查询oracle比较慢的session和sql
Posted ✧*꧁一品堂.技术学习笔记꧂*✧.
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了查询oracle比较慢的session和sql相关的知识，希望对你有一定的参考价值。
注：本文来源：sxhong 《查询oracle比较慢的session和sql》
1 ---查询最慢的sql 2 3 select * from ( 4 select parsing_user_id,executions,sorts 5 command_type,disk_reads,sql_text from v$sqlarea order by disk_reads desc 6 )where rownum<10 7 8 ---查询对应session 9 10 select SE.SID,SE.SERIAL#,PR.SPID, 11 SE.USERNAME,SE.STATUS,SE.TERMINAL, 12 SE.PROGRAM,SE.MODULE, 13 SE.SQL_ADDRESS,ST.EVENT, 14 ST.P1TEXT,SI.PHYSICAL_READS,SI.BLOCK_CHANGES from v$session se,v$session_wait st, 15 v$sess_io si,v$process pr 16 where st.SID=se.SID and st.SID=si.SID 17 AND SE.PADDR=PR.ADDR 18 AND SE.SID>6 19 AND ST.WAIT_TIME=0 20 AND ST.EVENT NOT LIKE ‘%SQL%‘ 21 ORDER BY PHYSICAL_READS DESC; 22 SELECT sql_address FROM V$SESSION SS,V$SQLTEXT TT 23 WHERE SS.SQL_HASH_VALUE=TT.HASH_VALUE AND SID=439; 24 25 26 --v$sqltext：存储的是完整的SQL,SQL被分割 27 28 --v$sqlarea：存储的SQL 和一些相关的信息，比如累计的执行次数，逻辑读，物理读等统计信息（统计） 29 30 --v$sql：内存共享SQL区域中已经解析的SQL语句。（即时） 31 32 33 34 --根据sid查找完整sql语句： 35 36 select sql_text from v$sqltext a where a.hash_value = (select sql_hash_value from v$session b where b.sid = ‘&sid‘ ) 37 order by piece asc 38 39 40 41 select a.CPU_TIME,--CPU时间 百万分之一（微秒） 42 a.OPTIMIZER_MODE,--优化方式 43 a.EXECUTIONS,--执行次数 44 a.DISK_READS,--读盘次数 45 a.SHARABLE_MEM,--占用shared pool的内存多少 46 a.BUFFER_GETS,--读取缓冲区的次数 47 a.COMMAND_TYPE,--命令类型(3:select,2:insert;6:update;7delete;47:pl/sql程序单元) 48 a.SQL_TEXT,--Sql语句 49 a.SHARABLE_MEM, 50 a.PERSISTENT_MEM, 51 a.RUNTIME_MEM, 52 a.PARSE_CALLS, 53 a.DISK_READS, 54 a.DIRECT_WRITES, 55 a.CONCURRENCY_WAIT_TIME, 56 a.USER_IO_WAIT_TIME 57 from SYS.V_$SQLAREA a 58 WHERE PARSING_SCHEMA_NAME = ‘CHEA_FILL‘--表空间 59 order by a.CPU_TIME desc 60 61 62 63 64 65 ---从V$SQLAREA中查询最占用资源的查询 66 select b.username username,a.disk_reads reads, 67 a.executions exec,a.disk_reads/decode(a.executions,0,1,a.executions) rds_exec_ratio, 68 a.sql_text Statement 69 from v$sqlarea a,dba_users b 70 where a.parsing_user_id=b.user_id 71 and a.disk_reads > 100000 72 order by a.disk_reads desc; 73 --用buffer_gets列来替换disk_reads列可以得到占用最多内存的sql语句的相关信息。 74 75 --v$sql：内存共享SQL区域中已经解析的SQL语句。（即时） 76 77 --列出使用频率最高的5个查询： 78 select sql_text,executions 79 from (select sql_text,executions, 80 rank() over 81 (order by executions desc) exec_rank 82 from v$sql) 83 where exec_rank <=5; 84 --消耗磁盘读取最多的sql top5： 85 select disk_reads,sql_text 86 from (select sql_text,disk_reads, 87 dense_rank() over 88 (order by disk_reads desc) disk_reads_rank 89 from v$sql) 90 where disk_reads_rank <=5; 91 92 --找出需要大量缓冲读取（逻辑读）操作的查询： 93 select buffer_gets,sql_text 94 from (select sql_text,buffer_gets, 95 dense_rank() over 96 (order by buffer_gets desc) buffer_gets_rank 97 from v$sql) 98 where buffer_gets_rank<=5; 99 100 v$sqlarea字段定义：http://happyhou.blog.sohu.com/60494432.html
