欢迎大家来到IT世界,在知识的湖畔探索吧!
文中使用的Oracle版本为10g。
1. 查找当前表级锁
select sess.sid, sess.serial#, lo.oracle_username, lo.os_user_name, ao.object_name, lo.locked_mode from v$locked_object lo, dba_objects ao, v$session sess where ao.object_id = lo.object_id and lo.session_id = sess.sid;
欢迎大家来到IT世界,在知识的湖畔探索吧!
- 杀掉锁表进程
欢迎大家来到IT世界,在知识的湖畔探索吧!alter system kill session '436,35123';
- RAC环境中锁查找
SELECT inst_id, DECODE(request,0,'Holder: ','Waiter: ')||sid sess, id1, id2, lmode, request, type,block,ctime FROM GV$LOCK WHERE (id1, id2, type) IN (SELECT id1, id2, type FROM GV$LOCK WHERE request>0) ORDER BY id1, request;
- 监控当前数据库谁在运行什么
欢迎大家来到IT世界,在知识的湖畔探索吧!select osuser, username, sql_text from v$session a, v$sqltext b where a.sql_address =b.address order by address, piece;
- 使用CPU多的用户session
select a.sid,spid,status, substr(a.program,1,40) prog, a.terminal,osuser,value/60/100 value from v$session a,v$process b,v$sesstat c where c.statistic#=12 and c.sid=a.sid and a.paddr=b.addr order by value desc;
- 查看死锁信息
欢迎大家来到IT世界,在知识的湖畔探索吧!SELECT (SELECT username FROM v$session WHERE SID = a.SID) blocker, a.SID, 'is blocking', (SELECT username FROM v$session WHERE SID = b.SID) blockee, b.SID FROM v$lock a, v$lock b WHERE a.BLOCK = 1 AND b.request > 0 AND a.id1 = b.id1 AND a.id2 = b.id2;
- 查询具有最高等待的对象
SELECT o.OWNER,o.object_name, o.object_type, a.event, SUM (a.wait_time + a.time_waited) total_wait_time FROM v$active_session_history a, dba_objects o WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE AND a.current_obj# = o.object_id GROUP BY o.OWNER,o.object_name, o.object_type, a.event ORDER BY total_wait_time DESC;
欢迎大家来到IT世界,在知识的湖畔探索吧!SELECT a.session_id, s.osuser, s.machine, s.program, o.owner, o.object_name,o.object_type, a.event, SUM (a.wait_time + a.time_waited) total_wait_time FROM v$active_session_history a, dba_objects o, v$session s WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE AND a.current_obj# = o.object_id AND a.session_id = s.SID GROUP BY o.owner, o.object_name,o.object_type, a.event,a.session_id, s.program, s.machine,s.osuser ORDER BY total_wait_time DESC;
- 查询当前连接会话数
select s.value,s.sid,a.username from v$sesstat S,v$statname N,v$session A where n.statistic#=s.statistic# and name='session pga memory' and s.sid=a.sid order by s.value;
- 等待最多的用户
欢迎大家来到IT世界,在知识的湖畔探索吧!SELECT s.SID, s.username, SUM (a.wait_time + a.time_waited) total_wait_time FROM v$active_session_history a, v$session s WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE GROUP BY s.SID, s.username ORDER BY total_wait_time DESC;
- 等待最多的会话
SELECT a.program, a.session_id, a.user_id, d.username, s.sql_text, SUM (a.wait_time + a.time_waited) total_wait_time FROM v$active_session_history a, v$sqlarea s, dba_users d WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE AND a.sql_id = s.sql_id AND a.user_id = d.user_id GROUP BY a.program, a.session_id, a.user_id, s.sql_text, d.username;
- 查看消耗资源最多的SQL
欢迎大家来到IT世界,在知识的湖畔探索吧!SELECT hash_value, executions, buffer_gets, disk_reads,parse_calls FROM V$SQLAREA WHERE buffer_gets > OR disk_reads > ORDER BY buffer_gets + 100 * disk_reads DESC;
