Re: Win32 GiST bug - more info

Hi Tom,

Thanks for your reply. I found that I got a "better" backtrace by
executing a couple of commands in the psql.exe session before creating
the index. The improved backtrace was given below:

$ 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
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Type "show copying" to see the conditions.
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This GDB was configured as "i686-pc-mingw32"...
(gdb) attach 3804
Attaching to program `c:\pgsql75win\bin/postgres.exe', process 3804
[Switching to thread 3804.0xec]
(gdb) continue
Continuing.

Program received signal SIGSEGV, Segmentation fault.
[Switching to thread 3804.0xe30]
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 0x77f57d70 in _libmsvcrt_a_iname ()
#2 0x0060896a in FunctionCall2 (flinfo=0x22e530, arg1=21174392,
arg2=2282844)
at fmgr.c:1132
#3 0x004078f5 in gistgetadjusted (r=0x13caef8, oldtup=0x188ad30,
addtup=0x14318c8, giststate=0x22e230) at gist.c:813
#4 0x00406ba1 in gistlayerinsert (r=0x13caef8, blkno=0, itup=0x22e044,
len=0x22e048, res=0x0, giststate=0x22e230) at gist.c:483
#5 0x0040642f in gistdoinsert (r=0x13caef8, itup=0x1411048, res=0x0,
giststate=0x22e230) at gist.c:426
#6 0x0040616b in gistbuildCallback (index=0x13caef8, htup=0x1431edc,
attdata=0x22e150, nulls=0x22e130 " ", tupleIsAlive=1,
state=0x22e230)
at gist.c:274
#7 0x00454e0a in IndexBuildHeapScan (heapRelation=0x13aefe8,
indexRelation=0x13caef8, indexInfo=0x14110e8,
callback=0x4060b0 <gistbuildCallback>, callback_state=0x22e230)
at index.c:1599
#8 0x00405ff2 in gistbuild (fcinfo=0x22f770) at gist.c:185
#9 0x00609184 in OidFunctionCall3 (functionId=782, arg1=20639720,
arg2=20754168, arg3=21041384) at fmgr.c:1399
#10 0x004549eb in index_build (heapRelation=0x13aefe8,
indexRelation=0x13caef8, indexInfo=0x14110e8) at index.c:1348
#11 0x0045373c in index_create (heapRelationId=33591,
indexRelationName=0x13b4cb8 "geomtest_idx", indexInfo=0x14110e8,
accessMethodObjectId=783, classObjectId=0x1411028, primary=0 '\0',
isconstraint=0 '\0', allow_system_table_mods=0 '\0', skip_build=0
'\0')
at index.c:747
#12 0x004d1321 in DefineIndex (heapRelation=0x13b4cf8,
indexRelationName=0x13b4cb8 "geomtest_idx",
accessMethodName=0x13b4d28 "gist", attributeList=0x13b4df8,
predicate=0x0,
rangetable=0x0, unique=0 '\0', primary=0 '\0', isconstraint=0 '\0',
is_alter_table=0 '\0', check_rights=1 '\001', skip_build=0 '\0',
quiet=0 '\0') at indexcmds.c:339
#13 0x0058d801 in ProcessUtility (parsetree=0x13b4e18, dest=0x13b4e68,
completionTag=0x22fac0 "") at utility.c:634
#14 0x0058bab5 in PortalRunUtility (portal=0x13fedb0, query=0x13b4b98,
dest=0x13b4e68, completionTag=0x22fac0 "") at pquery.c:780
#15 0x0058be34 in PortalRunMulti (portal=0x13fedb0, dest=0x13b4e68,
altdest=0x13b4e68, completionTag=0x22fac0 "") at pquery.c:844
#16 0x0058b4d2 in PortalRun (portal=0x13fedb0, count=2147483647,
dest=0x13b4e68, altdest=0x13b4e68, completionTag=0x22fac0 "")
at pquery.c:501
#17 0x005869de in exec_simple_query (
query_string=0x13b4978 "create index geomtest_idx on geomtest using
gist (geom gist_geometry_ops);") at postgres.c:930
#18 0x0058a206 in PostgresMain (argc=6, argv=0x3d4960, username=0x3d50b0
"mca")
at postgres.c:2925
#19 0x00558ca3 in BackendRun (port=0x22fc40) at postmaster.c:2660
#20 0x00558e6f in SubPostmasterMain (argc=2, argv=0x3d24d8)
at postmaster.c:2716
#21 0x0051d821 in main (argc=4, argv=0x3d24d0) at main.c:286
(gdb)

Does this give you a better idea of exactly what's happening?

Many thanks,

Mark.

---

Mark Cave-Ayland
Webbased Ltd.
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> -----Original Message-----
> From: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]
> Sent: 26 May 2004 13:45
> To: Mark Cave-Ayland
> Cc: pgsql-hackers-win32(at)postgresql(dot)org
> Subject: Re: [pgsql-hackers-win32] Win32 GiST bug - more info
>
>
> "Mark Cave-Ayland" <m(dot)cave-ayland(at)webbased(dot)co(dot)uk> writes:
> > (gdb) print cur
> > $2 = (BOX *) 0x7f7f7f7e
>
> > Looking at the pointers, the value for cur looks quite suspicious ;)
>
> Yeah, it's been taken from memory that's not been
> initialized, or has already been pfree'd. In other words the
> caller is at fault, not this subroutine. Can't say much more
> than that though.
>
> regards, tom lane
>