Re: [PATCHES] [HACKERS] WITH RECUSIVE patches 0723

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.

(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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