Re: Reading resource busy error system trace

From: Pap <oracle.developer35_at_gmail.com>
Date: Sat, 2 Jul 2022 23:27:09 +0530
Message-ID: <CAEjw_fgrLLx6Z-BAZkUQVrCe=7_rG+TnJng8VcZMr9VnyU2=hw_at_mail.gmail.com>



Hello All, I followed the blog below and tried debugging the system trace to find the blocking session/sql which caused this resource busy error, Ora-0054. But I am encountering strange behaviour. It appears to be the same session blocking itself.The session which did the direct path load and commit seems not releasing exclusive lock for some duration post commit. Below are the details of the behaviour. Has anybody encountered such a scenario?

https://nenadnoveljic.com/blog/troubleshooting-ora-00054-resource-busy-and-acquire-with-nowait-specified-or-timeout-expired/

So the code which is encountering the error is below. Its disabling all constraints + Making index unusable and then does direct path load to that table and then after while trying to enable the constraint of the same table using 'ALTER' and its failing with Ora-0054. The sample code for data load and ALTER table is as below.

****Sample code *****

INSERT /*+Append*/ INTO TAB1 (c1,c2.....)

        SELECT (ROWNUM + sqq_key) ,col1, col2, col3..... from....tab2, tab3, tab4.....;
COMMIT; FOR I IN (SELECT TABLE_NAME, CONSTRAINT_NAME FROM ALL_CONSTRAINTS WHERE TABLE_NAME = v_table_nm AND CONSTRAINT_TYPE = 'R' AND STATUS = 'DISABLED')  LOOP
   EXECUTE IMMEDIATE ('ALTER TABLE ' || v_table_nm || ' ENABLE NOVALIDATE CONSTRAINT '|| I.CONSTRAINT_NAME);
 END LOOP I;


When i scan through trace file as per the blog step by step, i see below

*Step- 1 -* I searched through the object_Id(101739) for TAB1 and got the
section below, i.e pointing towards a DML lock on the table. And the process state object is proc: 0x243efffc0.



   SO: 0x233cd8bc8, type: DML lock (83), map: 0x237d28a10
      state: LIVE (0x4532), flags: 0x0
      owner: 0x233b9af60, proc: 0x243efffc0
      link: 0x233cd8be8[0x28acf1e58, 0x1d793c780]
      pg: 0
   SOC: 0x237d28a10, type: *DML lock* (83), map: 0x233cd8bc8
      state: LIVE (0x99fc), flags: INIT (0x1)
   DML LOCK: tab=101739 flg=11 chi=0
          his[0]: mod=4 spn=69302
2022-07-01 05:44:10.662*:ksq.c_at_10787:ksqdmc(): Enqueue Dump       (enqueue)
TM-00018D6B-00000000-00000000-00000000 DID: ksqlkdid: 0001-00CF-000ACD5C

   lv: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 res_flag: 0x7    mode: S, lock_flag: 0x20, lock: 0x237d28a38, res: 0x2499f3798    own: 0x2488605f8, sess: 0x2488605f8, *proc: 0x2403a4510*, prv: 0x2499f37a8

   slk: 0x2530967c8


*STEP - 2:-* Then i searched through the trace for the state object address
i.e. "*SO: 0x243efffc0*" and got below. its pointing to pid:207 as below.

