[postgis-tickets] [PostGIS] #4747: Re: [PostGIS] #4745: Possible problem with new version 2.5.5

[PostGIS]

#4747: Re: [PostGIS] #4745: Possible problem with new version 2.5.5
------------------------+---------------------------
  Reporter:  ezimanyi   |      Owner:  pramsey
      Type:  defect     |     Status:  closed
  Priority:  medium     |  Milestone:  PostGIS 3.1.0
 Component:  postgis    |    Version:  2.5.x
Resolution:  duplicate  |   Keywords:
------------------------+---------------------------

Comment (by Algunenano):

 > In order to call the CallerFInfoFunctionCallXXXX function I need to have
 a hold of the fcinfo obtained for the very first external MobilityDB
 function call so this should be propagated in a long chain of functions.

 That's what Postgis has to do. You could probably get away with caching it
 in a global static variable, but I would rather keep the reference when we
 need it. If you find a better solution I'm all ears.

 > Wouldn't be possible to add a call

 AFAIC, that wouldn't solve anything; `postgis_initialize_cache` is already
 being called by `transform` via `GetPJUsingFCInfo`
 (`GetProjectionsUsingFCInfo` is 2.5 from what I see), which receives the
 fcinfo of the C function. If `transform` doesn't receive a "full" fcinfo
 it can't initialize the cache, so it doesn't matter who calls it.

 Anyhow, this is all based on how I think this works, I haven't actually
 tested it so I'd recommend you to check it first to confirm if that's
 actually the issue. Also, keep in mind that this is heavily tied to how
 Postgis is setup and installed, as it's looking for the namespace where
 the function is installed, at that might be different in mobilitydb. I
 would strongly recommend against depending on the behaviour of Postgis C
 functions; an instead depend on the SQL API, which is stable and how many
 other projects use make use of its features.

-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/4747#comment:5>
PostGIS <http://trac.osgeo.org/postgis/>
The PostGIS Trac is used for bug, enhancement & task tracking, a user and developer wiki, and a view into the subversion code repository of PostGIS project.