ash是很有效的监控工具之中的一个。1秒抓一次 select max(sample_time)over(),min(sample_time)over() from dba_hist_active_sess_history; --8天 select max(sample_time)over(),min(sample_time)over() from v$active_session_history; --当天 首先先了解几个视图： V$ACTIVE_SESSION_HISTORY: 是ASH的核心。用以记录活动SESSION的历史等待信息。每秒採样一次。这部分内容记录在内存中，期望值是记录一个小时的内容。 WRH#_ACTIVE_SESSION_HISTORY : 是V$ACTIVE_SESSION_HISTORY在AWR的存储地。 V$ACTIVE_SESSION_HISTORY: 中的信息会被定期(每小时一次)的刷新到负载库中，并缺省保留一个星期用于分析。 DBA_HIST_ACTIVE_SESS_HISTORY: 视图是WRH#_ACTIVE_SESSION_HISTORY视图和其它几个视图的联合展现，通常通过这个视图进行历史数据的訪问。------------------------------------ --V$ACTIVE_SESSION_HISTORY的监控：-- ------------------------------------ ------------session：1----------------- SQL> @big SID ---------- 131 Elapsed: 00:00:00.00 drop table big * ERROR at line 1: ORA-00942: table or view does not exist Elapsed: 00:00:00.03 Elapsed: 00:00:00.31 Elapsed: 00:00:00.34 Elapsed: 00:00:00.29 Elapsed: 00:00:00.73 Elapsed: 00:00:01.75 Elapsed: 00:00:10.59 Elapsed: 00:00:24.62 Elapsed: 00:00:00.01 BIG_M ---------- 522 Elapsed: 00:00:00.36 COUNT(*) ---------- 4650368 Elapsed: 00:00:26.70 ------------session：2----------------- SQL> @getash_sid Enter value for sid: 131 SESSION_ID NAME P_NAME P_VALUE SQL_ID WAIT_TIME CURRENT_OBJ# CURRENT_FILE# CURRENT_BLOCK# ---------- ---------------------------------------------------------------- --------------- --------------- ------------- ---------- ------------ ------------- --------- 131 db file sequential read file# 1 d2wbn28rdk8z4 0 547 1 3604 block# 53206 blocks 1 131 db file sequential read file# 1 d2wbn28rdk8z4 0 -1 0 0 block# 3009 blocks 1 131 db file scattered read file# 4 03b71c07nsc1a 0 134 1 1064 block# 4845 blocks 8 131 log buffer space 0 aq32z6wjx1s4h 0 76851 4 6046 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 6046 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 6046 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 6046 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 6046 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 6046 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 6046 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 6046 0 0 131 log file switch completion 0 aq32z6wjx1s4h 0 76851 4 6046 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 6046 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 6046 0 0 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 4995 block# 4995 blocks 5 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 7170 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 7170 0 0 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 8578 block# 8578 blocks 126 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 12802 block# 12802 blocks 126 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 12930 0 0 131 db file sequential read file# 1 aq32z6wjx1s4h 0 65921 201 3585 block# 2854 blocks 1 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 14084 block# 14084 blocks 124 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 18436 block# 18436 blocks 128 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 19972 block# 19972 blocks 128 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 21252 block# 21252 blocks 124 131 db file parallel read files 1 aq32z6wjx1s4h 0 76851 4 23424 blocks 29 requests 29 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 24320 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 24320 0 0 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 25856 block# 25856 blocks 128 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 27652 block# 27652 blocks 124 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 29312 block# 29312 blocks 32 131 Disk file operations I/O FileOperation 2 aq32z6wjx1s4h 0 76851 4 29952 fileno 0 filetype 2 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 30724 block# 30724 blocks 124 131 db file scattered read file# 4 aq32z6wjx1s4h 0 76851 4 34530 block# 34530 blocks 14 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 35716 0 0 131 log file switch (checkpoint incomplete) 0 aq32z6wjx1s4h 0 76851 4 35716 0 0 131 Disk file operations I/O FileOperation 5 aq32z6wjx1s4h 0 76851 4 37632 fileno 0 filetype 2 131 db file sequential read file# 4 fqcxb1n33642x 0 9 1 86832 block# 4999 blocks 1 131 db file scattered read file# 4 fqcxb1n33642x 0 9 1 86832 block# 10344 blocks 8 131 db file scattered read file# 4 fqcxb1n33642x 0 9 1 86832 block# 17409 blocks 8 131 db file scattered read file# 4 fqcxb1n33642x 0 9 1 86832 block# 22083 blocks 8 131 db file scattered read file# 4 fqcxb1n33642x 0 9 1 86832 block# 28549 blocks 8 131 db file scattered read file# 4 fqcxb1n33642x 0 9 1 86832 block# 34733 blocks 8 131 db file scattered read file# 4 fqcxb1n33642x 0 9 1 86832 block# 39217 blocks 8 131 db file scattered read file# 4 fqcxb1n33642x 0 9 1 86832 block# 45114 blocks 8 131 db file scattered read file# 4 fqcxb1n33642x 0 9 1 86832 block# 48836 blocks 8 131 db file scattered read file# 4 fqcxb1n33642x 0 9 1 86832 