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mifly on 01/19/10


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sql Oracle


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oracle 性能监控 sql


 / Published in: SQL
 

  1. 性能监控之监控SQL语句
  2.  
  3. 分析表
  4. analyze TABLE tablename compute statistics FOR ALL indexes;
  5. analyze TABLE tablename compute statistics FOR ALL indexed COLUMNS;
  6. analyze TABLE tablename compute statistics FOR TABLE;
  7.  
  8. 监控事例的等待
  9.  
  10. SELECT event,sum(decode(wait_Time,0,0,1)) "Prev",
  11. sum(decode(wait_Time,0,1,0)) "Curr",count(*) "Tot"
  12. FROM v$session_Wait
  13. GROUP BY event ORDER BY 4;
  14.  
  15. 查看碎片程度高的表
  16.  
  17. SELECT segment_name table_name , COUNT(*) extents
  18. FROM dba_segments WHERE owner NOT IN (SYS, SYSTEM) GROUP BY segment_name
  19. HAVING COUNT(*) = (SELECT MAX( COUNT(*) FROM dba_segments GROUP BY segment_name);
  20.  
  21. 表、索引的存储情况检查
  22.  
  23. SELECT segment_name,sum(bytes),count(*) ext_quan FROM dba_extents WHERE
  24. tablespace_name=&tablespace_name AND segment_type=TABLE GROUP BY tablespace_name,segment_name;
  25.  
  26. SELECT segment_name,count(*) FROM dba_extents WHERE segment_type=INDEX AND owner=&owner
  27. GROUP BY segment_name;
  28.  
  29. 找使用CPU多的用户session
  30.  
  31. 12是cpu used BY this session
  32.  
  33. SELECT a.sid,spid,STATUS,substr(a.program,1,40) prog,a.terminal,osuser,value/60/100 value
  34. FROM v$session a,v$process b,v$sesstat c
  35. WHERE c.statistic#=12 and c.sid=a.sid and a.paddr=b.addr order by value desc;
  36.  
  37. 监控表空间的 I/O 比例
  38.  
  39. SELECT df.tablespace_name name,df.file_name "file",f.phyrds pyr,
  40. f.phyblkrd pbr,f.phywrts pyw, f.phyblkwrt pbw
  41. FROM v$filestat f, dba_data_files df
  42. WHERE f.file# = df.file_id
  43. ORDER BY df.tablespace_name;
  44.  
  45.  
  46. 回滚段的争用情况
  47.  
  48. SELECT name, waits, gets, waits/gets "Ratio"
  49. FROM v$rollstat a, v$rollname b
  50. WHERE a.usn = b.usn;
  51.  
  52. 在某个用户下找所有的索引
  53.  
  54. SELECT user_indexes.table_name, user_indexes.index_name,uniqueness, column_name
  55. FROM user_ind_columns, user_indexes
  56. WHERE user_ind_columns.index_name = user_indexes.index_name
  57. AND user_ind_columns.table_name = user_indexes.table_name
  58. ORDER BY user_indexes.table_type, user_indexes.table_name,
  59. user_indexes.index_name, column_position;
  60.  
  61.  
  62. 监控文件系统的 I/O 比例
  63.  
  64. SELECT substr(a.file#,1,2) "#", substr(a.name,1,30) "Name",
  65. a.STATUS, a.bytes, b.phyrds, b.phywrts
  66. FROM v$datafile a, v$filestat b
  67. WHERE a.file# = b.file#;
  68.  
  69. 监控 SGA 中字典缓冲区的命中率
  70.  
  71. SELECT parameter, gets,Getmisses , getmisses/(gets+getmisses)*100 "miss ratio",
  72. (1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit ratio"
  73. FROM v$rowcache
  74. WHERE gets+getmisses <>0
  75. GROUP BY parameter, gets, getmisses;
  76.  
  77. 监控 SGA 中共享缓存区的命中率,应该小于1
  78.  
  79. SELECT sum(pins) "Total Pins", sum(reloads) "Total Reloads",
  80. sum(reloads)/sum(pins) *100 libcache
