Hi to all

because I need polygons with a counterclockwise-orientation (and their holes in clockwise direction) I have dealt with the extension SFCGAL and ST_ForceLHR. A few questions have emerged ...

1.
I have updated postgis to 2.2.0 and installed the PostGIS extension postgis_sfcgal. According to the documentation I can switch between sfcgal postgis.backend  / postgis.backend geos. Why is it possible to run sfcgal functions even when I specify explicitly geos as backend? And which version of the mentioned function is then used (sfcgal, geos)? "Some SFCGAL functions replace standard ones (ST_Intersects, ST_Intersection, ST_Difference, ST_Union, ST_Area and ST_Distance)"
2.
Why is it not possible to use the functions ST_ForceLHR / ForceRHR on geography?
3.
Why is the orientation of the "holes" in polygons using ST_ForceRHR considered, but not when using ST_ForceLHR? --> Is there an easy way to change that or a workaround?
4.
Why does ST_ForceRHR work only with polygons and not as ST_ForceLHR also with multipolygons?
 
The Version I am using:
PostgreSQL 9.3.5, compiled by Visual C++ build 1600, 64-bit on Windows
Postgis 2.2.0
 
Biggest Problem of all:
If I use ST_ForceLHR with a bigger polygon or a multipolygon postgresql crashes and is not able to recover because of  a “pre-existing shared memory block is still in use”
LOG:  server process (PID 30468) was terminated by exception 0xC00000FD
DETAIL:  Failed process was running: SELECT xy(4056532,12283)                         <-- Function including ST_ForceLHR
HINT:  See C include file "ntstatus.h" for a description of the hexadecimal value.
LOG:  terminating any other active server processes
postgres@Test FATAL:  the database system is in recovery mode
LOG:  all server processes terminated; reinitializing
FATAL:  pre-existing shared memory block is still in use
HINT:  Check if there are any old server processes still running, and terminate them.
 
Any help will be great!!
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