PLSQL_统计信息系列10_统计信息过旧导致程序出现性能问题

2014-11-15 Created By BaoXinjian

一、摘要

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在性能的稳定数据库中，所有的job都需要在一定时间内完成

以前在一个银行系统中，突然某一个job原本在30minutes内完成的，但是在3hours之后，还在运行

排除了数据量大小变化的影响，需要查看该程序的解析计划是否变更，在稳定的系统中，job对应的explain plan一般通过sqlplan management固定，很少变化

所以需要查看，是否job对应的sqlplan explain是否变化

一般来说，解析计划变更也会导致此类问题

 

二、解决方式

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Step1. 查看程序对应的session

select sid, sql_id from v$session where sid = 1001

Step2. 查看该长时间运行sql对应的解析计划是否在这段时间有过变更

select b.begin_interval_time, 
       a.disk_reads_total, 
       a.buffer_gets_total,
       a.buffer_gets_delta, 
       a.rows_processed_total, 
       a.plan_hash_value
  from dba_hist_sqlstat a, dba_hist_snapshot b  
 where a.snap_id = b.snap_id 
   and sql_id = '466bpq7055f4c' 
order by 1 desc;  

Step3. 查看对应session目前在运行的sql text

select* from v$sql_plan

Step4. 查看表的统计时间

select name, last_analized from dba_tables

Step5. 对表进行产生统计信息

exec dbms_stats.gather_table_stats(
            ownname=>'SCOT',
            tabname=>'GAVIN',
            estimate_percent=>3,
            degree=>32,
            granularity=>'GLOBAL',
            cascade=>FALSE,
            no_invalidate=>FALSE);

