Thread: problem of geometric operator in v8.2.1

=> select @-@ lseg '((0,0),(1,0))';?column?
----------       1
(1 row)

=> select @-@ path '((0,0),(1,0))';?column?
----------       2
(1 row)

----------

It's maybe bug in v8.2.1

"Ioseph Kim" <pgsql-kr@postgresql.or.kr> writes:
> => select @-@ lseg '((0,0),(1,0))';
>  ?column?
> ----------
>         1
> (1 row)

> => select @-@ path '((0,0),(1,0))';
>  ?column?
> ----------
>         2
> (1 row)

> It's maybe bug in v8.2.1

What do you think is wrong with those answers?
        regards, tom lane

when @-@ operator used at path type,
below query maybe returns 1.
because this path is just line.


----- Original Message ----- 
From: "Tom Lane" <tgl@sss.pgh.pa.us>
To: "Ioseph Kim" <pgsql-kr@postgresql.or.kr>
Cc: <pgsql-hackers@postgresql.org>
Sent: Saturday, February 03, 2007 5:36 AM
Subject: Re: [HACKERS] problem of geometric operator in v8.2.1 


> "Ioseph Kim" <pgsql-kr@postgresql.or.kr> writes:
>> => select @-@ lseg '((0,0),(1,0))';
>>  ?column?
>> ----------
>>         1
>> (1 row)
> 
>> => select @-@ path '((0,0),(1,0))';
>>  ?column?
>> ----------
>>         2
>> (1 row)
> 
>> It's maybe bug in v8.2.1
> 
> What do you think is wrong with those answers?
> 
> regards, tom lane
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 2: Don't 'kill -9' the postmaster
>

I misunderstood. :)

path '((0,0),(1,0))' is 'closed' path.

in this case, it's maybe operator calculated return length too.

----- Original Message ----- 
From: "Ioseph Kim" <pgsql-kr@postgresql.or.kr>
To: <pgsql-hackers@postgresql.org>
Sent: Saturday, February 03, 2007 6:00 AM
Subject: Re: [HACKERS] problem of geometric operator in v8.2.1 


> when @-@ operator used at path type,
> below query maybe returns 1.
> because this path is just line.
> 
> 
> ----- Original Message ----- 
> From: "Tom Lane" <tgl@sss.pgh.pa.us>
> To: "Ioseph Kim" <pgsql-kr@postgresql.or.kr>
> Cc: <pgsql-hackers@postgresql.org>
> Sent: Saturday, February 03, 2007 5:36 AM
> Subject: Re: [HACKERS] problem of geometric operator in v8.2.1 
> 
> 
>> "Ioseph Kim" <pgsql-kr@postgresql.or.kr> writes:
>>> => select @-@ lseg '((0,0),(1,0))';
>>>  ?column?
>>> ----------
>>>         1
>>> (1 row)
>> 
>>> => select @-@ path '((0,0),(1,0))';
>>>  ?column?
>>> ----------
>>>         2
>>> (1 row)
>> 
>>> It's maybe bug in v8.2.1
>> 
>> What do you think is wrong with those answers?
>> 
>> regards, tom lane
>> 
>> ---------------------------(end of broadcast)---------------------------
>> TIP 2: Don't 'kill -9' the postmaster
>>
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 5: don't forget to increase your free space map settings
>

"Ioseph Kim" <pgsql-kr@postgresql.or.kr> writes:
> when @-@ operator used at path type,
> below query maybe returns 1.
> because this path is just line.

No, because it's a closed path, so it's a loop from (0,0) to (1,0)
and back again.  If you don't want to count the return segment,
use an open path.
        regards, tom lane