Re: BUG #5798: Some weird error with pl/pgsql procedure

Hi all and Hi Robert

I finally managed create working slave server with non-stripped Postgresql
8.4.7 and working gdb.
(sorry for such long delay).
And i can reproduce situation quite easy now, so i managed get stack
backtrace with that error.
What i need to do now? I have some expirience with gbd now but i have no
idea where to look next.

Full backtrace:

Breakpoint 1, slot_getattr (slot=0xdd09ea468, attnum=-1, isnull=0xdd09b4a68
"") at heaptuple.c:1185
1185 elog(ERROR, "cannot extract system attribute
from virtual tuple");
(gdb) bt
#0 slot_getattr (slot=0xdd09ea468, attnum=-1, isnull=0xdd09b4a68 "") at
heaptuple.c:1185
#1 0x000000000058a5f8 in ExecEvalScalarVar (exprstate=0xdd09b4b60,
econtext=0xdd09b4a80, isNull=0xdd09b4a68 "", isDone=0xdd09b4ce0)
at execQual.c:787
#2 0x00000000005933d7 in ExecTargetList (targetlist=0xdd09b4cb0,
econtext=0xdd09b4a80, values=0xdd09b4a50, isnull=0xdd09b4a68 "",
itemIsDone=0xdd09b4ce0, isDone=0x0) at execQual.c:5118
#3 0x00000000005939a3 in ExecProject (projInfo=0xdd09b4be0, isDone=0x0) at
execQual.c:5333
#4 0x00000000005879c7 in ExecProcessReturning
(projectReturning=0xdd09b4be0, tupleSlot=0xdd09ea468, planSlot=0xdd09ea3a8,
dest=0xdd09de5c8) at execMain.c:2273
#5 0x00000000005875fe in ExecUpdate (slot=0xdd09ea468,
tupleid=0x7fffffffd2e0, planSlot=0xdd09ea3a8, dest=0xdd09de5c8,
estate=0xdd09e6030) at execMain.c:2142
#6 0x0000000000586c68 in ExecutePlan (estate=0xdd09e6030,
planstate=0xdd09ea550, operation=CMD_UPDATE, numberTuples=0,
direction=ForwardScanDirection, dest=0xdd09de5c8) at execMain.c:1681
#7 0x00000000005849a5 in standard_ExecutorRun (queryDesc=0xdd09de658,
direction=ForwardScanDirection, count=0) at execMain.c:309
#8 0x00000000005848a5 in ExecutorRun (queryDesc=0xdd09de658,
direction=ForwardScanDirection, count=0) at execMain.c:258
#9 0x0000000000673d43 in ProcessQuery (plan=0xdd0998890,
sourceText=0xdd09c5830 "UPDATE ONLY bill.ctrl_servers SET opt = opt
WHERE ctid=ANY($1) RETURNING ctid", params=0xdd09c58c0,
dest=0xdd09de5c8, completionTag=0x7fffffffd4e0 "") at pquery.c:196
#10 0x00000000006754e5 in PortalRunMulti (portal=0xdd08c8140, isTopLevel=0
'\000', dest=0xdd09de5c8, altdest=0x9dfdc0,
completionTag=0x7fffffffd4e0 "") at pquery.c:1269
#11 0x0000000000675127 in FillPortalStore (portal=0xdd08c8140, isTopLevel=0
'\000') at pquery.c:1061
#12 0x00000000006757f8 in PortalRunFetch (portal=0xdd08c8140,
fdirection=FETCH_FORWARD, count=10, dest=0x9dfe40) at pquery.c:1397
#13 0x00000000005b24e1 in _SPI_cursor_operation (portal=0xdd08c8140,
direction=FETCH_FORWARD, count=10, dest=0x9dfe40) at spi.c:2088
#14 0x00000000005b11a8 in SPI_cursor_fetch (portal=0xdd08c8140, forward=1
'\001', count=10) at spi.c:1258
#15 0x0000000dd0b1e199 in exec_for_query (estate=0x7fffffffda50,
stmt=0xdd098bfc8, portal=0xdd08c8140, prefetch_ok=1 '\001')
at pl_exec.c:4262
#16 0x0000000dd0b1bc43 in exec_stmt_dynfors (estate=0x7fffffffda50,
stmt=0xdd098bfc8) at pl_exec.c:3107
#17 0x0000000dd0b1881a in exec_stmt (estate=0x7fffffffda50,
stmt=0xdd098bfc8) at pl_exec.c:1308
#18 0x0000000dd0b1859a in exec_stmts (estate=0x7fffffffda50,
stmts=0xdd098bc28) at pl_exec.c:1203
#19 0x0000000dd0b18f38 in exec_stmt_while (estate=0x7fffffffda50,
stmt=0xdd098d6f8) at pl_exec.c:1608
#20 0x0000000dd0b18733 in exec_stmt (estate=0x7fffffffda50,
stmt=0xdd098d6f8) at pl_exec.c:1264
#21 0x0000000dd0b1859a in exec_stmts (estate=0x7fffffffda50,
stmts=0xdd098a650) at pl_exec.c:1203
#22 0x0000000dd0b183df in exec_stmt_block (estate=0x7fffffffda50,
