[postgis-devel] Re: getrelid && list_nth

['strk']

On Wed, Jun 09, 2004 at 09:39:26AM +0100, Mark Cave-Ayland wrote:
> Hi strk,
> 
> > -----Original Message-----
> > From: strk [mailto:strk at keybit.net] 
> > Sent: 08 June 2004 18:19
> > To: Mark Cave-Ayland
> > Cc: postgis-devel at postgis.refractions.net
> > Subject: getrelid && list_nth
> > 
> > 
> > Hello Mark,
> > I was writing this to pgsql-hackers, but I've solved it
> > so I turned it into a report.
> > 
> > Working on postgis selectivity function for type 'geometry' 
> > I've incurred in the following problem:
> > 
> > The getrelid() macro defined in parser/parsetree.h invokes
> > the rt_fetch() macro therein defined, which in turn invokes list_nth. 
> > 
> > Now list_nth() is not a macro, and postgis
> > is not linked to postgresql dynamic library, so
> > it fails to load.
> > 
> > This worked until some months ago (PG was already
> > versioned as 75dev).
> 
> FYI the List API has recently changed in PostgreSQL 7.5 which is
> probably why this has broken - please see the following links:
> 
> http://archives.postgresql.org/pgsql-patches/2004-05/msg00344.php
> http://archives.postgresql.org/pgsql-patches/2004-05/msg00376.php
> 
> and the thread here:
> 
> http://archives.postgresql.org/pgsql-patches/2004-05/msg00500.php
> 
> 
> > To fix this I've copied list_nth and list_nth_cell into 
> > postgis_estimate.c removing superflous ( I hope ) checks on 
> > boundaries.
> 
> Yuck. I don't think we should be duplicating the PostgreSQL list API
> just because the API has changed between versions. Any chance you could
> look at the posted patch and correct CVS so that this is not needed?

Do you mean the PGSQL List API change patch ?

> 
> > Now estimation selectivity is back up and runnign for PG75
> > 
> > Still... any stable utility interface would be appreciated.
> 
> BTW did you find that building large GiST indices crashes PostgreSQL?

Nope. I haven't been playing with PG75 for a while.

> Since the GiST API has changed you will probably need to apply my "super
> patch" in order to get things working correctly as the problem wasn't
> just a Win32 issue (see
> http://postgis.refractions.net/pipermail/postgis-users/2004-May/004918.h
> tml)
> 
> Would any developers object if the "super patch" for 7.5 were to be
> applied to CVS? If no-one objects I'd like to apply it real soon....

I'll take a look at it.

--strk;

> 
> 
> 
> Cheers,
> 
> Mark.
> 
> ---
> 
> Mark Cave-Ayland
> Webbased Ltd.
> Tamar Science Park
> Derriford
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> England
> 
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> 
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