> FROM would do anything intelligent for inheritance.

Dump would have to switch to the more consistent syntax using the
   COPY ONLY <table> ...

form. As simple as that.

You are right that COPY ONLY ... FROM makes no sense at all. But I would 
consider that the corner case, not the defining general rule. One could 
make exactly the save inconsistency argument about the fact that there 
is a SELECT ... FROM ONLY, UPDATE ONLY and DELETE FROM ONLY, but no 
INSERT INTO ONLY.

As of right now, all commands that retrieve or affect existing rows, 
except for COPY, do honor the ONLY keyword to stop inheritance. And 
while pg_dump may be one of the main users of COPY, I think there are 
quite a few other. I don't really see why COPY is so special.


Jan

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