  • 2022-07-01T05:44:10.538156-04:00 PROCESS 207:
    *SO: 0x243efffc0*, type: process (2), map: 0x2403a4510 state: LIVE (0x4532), flags: 0x1 owner: (nil), proc: 0x243efffc0 link: 0x243efffe0[0x243efffe0, 0x243efffe0] child list count: 15, link: 0x243f00030[0x243b7f190, 0x1d7903b10] pg: 0 SOC: 0x2403a4510, type: process (2), map: 0x243efffc0 state: LIVE (0x99fc), flags: INIT (0x1) (process) *Oracle pid:207,* ser:3445, calls cur/top: 0x1a0372f08/0x1d2ee6c70 flags : (0x0) - icon_uid:0 logon_pdbid=0 flags2: (0x1000), flags3: (0x510) call error: 0, sess error: 0, txn error 0 intr queue: empty (post info) last post received: 0 0 277 last post received-location: kcl2.h LINE:5703 ID:kclcget last process to post me: 0x24c3b2180 1 6 last post sent: 0 0 33 last post sent-location: ksa2.h LINE:298 ID:ksasnd last process posted by me: 0x24837eaa0 1 6 waiter on post event: 0 (latch info) hold_bits=0x0 ud_influx=0x4101b (osp latch info) hold_bits=0x0 ud_influx=0x0 Process Group: DEFAULT, pseudo proc: 0x2484c5d70 O/S info: user: grid, term: UNKNOWN, ospid: 383076 OSD pid info: Short stack dump: ksedsts()+426<-ksdxfstk()+58<-ksdxdocmdmultex()+5961<-ksdxdocmdmult()+55<-ksudmp_proc()+1626<-ksudss_main()+1976<-ksudss_opt()+1544<-dbkdaKsdActDriver()+2484<-dbgdaExecuteAction()+354<-dbgdaRunAction()+770<-dbgdRunActions()+83<-dbgdProcessEventActions()+525<-dbgdChkEventKgErr()+394<-dbkdChkEventRdbmsErr()+65<-dbgePostErrorKGE()+1066<-dbkePostKGE_kgsf()+71<-kgeade()+338<-kgeselv()+89<-ksesecl0()+189<-ktaiam()+1110<-ktagetg0()+929<-ktagetp_internal()+141<-ktagetg_ddlX()+323<-ktagetg_ddl()+30<-kkdllk0()+1551<-kkdcprc()+711<-kkdcmco()+3682<-atbadd()+8770<-atbdrv()+14663<-opiexe()+30061<-opiosq0()+4575<-opipls()+14619<-opiodr()+1202<-rpidrus()+198<-skgmstack()+65<-rpidru()+132<-rpiswu2()+614<-rpidrv()+1494<-psddr0()+467<-psdnal()+646<-pevm_EXIM()+276<-pfrinstr_EXIM()+43<-pfrrun_no_tool()+52<-pfrrun()+902<-plsql_run()+755<-peicnt()+279<-kkxexe()+720<-opiexe()+24762<-kpoal8()+2226<-opiodr()+1202<-ttcpip()+1239<-opitsk()+1897<-opiino()+936<-opiodr()+1202<-opidrv()+1094<-sou2o()+165<-opimai_real()+422<-ssthrdmain()+417<-main()+256<-__libc_start_main()+245

   KGL-UOL (Process state object)
   KGX Atomic Operation Log 0x2403a5690
    Mutex (nil)(0, 0) idn 0 oper NONE(0)     FSO mutex uid 262142 efd 0 whr 0 slp 0    KGX Atomic Operation Log 0x2403a56f8
    Mutex (nil)(0, 0) idn 0 oper NONE(0)     FSO mutex uid 262142 efd 0 whr 0 slp 0    KGX Atomic Operation Log 0x2403a5760
    Mutex (nil)(0, 0) idn 0 oper NONE(0)     FSO mutex uid 262142 efd 0 whr 0 slp 0    KGX Atomic Operation Log 0x2403a57c8
    Mutex (nil)(0, 0) idn 0 oper NONE(0)     FSO mutex uid 262142 efd 0 whr 0 slp 0    KGX Atomic Operation Log 0x2403a5830
    Mutex (nil)(0, 0) idn 0 oper NONE(0)     FSO mutex uid 262142 efd 0 whr 0 slp 0    KGX Atomic Operation Log 0x2403a5898
    Mutex (nil)(0, 0) idn 0 oper NONE(0)     FSO mutex uid 262142 efd 0 whr 0 slp 0    KGX Atomic Operation Log 0x2403a5900
    Mutex (nil)(0, 0) idn 0 oper NONE(0)     FSO mutex uid 262142 efd 0 whr 0 slp 0    KGX Atomic Operation Log 0x2403a5968
    Mutex (nil)(0, 0) idn 0 oper NONE(0)     FSO mutex uid 262142 efd 0 whr 0 slp 0    KGX Atomic Operation Log 0x2403a59d0
    Mutex (nil)(0, 0) idn 0 oper NONE(0)     FSO mutex uid 262142 efd 0 whr 0 slp 0


