图灵小队—Oracle 常用的性能查询SQL语句

--查看硬解析比

select (select value from v$sysstat where name ='parse count (hard)')/(select value from v$sysstat where name='parse count (total)') from dual;
值越小越好。
--将常量解析改为强制软解析

alter system set cursor_sharing=force scope=both;

--查看表锁

select * from sys.v_$sqlarea where disk_reads>100

--监控事例的等待

select event,
       sum(decode(wait_Time, 0, 0, 1)) "Prev",
       sum(decode(wait_Time, 0, 1, 0)) "Curr",
       count(*) "Tot"
  from v$session_Wait
 group by event
 order by 4

--回滚段的争用情况

select name, waits, gets, waits / gets "Ratio"
  from v$rollstat a, v$rollname b
 where a.usn = b.usn

--查看前台正在发出的SQL语句

select user_name, sql_text 　　
  from v$open_cursor 　　
 where sid in (select sid
                 from (select sid, serial#, username, program 　　
                         from v$session 　　
                        where status = 'ACTIVE'))

--数据表占用空间大小情况

select segment_name, tablespace_name, bytes, blocks
from user_segments
where segment_type = 'TABLE'
ORDER BY bytes DESC, blocks DESC

--查看表空间碎片大小

select tablespace_name,
round(sqrt(max(blocks) / sum(blocks)) *
(100 / sqrt(sqrt(count(blocks)))),
2) FSFI
from dba_free_space
group by tablespace_name
order by 1

--查看碎片程度高的表

SELECT segment_name table_name, COUNT(*) extents
FROM dba_segments
WHERE owner NOT IN ('SYS', 'SYSTEM')
GROUP BY segment_name
HAVING COUNT(*) = (SELECT MAX(COUNT(*))
FROM dba_segments
GROUP BY segment_name);

--查看表空间占用磁盘情况

select b.file_id 文件id,
b.tablespace_name 表空间名,
b.bytes / 1024 / 1024 总大小,
(b.bytes - sum(nvl(a.bytes, 0))) / 1024 / 1024 已使用大小,
sum(nvl(a.bytes, 0)) / 1024 / 1024 剩余空间,
sum(nvl(a.bytes, 0)) / (b.bytes) * 100 剩余百分比
from dba_free_space a, dba_data_files b
where a.file_id = b.file_id
group by b.tablespace_name, b.file_id, b.bytes
order by b.file_id;

--查看session使用回滚段

SELECT r.name 回滚段名,
s.sid,
s.serial#,
s.username 用户名,
t.status,
t.cr_get,
t.phy_io,
t.used_ublk,
t.noundo,
substr(s.program, 1, 78) 操作程序
FROM sys.v_$session s, sys.v_$transaction t, sys.v_$rollname r
WHERE t.addr = s.taddr
and t.xidusn = r.usn
ORDER BY t.cr_get, t.phy_io

--查看SGA区剩余可用内存

select name,
sgasize / 1024 / 1024　　　　　　　　"Allocated(M)",
bytes / 1024/1024　　　　　　　　　　"自由空间(M)",
round(bytes / sgasize * 100, 2) 　　"自由空间百分比(%)"
from (select sum(bytes) sgasize from sys.v_$sgastat) s,
sys.v_$sgastat f
where f.name = 'free memory'

--监控表空间I/O比例

select df.tablespace_name name,
df.file_name       "file",
f.phyrds           pyr,
f.phyblkrd         pbr,
f.phywrts          pyw,
f.phyblkwrt        pbw
from v$filestat f, dba_data_files df
where f.file# = df.file_id
order by df.tablespace_name;

--监控文件系统的I/O比例

select substr(a.file#, 1, 2) "#",
substr(a.name, 1, 30) "name",
a.status,
a.bytes,
b.phyrds,
b.phywrts
from v$datafile a, v$filestat b
where a.file# = b.file#

--在某个用户下找所有的索引：

select user_indexes.table_name,
user_indexes.index_name,
uniqueness,
column_name
from user_ind_columns, user_indexes
where user_ind_columns.index_name = user_indexes.index_name
and user_ind_columns.table_name = user_indexes.table_name
order by user_indexes.table_type,
user_indexes.table_name,
user_indexes.index_name,
column_position;

--表、索引的存储情况检查

select segment_name, sum(bytes), count(*) ext_quan
from dba_extents
where tablespace_name = '&tablespace_name'
and segment_type = 'TABLE'
group by tablespace_name, segment_name;

select segment_name, count(*)
from dba_extents
where segment_type = 'INDEX'
and owner = '&owner'
group by segment_name;

