sqlplus /nolog
select count(*) from v$process;
conn system/123456@orcl as sysdba
show parameter processes
show parameter sessions
修改processes和sessions值:sessions=(1.1*process+5)
select count(*) from v$process; --取得数据库目前的进程数。
select value from v$parameter where name = 'processes'; --取得进程数的上限。
select count(*) from v$session; --取得数据库目前的会话数。
select value from v$parameter where name = 'sessions'; --取得会话数的上限。
系统进程数process和系统会话数session之间存在一个关系：
session数=process数*1.1+5
a) 修改process值
alter system set processes=1000 scope=spfile; --将process值改为1000
b) 修改session值
alter system set sessions=1105 scope=spfile; --将sessions值改为1105
create pfile from spfile= 'D:\pfile.ora' --从D:\pfile.ora(之前备份出来的pfile文件)创建系统配置信息。
shutdowm immediate
startup
-----------------------------------------------------------------------------
sqlplus /nolog
select count(*) from v$process;
conn system/123456@orcl as sysdba
show parameter processes
show parameter sessions
--------------------------------需要在系统的环境下执行---------------------------------
查看状态命令：lsnrctl status
启动监听：lsnrctl start
关闭监听:lsnrctl stop
---------------------------------------------------------------------------------------
通过pfile来启动数据库．然后重建spfile了
startup pfile='D:/app/Administrator/admin/orcl/pfile/init.ora';
create spfile from pfile='D:/app/Administrator/admin/orcl/pfile/init.ora';
shutdown immediate;
startup;
------------------------------------------------------------------------------------
怎么可以快速做一个和原表一样的备份表?
create table new_table as (select * from old_table);
select a.tablespace_name,
a.bytes / 1024 / 1024 "Sum MB",
(a.bytes - b.bytes) / 1024 / 1024 "used MB",
b.bytes / 1024 / 1024 "free MB",
round(((a.bytes - b.bytes) / a.bytes) * 100, 2) "percent_used"
from (select tablespace_name, sum(bytes) bytes
from dba_data_files
group by tablespace_name) a,
(select tablespace_name, sum(bytes) bytes, max(bytes) largest
from dba_free_space
group by tablespace_name) b
where a.tablespace_name = b.tablespace_name
order by ((a.bytes - b.bytes) / a.bytes) desc
--使用语法表空间检查情况：
SELECT UPPER(F.TABLESPACE_NAME) "表空间名",
D.TOT_GROOTTE_MB "表空间大小(M)",
D.TOT_GROOTTE_MB - F.TOTAL_BYTES "已使用空间(M)",
TO_CHAR(ROUND((D.TOT_GROOTTE_MB - F.TOTAL_BYTES) / D.TOT_GROOTTE_MB * 100,
2),
'990.99') "使用比",
F.TOTAL_BYTES "空闲空间(M)",
F.MAX_BYTES "最大块(M)"
FROM (SELECT TABLESPACE_NAME,
ROUND(SUM(BYTES) / (1024 * 1024), 2) TOTAL_BYTES,
ROUND(MAX(BYTES) / (1024 * 1024), 2) MAX_BYTES
FROM SYS.DBA_FREE_SPACE
GROUP BY TABLESPACE_NAME) F,
(SELECT DD.TABLESPACE_NAME,
ROUND(SUM(DD.BYTES) / (1024 * 1024), 2) TOT_GROOTTE_MB
FROM SYS.DBA_DATA_FILES DD
GROUP BY DD.TABLESPACE_NAME) D
WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME
ORDER BY 4 DESC
-------------------------------
SELECT t.tablespace_name, round(SUM(bytes / (1024 * 1024)), 0) ts_size
FROM dba_tablespaces t, dba_data_files d
WHERE t.tablespace_name = d.tablespace_name
GROUP BY t.tablespace_name;