first modification :
added a new plpgsql function,
added the equivalent c functionn un pc_access.c
added a new function in pc_patch.c

This pc_patch funton is not completed.
under dev, compil but not completed :
done :
clone of schema  subset
clone of dimstats subset
dimension_reduction now correct signature

remaining :
clone stats subset (not dimstats)
clone bytes subset
test ...
correct plug of plpgsql text[] to C char **
added a function stats->json
eveithing is in place,
but still segfault, adding printf in the serialize function
added  a bounds_to_string function
working function !
probleme is there is nothing to work with the patch, and it can't be displayed.
next step : function pc_explode_subset
changes made to accept anoter argupment as a array[text], but reading this gives segfault
working version with correct text[] input.
DO nothing out of patch for the moment
Modified version with the text[] arg retrievalsperated into a function
working version ,
a bit cleaned,
but stil la lots of print
Cleaned version,
all print commented,
still does nothing
updated the cunit part to comment print and added a meaningfull test
a bit of cleaning and some minor interface modifications.
This version works
closing the branch
removing some pcinfo, but the function being developped are still heavily pcinfo-ed
tested and benched version, complet
Merge back into "main" branch
adding the short sql script to bench performance of different options