Re: [HACKERS] SIGSEGV in sebselect.

This is a bug. I can reproduct it here with:

select * from pguser where usesysid in (select distinct usesysid
from pg_user);

The Unique node copy has a NULL uniqueAttr value.

Vadim is this related to subselect distinct handling, or is there some
larger bug here?

>
> Hi All,
>
> I'm getting a SIGSEGV with the following subselect:-
>
> select * from disks where diskid in
> ( select distinct diskid from tracks where artist = 'Led Zeppelin');
>
> The source tree is a cvsup from 22nd Feb (AM GMT)
> Platform is Linux/SPARC
>
> I'm afraid my debugging skills are limited to generating a backtrace
> so here goes....
>
> Keith.
>
> Program received signal SIGSEGV, Segmentation fault.
> 0xe0104ee4 in strlen ()
> (gdb) bt
> #0 0xe0104ee4 in strlen ()
> #1 0xd1264 in pstrdup (string=0x0) at palloc.c:115
> #2 0x696c0 in _copyUnique (from=0x1b0b90) at copyfuncs.c:552
> #3 0x6abdc in copyObject (from=0x1b0b90) at copyfuncs.c:1687
> #4 0x69754 in _copySubPlan (from=0x1a83d0) at copyfuncs.c:594
> #5 0x6abfc in copyObject (from=0x1a83d0) at copyfuncs.c:1693
> #6 0x698b0 in _copyExpr (from=0x1b1f90) at copyfuncs.c:679
> #7 0x6ac2c in copyObject (from=0x1b1f90) at copyfuncs.c:1706
> #8 0x6a304 in _copyCInfo (from=0x1b1710) at copyfuncs.c:1334
> #9 0x6ad5c in copyObject (from=0x1b1710) at copyfuncs.c:1767
> #10 0x6ae54 in copyObject (from=0x1b2d10) at copyfuncs.c:1829
> #11 0x7e8b8 in create_seqscan_path (rel=0x1b0a90) at pathnode.c:228
> #12 0x737c4 in find_rel_paths (root=0x15d390, rels=0x1b2f70) at allpaths.c:118
> #13 0x73778 in find_paths (root=0x15d390, rels=0x1b2f70) at allpaths.c:72
> #14 0x78ae4 in subplanner (root=0x15d390, flat_tlist=0x1ae330, qual=0x1ae3f0) at
> planmain.c:271
> #15 0x789fc in query_planner (root=0x15d390, command_type=1, tlist=0x1aa910,
> qual=0x1ae3f0) at planmain.c:181
> #16 0x79040 in union_planner (parse=0x15d390) at planner.c:138
> #17 0x78f2c in planner (parse=0x15d390) at planner.c:72
> #18 0xa80f4 in pg_parse_and_plan (
> query_string=0xefffdc38 "select * from disks where diskid in ( select
> distinct diskid from tracks where artist = 'Led Zeppelin');", typev=0x0,
> nargs=0, queryListP=0xefffdb64, dest=Remote) at postgres.c:534
> #19 0xa81e0 in pg_exec_query_dest (
> query_string=0xefffdc38 "select * from disks where diskid in ( select
> distinct diskid from tracks where artist = 'Led Zeppelin');", argv=0x0,
> typev=0x0, nargs=0, dest=Remote) at postgres.c:615
> #20 0xa81bc in pg_exec_query (
> query_string=0xefffdc38 "select * from disks where diskid in ( select
> distinct diskid from tracks where artist = 'Led Zeppelin');", argv=0x0,
> typev=0x0, nargs=0) at postgres.c:597
> #21 0xa90c4 in PostgresMain (argc=1122304, argv=0xeffffc38) at postgres.c:1373
> #22 0x68788 in main (argc=11, argv=0xeffffd04) at main.c:97
>
>
>

--
Bruce Momjian
maillist(at)candle(dot)pha(dot)pa(dot)us