DB2中storage group的概念，以及建立各種型別的表空間
阿新 • • 發佈：2019-02-10
DB2的表空間根據是否是自動儲存型別的，可以分為兩種，Automatic Storage(AS)和非Automatic Storage，如果是Automatic Storage型別的，建立時不能指定容器的路徑，那麼DB2是怎麼知道它存放的位置的呢？這裡要引申出一個概念：Storage Group， 一個Storage Group定義了一個或者多個路徑，示例如下：
db2 "CREATE STOGROUP storage_group_name ON 'path1', ..., 'pathn'"
當然，db2已經建立好了一個storage group，叫IBMSTOGROUP，它是預設的storage group，如果建立AS型別的表空間的時候，不指定‘USING STOGROUP'，那就會使用IBMSTOGROUP storage group.
下面看一個例項，建立一個數據庫，並自定義一個storage group， 檢視storage group 的資訊:
$ db2 "create db test" $ db2 "connect to test" $ db2 "create STOGROUP MQSGROUP ON '/home/db2users/e105q6a/conpath1', '/home/db2users/e105q6a/conpath2'" $db2 "SELECT VARCHAR(STORAGE_GROUP_NAME, 30) AS STOGROUP, STORAGE_GROUP_ID, VARCHAR(DB_STORAGE_PATH, 40) AS STORAGE_PATH FROM TABLE(ADMIN_GET_STORAGE_PATHS('',-1)) AS T" STOGROUP STORAGE_GROUP_ID STORAGE_PATH ------------------------------ ---------------- ---------------------------------------- IBMSTOGROUP 0 /home/db2users/e105q6a MQSGROUP 1 /home/db2users/e105q6a/conpath1 MQSGROUP 1 /home/db2users/e105q6a/conpath2 3 record(s) selected.
建立各種型別的表空間
a)AS型別的SMS: $ db2 "create user temporary tablespace usrtmp1 managed by automatic storage" b)AS型別的DMS: $ db2 "create regular tablespace rglrtbs1 managed by automatic storage USING STOGROUP MQSGROUP" c)非AS型別的SMS: $ db2 "create tablespace tbs1 managed by system using ('/home/db2users/e105q6a/path1')" d)非AS型別的DMS: $ db2 "create tablespace tbs2 managed by database using (file 'con2' 4000)"
從下面簡化的輸出中可以看到，建立資料庫時自帶的幾個表空間都是AS型別的，且使用了IBMSTOGROUP。表空間rglrtbs1使用了自定義的storage group.
$ db2pd -db test -tab
Database Member 0 -- Database TEST -- Active -- Up 0 days 00:16:02 -- Date 2017-02-25-10.28.54.331489
Tablespace Configuration:
Address Id AS AR Type Content SGID Name
0x070000005D9687E0 0 Yes Yes DMS Regular 0 SYSCATSPACE
0x070000005D975980 1 Yes No SMS SysTmp 0 TEMPSPACE1
0x070000005D982B20 2 Yes Yes DMS Large 0 USERSPACE1
0x0700000061E48FC0 3 Yes Yes DMS Large 0 SYSTOOLSPACE
0x0700000064080200 4 Yes No SMS UsrTmp 0 USRTMP1
0x070000006408D3A0 5 Yes Yes DMS Regular 1 RGLRTBS1
0x070000006409A540 6 No No SMS Regular - TBS1
0x07000000640B4960 7 No No DMS Large - TBS2
Containers:
Address TspId Type Container
0x07000000552EFD60 0 File /home/db2users/e105q6a/e105q6a/NODE0000/TEST/T0000000/C0000000.CAT
0x070000005D990000 1 Path /home/db2users/e105q6a/e105q6a/NODE0000/TEST/T0000001/C0000000.TMP
0x070000005122FAC0 2 File /home/db2users/e105q6a/e105q6a/NODE0000/TEST/T0000002/C0000000.LRG
0x0700000061E58000 3 File /home/db2users/e105q6a/e105q6a/NODE0000/TEST/T0000003/C0000000.LRG
0x0700000061E1B000 4 Path /home/db2users/e105q6a/e105q6a/NODE0000/TEST/T0000004/C0000000.UTM
0x0700000061E22000 5 File /home/db2users/e105q6a/conpath1/e105q6a/NODE0000/TEST/T0000005/C0000000.USR
0x0700000061E22230 5 File /home/db2users/e105q6a/conpath2/e105q6a/NODE0000/TEST/T0000005/C0000001.USR
0x0700000061E245C0 6 Path /home/db2users/e105q6a/path1
0x07000000640C2E80 7 File /home/db2users/e105q6a/e105q6a/NODE0000/SQL00001/con2參考資料：
https://www.ibm.com/support/knowledgecenter/SSEPGG_11.1.0/com.ibm.db2.luw.sql.rtn.doc/doc/r0055331.html
https://www.ibm.com/support/knowledgecenter/SSEPGG_11.1.0/com.ibm.db2.luw.sql.ref.doc/doc/r0000929.html