*Step-3 :- * Then searching for the *pid-207* in the start of the trace ,
i found *sid - 1072 ser 23 *and its pointing to the same ALTER TABLE statement. The OSPID is the same one for which the trace gets generated. And if I try to see the DML in this sesion before this ALTER it's the same one, which has just finished up doing the COMMIT for the direct path load.

 So I am wondering , is it possible that we are hitting any bug due to which Oracle is actually not releasing the Exclusive table lock immediately post Commit of the direct path load ? And that is why , even if we are trying to do the ALTER post COMMIT in the same session we are hitting Ora-0054 as it blocks itself? And then should we put some wait/sleep statement post commit i.e. before the ALTER to avoid this bug?

 207: USER ospid 383076 sid 1072 ser 23,

         Cmd: ALTER TABLE

On Mon, Jun 13, 2022 at 4:28 PM Pap <oracle.developer35_at_gmail.com> wrote:

> Thank You So much Nenad.
>
> Unfortunately while checking with the team got to know that the other
> trace files has been removed from the location. So i will wait for the next
> occurrence of the error to capture and analyze all the traces wrt that one
> ospid.
>
>
> On Sun, 12 Jun 2022, 9:24 pm Noveljic Nenad, <nenad.noveljic_at_vontobel.com>
> wrote:
>
>> Your system dump apparently consists of several files.
>>
>>
>>
>> At the very beginning of the system dump there must be a section that
>> identifies the blockers for each process and looks something like this:
>>
>> 157: USER ospid 1385877 sid 786 ser 49681, waiting for 'log file switch
>> (checkpoint incomplete)'
>>
>>   Cmd: INSERT
>>
>>   Blocked by inst: 1, sid: 266, ser: 13238
>>
>>   Final Blocker inst: 1, sid: 266, ser: 13238
>>
>> 159: USER ospid 1295896 sid 796 ser 48963, waiting for 'log file switch
>> (checkpoint incomplete)'
>>
>>   Cmd: INSERT
>>
>>  Blocked by inst: 1, sid: 266, ser: 13238
>>
>>   Final Blocker inst: 1, sid: 266, ser: 13238
>>
>>
>>
>> First, check who was blocking the Powercenter process with ospid 89092
>> (Blocked by…). Then search **all** system dump trace files (**89092**.trc)
>> for the blocker to look at its state objects. Once you now the sid and
>> serial of the blocker, you can position yourself to its state objects with
>> the following search expression: sid: xxx ser: xxx . One of the state
>> objects will be for the cursor that blocked your DDL on MAIN_TAB.
>>
>>
>>
>> Best regards,
>>
>>
>>
>> Nenad
>>
>>
>>
>> *From:* Pap <oracle.developer35_at_gmail.com>
>> *Sent:* Sonntag, 12. Juni 2022 14:06
>> *To:* Noveljic Nenad <nenad.noveljic_at_vontobel.com>
>> *Cc:* Oracle L <oracle-l_at_freelists.org>
>> *Subject:* Re: Reading resource busy error system trace
>>
>>
>>
>> Thank You Nenad.
>>
>> So actually here the session/Alter statement, which failed, is from the
>> informatica power center session only. So do you mean we should search the
>> body of the original trace file from which this trace continued from i.e  "u01/app/oracle/diag/rdbms/DB1p/DB11/trace/DB11_ora_89092_8.trc"
>> rather this one. And in that trace the sql statements near the "final
>> blocker" string will be the cause of this error?
>>
>>
>>
>>
>>
>>
>>
>>
>>
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Received on Sat Jul 02 2022 - 19:57:09 CEST

Original text of this message