Re: BUG #2129: dblink problem

We have significantly improved dblink since 7.4.  Would you try 8.1 and
see if you can reproduce the problem?

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Akio Iwaasa wrote:
>
> The following bug has been logged online:
>
> Bug reference:      2129
> Logged by:          Akio Iwaasa
> Email address:      iwaasa@mxs.nes.nec.co.jp
> PostgreSQL version: 7.4.10
> Operating system:   Redhat EL ES 3.0
> Description:        dblink problem
> Details:
>
> I'm very sorry for my poor English.
>
> "postgres" process terminated with "signal 11"
> because of my wrong SQL statement using "dblink".
>
> --- SQL statement(Select statement a function) ---
>  select into RET *
>   from dblink(''select C1,C2,C3 from TABLE01 where ... '') <<<<< 3 column
>    as LINK_TABLE01(LC1 varchar(5),LC2 varchar(5),
>                    LC3 varchar(5),LC4 varchar(5)) ;        <<<<< 4 column
> ---------------------------------------------------
>
> Backtrace is below.
>
> ---
> (gdb) core /usr/local/pgsql74a/data/base/10218530/core.20823
> Core was generated by `postgres: postgres nwops [local] CO'.
> Program terminated with signal 11, Segmentation fault.
>  :
> (gdb) bt
> #0  0x00575ffb in strlen () from /lib/tls/libc.so.6
> #1  0x081f222a in varcharin (fcinfo=0xbfffbf70) at
>     varchar.c:368
> #2  0x0821b86e in FunctionCall3 (flinfo=0x89f5b60,
>     arg1=29795, arg2=0, arg3=64) at fmgr.c:1016
> #3  0x08120647 in BuildTupleFromCStrings (attinmeta=
>     0x89f5b00, values=0x8a2e2f0) at execTuples.c:730
> #4  0x00b5173d in dblink_record (fcinfo=0xbfffc160)
>     at dblink.c:699
> #5  0x0811c8c8 in ExecMakeTableFunctionResult
>     (funcexpr=0x89f5058, econtext=0x89f4c70,
>      expectedDesc=0x89f4e08, returnDesc=0xbfffc244)
>     at execQual.c:1057
> #6  0x0812882c in FunctionNext (node=0x89f4be8) at
>     nodeFunctionscan.c:78
> #7  0x0811fba6 in ExecScan (node=0x89f4be8,
>     accessMtd=0x81287dc  <FunctionNext>) at
>     execScan.c:98
> #8  0x08128906 in ExecFunctionScan (node=0x89f4be8) at
>     nodeFunctionscan.c:128
> #9  0x0811aa0c in ExecProcNode (node=0x89f4be8) at
>     execProcnode.c:322
> #10 0x081190b8 in ExecutePlan (estate=0x89f4ad8,
>     planstate=0x89f4be8, operation=CMD_SELECT,
>     numberTuples=1,  direction=ForwardScanDirection,
>     dest=0x82b4734) at execMain.c:1103
> #11 0x081182f5 in ExecutorRun (queryDesc=0x89e66b0,
>     direction=ForwardScanDirection, count=1) at
>     execMain.c:249
> #12 0x0812fb65 in _SPI_pquery (queryDesc=0x89e66b0,
>     runit=1 '\001', useCurrentSnapshot=0 '\0',
>     tcount=1) at spi.c:1254
> #13 0x0812fa5c in _SPI_execute_plan (plan=0x8a1b728,
>     ValuNulls=0x8a19398 " 1111112", useCurrentSnapshot=0
>     '\0', tcount=1) at spi.c:1201
> #14 0x0812da75 in SPI_execp (plan=0x8a1b728, Values=
>     0x8a193e0, Nulls=0x8a19398 " 1111112", tcount=1) at
>     spi.c:241
> #15 0x00ed97a3 in exec_run_select (estate=0xbfffc620,
>     expr=0x89e9170, maxtuples=1, portalP=0x0) at
>     pl_exec.c:3223
> #16 0x00ed6abe in exec_stmt_select (estate=0xbfffc620,
>     stmt=0x89e9250) at pl_exec.c:1519
> #17 0x00ed5eb6 in exec_stmt (estate=0xbfffc620,
>     stmt=0x89e9250) at pl_exec.c:967
> #18 0x00ed5d3e in exec_stmts (estate=0xbfffc620,
>     stmts=0x89e8ed0) at pl_exec.c:903
> #19 0x00ed5c28 in exec_stmt_block (estate=0xbfffc620,
>     block=0x89ebfd8) at pl_exec.c:859
