在Oracle 12c/19c多租戶環(huán)境中，默認(rèn)情況下，使用startup命令啟動(dòng)數(shù)據(jù)庫實(shí)例后，你會(huì)發(fā)現(xiàn)PDB數(shù)據(jù)庫的狀態(tài)為MOUNT狀態(tài),PDB不會(huì)隨著CDB啟動(dòng)而啟動(dòng)。如下例子所示：
SQL>?startup
ORACLE?instance?started.
Total?System?Global?Area?2432695872?bytes
Fixed?Size??????????????????9137728?bytes
Variable?Size?????????????620756992?bytes
Database?Buffers?????????1795162112?bytes
Redo?Buffers????????????????7639040?bytes
Database?mounted.
Database?opened.
SQL>?show?pdbs;
????CON_ID?CON_NAME???????????????????????OPEN?MODE??RESTRICTED
----------?------------------------------?----------?----------
?????????2?PDB$SEED???????????????????????READ?ONLY??NO
?????????3?PSUAT??????????????????????????MOUNTED
SQL>?
Oracle 12.1.0.2之前，CDB啟動(dòng)后，所有的PDB都處于加載狀態(tài)（MOUNTED）。CDB啟動(dòng)時(shí)，沒有默認(rèn)機(jī)制自動(dòng)啟動(dòng)PDB。只能通過在CDB上建立一個(gè)系統(tǒng)觸發(fā)器來自動(dòng)啟動(dòng)部分或所有PDB，如下所示：
CREATE?OR?REPLACE?TRIGGER?open_pdbs
AFTER?STARTUP?ON?DATABASE
BEGIN
EXECUTE?IMMEDIATE?'ALTER?PLUGGABLE?DATABASE?ALL?OPEN';
END?open_pdbs;
/
Oracle12.1.0.2補(bǔ)丁集已引入了保持PDB啟動(dòng)狀態(tài)的能力，因此，不用再通過上面的觸發(fā)器方式來實(shí)現(xiàn)自動(dòng)打開PDB?？梢酝ㄟ^下面方式讓PDB數(shù)據(jù)庫自動(dòng)啟動(dòng)。
SQL>ALTER?PLUGGABLE?DATABASE?PTEST1?OPEN;
SQL>ALTER?PLUGGABLE?DATABASE?PTEST1?SAVE?STATE;
SQL>SHUTDOWN?IMMEDIATE;
SQL>STARTUP
SQL>SHOW?PDBS;
????CON_ID?CON_NAME???????????????????????OPEN?MODE??RESTRICTED
----------?------------------------------?----------?----------
?????????2?PDB$SEED???????????????????????READ?ONLY??NO
?????????3?PTEST2?????????????????????????MOUNTED
?????????4?PTEST1?????????????????????????READ?WRITE?
如上所示，使用命令保存了PDB的STATE后，下次使用命令startup重啟實(shí)例，對(duì)應(yīng)的PDB就會(huì)啟動(dòng)到相應(yīng)狀態(tài)（READ WRITE)
--查看PDB保存的狀態(tài)
COLUMN?CON_NAME?FORMAT?A20
COLUMN?INSTANCE_NAME?FORMAT?A20
SELECT?CON_NAME,?INSTANCE_NAME,?STATE?FROM?DBA_PDB_SAVED_STATES;
--被保存的狀態(tài)可以通過如下命令被廢棄。文章來源：http://www.zghlxwxcb.cn/news/detail-465820.html
ALTER?PLUGGABLE?DATABASE?T1PDB?DISCARD?STATE;
更多詳細(xì)信息，可以參考官方文檔How to Preserve Open Mode of PDBs When the CDB Restarts (?文檔?ID 1933511.1) 。文章來源地址http://www.zghlxwxcb.cn/news/detail-465820.html
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