Thread

1. Backend Question

   Chris Bitmead <chris@bitmead.com> — 2000-07-03T13:10:25Z

   Can anyone tell me what the concept of a "group" is in
   backend/libpq/portal.c? There are functions like PQntuplesGroup,
   PQfnumberGroup, PQfsizeGroup, PQftypeGroup etc etc.
   
   

2. Re: Backend Question

   Tom Lane <tgl@sss.pgh.pa.us> — 2000-07-03T14:31:49Z

   Chris Bitmead <chris@bitmead.com> writes:
   > Can anyone tell me what the concept of a "group" is in
   > backend/libpq/portal.c? There are functions like PQntuplesGroup,
   > PQfnumberGroup, PQfsizeGroup, PQftypeGroup etc etc.
   
   Once upon a time it probably supported something like the ability to
   merge tuples of different types into a SELECT result.  It does not
   now: a little scanning shows there is no way to get no_groups above 1
   in the current logic.
   
   You should realize, however, that all that backend-PQexec code is dead
   code and has been for a long time.  It's unlikely that it works at all
   any more, considering all the changes that have gone on while it sits
   untested on the sidelines.  I proposed ripping it out a few months ago,
   and no one objected ... but I haven't got round to it yet.
   
   			regards, tom lane
   
   

3. Re: Backend Question

   Chris Bitmead <chris@bitmead.com> — 2000-07-03T14:38:38Z

   Tom Lane wrote:
   > 
   > Chris Bitmead <chris@bitmead.com> writes:
   > > Can anyone tell me what the concept of a "group" is in
   > > backend/libpq/portal.c? There are functions like PQntuplesGroup,
   > > PQfnumberGroup, PQfsizeGroup, PQftypeGroup etc etc.
   > 
   > Once upon a time it probably supported something like the ability to
   > merge tuples of different types into a SELECT result.  It does not
   > now: a little scanning shows there is no way to get no_groups above 1
   > in the current logic.
   > 
   > You should realize, however, that all that backend-PQexec code is dead
   > code and has been for a long time.  It's unlikely that it works at all
   > any more, considering all the changes that have gone on while it sits
   > untested on the sidelines.  I proposed ripping it out a few months ago,
   > and no one objected ... but I haven't got round to it yet.
   
   Why is it dead code? Why is it no longer necessary?
   
   

4. Re: Backend Question

   Tom Lane <tgl@sss.pgh.pa.us> — 2000-07-03T14:47:07Z

   Chris Bitmead <chris@bitmead.com> writes:
   >> You should realize, however, that all that backend-PQexec code is dead
   >> code and has been for a long time.
   
   > Why is it dead code? Why is it no longer necessary?
   
   It's dead code because it's not called from anywhere.
   
   Once upon a time it was intended to be called by dynamically-loaded
   C functions, but the SPI interface superseded it a long time ago.
   
   The only reason for not ripping it out is the faint possibility that
   somewhere out there is someone with hoary old C-function code that
   still does queries via the backend-PQexec interface instead of SPI.
   But considering that backend-PQexec has been undocumented at least
   since Berkeley days, I rather doubt it.
   
   			regards, tom lane
   
   

5. Re: Backend Question

   Chris Bitmead <chris@bitmead.com> — 2000-07-03T14:47:49Z

   Tom Lane wrote:
   
   > You should realize, however, that all that backend-PQexec code is dead
   > code and has been for a long time.  It's unlikely that it works at all
   > any more, considering all the changes that have gone on while it sits
   > untested on the sidelines.  I proposed ripping it out a few months ago,
   > and no one objected ... but I haven't got round to it yet.
   
   Oh does it allow you to execute queries from within the backend? Sounds
   like a good thing to resurrect at some stage.