知识大全 oracle性能检测sql语句

Posted 2022-07-15 语句

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　　监控事例的等待

　　select event sum(decode(wait_Time )) Prev

　　sum(decode(wait_Time )) Curr count(*) 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 a usn = b usn;

　　监控表空间的 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# ) # substr(a name ) 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;

　　监控 SGA 的命中率

　　select a value + b value logical_reads c value phys_reads

　　round( * ((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# = and b statistic# =

　　and c statistic# = ;

　　监控 SGA 中字典缓冲区的命中率

　　select parameter gets Getmisses 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(pinhits reloads)/sum(pins) hit radio sum(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(gets misses/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 a sql_address =b address order by address piece;

　　监控字典缓冲区

　　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 GETS SUM(GETMISSES) DICTIONARY CACHE GET MISSES

　　FROM V$ROWCACHE

　　找ORACLE字符集

　　select * from sys props$ where name= NLS_CHARACTERSET ;

　　监控 MTS

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

　　此值大于时参数需加大

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

　　select count(*) from v$dispatcher;

　　select servers_highwater from v$mts;

　　servers_highwater接近mts_max_servers时参数需加大

　　碎片程度

　　select tablespace_name count(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_name block_id bytes blocks free space segment_name from dba_free_space

　　union all

　　select tablespace_name block_id bytes blocks segment_name from dba_extents;

　　select * from ts_blocks_v;

　　select tablespace_name sum(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);

　　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;

　　找使用CPU多的用户session

　　是cpu used by this session

　　select a sid spid status substr(a program ) prog a terminal osuser value/ / value

　　from v$session a v$process b v$sesstat c

　　where c statistic#= and c sid=a sid and a paddr=b addr order by value desc;

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