select se.username, se.sid, su.extents, su.blocks * to_number(rtrim(p.value)) as Space, tablespace, segtype, sql_text from v$sort_usage su, v$parameter p, v$session se, v$sql s where p.name = 'db_block_size' and su.session_addr = se.saddr and s.hash_value = su.sqlhash and s.address = su.sqladdr order by se.username, se.sid
- 查看某条SQL语句的资源消耗
欢迎大家来到IT世界,在知识的湖畔探索吧!SELECT hash_value,buffer_gets,disk_reads, executions,parse_calls FROM V$SQLAREA WHERE hash_Value = AND address = hextoraw('CBD8E4B0');
- 查询会话执行的实际SQL
SELECT a.SID,a.username,s.sql_text FROM v$session a, v$sqltext s WHERE a.sql_address = s.address AND a.sql_hash_value = s.hash_value AND a.status = 'ACTIVE' ORDER BY a.username, a.SID, s.piece;
- 显示正在等待锁的所有会话
欢迎大家来到IT世界,在知识的湖畔探索吧!SELECT * FROM DBA_WAITERS;
- 查询表空间使用情况
SELECT UPPER(F.TABLESPACE_NAME) "表空间名", D.TOT_GROOTTE_MB "表空间大小(M)", D.TOT_GROOTTE_MB - F.TOTAL_BYTES "已使用空间(M)", TO_CHAR(ROUND((D.TOT_GROOTTE_MB - F.TOTAL_BYTES) / D.TOT_GROOTTE_MB * 100,2),'990.99') || '%' "使用比", F.TOTAL_BYTES "空闲空间(M)", F.MAX_BYTES "最大块(M)" FROM (SELECT TABLESPACE_NAME, ROUND(SUM(BYTES) / (1024 * 1024), 2) TOTAL_BYTES, ROUND(MAX(BYTES) / (1024 * 1024), 2) MAX_BYTES FROM SYS.DBA_FREE_SPACE GROUP BY TABLESPACE_NAME) F, (SELECT DD.TABLESPACE_NAME, ROUND(SUM(DD.BYTES) / (1024 * 1024), 2) TOT_GROOTTE_MB FROM SYS.DBA_DATA_FILES DD GROUP BY DD.TABLESPACE_NAME) D WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME ORDER BY 1;
- 查询表空间的free space
欢迎大家来到IT世界,在知识的湖畔探索吧!select tablespace_name, count(*) as extends, round(sum(bytes) / 1024 / 1024, 2) as MB, sum(blocks) as blocks from dba_free_space group by tablespace_name;
- 查询表空间的总容量
select tablespace_name, sum(bytes) / 1024 / 1024 as MB from dba_data_files group by tablespace_name;
- 查询表空间使用率
欢迎大家来到IT世界,在知识的湖畔探索吧!select total.tablespace_name, round(total.MB, 2) as Total_MB, round(total.MB - free.MB, 2) as Used_MB, round((1 - free.MB / total.MB) * 100, 2) || '%' as Used_Pct from (select tablespace_name, sum(bytes) / 1024 / 1024 as MB from dba_free_space group by tablespace_name) free, (select tablespace_name, sum(bytes) / 1024 / 1024 as MB from dba_data_files group by tablespace_name) total where free.tablespace_name = total.tablespace_name;
- 查询数据库最大连接数
select value from v$parameter where name = 'processes';
20. 对象不再存在(ORA-08103)解决方法
先查询出“xxx”对象信息
欢迎大家来到IT世界,在知识的湖畔探索吧!SQL> select obj#,dataobj#,name,type#,owner# from obj$ where name='xxx'; OBJ# DATAOBJ# NAME TYPE# OWNER# ----- ---------- ---------------- ---------- ---------- 5368 xxx 5 1 5993 xxx 42 66
根据obj#对应的id值精确定位到对象(根据OWNER字段判断对象归属,这个不再详述)
SQL> select obj#,dataobj#,name,type#,owner# from obj$ where obj#=5993; OBJ# DATAOBJ# NAME TYPE# OWNER# ----- ---------- ---------------- ---------- ---------- 5993 xxx 42 66
确认obj#对象后使用delete from命令进行删除
欢迎大家来到IT世界,在知识的湖畔探索吧!SQL> delete from obj$ where obj#=5993; 已删除 1 行。 SQL> commit; 提交完成。
提交之后再重新查询对象
SQL> select obj#,dataobj#,name,type#,owner# from obj$ where name='xxx'; OBJ# DATAOBJ# NAME TYPE# OWNER# ----- ---------- ---------------- ---------- ---------- 5368 xxx 5 1
- 生成10以内随机数语句
欢迎大家来到IT世界,在知识的湖畔探索吧!select round(to_number(dbms_random.value)*10,0) from dual;
- 数字非科学计数法输出
select to_char('65647.0',.9999) from dual;
- 解决ORA-22992问题
在存储过程中使用游标进行数据插入,在执行了一半时抛出以下错误:
ORA-22992 cannot use LOB locators selected from remote tables
可使用
欢迎大家来到IT世界,在知识的湖畔探索吧!create table
as select ...
