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oracle数据库性能监控的SQL的几种情况


发布日期:2019年08月27日
 
oracle数据库性能监控的SQL的几种情况

监控事例的等待

select eventsum(decode(wait_Time)) Prev

sum(decode(wait_Time)) Currcount(*) Tot

from v$session_Wait

group by event order by ;

回滚段的争用情况

select name waits gets waits/gets Ratio

from v$rollstat a v$rollname b

where ausn = busn;

监控表空间的 I/O 比例

select dftablespace_name namedffile_name filefphyrds pyr

fphyblkrd pbrfphywrts pyw fphyblkwrt pbw

from v$filestat f dba_data_files df

where ffile# = dffile_id

order by dftablespace_name;

监控文件系统的 I/O 比例

select substr(afile#) # substr(aname) Name

astatus abytes bphyrds bphywrts

from v$datafile a v$filestat b

where afile# = bfile#;

在某个用户下找所有的索引

select user_indexestable_name user_indexesindex_nameuniqueness column_name

from user_ind_columns user_indexes

where user_ind_columnsindex_name = user_indexesindex_name

and user_ind_columnstable_name = user_indexestable_name

order by user_indexestable_type user_indexestable_name

user_indexesindex_name column_position;

监控 SGA 的命中率

select avalue + bvalue logical_reads cvalue phys_reads

round( * ((avalue+bvalue)cvalue) / (avalue+bvalue)) BUFFER HIT RATIO

from v$sysstat a v$sysstat b v$sysstat c

where astatistic# = and bstatistic# =

and cstatistic# = ;

监控 SGA 中字典缓沖区的命中率

select parameter getsGetmisses getmisses/(gets+getmisses)* miss ratio

((sum(getmisses)/ (sum(gets)+sum(getmisses))))* Hit ratio

from v$rowcache

where gets+getmisses <>

group by parameter gets getmisses;

监控 SGA 中共享缓存区的命中率应该小于%

select sum(pins) Total Pins sum(reloads) Total Reloads

sum(reloads)/sum(pins) * libcache

from v$librarycache;

select sum(pinhitsreloads)/sum(pins) hit radiosum(reloads)/sum(pins) reload percent

from v$librarycache;

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 ;

监控 SGA 中重做日志缓存区的命中率应该小于%

SELECT name gets misses immediate_gets immediate_misses

Decode(getsmisses/gets*) ratio

Decode(immediate_gets+immediate_misses

immediate_misses/(immediate_gets+immediate_misses)*) ratio

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 增加 sort_area_size

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

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 asql_address =baddress order by address piece;

监控字典缓沖区

SELECT (SUM(PINS RELOADS)) / SUM(PINS) LIB CACHE FROM V$LIBRARYCACHE;

SELECT (SUM(GETS GETMISSES USAGE FIXED)) / SUM(GETS) ROW CACHE FROM V$ROWCACHE;

SELECT SUM(PINS) EXECUTIONS SUM(RELOADS) CACHE MISSES WHILE EXECUTING FROM V$LIBRARYCACHE;

后者除以前者此比率小于%接近%为好

SELECT SUM(GETS) DICTIONARY GETSSUM(GETMISSES) DICTIONARY CACHE GET MISSES

FROM V$ROWCACHE

找ORACLE字符集

select * from sysprops$ where name=NLS_CHARACTERSET;

监控 MTS

select busy/(busy+idle) shared servers busy from v$dispatcher;

此值大于参数需加大

select sum(wait)/sum(totalq) dispatcher waits from v$queue where type=dispatcher;

select count(*) from v$dispatcher;

select servers_highwater from v$mts;

servers_highwater接近mts_max_servers时参数需加大

碎片程度

select tablespace_namecount(tablespace_name) from dba_free_space group by tablespace_name

having count(tablespace_name)>;

alter tablespace name coalesce;

alter table name deallocate unused;

create or replace view ts_blocks_v as

select tablespace_nameblock_idbytesblocksfree space segment_name from dba_free_space

union all

select tablespace_nameblock_idbytesblockssegment_name from dba_extents;

select * from ts_blocks_v;

select tablespace_namesum(bytes)max(bytes)count(block_id) from dba_free_space

group by tablespace_name;

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);

索引的存储情况检查

select segment_namesum(bytes)count(*) ext_quan from dba_extents where

tablespace_name=&tablespace_name and segment_type=TABLE group by tablespace_namesegment_name;

select segment_namecount(*) from dba_extents where segment_type=INDEX and owner=&owner

group by segment_name;

找使用CPU多的用户session

是cpu used by this session

select asidspidstatussubstr(aprogram) progaterminalosuservalue// value

from v$session av$process bv$sesstat c

where cstatistic#= and csid=asid and apaddr=baddr order by value desc;

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