表不存在，但是可以查詢、刪除（沒有返回結果，一直hang住）
問題：使用者log_user下用一張表存在如下情況：
C$_0JCZL_CB這張表在user_tables裡不存在，查詢不到 ，元資料也查不到，user_segments，user_extents都查不到這張表。
但是select * from log_user.C$_0JCZL_CB;或者drop這張表確實是可以執行的，只不過會被hang住。
一、做systemstate
SQL> oradebug setmypid
Statement processed.
SQL> oradebug unlimit
Statement processed.
SQL>
oradebug dump systemstate 10
Statement processed.
SQL>
oradebug tracefile_name
/u01/app/oracle/diag/rdbms/ytyzx/ytyzx1/trace/ytyzx1_ora_76117.trc
#vi /u01/app/oracle/diag/rdbms/ytyzx/ytyzx1/trace/ytyzx1_ora_76117.trc
Session Wait History:
elapsed time of 0.000789 sec since current wait
0: waited for 'pmon timer'
duration=0x12c, =0x0, =0x0
wait_id=2653893 seq_num=32496 snap_id=1
wait times: snap=2.999524 sec, exc=2.999524 sec, total=2.999524 sec
wait times: max=3.000000 sec
wait counts: calls=1 os=1
occurred after 0.000552 sec of elapsed time
1: waited for 'pmon timer'
duration=0x12c, =0x0, =0x0
wait_id=2653892 seq_num=32495 snap_id=1
wait times: snap=2.999279 sec, exc=2.999279 sec, total=2.999279 sec
wait times: max=3.000000 sec
wait counts: calls=1 os=1
occurred after 0.000785 sec of elapsed time
2: waited for 'pmon timer'
duration=0x12c, =0x0, =0x0
wait_id=2653891 seq_num=32494 snap_id=1
wait times: snap=2.999487 sec, exc=2.999487 sec, total=2.999487 sec
wait times: max=3.000000 sec
wait counts: calls=1 os=1
occurred after 0.000599 sec of elapsed time
3: waited for 'pmon timer'
duration=0x12c, =0x0, =0x0
wait_id=2653890 seq_num=32493 snap_id=1
wait times: snap=3.001268 sec, exc=3.001268 sec, total=3.001268 sec
wait times: max=3.000000 sec
wait counts: calls=4 os=4
occurred after 0.000827 sec of elapsed time
4: waited for 'pmon timer'
duration=0x12c, =0x0, =0x0
wait_id=2653889 seq_num=32492 snap_id=1
wait times: snap=3.000434 sec, exc=3.000434 sec, total=3.000434 sec
wait times: max=3.000000 sec
wait counts: calls=1 os=1
occurred after 0.000628 sec of elapsed time
5: waited for 'pmon timer'
duration=0x12c, =0x0, =0x0
wait_id=2653888 seq_num=32491 snap_id=1
wait times: snap=3.000275 sec, exc=3.000275 sec, total=3.000275 sec
wait times: max=3.000000 sec
wait counts: calls=1 os=1
occurred after 0.000825 sec of elapsed time
6: waited for 'pmon timer'
duration=0x12c, =0x0, =0x0
wait_id=2653887 seq_num=32490 snap_id=1
wait times: snap=3.000400 sec, exc=3.000400 sec, total=3.000400 sec
wait times: max=3.000000 sec
wait counts: calls=1 os=1
occurred after 0.000669 sec of elapsed time
7: waited for 'pmon timer'
duration=0x12c, =0x0, =0x0
wait_id=2653886 seq_num=32489 snap_id=1
wait times: snap=3.000020 sec, exc=3.000020 sec, total=3.000020 sec
wait times: max=3.000000 sec
wait counts: calls=1 os=1
occurred after 0.011046 sec of elapsed time
8: waited for 'pmon timer'
duration=0x12c, =0x0, =0x0
wait_id=2653885 seq_num=32488 snap_id=1
wait times: snap=3.000554 sec, exc=3.000554 sec, total=3.000554 sec
wait times: max=3.000000 sec
wait counts: calls=1 os=1
occurred after 0.000509 sec of elapsed time
9: waited for 'pmon timer'
duration=0x12c, =0x0, =0x0
wait_id=2653884 seq_num=32487 snap_id=1
wait times: snap=3.000333 sec, exc=3.000333 sec, total=3.000333 sec
wait times: max=3.000000 sec
wait counts: calls=1 os=1
occurred after 0.000752 sec of elapsed time
Sampled Session History of session 99 serial 1
---------------------------------------------------
The sampled session history is constructed by sampling
the target session every 1 second. The sampling process
captures at each sample if the session is in a non-idle wait,
an idle wait, or not in a wait. If the session is in a
non-idle wait then one interval is shown for all the samples
the session was in the same non-idle wait. If the
session is in an idle wait or not in a wait for
consecutive samples then one interval is shown for all
the consecutive samples. Though we display these consecutive
samples in a single interval the session may NOT be continuously
idle or not in a wait (the sampling process does not know).