Step6. 该sql_id所对应的执行时间和次数

  SELECT DBMS_LOB.SUBSTR (sql_text, 100, 1) SQL_SHORT,
         tab1.sql_id,
         DBMS_LOB.getlength (sql_text) SQL_Len,
         ROUND (TOTAL_WAIT / 1000000, 2) TOTAL_WAIT_SECS,
         ROUND (ELAPSED_TIME_DELTA / 1000000, 2) TOTAL_TIME_SECS,
         TO_CHAR (BEGIN_INTERVAL_TIME, 'DAY', 'NLS_DATE_LANGUAGE=AMERICAN')
            Week_Day,
         BEGIN_INTERVAL_TIME,
         END_INTERVAL_TIME,
         EXEC_COUNT,
         AVG_CPU_TIME_SECS,
         AVG_ELAPSED_SECS,
         ROUND (ELAPSED_TIME_DELTA / 1000000, 0) ELAPSED_TIME_DELTA,
         ROUND (AVG_ROWS_PROCESSED, 1) AVG_ROWS_PROCESSED,
         PLAN_HASH_VALUE,
         MODULE,
         ACTION,
         PARSING_SCHEMA_NAME,
         (SELECT username
            FROM dba_users
           WHERE user_id = PARSING_USER_ID)
            PARSING_USER,
         AVG_BUFFER_GETS,
         AVG_DISK_READS,
         AVG_IOWAIT AVG_iowai_secs,
         AVG_CCWAIT AVG_ccwait_secs,
         AVG_CLWAIT AVG_clwait_secs,
         AVG_APWAIT AVG_apwait_secs,
         AVG_PX_SERVERS,
         AVG_PARSE_CALLS,
         tab1.SNAP_ID,
         tab1.INSTANCE_NUMBER,
         AVG_CELL_UNCOMPRESSED_BYTES,
         AVG_DIRECT_WRITES,
         AVG_IO_INTERCONNECT_BYTES,
         AVG_IO_OFFLOAD_ELIG_BYTES,
         AVG_IO_OFFLOAD_RETURN_BYTES,
         AVG_JAVEXEC_TIME,
         AVG_OPTIMIZED_PHYSICAL_READS,
         AVG_PLSEXEC_TIME_DELTA,
         AVG_SORTS_DELTA,
         -- BIND_DATA,    -- -- (Falta arreglar) listagg( (select * from table(dbms_sqltune.extract_binds(bind_data)), '#') WITHIN GROUP (ORDER BY 1)) Binds ,
         DBMS_LOB.SUBSTR (sql_text, 2000, 1) SQL_TEXT1,
         DBMS_LOB.SUBSTR (sql_text, 2000, 2001) SQL_TEXT2,
         DBMS_LOB.SUBSTR (sql_text, 2000, 4001) SQL_TEXT3,
         DBMS_LOB.SUBSTR (sql_text, 2000, 6001) SQL_TEXT4,
         DBMS_LOB.SUBSTR (sql_text, 2000, 8001) SQL_TEXT5,
         DBMS_LOB.SUBSTR (sql_text, 2000, 10001) SQL_TEXT6,
         DBMS_LOB.SUBSTR (sql_text, 2000, 12001) SQL_TEXT7,
         DBMS_LOB.SUBSTR (sql_text, 2000, 14001) SQL_TEXT8,
         DBMS_LOB.SUBSTR (sql_text, 2000, 16001) SQL_TEXT9,
         DBMS_LOB.SUBSTR (sql_text, 2000, 18001) SQL_TEXT10
    FROM DBA_HIST_SQLTEXT D,
         DBA_HIST_SNAPSHOT N,
         (  SELECT S.SQL_ID SQL_ID,
                   instance_number,
                   SUM (EXECUTIONS) EXEC_COUNT,
                   ROUND ( (SUM (CPU_TIME_DELTA) / SUM (EXECUTIONS)) / 1000000,
                          4)
                      AVG_CPU_TIME_SECS,
                   ROUND (
                      (SUM (ELAPSED_TIME_DELTA) / SUM (EXECUTIONS)) / 1000000,
                      4)
                      AVG_ELAPSED_SECS,
                   SUM (ELAPSED_TIME_DELTA) ELAPSED_TIME_DELTA,
                   ROUND ( (SUM (ROWS_PROCESSED_DELTA) / SUM (EXECUTIONS)), 4)
                      AVG_ROWS_PROCESSED,
                   PLAN_HASH_VALUE,
                   MODULE,
                   ACTION,
                   PARSING_SCHEMA_NAME,
                   PARSING_USER_ID,
                   ROUND (SUM (BUFFER_GETS_DELTA) / SUM (EXECUTIONS), 4)
                      AVG_BUFFER_GETS,
                   ROUND (SUM (DISK_READS_DELTA) / SUM (EXECUTIONS), 0)
                      AVG_DISK_READS,
                   SNAP_ID,
                   ROUND ( (SUM (IOWAIT_DELTA) / SUM (EXECUTIONS)) / 1000000, 4)
                      AVG_IOWAIT,
                   ROUND ( (SUM (CCWAIT_DELTA) / SUM (EXECUTIONS)) / 1000000, 4)
                      AVG_CCWAIT,
                   ROUND ( (SUM (CLWAIT_DELTA) / SUM (EXECUTIONS)) / 1000000, 4)
                      AVG_CLWAIT,
                   ROUND ( (SUM (APWAIT_DELTA) / SUM (EXECUTIONS)) / 1000000, 4)
                      AVG_APWAIT,