> #20 0x00ed56f0 in plpgsql_exec_trigger (func=0x89e86a8,
>     trigdata=0xbfffc830) at pl_exec.c:645
> #21 0x00ed149f in plpgsql_call_handler
>     (fcinfo=0xbfffc700) at pl_handler.c:121
> #22 0x0810442b in ExecCallTriggerFunc
>     (trigdata=0xbfffc830, finfo=0x89e26d8,
>     per_tuple_context=0x89e0500) at trigger.c:1150
> #23 0x0810562c in DeferredTriggerExecute
>     (event=0x89eeb10, itemno=0, rel=0xb5549300,
>      trigdesc=0x89e2370, finfo=0x89e26c0,
>      per_tuple_context=0x89e0500) at trigger.c:1867
> #24 0x0810589a in deferredTriggerInvokeEvents (
>     immediate_only=1 '\001') at trigger.c:2008
> #25 0x08105a38 in DeferredTriggerEndQuery ()
>     at trigger.c:2143
> #26 0x0819d61a in finish_xact_command () at
>     postgres.c:1757
> #27 0x0819c427 in exec_simple_query
>     (query_string=0x89dcfb8 "COPY user_info_tbl FROM
>      STDIN ;") at postgres.c:946
> #28 0x0819eb0e in PostgresMain (argc=4, argv=0x8990430,
>     username=0x89903a0 "postgres") at postgres.c:2918
> #29 0x081728b8 in BackendFork (port=0x899cd70) at
>     postmaster.c:2564
> #30 0x08171fe2 in BackendStartup (port=0x899cd70) at
>     postmaster.c:2207
> #31 0x08170661 in ServerLoop () at postmaster.c:1119
> #32 0x08170100 in PostmasterMain (argc=1, argv=0x898f538)
>     at postmaster.c:897
> #33 0x08137ccb in main (argc=1, argv=0xbfffd9e4)
>     at main.c:214
> (gdb) up
> #1  0x081f222a in varcharin (fcinfo=0xbfffbf70)
>     at varchar.c:368
> (gdb) p s
> $10 = 0x7463 <Address 0x7463 out of bounds>
> (gdb) up
> #2  0x0821b86e in FunctionCall3 (flinfo=0x89f5b60,
>     arg1=29795, arg2=0, arg3=64) at fmgr.c:1016
> (gdb) up
> #3  0x08120647 in BuildTupleFromCStrings (attinmeta=
>     0x89f5b00, values=0x8a2e2f0) at execTuples.c:730
> (gdb) p i
> $12 = 3
> (gdb) p values[0]
> $13 = 0x8a2066c "11111112"
> (gdb) p values[1]
> $16 = 0x8a20675 "11111112"
> (gdb) p values[2]
> $14 = 0x8a2067e "1"
> (gdb) p values[3]
> $15 = 0x7463 <Address 0x7463 out of bounds>
> (gdb) up
> #4  0x00b5173d in dblink_record (fcinfo=0xbfffc160)
>     at dblink.c:699
> (gdb) p *((PGresult *)funcctx->user_fctx)
> $9 = {
>   ntups = 1,
>   numAttributes = 3,
>   attDescs = 0x8a205dc,
>   tuples = 0x8a21470,
>   tupArrSize = 128,
>   resultStatus = PGRES_TUPLES_OK,
>   cmdStatus = "SELECT", '\0' <repeats 33 times>,
>   binary = 0,
>   noticeHooks = {
>     noticeRec = 0xac0635 <defaultNoticeReceiver>,
>     noticeRecArg = 0x0,
>     noticeProc = 0xac0679 <defaultNoticeProcessor>,
>     noticeProcArg = 0x0
>   },
>   client_encoding = 1,
>   errMsg = 0x0,
>   errFields = 0x0,
>   null_field = "",
>   curBlock = 0x8a205d8,
>   curOffset = 168,
>   spaceLeft = 1880
> }
> (gdb) p *(funcctx->attinmeta->tupdesc)
> $18 = {
>   natts = 4,
>   attrs = 0x89f58a0,
>   constr = 0x0,
>   tdhasoid = 0 '\0'
> }
> (gdb)
> ---
>
> Of course this trouble occurred because of my
> mistake, but I think that it is better if "dblink"
> returns an error for a wrong SQL statement.
>
> If "numAttributes"*1 was smaller than "natts"*2
> before "dblink_record" calls "BuildTupleFromCStrings",
> dblink can not return error ?
>
>  *1 funcctx->user_fctx->numAttributes
>  *2 funcctx->attinmeta->tupdesc->natts
>
> ---------------------------(end of broadcast)---------------------------
> TIP 2: Don't 'kill -9' the postmaster
>

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