Thread

1. What is ##?

   Marc G. Fournier <scrappy@hub.org> — 1998-02-02T02:24:04Z

   geometry regression test:
   
   
   QUERY: SELECT '' AS thirty, p.f1, l.s, p.f1 ## l.s AS closest
      FROM LSEG_TBL l, POINT_TBL p;
   thirty|f1        |s                            |closest
   
   ------+----------+-----------------------------+--------------------------------
   ----
         |(0,0)     |[(1,2),(3,4)]                |(1,2)
   
         |(-10,0)   |[(1,2),(3,4)]                |(1,2)
   
         |(-3,4)    |[(1,2),(3,4)]                |(1,2)
   
         |(5.1,34.5)|[(1,2),(3,4)]                |(3,4)
   
         |(-5,-12)  |[(1,2),(3,4)]                |(1,2)
   
         |(10,10)   |[(1,2),(3,4)]                |(3,4)
   
         |(0,0)     |[(0,0),(6,6)]                |(-0,0)
   
   This last line, in the current results, provides a value of (0,0) for
   closest, but I can't find what ## means in order to determine if this is
   as expected...
   
   
   Marc G. Fournier                                
   Systems Administrator @ hub.org 
   primary: scrappy@hub.org           secondary: scrappy@{freebsd|postgresql}.org 
   
   
   

2. Re: [HACKERS] What is ##?

   Thomas Lockhart <lockhart@alumni.caltech.edu> — 1998-02-02T05:56:43Z

   > geometry regression test:
   >
   > QUERY: SELECT '' AS thirty, p.f1, l.s, p.f1 ## l.s AS closest
   >    FROM LSEG_TBL l, POINT_TBL p;
   > thirty|f1        |s                            |closest
   >
   > ------+----------+-----------------------------+--------------------------------
   > ----
   >       |(0,0)     |[(1,2),(3,4)]                |(1,2)
   >
   >       |(-10,0)   |[(1,2),(3,4)]                |(1,2)
   >
   >       |(-3,4)    |[(1,2),(3,4)]                |(1,2)
   >
   >       |(5.1,34.5)|[(1,2),(3,4)]                |(3,4)
   >
   >       |(-5,-12)  |[(1,2),(3,4)]                |(1,2)
   >
   >       |(10,10)   |[(1,2),(3,4)]                |(3,4)
   >
   >       |(0,0)     |[(0,0),(6,6)]                |(-0,0)
   >
   > This last line, in the current results, provides a value of (0,0) for
   > closest, but I can't find what ## means in order to determine if this is
   > as expected...
   
   It is the "closest point on" operator. I've been working on the geometric operators
   today, and will submit some fix-up patches soon (hopefully by Tuesday). Will
   augment the regression test for geometry also. (I've been adding entries to the
   "DESCR" macros in pg_proc.h and pg_operator.h, so there will be a description
   available.)
   
   I assume that the "-0" is just a rounding artifact on your machine.
   
   There were two regression tests whose CVS expected results should probably be
   backed out. I was getting different results and had convinced myself that they were
   reasonable, but a week or two later someone fixed the backend problem and the
   behavior reverted to the original. Look for the last two cvs updates by thomas in
   the expected subdirectory.
   
                                                         - Tom