--监控SGA命中率  

select a.value + b.value "logical_reads",
c.value "phys_reads",
round(100 * ((a.value + b.value) - c.value) / (a.value + b.value)) "BUFFER HIT RATIO"
from v$sysstat a, v$sysstat b, v$sysstat c
where a.statistic# = 48
and b.statistic# = 51
and c.statistic# = 55;

--监控SGA中字典缓冲区的命中率

select parameter,
gets,
Getmisses,
getmisses / (gets + getmisses) * 100 "miss ratio",
(1 - (sum(getmisses) / (sum(gets) + sum(getmisses)))) * 100 "Hit ratio"
from v$rowcache
where gets + getmisses <> 0
group by parameter, gets, getmisses;

--监控 SGA 中共享缓存区的命中率，应该小于1%

select sum(pins) "Total Pins",
sum(reloads) "Total Reloads",
sum(reloads) / sum(pins) * 100 libcache
from v$librarycache;

--监控 SGA 中重做日志缓存区的命中率，应该小于1%

SELECT name,
gets,
misses,
immediate_gets,
immediate_misses,
Decode(gets, 0, 0, misses / gets * 100) ratio1,
Decode(immediate_gets + immediate_misses,
0,
0,
immediate_misses / (immediate_gets + immediate_misses) * 100) ratio2
FROM v$latch
WHERE name IN ('redo allocation', 'redo copy');

--监控内存和硬盘的排序比率，最好使它小于 .10

SELECT name, value FROM v$sysstat WHERE name IN ('sorts (memory)', 'sorts (disk)');

--监控字典缓冲区

SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES" FROM V$ROWCACHE

--显示所有数据库对象的类别和大小

select count(name) num_instances,
type,
sum(source_size) source_size,
sum(parsed_size) parsed_size,
sum(code_size) code_size,
sum(error_size) error_size,
sum(source_size) + sum(parsed_size) + sum(code_size) +
sum(error_size) size_required
from dba_object_size
group by type
order by 2;

--监控当前数据库谁在运行什么SQL 语句

SELECT osuser, username, sql_text
from v$session a, v$sqltext b
where a.sql_address = b.address
order by address, piece;

--v$dispatcher

select busy/(busy+idle) "shared servers busy" from v$dispatcher; --此值大于0.5时，参数需加大
select sum(wait)/sum(totalq) "dispatcher waits" from v$queue where type='dispatcher';
select count(*) from v$dispatcher;
select servers_highwater from V$SHARED_SERVER_MONITOR;--servers_highwater接近MAX_SHARED_SERVERS时，参数需加大

--非系统用户建在SYSTEM表空间中的表

SELECT owner, table_name
FROM DBA_TABLES
WHERE tablespace_name in ('SYSTEM', 'USER_DATA')
AND owner NOT IN
('SYSTEM', 'SYS', 'OUTLN', 'ORDSYS', 'MDSYS', 'SCOTT', 'HOSTEAC')

--性能最差的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<100;

--读磁盘数超100次的sql

select * from sys.v_$sqlarea where disk_reads>100;

--最频繁执行的sql

select * from sys.v_$sqlarea where executions>100

--查询使用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

--当前每个会话使用的对象数

SELECT a.sid, s.terminal, s.program, count(a.sid)
FROM V$ACCESS a, V$SESSION s
WHERE a.owner <> 'SYS'
AND s.sid = a.sid
GROUP BY a.sid, s.terminal, s.program
ORDER BY count(a.sid)

--监控log_buffer的使用情况：(值最好小于1%，否则增加log_buffer 的大小)

select rbar.name,
rbar.value,
re.name,
re.value,
(rbar.value * 100) / re.value || '%' "radio"
from v$sysstat rbar, v$sysstat re
where rbar.name = 'redo buffer allocation retries'
and re.name = 'redo entries';

