oracle基础杂记

select session_id sid ,owner,name,type,mode_held held,mode_requested request from dba_ddl_locks;
select count(*) from v$process;
select count(*) from v$session;

show parameter session;
show parameter session;
--索引是需要排序的，因此需要临时表空间
--临时表空间
select * from dba_temp_files;
create index need sort store in temp tbs;

--表空间的使用率
select d.tablespace_name,space "sum_space(m)",blocks sum_blocks,used_space "used_space(m)", round(nvl(used_space, 0) / space * 100,

2) "used_rate(%)",nvl(free_space, 0) "free_space(m)"
from (select tablespace_name,round(sum(bytes) / (1024 * 1024), 2) space,sum

(blocks) blocks
from dba_temp_files group by tablespace_name) d,
(select tablespace_name,round(sum(bytes_used) / (1024 * 1024), 2)

used_space, round(sum(bytes_free) / (1024 * 1024), 2) free_space
from v$temp_space_header group by tablespace_name) f
where

d.tablespace_name = f.tablespace_name(+);

select * from v$database;
select * from v$process;
select * from v$session;
select * from v$active_instances;
select * from v$instance;

lsnrctl status
listener service
tnsping service[orcl]

GRANT execute on DBMS_PIPE to "XZXNB";

SQL> select count(*) from v$session #连接数
SQL> Select count(*) from v$session where status='ACTIVE'　#并发连接数
SQL> show parameter processes #最大连接
SQL> alter system set processes = value scope = spfile;重启数据库 #修改连接

process:这个参数限制了能够连接到SGA的操作系统进程数(或者是 Windows 系统中的线程数),这个总数必须足够大,从而能够适用于后台进程与所有的

专用服务器进程,此外,共享服务器进程与调度进程的数目也被计算在内.此外,共享服务器进程与调度进程的数目也被计算在内.因此,在专用服务器环境

中,这是一种限制并发连接数的方法.

Sessions:是被应用于oracle层次而非操作系统层次.在不考虑通过专用服务器或共享服务器进行登录的情况下,这个参数限制了对指定实例的并发登陆

数.

SQL> Select count(*) from v$session where status='ACTIVE' ;

SELECT to_timestamp('20080904100555,055','yyyymmddhh24miss,ff') FROM dual;

--1、建立表空间
CREATE SMALLFILE TABLESPACE "DATA" DATAFILE 'D:\MyWork\data\DATA'
SIZE 100M LOGGING EXTENT MANAGEMENT LOCAL SEGMENT SPACE MANAGEMENT AUTO;

alter database datafile 'D:\MyWork\data\DATA' autoextend on;

--2、建立用户
drop user XZXNB cascade;
CREATE USER "XZXNB" PROFILE "DEFAULT" IDENTIFIED BY "xzxnb" DEFAULT TABLESPACE "DATA" TEMPORARY TABLESPACE "TEMP" ACCOUNT UNLOCK;
GRANT CREATE ANY VIEW TO "XZXNB";
GRANT UNLIMITED TABLESPACE TO "XZXNB";
GRANT "CONNECT" TO "XZXNB";
GRANT "DBA" TO "XZXNB";
GRANT "RESOURCE" TO "XZXNB";
commit;

查询Oracle正在执行和执行过的SQL语句

2009-02-17 10:47:09| 分类：数据库 |字号订阅
---正在执行的

select a.username, a.sid,b.SQL_TEXT, b.SQL_FULLTEXT
from v$session a, v$sqlarea b
where a.sql_address = b.address
---执行过的
select b.SQL_TEXT,b.FIRST_LOAD_TIME,b.SQL_FULLTEXT
from v$sqlarea b
where b.FIRST_LOAD_TIME between '2009-10-15/09:24:47' and
       '2009-10-15/09:24:47' order by b.FIRST_LOAD_TIME
（此方法好处可以查看某一时间段执行过的sql，并且 SQL_FULLTEXT 包含了完整的 sql 语句）

其他
select OSUSER,PROGRAM,USERNAME,SCHEMANAME,B.Cpu_Time,STATUS,B.SQL_TEXT
from V$SESSION A LEFT JOIN V$SQL B ON A.SQL_ADDRESS=B.ADDRESS AND A.SQL_HASH_VALUE=B.HASH_VALUE order by b.cpu_time desc

select address, sql_text, piece
from v$session, v$sqltext
where address = sql_address
-- and machine = < you machine name >
order by address, piece

查找前十条性能差的sql.

SELECT * FROM (select PARSING_USER_ID,EXECUTIONS,SORTS,
COMMAND_TYPE,DISK_READS,sql_text FROM v$sqlarea
order BY disk_reads DESC )where ROWNUM<10 ;

查看占io较大的正在运行的session

SELECT se.sid,se.serial#,pr.SPID,se.username,se.status,
se.terminal,se.program,se.MODULE,、se.sql_address,st.event,st.
p1text,si.physical_reads,
si.block_changes FROM v$session se,v$session_wait st,
v$sess_io si,v$process pr WHERE st.sid=se.sid AND st.
sid=si.sid AND se.PADDR=pr.ADDR AND se.sid>6 AND st.
wait_time=0 AND st.event NOT LIKE '%SQL%' ORDER BY physical_reads DESC

ALTER TABLE [ database_name . [ schema_name ] . | schema_name . ] table_name
{
    ALTER COLUMN column_name
    {
        [ type_schema_name. ] type_name [ ( { precision [ , scale ]
            | max | xml_schema_collection } ) ]
        [ COLLATE collation_name ]
        [ SPARSE | NULL | NOT NULL ]
    | {ADD | DROP }
        { ROWGUIDCOL | PERSISTED | NOT FOR REPLICATION | SPARSE }
    }
        | [ WITH { CHECK | NOCHECK } ]

    | ADD
    {
        <column_definition>
      | <computed_column_definition>
      | <table_constraint>
      | <column_set_definition>
    } [ ,...n ]

ALTER TABLE ryda
    add t1 char(20);

可导出空表
sql >> select 'alter table '||table_name||' allocate extent(size 1m);' from user_tables where num_rows=0
|
---->>>>
alter table AA40 allocate extent(size 1m);
alter table AA41 allocate extent(size 1m);
alter table AA46 allocate extent(size 1m);
alter table AA50 allocate extent(size 1m);
alter table AA79 allocate extent(size 1m);
alter table AA84 allocate extent(size 1m);
alter table AA90 allocate extent(size 1m);

有时候数据死了，或者没有监听，不必重启机子，重启一下数据库服务行了，下面是linux下的启动步骤，没有在win下执行过，可能也可以！
以oracle9i为例
（1）以oracle身份登录数据库，命令：su – oracle
（2）进入Sqlplus控制台，命令：sqlplus /nolog
（3）以系统管理员登录，命令：connect / as sysdba
（4）启动数据库，命令：startup
（5）如果是关闭数据库，命令：shutdown immediate
（6）退出sqlplus控制台，命令：exit
（7）进入监听器控制台，命令：lsnrctl
（8）启动监听器，命令：start
（9）退出监听器控制台，命令：exit
（10）重启数据库结束

SELECT EXTRACT(MINUTE[HOUR,SECOND] FROM TIMESTAMP '2001-02-16 11:38:40') from dual ;
select flashback_on from v$database;
show parameter flash
show parameter retention

猜你喜欢