Re: [PATCHES] WITH RECUSIVE patches 0723

#1 (**permalink**) 07-28-2008, 06:41 PM

> On Wed, Jul 23, 2008 at 10:59:20AM -0400, Tom Lane wrote:
> > Tatsuo Ishii <ishii@postgresql.org> writes:
> > > Reviewers, please let me know if you find problems with the
> > > patches. If none, I would like to commit this weekend.
> >
> > Has this patch actually been reviewed yet? The only reports I've
> > seen are from testing; nothing from anyone actually reading the
> > code. I know I've not looked at it yet.
>
> I've read the code, for what that's worth, which isn't much. I just
> tried out this patch on a fresh checkout of CVS TIP and found:
>
> EXPLAIN WITH RECURSIVE t(i) AS (VALUES(1::int) UNION ALL SELECT i+1 FROM t WHERE i < 5) SELECT * FROM t AS t1 JOIN t AS t2 USING(i);
> QUERY PLAN
> -------------------------------------------------------------------------------------
> Hash Join (cost=0.08..0.16 rows=2 width=4)
> Hash Cond: (t1.i = t2.i)
> -> Recursion on t1 (cost=0.00..0.06 rows=2 width=4)
> -> Append (cost=0.00..0.04 rows=2 width=4)
> -> Values Scan on "*VALUES*" (cost=0.00..0.01 rows=1 width=4)
> -> Recursive Scan on t (cost=0.00..0.00 rows=1 width=4)
> Filter: (i < 5)
> -> Hash (cost=0.06..0.06 rows=2 width=4)
> -> Recursion on t2 (cost=0.00..0.06 rows=2 width=4)
> -> Append (cost=0.00..0.04 rows=2 width=4)
> -> Values Scan on "*VALUES*" (cost=0.00..0.01 rows=1 width=4)
> -> Recursive Scan on t (cost=0.00..0.00 rows=1 width=4)
> Filter: (i < 5)
> (13 rows)
>
> When I try to execute the query without the EXPLAIN, having attached a debugger
> to the back-end, I get.

Thanks for the report. We will look into this.
--
Tatsuo Ishii
SRA OSS, Inc. Japan

> (gdb) continue
> Continuing.
>
> Program received signal SIGSEGV, Segmentation fault.
> 0x08192dcd in ExecQual (qual=0xa183824, econtext=0xa183230, resultForNull=0 '\0') at execQual.c:4513
> 4513 expr_value = ExecEvalExpr(clause, econtext, &isNull, NULL);
> (gdb) i s
> #0 0x08192dcd in ExecQual (qual=0xa183824, econtext=0xa183230, resultForNull=0 '\0') at execQual.c:4513
> #1 0x08199b23 in ExecScan (node=0xa1831a4, accessMtd=0x81a6bb0 <RecursivescanNext>) at execScan.c:131
> #2 0x081a6ba9 in ExecRecursiveScan (node=0xa1831a4) at nodeRecursivescan.c:48
> #3 0x08192320 in ExecProcNode (node=0xa1831a4) at execProcnode.c:380
> #4 0x081a6923 in RecursionNext (node=0xa17fe18) at nodeRecursion.c:68
> #5 0x08199a83 in ExecScan (node=0xa17fe18, accessMtd=0x81a6840 <RecursionNext>) at execScan.c:68
> #6 0x081a6839 in ExecRecursion (node=0xa17fe18) at nodeRecursion.c:116
> #7 0x081923e0 in ExecProcNode (node=0xa17fe18) at execProcnode.c:339
> #8 0x081a1c13 in MultiExecHash (node=0xa17fcc4) at nodeHash.c:94
> #9 0x081a28b9 in ExecHashJoin (node=0xa17b654) at nodeHashjoin.c:159
> #10 0x081922d8 in ExecProcNode (node=0xa17b654) at execProcnode.c:395
> #11 0x081901db in standard_ExecutorRun (queryDesc=0xa15c334, direction=ForwardScanDirection, count=0) at execMain.c:1271
> #12 0x08240dc4 in PortalRunSelect (portal=0xa15631c, forward=1 '\001', count=0, dest=0xa1733d8) at pquery.c:937
> #13 0x082420e6 in PortalRun (portal=0xa15631c, count=2147483647, isTopLevel=1 '\001', dest=0xa1733d8, altdest=0xa1733d8,
> completionTag=0xbfcacaea "") at pquery.c:793
> #14 0x0823d0a7 in exec_simple_query (
> query_string=0xa12fc9c "WITH RECURSIVE t(i) AS (VALUES(1::int) UNION ALL SELECT i+1 FROM t WHERE i < 5) SELECT * FROM t AS t1 JOIN t AS t2 USING(i);") at postgres.c:977
> #15 0x0823e84c in PostgresMain (argc=4, argv=0xa0d0dac, username=0xa0d0d7c "shackle") at postgres.c:3559
> #16 0x0820957f in ServerLoop () at postmaster.c:3238
> #17 0x0820a4e0 in PostmasterMain (argc=3, argv=0xa0ced50) at postmaster.c:1023
> #18 0x081b69d6 in main (argc=3, argv=0xa0ced50) at main.c:188
>
> What other information could help track down this problem?
>
> Cheers,
> David.
> --
> David Fetter <david@fetter.org> http://fetter.org/
> Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
> Skype: davidfetter XMPP: david.fetter@gmail.com
>
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