1. 查看processes和sessions參數(shù)
SQL> show parameter processes
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
aq_tm_processes integer 1
db_writer_processes integer 1
job_queue_processes integer 10
log_archive_max_processes integer 2
processes integer 150
SQL> show parameter sessions
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
java_max_sessionspace_size integer 0
java_soft_sessionspace_limit integer 0
license_max_sessions integer 0
license_sessions_warning integer 0
logmnr_max_persistent_sessions integer 1
mts_sessions integer 165
sessions integer 170
shared_server_sessions integer 165
SQL>
2. 修改processes和sessions值
SQL> alter system set processes=300 scope=spfile;
系統(tǒng)已更改。
SQL> alter system set sessions=335 scope=spfile;
系統(tǒng)已更改。
3. 修改processes和sessions值必須重啟oracle服務(wù)器才能生效
ORACLE的連接數(shù)(sessions)與其參數(shù)文件中的進(jìn)程數(shù)(process)有關(guān)，它們的關(guān)系如下：
sessions=(1.1*process+5)
查詢數(shù)據(jù)庫當(dāng)前進(jìn)程的連接數(shù)：
select count(*) from v$process;
查看數(shù)據(jù)庫當(dāng)前會(huì)話的連接數(shù)：
select count(*) from v$session;
查看數(shù)據(jù)庫的并發(fā)連接數(shù)：
select count(*) from v$session where status='ACTIVE';
查看當(dāng)前數(shù)據(jù)庫建立的會(huì)話情況：
select sid,serial#,username,program,machine,status from v$session;
查詢數(shù)據(jù)庫允許的最大連接數(shù)：
select value from v$parameter where name = 'processes';
或者：show parameter processes;
修改數(shù)據(jù)庫允許的最大連接數(shù)：
alter system set processes = 300 scope = spfile;
(需要重啟數(shù)據(jù)庫才能實(shí)現(xiàn)連接數(shù)的修改)
重啟數(shù)據(jù)庫：
shutdown immediate;
startup;
查看當(dāng)前有哪些用戶正在使用數(shù)據(jù)：
select osuser,a.username,cpu_time/executions/1000000||'s',sql_fulltext,machine
from v$session a,v$sqlarea b
where a.sql_address = b.address
order by cpu_time/executions desc;
備注：UNIX 1個(gè)用戶session對(duì)應(yīng)一個(gè)操作系統(tǒng)process，而Windows體現(xiàn)在線程。
啟動(dòng)oracle
su - oracle
sqlplus system/pwd as sysdba //進(jìn)入sql
startup //啟動(dòng)數(shù)據(jù)庫
lsnrctl start //啟動(dòng)監(jiān)聽
sqlplus "/as sysdba"
shutdown immediate;
startup mount;
alter database open;