Win32 GiST bug - more info - Mailing list pgsql-hackers-win32
From | Mark Cave-Ayland |
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Subject | Win32 GiST bug - more info |
Date | |
Msg-id | 8F4A22E017460A458DB7BBAB65CA6AE50265D4@openmanage Whole thread Raw |
Responses |
Re: Win32 GiST bug - more info
|
List | pgsql-hackers-win32 |
Hi guys, Further to Paul Ramsey's email regarding problems with GiST under Win32, I've been able to get some more information using gdb under MingW. It looks as if something strange is going on with one of the pointers being used during the creation of the GiST index. Here is the output from gdb which shows that the problem occurs in the gbox_union() function when trying to build a GiST index using the PostGIS spatial extensions to PostgreSQL: $ gdb ./postgres.exe GNU gdb 5.2.1 Copyright 2002 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i686-pc-mingw32"... (gdb) attach 3984 Attaching to program `c:\pgsql75win\bin/./postgres.exe', process 3984 [Switching to thread 3984.0xdbc] (gdb) continue Continuing. Program received signal SIGSEGV, Segmentation fault. [Switching to thread 3984.0x1a8] 0x6d850a9a in gbox_union (fcinfo=0x22d470) at postgis_gist_72.c:342 342 if (pageunion->high.x < cur->high.x) (gdb) bt #0 0x6d850a9a in gbox_union (fcinfo=0x22d470) at postgis_gist_72.c:342 #1 0x00000000 in ?? () (gdb) print pageunion $1 = (BOX *) 0x141b6b0 (gdb) print cur $2 = (BOX *) 0x7f7f7f7e (gdb) print entryvec $3 = (bytea *) 0x1453e24 (gdb) print sizep $4 = (int *) 0x22d55c The actual function itself looks like this: Datum gbox_union(PG_FUNCTION_ARGS) { bytea *entryvec = (bytea *) PG_GETARG_POINTER(0); int *sizep = (int *) PG_GETARG_POINTER(1); int numranges, i; BOX *cur, *pageunion; #ifdef DEBUG_GIST elog(NOTICE,"GIST: gbox_union called\n"); fflush( stdout ); #endif numranges = (VARSIZE(entryvec) - VARHDRSZ) / sizeof(GISTENTRY); pageunion = (BOX *) palloc(sizeof(BOX)); cur = DatumGetBoxP(((GISTENTRY *) VARDATA(entryvec))[0].key); memcpy((void *) pageunion, (void *) cur, sizeof(BOX)); for (i = 1; i < numranges; i++) { cur = DatumGetBoxP(((GISTENTRY *) VARDATA(entryvec))[i].key); if (pageunion->high.x < cur->high.x) pageunion->high.x = cur->high.x; if (pageunion->low.x > cur->low.x) pageunion->low.x = cur->low.x; if (pageunion->high.y < cur->high.y) pageunion->high.y = cur->high.y; if (pageunion->low.y > cur->low.y) pageunion->low.y = cur->low.y; } *sizep = sizeof(BOX); PG_RETURN_POINTER(pageunion); } Looking at the pointers, the value for cur looks quite suspicious ;) Could it be some sort of alignment/pointer problem with the GISTENTRY or VAR* macros? I can provide as much information as required if someone can talk me through what I need to do using gdb. The version of PostgreSQL being used was taken from CVS last Friday (21/05/2004). Many thanks, Mark. --- Mark Cave-Ayland Webbased Ltd. Tamar Science Park Derriford Plymouth PL6 8BX England Tel: +44 (0)1752 764445 Fax: +44 (0)1752 764446 This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person.
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