  81. FROM v$librarycache;
  82.  
  83. SELECT sum(pinhits-reloads)/sum(pins) "hit radio",sum(reloads)/sum(pins) "reload percent"
  84. FROM v$librarycache;
  85.  
  86. 监控 SGA 的命中率
  87.  
  88. SELECT a.value + b.value "logical_reads", c.value "phys_reads",
  89. round(100 * ((a.value+b.value)-c.value) / (a.value+b.value)) "BUFFER HIT RATIO"
  90. FROM v$sysstat a, v$sysstat b, v$sysstat c
  91. WHERE a.statistic# = 38 and b.statistic# = 39
  92. AND c.statistic# = 40;
  93.  
  94. 监控 SGA 中重做日志缓存区的命中率,应该小于1
  95.  
  96. SELECT name, gets, misses, immediate_gets, immediate_misses,
  97. Decode(gets,0,0,misses/gets*100) ratio1,
  98. Decode(immediate_gets+immediate_misses,0,0,
  99. immediate_misses/(immediate_gets+immediate_misses)*100) ratio2
  100. FROM v$latch WHERE name IN (redo allocation, redo copy);
  101.  
  102. 显示所有数据库对象的类别和大小
  103.  
  104. SELECT count(name) num_instances ,type ,sum(source_size) source_size ,
  105. sum(parsed_size) parsed_size ,sum(code_size) code_size ,sum(error_size) error_size,
  106. sum(source_size) +sum(parsed_size) +sum(code_size) +sum(error_size) size_required
  107. FROM dba_object_size
  108. GROUP BY type ORDER BY 2;
  109.  
  110. 监控内存和硬盘的排序比率,最好使它小于 .10,增加 sort_area_size
  111.  
  112. SELECT name, value FROM v$sysstat WHERE name IN (sorts (memory), sorts (disk));
  113.  
  114.  
  115. 监控当前数据库谁在运行什么SQL语句
  116.  
  117. SELECT osuser, username, sql_text FROM v$session a, v$sqltext b
  118. WHERE a.sql_address =b.address ORDER BY address, piece;
  119.  
  120. 监控字典缓冲区
  121.  
  122. SELECT (SUM(PINS - RELOADS)) / SUM(PINS) "LIB CACHE" FROM V$LIBRARYCACHE;
  123. SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROW CACHE" FROM V$ROWCACHE;
  124. SELECT SUM(PINS) "EXECUTIONS", SUM(RELOADS) "CACHE MISSES WHILE EXECUTING" FROM V$LIBRARYCACHE;
  125.  
  126. 后者除以前者,此比率小于1,接近0%为好。
  127.  
  128. SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES"
  129. FROM V$ROWCACHE
  130.  
  131. 监控 MTS
  132.  
  133. SELECT busy/(busy+idle) "shared servers busy" FROM v$dispatcher;
  134.  
  135. 此值大于0.5时,参数需加大
  136.  
  137. SELECT sum(wait)/sum(totalq) "dispatcher waits" FROM v$queue WHERE type=dispatcher;
  138. SELECT count(*) FROM v$dispatcher;
  139. SELECT servers_highwater FROM v$mts;
  140.  
  141. servers_highwater接近mts_max_servers时,参数需加大
  142.  
  143. 碎片程度
  144.  
  145. SELECT tablespace_name,count(tablespace_name) FROM dba_free_space GROUP BY tablespace_name
  146. HAVING count(tablespace_name)>10;
  147.  
  148. ALTER tablespace name coalesce;
  149. ALTER TABLE name deallocate unused;
  150.  
  151. CREATE OR REPLACE VIEW ts_blocks_v AS
  152. SELECT tablespace_name,block_id,bytes,blocks,free space segment_name FROM dba_free_space
  153. union ALL
  154. SELECT tablespace_name,block_id,bytes,blocks,segment_name FROM dba_extents;
  155.  
  156. SELECT * FROM ts_blocks_v;
  157.  
  158. SELECT tablespace_name,sum(bytes),max(bytes),count(block_id) FROM dba_free_space
  159. GROUP BY tablespace_name;

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