[20190104]ipcs檢視共享記憶體段.txt

--//資料庫啟動異常,有時候會留下一些共享記憶體段沒有清理,需要使用ipcrm清理.

--//由於伺服器上跑2個例項,必須選擇正確的共享記憶體段,否則會導致別的資料庫crash.

--//在我工作中,這是遇到的第2次,做一些複習與整理:

--//在linux下有一個命令sysresv可以檢視某例項使用的共享記憶體段.

$ ipcs

------ Shared Memory Segments --------

key shmid owner perms bytes nattch status

0x00000000 287440897 oracle 600 12288 2 dest

0x00000000 287473666 oracle 600 196608 2 dest

0x00000000 287506435 oracle 600 12288 2 dest

0x00000000 287211524 oracle 600 393216 2 dest

0x00000000 287244293 oracle 600 393216 2 dest

0x00000000 287277062 oracle 600 393216 2 dest

0x00000000 287309831 oracle 600 196608 2 dest

0x00000000 287342600 oracle 600 393216 2 dest

0x00000000 287375369 oracle 600 196608 2 dest

0x00000000 287408138 oracle 600 393216 2 dest

0x00000000 301334539 oracle 640 12582912 25

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

0x00000000 301367308 oracle 640 633339904 25

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

0xe8a8ec10 301400077 oracle 640 2097152 25

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

0x790209cd 294617102 oracle 666 808 0

0x79020002 294649871 oracle 666 808 0

------ Semaphore Arrays --------

key semid owner perms nsems

0x6aa88594 275578880 oracle 640 184

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

0x790209cd 269713409 oracle 666 1

0x79020002 269746178 oracle 666 1

------ Message Queues --------

key msqid owner perms used-bytes messages

$ export ORACLE_SID=book

$ sysresv

IPC Resources for ORACLE_SID "book" :

Shared Memory:

ID KEY

301334539 0x00000000

301367308 0x00000000

301400077 0xe8a8ec10

Semaphores:

ID KEY

275578880 0x6aa88594

Oracle Instance alive for sid "book"

--//下劃線內容可以對上.

--//注意執行前最好指定確認ORACLE_SID環境變數.

man ipcrm

-m shmid removes the shared memory segment identified by shmid after the last detach is performed.

--//ipcrm 引數-m 對應 shmid.

--//另外ipcs有一個引數-t參看time.

$ ipcs -t

------ Shared Memory Attach/Detach/Change Times --------

shmid owner attached detached changed

287440897 oracle Dec 12 17:37:06 Dec 12 17:37:07 Dec 5 17:32:14

287473666 oracle Dec 12 17:37:06 Dec 12 17:37:07 Dec 5 17:32:14

287506435 oracle Dec 12 17:37:06 Dec 12 17:37:07 Dec 5 17:32:14

287211524 oracle Dec 12 17:37:06 Dec 12 17:37:07 Dec 5 15:42:08

287244293 oracle Dec 12 17:37:06 Dec 12 17:37:07 Dec 5 15:42:08

287277062 oracle Dec 12 17:37:06 Dec 12 17:37:07 Dec 5 15:42:08

287309831 oracle Dec 12 17:37:06 Dec 12 17:37:07 Dec 5 15:42:08

287342600 oracle Dec 12 17:37:06 Dec 12 17:37:07 Dec 5 15:42:09

287375369 oracle Dec 12 17:37:06 Dec 12 17:37:07 Dec 5 15:42:17

287408138 oracle Dec 12 17:37:06 Dec 12 17:37:07 Dec 5 15:42:17

301334539 oracle Jan 4 10:13:32 Jan 4 10:14:02 Jan 4 09:53:20

301367308 oracle Jan 4 10:13:32 Jan 4 10:14:02 Jan 4 09:53:20

301400077 oracle Jan 4 10:13:32 Jan 4 10:14:02 Jan 4 09:53:20

294617102 oracle Dec 24 09:22:37 Dec 24 09:22:37 Dec 24 09:22:37

294649871 oracle Dec 24 10:03:22 Dec 24 10:08:55 Dec 24 09:23:01

------ Semaphore Operation/Change Times --------

semid owner last-op last-changed

275578880 oracle Fri Jan 4 10:14:43 2019 Fri Jan 4 10:14:43 2019

269713409 oracle Mon Dec 24 09:22:37 2018 Mon Dec 24 09:22:37 2018

269746178 oracle Mon Dec 24 10:08:55 2018 Mon Dec 24 09:23:01 2018

------ Message Queues Send/Recv/Change Times --------

msqid owner send recv change

--//我仔細看了一下.如果有使用者連上attached會變化,退出後detached時間也會變化.說明有使用者使用.

--//最後一列changed視乎都不變,不知道是否對應oracle例項的啟動時間.

SYS@book> select startup_time from v$instance ;

STARTUP_TIME

-------------------

2019-01-04 09:53:21

--//視乎可以對上.

--//另外使用oradebug ipc命令也可以檢視.

SYS@book> oradebug setmypid

Statement processed.

SYS@book> oradebug ipc

IPC information written to the trace file

SYS@book> oradebug tracefile_name

/u01/app/oracle/diag/rdbms/book/book/trace/book_ora_7252.trc

*** 2019-01-04 10:25:15.026

Processing Oradebug command 'ipc'

Dump of unix-generic skgm context

areaflags 000000f7

realmflags 0000001f

mapsize 00000800

protectsize 00001000

lcmsize 00001000

seglen 00200000

largestsize 0000000480000000

smallestsize 0000000000400000

stacklimit 0x7fffc0268300

stackdir -1

mode 640

magic acc01ade

Handle: 0x7f0b488e40b0 `/u01/app/oracle/product/11.2.0.4/dbhome_1book'

--//注意這是控制程式碼,還記得環境變數ORACLE_HOME後面帶斜線的設定導致無法連上資料庫的問題嗎?11.2.0.4已經沒有這個問題了.

$ echo $ORACLE_HOME

/u01/app/oracle/product/11.2.0.4/dbhome_1

--//參看連結:http://blog.itpub.net/267265/viewspace-2055052/=>[20160310]神奇的斜線.txt

Dump of unix-generic realm handle `/u01/app/oracle/product/11.2.0.4/dbhome_1book', flags = 00000000

Area #0 `Fixed Size' containing Subareas 0-0

Total size 0000000000226c00 Minimum Subarea size 00000000