block=0xdd098d778) at pl_exec.c:1140
#23 0x0000000dd0b16a29 in plpgsql_exec_function (func=0xdd087abd8,
fcinfo=0x7fffffffdcf0) at pl_exec.c:315
#24 0x0000000dd0b1260f in plpgsql_call_handler (fcinfo=0x7fffffffdcf0) at
pl_handler.c:95
---Type <return> to continue, or q <return> to quit---
#25 0x000000000058c902 in ExecMakeTableFunctionResult (funcexpr=0xdd08ca730,
econtext=0xdd08ca460, expectedDesc=0xdd08ca5f0,
randomAccess=0 '\000') at execQual.c:2016
#26 0x00000000005a3e7d in FunctionNext (node=0xdd08ca350) at
nodeFunctionscan.c:64
#27 0x0000000000593a10 in ExecScan (node=0xdd08ca350, accessMtd=0x5a3e10
<FunctionNext>) at execScan.c:68
#28 0x00000000005a3eea in ExecFunctionScan (node=0xdd08ca350) at
nodeFunctionscan.c:98
#29 0x0000000000588fdf in ExecProcNode (node=0xdd08ca350) at
execProcnode.c:385
#30 0x0000000000586794 in ExecutePlan (estate=0xdd08ca030,
planstate=0xdd08ca350, operation=CMD_SELECT, numberTuples=0,
direction=ForwardScanDirection, dest=0xdd08996f0) at execMain.c:1504
#31 0x00000000005849a5 in standard_ExecutorRun (queryDesc=0xdd082f430,
direction=ForwardScanDirection, count=0) at execMain.c:309
#32 0x00000000005848a5 in ExecutorRun (queryDesc=0xdd082f430,
direction=ForwardScanDirection, count=0) at execMain.c:258
#33 0x0000000000674e18 in PortalRunSelect (portal=0xdd08c8030, forward=1
'\001', count=0, dest=0xdd08996f0) at pquery.c:953
#34 0x0000000000674ab9 in PortalRun (portal=0xdd08c8030,
count=9223372036854775807, isTopLevel=1 '\001', dest=0xdd08996f0,
altdest=0xdd08996f0, completionTag=0x7fffffffe570 "") at pquery.c:779
#35 0x000000000066f0e6 in exec_simple_query (
query_string=0x8037e5030 "\nSELECT * from
__clear_table_tail('ctrl_servers', 'bill', 'opt', 13, 1)\n") at
postgres.c:997
#36 0x0000000000672f72 in PostgresMain (argc=4, argv=0x803732930,
username=0x803732900 "pgsql") at postgres.c:3676
#37 0x000000000063b5cd in BackendRun (port=0x803703c00) at postmaster.c:3467
#38 0x000000000063ab2a in BackendStartup (port=0x803703c00) at
postmaster.c:3081
#39 0x00000000006382dc in ServerLoop () at postmaster.c:1387
#40 0x0000000000637abb in PostmasterMain (argc=3, argv=0x7fffffffeb88) at
postmaster.c:1040
#41 0x00000000005c0b5a in main (argc=3, argv=0x7fffffffeb88) at main.c:188

On Wed, Jan 5, 2011 at 4:28 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:

> On Wed, Dec 22, 2010 at 4:53 PM, Maxim Boguk <maxim(dot)boguk(at)gmail(dot)com>
> wrote:
> > About stack backtrace I not sure how to get it (and even worse the
> > database is heavily loaded production DB so I not sure creating core
> > dump would be good idea).
> > Still I would like to receive any help with creating a stack backtrace.
>
> Well, if you can reproduce this problem in a given session, you can
> use pg_backend_pid() at the start of the session to get the backend
> ID, and then if your build has debugging symbols (or separate
> debuginfos you can install), you could attach gdb to it, set a
> breakpoint at the lines in heaptuple.c that can throw this error,
> reproduce the problem, and then get a backtrace. But if it's
> happening randomly I don't have a lot of ideas.
>
> I do wonder if this could be related to using TIDs that don't actually
> exist in the table. That might be worth some experimentation.
>
> --
> Robert Haas
> EnterpriseDB: http://www.enterprisedb.com
> The Enterprise PostgreSQL Company
>

--
Maxim Boguk
Senior Postgresql DBA.

Skype: maxim.boguk
Jabber: maxim(dot)boguk(at)gmail(dot)com

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