或
insert into
select ...
解决这个问题。
- 判断某字段中存在中文
欢迎大家来到IT世界,在知识的湖畔探索吧!select b.* from
b where asciistr(b.
) like '%\%';
- 查询资源消耗最多的语句
select se.username, se.sid, su.extents, su.blocks * to_number(rtrim(p.value)) as Space, tablespace, segtype, sql_text from v$sort_usage su, v$parameter p, v$session se, v$sql s where p.name = 'db_block_size' and su.session_addr = se.saddr and s.hash_value = su.sqlhash and s.address = su.sqladdr order by se.username, se.sid
- 查看当前数据库最大连接数
欢迎大家来到IT世界,在知识的湖畔探索吧!select value from v$parameter where name = 'processes';
- 设置回滚保留时间
ALTER SYSTEM SET UNDO_RETENTION=
SCOPE=BOTH;
- 去掉回车、换行、空格
欢迎大家来到IT世界,在知识的湖畔探索吧!-- 去除换行 update
t set t.
=replace(t.
,chr(10),''); -- 去掉回车 update
t set t.
=replace(t.
,chr(13),''); -- 去掉空格 update
t set t.
=trim(t.
);
- 根据sid查询pid
select pro.spid from v$session ses,v$process pro where ses.sid='
' and ses.paddr=pro.addr;
- 分段导出数据备份
欢迎大家来到IT世界,在知识的湖畔探索吧!exp based/password file=/oracle/DataBkup/
.dmp, /oracle/DataBkup/
.dmp, /oracle/DataBkup/
.dmp, /oracle/DataBkup/
.dmp filesize= owner=
- 查看正在运行的Job(定时器)
SELECT SID,JOB FROM DBA_JOBS_RUNNING;
- 创建表空间
欢迎大家来到IT世界,在知识的湖畔探索吧!create tablespace
logging datafile '
' size 50m autoextend on ; alter user
quota unlimited on
;
- 查看表空间
-- 表空间使用情况 SELECT UPPER(F.TABLESPACE_NAME) "表空间名", D.TOT_GROOTTE_MB "表空间大小(M)", D.TOT_GROOTTE_MB - F.TOTAL_BYTES "已使用空间(M)", TO_CHAR(ROUND((D.TOT_GROOTTE_MB - F.TOTAL_BYTES) / D.TOT_GROOTTE_MB * 100,2),'990.99') || '%' "使用比", F.TOTAL_BYTES "空闲空间(M)", F.MAX_BYTES "最大块(M)" FROM (SELECT TABLESPACE_NAME, ROUND(SUM(BYTES) / (1024 * 1024), 2) TOTAL_BYTES, ROUND(MAX(BYTES) / (1024 * 1024), 2) MAX_BYTES FROM SYS.DBA_FREE_SPACE GROUP BY TABLESPACE_NAME) F, (SELECT DD.TABLESPACE_NAME, ROUND(SUM(DD.BYTES) / (1024 * 1024), 2) TOT_GROOTTE_MB FROM SYS.DBA_DATA_FILES DD GROUP BY DD.TABLESPACE_NAME) D WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME --and F.TABLESPACE_NAME = '
' ORDER BY 1; -- 表空间大小以及存放位置 SELECT TABLESPACE_NAME,BYTES/1024/1024 FILE_SIZE_MB,FILE_NAME FROM DBA_DATA_FILES
- 额外增加表空间
欢迎大家来到IT世界,在知识的湖畔探索吧!alter tablespace
add datafile '
' size 2024M;
- 删除表空间
DROP USER
CASCADE; DROP TABLESPACE
INCLUDING CONTENTS AND DATAFILES;
- 重新解析表中索引增速
欢迎大家来到IT世界,在知识的湖畔探索吧!analyze table
compute statistics for all indexes;
- 统计字符出现次数
select length(replace(a.