block# 52391 blocks 8 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 5196 block# 5196 blocks 6 131 db file sequential read file# 4 fqcxb1n33642x 0 76851 4 8261 block# 8261 blocks 1 131 db file sequential read file# 4 fqcxb1n33642x 0 76851 4 11318 block# 11318 blocks 1 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 14489 block# 14489 blocks 56 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 17935 block# 17935 blocks 50 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 21195 block# 21195 blocks 20 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 25170 block# 25170 blocks 2 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 28453 block# 28453 blocks 34 131 db file sequential read file# 4 fqcxb1n33642x 0 76851 4 33067 block# 33067 blocks 1 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 36991 block# 36991 blocks 13 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 41616 block# 41616 blocks 21 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 44055 block# 44055 blocks 8 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 2723 block# 2723 blocks 44 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 50056 block# 50056 blocks 9 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 53658 block# 53658 blocks 102 131 db file scattered read file# 4 fqcxb1n33642x 0 76851 4 56580 block# 56580 blocks 128 131 db file sequential read file# 4 fqcxb1n33642x 0 76851 4 60256 block# 60256 blocks 1 64 rows selected. Elapsed: 00:00:00.40 SQL> @getsql_sqlid Enter 1 for curr sql, 2 for hist sql,default 1: Enter value for sqlid: fqcxb1n33642x SQL_FULLTEXT --------------------------------------------------------------------------------------------- select count(*) from big Elapsed: 00:00:00.00 Elapsed: 00:00:00.00 SQL> @getobj_id Enter value for dblink: Enter value for obj_id: 76851 OWNER OBJECT_NAME OBJECT_TYPE CREATED STATUS -------------------- ------------------------------ ------------------- ------------------- ------- SCOTT BIG TABLE 2014-11-20 15:56:23 VALID 1 row selected. Elapsed: 00:00:00.01 SQL> @getobj_fb Enter value for file_id: 4 Enter value for block_id: 60256 OWNER SEGMENT_NAME SEGMENT_TY --------------- -------------------- ---------- SCOTT BIG TABLE 1 row selected. Elapsed: 00:00:00.37 --------------------------@脚本-------------------- --@big @sid set feedback off drop table big; create table big as select * from dba_objects; insert into big select * from big; / / / / / commit; select SUM(bytes) / 1024 / 1024 big_M from dba_segments where segment_name = 'BIG'; select count(*) from big; set feedback on --@getash_sid col p_name for a15 col p_value for a15 select SESSION_ID, NAME, P1TEXT||chr(10)||P2TEXT||chr(10)||P3TEXT p_name, p1||chr(10)||p2||chr(10)||p3 p_value, sql_id, WAIT_TIME, CURRENT_OBJ#, CURRENT_FILE#, CURRENT_BLOCK# from v$active_session_history ash, v$event_name enm where ash.event# = enm.event# and SESSION_ID = &sid order by sample_time; ---------------------------------------- --DBA_HIST_ACTIVE_SESS_HISTORY的监控：-- ---------------------------------------- --查当前时间 select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual; --依据时间找到snap_id（8天内，1小时前），由于基表很大，利用snap_id的索引才干高速查询 select distinct snap_id from dba_hist_snapshot b where to_date('2014-11-20 14:08:12','yyyy-mm-dd hh24:mi:ss') between b.begin_interval_time and b.end_interval_time; --top instance select /*+parallel(a,8)*/instance_number,count(*) from dba_hist_active_sess_history a where a.snap_id=67421 group by instance_number; --top event select /*+parallel(a,8)*/event,count(*) from dba_hist_active_sess_history a where a.snap_id=67421 and instance_number=2 and sample_time>=to_timestamp('2014-11-20 14:07:12','yyyy-mm-dd hh24:mi:ss') and sample_time<=to_timestamp('2014-11-20 14:08:12','yyyy-mm-dd hh24:mi:ss') group by event order by count(*) desc; --top user select /*+parallel(a,8)*/user_id,(select username from dba_users b where b.user_id=a.user_id) username,count(*) from dba_hist_active_sess_history a where a.snap_id=67421 and instance_number=2 and sample_time>=to_timestamp('2014-11-20 14:07:12','yyyy-mm-dd hh24:mi:ss') and sample_time<=to_timestamp('2014-11-20 14:08:12','yyyy-mm-dd hh24:mi:ss') group by user_id order by count(*) desc; --top sql select /*+parallel(a,8)*/sql_id,count(*) from dba_hist_active_sess_history a where a.snap_id=67421 and instance_number=2 and sample_time>=to_timestamp('2014-11-20 14:07:12','yyyy-mm-dd hh24:mi:ss') and sample_time<=to_timestamp('2014-11-20 14:08:12','yyyy-mm-dd hh24:mi:ss') group by sql_id order by count(*) desc; -- select SQL_TEXT from dba_hist_sqltext where sql_id='49p4hfj6azw19'; --top program select /*+parallel(a,8)*/program,count(*) from dba_hist_active_sess_history a where a.snap_id=67421 and instance_number=2 and sample_time>=to_timestamp('2014-11-20 14:07:12','yyyy-mm-dd hh24:mi:ss') and sample_time<=to_timestamp('2014-11-20 14:08:12','yyyy-mm-dd hh24:mi:ss') group by program order by count(*) desc;