The history is displayed in reverse chronological order.
sample interval: 1 sec, max history 120 sec
---------------------------------------------------
[121 samples, 14:56:10 - 14:58:10]
idle wait at each sample
temporary object counter: 0
----------------------------------------
Virtual Thread:
kgskvt: 0x63ca2e7c8, sess: 0x6387044b0 sid: 99 ser: 1
vc: (nil), proc: 0x63c6127f8, id: 99
consumer group cur: _ORACLE_BACKGROUND_GROUP_ (upd? 0), mapped: _ORACLE_BACKGROUND_GROUP_, orig:
vt_state: 0x100, vt_flags: 0x4030, blkrun: 0, numa: 1
inwait: 0, posted_run=0
location where insched last set: kgskthrexit
location where insched last cleared: kgskthrexit3
location where inwait last set: NULL
location where inwait last cleared: NULL
is_assigned: 0, in_sched: 0 (0)
qcls: (nil), qlink: FALSE
vt_active: 0 (pending: 0)
vt_pq_active: 0, dop: 0
used quanta: 0 (cg: 0) usec, num penalty: 0
cpu start time: 0
idle time: 0, active time: 0 (cg: 0)
cpu yields: 0 (cg: 0), waits: 0 (cg: 0), wait time: 0 (cg: 0) usec
io waits: 0 (cg: 0), wait time: 0 (cg: 0) usec
ASL queued time outs: 0, time: 0 (cur 0, cg 0)
PQQ queued time outs: 0, time: 0 (cur 0, cg 0)
Queue timeout violation: 0
calls aborted: 0, num est exec limit hit: 0
undo current: 0k max: 0k
I/O credits acquired:small=0 large=0
I/O credits waiting for:small=0 large=0
KTU Session Commit Cache Dump for IDLs:
KTU Session Commit Cache Dump for Non-IDLs:
----------------------------------------
二、分析
檢視等待事件都有waited for 'pmon timer' -->竟然是等待PMON TIMER，想想PMON 程序監視器，主要作用1.清理與例項非法斷開的server_procese殘留的資源 非正常終止的使用者程序產生的垃圾資源2.負責重啟以外死掉的排程器(網路監聽中使用的) 3.將例項的資訊註冊到監聽程式。初步懷疑是資源沒有清理乾淨。
在沒有人連線log_user使用者情況下，檢視連線狀態
SQL>select a.username,a.sid ,a.serial#,b.spid from v$session a,v$process b where a.paddr=b.addr and a.username='LOG_USER';
USERNAME SID SERIAL# SPID
------------------------------ ---------- ---------- ------------------------
LOG_USER 248 47495 24190
LOG_USER 857 52515 76015
LOG_USER 1054 22901 76017
LOG_USER 1251 31647 76012
LOG_USER 1443 47651 76021
LOG_USER 9 3375 76002
LOG_USER 258 56833 76023
LOG_USER 1109 32727 52422
LOG_USER 1133 20557 75990
LOG_USER 1249 7221 76008
LOG_USER 1107 55071 32057
.......足足36個殘存的資源沒有清理。
The database iswaiting for pmon to clean up processes, but pmon is unable to clean them. Theclient connections to the server are causing the shutdown immediate or normalto hang. Killing them allows pmon toclean up and release the associated Oracle processes and resources.
--資料庫等待PMON 程序清理這些LOCAL=NO的程序，但是PMON 程序不能清理他們，表的操作就會hang住，kill 掉這些程序，然後讓PMON 來清理和釋放其他的資料庫程序和資源，完成資料庫關閉操作。
三、解決辦法就是將這些殘存的會話，PMON沒有清理掉的會話kill掉。
SQL>set lines 250
SQL>set pages 100
SQL> select 'alter system kill session '||chr(39)||SID||','||SERIAL#||chr(39)||' ;' from v$session where username='LOG_USER';
alter system kill session '9,3375' ;
alter system kill session '171,21175' ;
alter system kill session '179,16085' ;
alter system kill session '221,53417' ;
alter system kill session '226,16347' ;
alter system kill session '258,56833' ;
alter system kill session '269,38591' ;
alter system kill session '274,699' ;
alter system kill session '471,3245' ;
alter system kill session '547,42781' ;
alter system kill session '590,40265' ;
alter system kill session '616,14941' ;
alter system kill session '662,52641' ;
alter system kill session '816,51301' ;
alter system kill session '849,11757' ;
alter system kill session '857,52515' ;
alter system kill session '909,21525' ;
......
因為會話多所以這樣寫，直接執行下生成的指令碼就可以了。
這回查詢 select a.username,a.logon_time,a.status,a.sid ,a.serial#,b.spid from v$session a,v$process b where a.paddr=b.addr and a.username='LOG_USER';
發現已經清理完畢。
在處理那個C$_0JCZL_CB這張表，發現就正常了。