, ',', ',,'))-length(a.
) from
;
- 变更分区信息
欢迎大家来到IT世界,在知识的湖畔探索吧!alter table
enable row movement;
- 查询表中外键
select * from user_constraints c where c.constraint_type = 'R' and c.table_name = '
'
- dmp导入指定表
欢迎大家来到IT世界,在知识的湖畔探索吧!imp system/manager@TEST file=d:\daochu.dmp tables=(table1)
- 查看正在运行的存储过程
select b.sid,b.SERIAL# from SYS.V_$ACCESS a, SYS.V_$session b where a.type = 'PROCEDURE' and (a.OBJECT like upper('%ZZ_Z%') or a.OBJECT like lower('%ZZ_Z%')) and a.sid = b.sid and b.status = 'ACTIVE';
- Unix下数据备份
欢迎大家来到IT世界,在知识的湖畔探索吧!# 先转成oracle用户 su - oracle #导出命令 $ exp
/
file=
tables=
- Job(定时器)正确写法
-- 每分钟执行 Interval => TRUNC(sysdate,'mi') + 1/ (24*60) -- 每天定时执行(每天的凌晨1点执行) Interval => TRUNC(sysdate) + 1 +1/ (24) -- 每周定时执行(每周一凌晨1点执行) Interval => TRUNC(NEXT_DAY(sysdate,'星期一'))+1/24 -- 每月定时执行(每月1日凌晨1点执行) Interval =>TRUNC(LAST_DAY(SYSDATE))+1+1/24 -- 每季度定时执行(每季度的第一天凌晨1点执行) Interval => TRUNC(ADD_MONTHS(SYSDATE,3),'Q') + 1/24 -- 每半年定时执行(每年7月1日和1月1日凌晨1点) Interval => ADD_MONTHS(TRUNC(sysdate,'yyyy'),6)+1/24 -- 每年定时执行(每年1月1日凌晨1点执行) Interval =>ADD_MONTHS(TRUNC(sysdate,'yyyy'),12)+1/24
- 增加临时表空间
欢迎大家来到IT世界,在知识的湖畔探索吧!alter tablespace TEMP add tempfile '
' size 2046M; alter database tempfile '
' autoextend on next 3M maxsize unlimited;
- 横表变纵表(行转列)
加入现在有一张表名为“tb”,且tb表中字段为Name(varchar2(12)),Subject(varchar2(128))和Result(int),如下:
Name Subject Result ---------- ----------- ----------- 张三 语文 74 张三 数学 83 张三 物理 93 李四 语文 74 李四 数学 84 李四 物理 94
现在需要对其进行行转列,我们先看静态SQL的转换
欢迎大家来到IT世界,在知识的湖畔探索吧!select name 姓名, max(case subject when '语文' then result else 0 end) 语文, max(case subject when '数学' then result else 0 end) 数学, max(case subject when '物理' then result else 0 end) 物理 from tb group by name
如果列字段并不固定,同时又想行转列,这种情况下需要使用函数处理
declare @sql varchar(8000) set @sql = 'select Name as ' + '姓名' select @sql = @sql + ' , max(case Subject when ''' + Subject + ''' then Result else 0 end) [' + Subject + ']' from (select distinct Subject from tb) as a set @sql = @sql + ' from tb group by name' exec(@sql)
结果输出为
欢迎大家来到IT世界,在知识的湖畔探索吧!姓名 语文 数学 物理 ---------- ----------- ----------- ----------- 李四 74 84 94 张三 74 83 93
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