SQL_TEXT VARCHAR2(1000) First thousand characters of the SQL text for the current cursor SQL_ID VARCHAR2(13) SQL identifier of the parent cursor in the library cache SHARABLE_MEM NUMBER Amount of shared memory used by a cursor. If multiple child cursors exist, then the sum of all shared memory used by all child cursors. PERSISTENT_MEM NUMBER Fixed amount of memory used for the lifetime of an open cursor. If multiple child cursors exist, the fixed sum of memory used for the lifetime of all the child cursors. RUNTIME_MEM NUMBER Fixed amount of memory required during execution of a cursor. If multiple child cursors exist, the fixed sum of all memory required during execution of all the child cursors. SORTS NUMBER Sum of the number of sorts that were done for all the child cursors VERSION_COUNT NUMBER Number of child cursors that are present in the cache under this parent LOADED_VERSIONS NUMBER Number of child cursors that are present in the cache and have their context heap (KGL heap 6) loaded OPEN_VERSIONS NUMBER The number of child cursors that are currently open under this current parent USERS_OPENING NUMBER Number of users that have any of the child cursors open FETCHES NUMBER Number of fetches associated with the SQL statement EXECUTIONS NUMBER Total number of executions, totalled over all the child cursors END_OF_FETCH_COUNT NUMBER Number of times this cursor was fully executed since the cursor was brought into the library cache. The value of this statistic is not incremented when the cursor is partially executed, either because it failed during the execution or because only the first few rows produced by this cursor are fetched before the cursor is closed or re-executed. By definition, the value of theEND_OF_FETCH_COUNT column should be less or equal to the value of the EXECUTIONS column. USERS_EXECUTING NUMBER Total number of users executing the statement over all child cursors LOADS NUMBER Number of times the object was loaded or reloaded FIRST_LOAD_TIME VARCHAR2(19) Timestamp of the parent creation time INVALIDATIONS NUMBER Total number of invalidations over all the child cursors PARSE_CALLS NUMBER Sum of all parse calls to all the child cursors under this parent DISK_READS NUMBER Sum of the number of disk reads over all child cursors DIRECT_WRITES NUMBER Sum of the number of direct writes over all child cursors BUFFER_GETS NUMBER Sum of buffer gets over all child cursors APPLICATION_WAIT_TIME NUMBER Application wait time CONCURRENCY_WAIT_TIME NUMBER Concurrency wait time CLUSTER_WAIT_TIME NUMBER Cluster wait time USER_IO_WAIT_TIME NUMBER User I/O Wait Time PLSQL_EXEC_TIME NUMBER PL/SQL execution time JAVA_EXEC_TIME NUMBER Java execution time ROWS_PROCESSED NUMBER Total number of rows processed on behalf of this SQL statement COMMAND_TYPE NUMBER Oracle command type definition OPTIMIZER_MODE VARCHAR2(25) Mode under which the SQL statement was executed PARSING_USER_ID NUMBER User ID of the user that has parsed the very first cursor under this parent
以上是关于查询oracle比较慢的session和sql的主要内容，如果未能解决你的问题，请参考以下文章