Can't replace default converter. - Mailing list pgsql-hackers

Hello!

There is a database in KOI8-R encoding. And we have a client who is 
querying the database:
set client_encoding TO 'ALT'
and then he write some data into the database.
I have a problem with some symbols which exists in ALT encoding and 
which are absent in KOI8-R encoding. As result, during inserting strings 
with such symbols postgresql returns an error, for example:
ERROR: character 0xfc of encoding "ALT" has no equivalent in 
"MULE_INTERNAL"
I've decided to write my own converter, so here is my code:

[code]

#include <postgres.h>
#include <fmgr.h>


#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif

PG_FUNCTION_INFO_V1(fix_alt_to_koi8r);
PG_FUNCTION_INFO_V1(fix_koi8r_to_alt);

Datum
fix_alt_to_koi8r(PG_FUNCTION_ARGS)
{      elog(NOTICE,"ALT_TO_KOI8");   unsigned char *src  = PG_GETARG_CSTRING(*2*);   unsigned char *dest =
PG_GETARG_CSTRING(*3*);  int        len = PG_GETARG_INT32(*4*);
 
   Assert(PG_GETARG_INT32(*0*) == PG_ALT);   Assert(PG_GETARG_INT32(*1*) == PG_KOI8R);   Assert(len >= *0*);


      static const unsigned char convert866toKOI8[] = {              
*0*,*1*,*2*,*3*,*4*,*5*,*6*,*7*,*8*,*9*,*10*,*11*,*12*,*13*,*14*,*15*,              
*16*,*17*,*18*,*19*,*20*,*21*,*22*,*23*,*24*,*25*,*26*,*27*,*28*,*29*,*30*,*31*, 
              
*32*,*33*,*34*,*35*,*36*,*37*,*38*,*39*,*40*,*41*,*42*,*43*,*44*,*45*,*46*,*47*, 
              
*48*,*49*,*50*,*51*,*52*,*53*,*54*,*55*,*56*,*57*,*58*,*59*,*60*,*61*,*62*,*63*, 
              
*64*,*65*,*66*,*67*,*68*,*69*,*70*,*71*,*72*,*73*,*74*,*75*,*76*,*77*,*78*,*79*, 
              
*80*,*81*,*82*,*83*,*84*,*85*,*86*,*87*,*88*,*89*,*90*,*91*,*92*,*93*,*94*,*95*, 
              
*96*,*97*,*98*,*99*,*100*,*101*,*102*,*103*,*104*,*105*,*106*,*107*,*108*,*109*,*110*,*111*, 
              
*112*,*113*,*114*,*115*,*116*,*117*,*118*,*119*,*120*,*121*,*122*,*123*,*124*,*125*,*126*,*127*, 
              
*225*,*226*,*247*,*231*,*228*,*229*,*246*,*250*,*233*,*234*,*235*,*236*,*237*,*238*,*239*,*240*, 
              
*242*,*243*,*244*,*245*,*230*,*232*,*227*,*254*,*251*,*253*,*255*,*249*,*248*,*252*,*224*,*241*, 
              
*193*,*194*,*215*,*199*,*196*,*197*,*214*,*218*,*201*,*202*,*203*,*204*,*205*,*206*,*207*,*208*, 
              
*210*,*211*,*212*,*213*,*198*,*200*,*195*,*222*,*219*,*221*,*223*,*217*,*216*,*220*,*192*,*209*, 
              
*180*,*164*,*183*,*167*,*196*,*197*,*198*,*199*,*200*,*201*,*202*,*203*,*204*,*205*,*206*,*207*, 
              
*208*,*209*,*210*,*211*,*212*,*213*,*214*,*215*,*216*,*217*,*218*,*219*,*220*,*221*,*222*,*223*, 
              
*210*,*211*,*212*,*213*,*198*,*200*,*195*,*222*,*219*,*221*,*223*,*217*,*216*,*220*,*192*,*209*, 
          
*179*,*241*,*242*,*243*,*244*,*245*,*246*,*247*,*248*,*249*,*250*,*251*,*252*,*253*,*254*,*255* 
      };


   while(len){       *dest = convert866toKOI8[(unsigned char)(*src)];       ++src;       ++dest;       --len;   }
   PG_RETURN_VOID();
}



Datum
fix_koi8r_to_alt(PG_FUNCTION_ARGS)
{      elog(NOTICE,"KOI8_TO_ALT");   unsigned char *src  = PG_GETARG_CSTRING(*2*);   unsigned char *dest =
PG_GETARG_CSTRING(*3*);  int        len = PG_GETARG_INT32(*4*);
 
   Assert(PG_GETARG_INT32(*0*) == PG_KOI8R);   Assert(PG_GETARG_INT32(*1*) == PG_ALT);   Assert(len >= *0*);


      static const unsigned char KOI8to866[] = {          
*0*,*1*,*2*,*3*,*4*,*5*,*6*,*7*,*8*,*9*,*10*,*11*,*12*,*13*,*14*,*15*,          
*16*,*17*,*18*,*19*,*20*,*21*,*22*,*23*,*24*,*25*,*26*,*27*,*28*,*29*,*30*,*31*, 
          