                   ROUND (SUM (PX_SERVERS_EXECS_DELTA) / SUM (EXECUTIONS), 4)
                      AVG_PX_SERVERS,
                   ROUND (SUM (PARSE_CALLS_DELTA) / SUM (EXECUTIONS), 4)
                      AVG_PARSE_CALLS,
                   ROUND (SUM (CELL_UNCOMPRESSED_BYTES_DELTA) / SUM (EXECUTIONS),
                          4)
                      AVG_CELL_UNCOMPRESSED_BYTES,
                   ROUND (SUM (DIRECT_WRITES_DELTA) / SUM (EXECUTIONS), 4)
                      AVG_DIRECT_WRITES,
                   ROUND (SUM (IO_INTERCONNECT_BYTES_DELTA) / SUM (EXECUTIONS),
                          4)
                      AVG_IO_INTERCONNECT_BYTES,
                   ROUND (SUM (IO_OFFLOAD_ELIG_BYTES_DELTA) / SUM (EXECUTIONS),
                          4)
                      AVG_IO_OFFLOAD_ELIG_BYTES,
                   ROUND (SUM (IO_OFFLOAD_RETURN_BYTES_DELTA) / SUM (EXECUTIONS),
                          4)
                      AVG_IO_OFFLOAD_RETURN_BYTES,
                   ROUND (SUM (JAVEXEC_TIME_DELTA) / SUM (EXECUTIONS), 4)
                      AVG_JAVEXEC_TIME,
                   ROUND (
                      SUM (OPTIMIZED_PHYSICAL_READS_DELTA) / SUM (EXECUTIONS),
                      4)
                      AVG_OPTIMIZED_PHYSICAL_READS,
                   ROUND (SUM (PLSEXEC_TIME_DELTA) / SUM (EXECUTIONS), 4)
                      AVG_PLSEXEC_TIME_DELTA,
                   ROUND (SUM (SORTS_DELTA) / SUM (EXECUTIONS), 4)
                      AVG_SORTS_DELTA,
                   SUM (
                      IOWAIT_DELTA + CCWAIT_DELTA + CLWAIT_DELTA + APWAIT_DELTA)
                      TOTAL_WAIT,
                   MAX (BIND_DATA) BIND_DATA
              FROM (SELECT S.*,
                           DECODE (EXECUTIONs_DELTA, 0, 1, EXECUTIONS_DELTA)
                              EXECUTIONS
                      FROM DBA_HIST_SQLSTAT S) S
             WHERE 1 = 1 -- and ( PARSING_SCHEMA_NAME like 'EUS%' )  -- Filter by schema name
          GROUP BY S.SQL_ID,
                   instance_number,
                   S.SNAP_ID,
                   PLAN_HASH_VALUE,
                   MODULE,
                   ACTION,
                   PARSING_SCHEMA_NAME,
                   S.INSTANCE_NUMBER,
                   PARSING_USER_ID
            HAVING ROUND (
                      (SUM (ELAPSED_TIME_DELTA) / SUM (EXECUTIONS)) / 1000000,
                      4) >= 10                             -- Filter >= n secs
          ORDER BY 5 DESC) TAB1
   WHERE D.SQL_ID = TAB1.SQL_ID AND TAB1.snap_id = N.snap_id --  and upper(tab1.module) like '%PKG_BATCH_PROCESSES_SDM%'
         AND d.sql_id IN ('6tmcqrydfgdtc') --  AND D.SQL_ID in ( select distinct sql_id from DBA_HIST_ACTIVE_SESS_HISTORY where top_level_sql_id = '85xkhugz5kt8h'  )
                                           --  AND upper(DBMS_LOB.SUBSTR (sql_text, 100, 1)) LIKE 'INSERT%'
                                           --  AND upper(DBMS_LOB.SUBSTR (sql_text, 1000, 1)) LIKE 'SELECT%'
                                           --  AND upper(DBMS_LOB.SUBSTR (sql_text, 3000, 1)) LIKE '%INACTIVE%'
         AND BEGIN_INTERVAL_TIME > SYSDATE - 60
-- and BEGIN_INTERVAL_TIME between to_date('05/09/2013 07:50:00', 'DD/MM/YYYY hh24:mi:ss') AND    to_date('05/09/2013 16:10:00', 'DD/MM/YYYY hh24:mi:ss')
-- and  BEGIN_INTERVAL_TIME >= (SELECT  job_start_datetime - (2/24)  FROM   job_status  WHERE   job_name = 'RAVLDBSK' AND cob_date =  (SELECT  current_cob_date  FROM  eus_cob))
-- and  BEGIN_INTERVAL_TIME <= (SELECT job_end_datetime + (2/24)  FROM   job_status  WHERE   job_name = 'RAVLDBSK' AND cob_date =  (SELECT  current_cob_date  FROM  eus_cob))
-- order by AVG_ELAPSED_SECS DESC
-- order by ELAPSED_TIME_DELTA DESC
ORDER BY BEGIN_INTERVAL_TIME DESC
-- order by TOTAL_WAIT_SECS desc；

 Thanks and Regards