It looks really strange which you have pointed in the trace file though.
Correct me if wrong, So your blocking session/pid for the 'ALTER' statement
in the trace is pointing to the same session. And that session has just
ended up doing direct path load by post disabling constraints/indexes and
is trying to enable the constraints using ALTER command and is failing with
Ora-0054. And that to post committing the direct load data. Just a thought,
are you doing any DML on the parent table which is linked to this
reference constraint which you are trying to enable here?
On Sat, Jul 2, 2022 at 11:27 PM Pap <oracle.developer35@xxxxxxxxx> wrote:
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@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@xxxxxxxxx> 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@xxxxxxxxxxxx>
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@xxxxxxxxx>
*Sent:* Sonntag, 12. Juni 2022 14:06
*To:* Noveljic Nenad <nenad.noveljic@xxxxxxxxxxxx>
*Cc:* Oracle L <oracle-l@xxxxxxxxxxxxx>
*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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