--查看运行过的SQL 语句：

SELECT SQL_TEXT FROM V$SQL

--客户端主机信息  SYS_CONTEXT sys_context函数调用userenv命名空间来获取相关信息

select SYS_CONTEXT('USERENV', 'TERMINAL') terminal,
SYS_CONTEXT('USERENV', 'LANGUAGE') language,
SYS_CONTEXT('USERENV', 'SESSIONID') sessionid,
SYS_CONTEXT('USERENV', 'INSTANCE') instance,
SYS_CONTEXT('USERENV', 'ENTRYID') entryid,
SYS_CONTEXT('USERENV', 'ISDBA') isdba,
SYS_CONTEXT('USERENV', 'NLS_TERRITORY') nls_territory,
SYS_CONTEXT('USERENV', 'NLS_CURRENCY') nls_currency,
SYS_CONTEXT('USERENV', 'NLS_CALENDAR') nls_calendar,
SYS_CONTEXT('USERENV', 'NLS_DATE_FORMAT') nls_date_format,
SYS_CONTEXT('USERENV', 'NLS_DATE_LANGUAGE') nls_date_language,
SYS_CONTEXT('USERENV', 'NLS_SORT') nls_sort,
SYS_CONTEXT('USERENV', 'CURRENT_USER') current_user,
SYS_CONTEXT('USERENV', 'CURRENT_USERID') current_userid,
SYS_CONTEXT('USERENV', 'SESSION_USER') session_user,
SYS_CONTEXT('USERENV', 'SESSION_USERID') session_userid,
SYS_CONTEXT('USERENV', 'PROXY_USER') proxy_user,
SYS_CONTEXT('USERENV', 'PROXY_USERID') proxy_userid,
SYS_CONTEXT('USERENV', 'DB_DOMAIN') db_domain,
SYS_CONTEXT('USERENV', 'DB_NAME') db_name,
SYS_CONTEXT('USERENV', 'HOST') host,
SYS_CONTEXT('USERENV', 'OS_USER') os_user,
SYS_CONTEXT('USERENV', 'EXTERNAL_NAME') external_name,
SYS_CONTEXT('USERENV', 'IP_ADDRESS') ip_address,
SYS_CONTEXT('USERENV', 'NETWORK_PROTOCOL') network_protocol,
SYS_CONTEXT('USERENV', 'BG_JOB_ID') bg_job_id,
SYS_CONTEXT('USERENV', 'FG_JOB_ID') fg_job_id,
SYS_CONTEXT('USERENV', 'AUTHENTICATION_TYPE') authentication_type,
SYS_CONTEXT('USERENV', 'AUTHENTICATION_DATA') authentication_data
from dual;

--查看回滚段名称及大小

SELECT a.owner || '.' || a.segment_name roll_name,
a.tablespace_name tablespace,
TO_CHAR(a.initial_extent) || ' / ' || TO_CHAR(a.next_extent) in_extents,
TO_CHAR(a.min_extents) || ' / ' || TO_CHAR(a.max_extents) m_extents,
a.status status,
b.bytes bytes,
b.extents extents,
d.shrinks shrinks,
d.wraps wraps,
d.optsize opt
FROM dba_rollback_segs a, dba_segments b, v$rollname c, v$rollstat d
WHERE a.segment_name = b.segment_name
AND a.segment_name = c.name(+)
AND c.usn = d.usn(+)
ORDER BY a.segment_name;

--parse to excute ratio（数据库的SQL语句执行和分析的比例） 越大越好 

select round((1 - a.VALUE / b.VALUE )* 100, 2) "parse to excute ratio"
from v$sysstat a, v$sysstat b
where a.STATISTIC#=331 and b.STATISTIC#=330;

--Parse CPU to Parse Elapsed(指数据库用在分析的CPU的时间和分析完成CPU时间对比)

select round((1 - a.VALUE / b.VALUE )* 100, 2) "Parse CPU to Parse Elapsed"
from v$sysstat a, v$sysstat b
where a.STATISTIC#=328 and b.STATISTIC#=329;

--Non-Parse CPU(用在非分析的过程中CPU 的等待了其它的资源)

select round((1 - a.VALUE / b.VALUE )* 100, 2) "Non-Parse CPU"
from v$sysstat a, v$sysstat b
where a.STATISTIC#=328 and b.STATISTIC#=12;

--Rollback segment(等待rollback segment 的header 比率,比率越小越好)

select waits,gets,round(waits/gets*100,2) from v$rollstat a,v$rollname b where a.USN=b.usn

--表字段的注释说明
select * from user_col_comments
数据字典：
select * from dict order by table_name;
锁及资源信息：
select * from v$lock;不包括DDL锁
数据库字符集：
select * from sys.props$ where name='NLS_CHARACTERSET';
inin.ora参数：
select name,value from v$parameter order by name;
SQL 共享池：
select sql_text from v$sqlarea;
数据库：
select * from v$database
控制文件：
select * from V$controlfile;
重做日志文件信息：
select * from V$logfile;
来自控制文件中的日志文件信息：
select * from V$log;
来自控制文件中的数据文件信息：
select * from V$datafile;
NLS参数当前值：
select * from V$nls_parameters;
ORACLE 版本信息：
select * from v$version;
描述后台进程：
select * from v$bgprocess;
查看版本信息：
select * from product_component_version;