不能連接Oracle數(shù)據(jù)庫(kù)了,提示相關(guān)的錯(cuò)誤

OERR: ORA-12519 TNS:no appropriate service handler found

客戶端連接間歇性失敗，報(bào)錯(cuò)ORA-12519

Cause: the listener could not find any available service handlers that are

appropriate for the client connection.

Action: run "lsnrctl services" to ensure that the instance(s) have registered

with the listener, and are accepting connections. 檢查lsnrctl service ，instance已經(jīng)注冊(cè)，

狀態(tài)顯示ready時(shí)，可以連接。

When the listener believes the current number of connections has reached maximum load,

it may set the state of the service handler for an instance to "blocked" and begin refusing

incoming client connections with either of the following errors: ora-12519 or ora-12516

采用服務(wù)動(dòng)態(tài)注冊(cè)的方式，由PMON 通過(guò)SERVICE_UPDATE 來(lái)得到目前連接情況，但SERVICE_UPDATE 有時(shí)間間隔，

所以，listener顯示的連接數(shù)和當(dāng)前實(shí)際的連接數(shù)可能不同。

查詢解決方法:

查看一下數(shù)據(jù)庫(kù)現(xiàn)有的進(jìn)程數(shù)，是否已經(jīng)達(dá)到參數(shù)processes的大小。

1.select count(*) from v$process; 取得數(shù)據(jù)庫(kù)目前的進(jìn)程數(shù)。

2.select value from v$parameter where name = 'processes'; 取得進(jìn)程數(shù)的上限。

3.如已達(dá)到上限，修改initSID.ora中的processes的大小。

4.重新啟動(dòng)數(shù)據(jù)庫(kù)到nomount狀態(tài)下，執(zhí)行create spfile from pfile; 并startup open。

查詢數(shù)據(jù)庫(kù)自啟動(dòng)以來(lái)最大的并發(fā)數(shù)量

修改最大連接數(shù):

alter system set processes = 300 scope = spfile;

重啟數(shù)據(jù)庫(kù):

shutdown immediate;

startup;

--查看當(dāng)前有哪些用戶正在使用數(shù)據(jù)

SELECT osuser, a.username,cpu_time/executions/1000000||'s', sql_fulltext,machine

from v$session a, v$sqlarea b

where a.sql_address =b.address order by cpu_time/executions desc;

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