*32*,*33*,*34*,*35*,*36*,*37*,*38*,*39*,*40*,*41*,*42*,*43*,*44*,*45*,*46*,*47*, 
          
*48*,*49*,*50*,*51*,*52*,*53*,*54*,*55*,*56*,*57*,*58*,*59*,*60*,*61*,*62*,*63*, 
          
*64*,*65*,*66*,*67*,*68*,*69*,*70*,*71*,*72*,*73*,*74*,*75*,*76*,*77*,*78*,*79*, 
          
*80*,*81*,*82*,*83*,*84*,*85*,*86*,*87*,*88*,*89*,*90*,*91*,*92*,*93*,*94*,*95*, 
          
*96*,*97*,*98*,*99*,*100*,*101*,*102*,*103*,*104*,*105*,*106*,*107*,*108*,*109*,*110*,*111*, 
          
*112*,*113*,*114*,*115*,*116*,*117*,*118*,*119*,*120*,*121*,*122*,*123*,*124*,*125*,*126*,*255*, 
          
*32*,*32*,*32*,*32*,*32*,*32*,*32*,*32*,*32*,*32*,*32*,*32*,*32*,*32*,*32*,*32*, 
          
*32*,*32*,*32*,*32*,*32*,*249*,*32*,*32*,*32*,*32*,*32*,*32*,*248*,*32*,*32*,*32*, 
          
*32*,*32*,*32*,*241*,*193*,*32*,*105*,*195*,*32*,*32*,*32*,*32*,*32*,*32*,*32*,*244*, 
          
*32*,*32*,*32*,*240*,*192*,*32*,*73*,*194*,*252*,*32*,*32*,*32*,*32*,*32*,*32*,*32*, 
          
*238*,*160*,*161*,*230*,*164*,*165*,*228*,*163*,*229*,*168*,*169*,*170*,*171*,*172*,*173*,*174*, 
          
*175*,*239*,*224*,*225*,*226*,*227*,*166*,*162*,*236*,*235*,*167*,*232*,*237*,*233*,*231*,*234*, 
          
*158*,*128*,*129*,*150*,*132*,*133*,*148*,*131*,*149*,*136*,*137*,*138*,*139*,*140*,*141*,*142*, 
          
*143*,*159*,*144*,*145*,*146*,*147*,*134*,*130*,*156*,*155*,*135*,*152*,*157*,*153*,*151*,*154*       };


   while(len){       *dest = KOI8to866[(unsigned char)(*src)];       ++src;       ++dest;       --len;   }
   PG_RETURN_VOID();

[/code]

I has copied this library into $libdir/funcs and I was trying to install 
the new converter instead of the old one,  in two directions alt->koi8 
and koi8->alt:

[code]

db_server=# CREATE FUNCTION 
fix_koi8r_to_alt(integer,integer,cstring,internal,integer) RETURNS 
integer AS '$libdir/funcs/fix_conv.so','fix_koi8r_to_alt' LANGUAGE C 
STRICT;
CREATE FUNCTION
db_server=# CREATE FUNCTION 
fix_alt_to_koi8r(integer,integer,cstring,internal,integer) RETURNS 
integer AS '$libdir/funcs/fix_conv.so','fix_alt_to_koi8r' LANGUAGE C 
STRICT;
CREATE FUNCTION
db_server=# CREATE DEFAULT CONVERSION koi2alt FOR 'KOI8' TO 'ALT' FROM 
fix_koi8r_to_alt;
CREATE CONVERSION
db_server=# CREATE DEFAULT CONVERSION alt2koi FOR 'ALT' TO 'KOI8' FROM 
fix_alt_to_koi8r;
CREATE CONVERSION
db_server=# set client_encoding to 'alt';

[/code]

I thought, that was all, but it was not. During the insert of 'bad' 
symbol in the test table i had the same error:
ERROR:  character 0xfc of encoding "ALT" has no equivalent in 
"MULE_INTERNAL"

I think that my conversion functions are not used. I saw in table 
pg_conversion:         conname           | connamespace | conowner | conforencoding | 
contoencoding |     conproc       | condefault         koi8_r_to_windows_866 |         *11* |        *1*    
|            *21*        |               *23*   |   koi8r_to_alt    | t          koi2alt               |         *2200*
    |          *1*  
 
|         *21*          |           *23*       | fix_koi8r_to_alt | t          windows_866_to_koi8_r         *11*
|   *1*     
 
|              *23*     |             *21*     | alt_to_koi8r      | t          alt2koi                    |
*2200*|        *1*    
 
|            *23*        |     *21*               | fix_alt_to_koi8r | t

and deleted two standard conversion functions:
[code]
db_server=# DROP CONVERSION koi8_r_to_windows_866;
DROP CONVERSION
db_server=# DROP CONVERSION windows_866_to_koi8_r;
DROP CONVERSION
[/code]

leaving only my own conversion functions.After this, when I'm trying to 
set the client encoding to ALT I got an error:

db_server=# set client_encoding to 'alt';
server closed the connection unexpectedly      This probably means the server terminated abnormally      before or
whileprocessing the request.
 
The connection to the server was lost. Attempting reset: Failed.
!> 

Is anyone can tell me what I'm doing wrong?
Thanks.