ORACLE 11g 通过ASH结合AWR实战解决cpu高负载的详细过程
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ASH結(jié)合AWR實戰(zhàn)解決oracle高負(fù)載
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??????????? 線上oracle數(shù)據(jù)庫負(fù)載比較高，所以需要優(yōu)化，一般進(jìn)去看負(fù)載高的進(jìn)程，如果是oracle進(jìn)程，那么就是oracle運(yùn)行不健康出異常了，我們通常可以用ash來分析問題，如果ash還無法解決，我們就需要擴(kuò)大分析范圍，需要采用awr分析日志來進(jìn)行分析。
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1、ASH分析日志分析Events
Top SQL with Top Events
| SQL ID | Planhash | Sampled # of Executions | % Activity | Event | % Event | Top Row Source | % RwSrc | SQL Text |
| 2xg4n5sj1sx5h | 2047223008 | 5066 | 11.18 | latch: cache buffers chains | 5.88 | TABLE ACCESS - FULL | 2.34 | select * from (select a.bis_pr... |
| ? | ? | ? | ? | CPU + Wait for CPU | 5.24 | TABLE ACCESS - FULL | 2.35 | |
| 19gkjf4r3zkpw | 2939541073 | 1013 | 2.23 | latch: cache buffers chains | 1.27 | TABLE ACCESS - FULL | 1.00 | select round(sum(t.current_fac... |
| 6qhrc4ax6zr1a | 2939541073 | 960 | 2.12 | latch: cache buffers chains | 1.21 | TABLE ACCESS - FULL | 0.96 | select round(sum(t.current_fac... |
| 6nmdjjxfv7aqp | 2939541073 | 847 | 1.87 | latch: cache buffers chains | 1.03 | TABLE ACCESS - FULL | 0.78 | select round(sum(t.current_fac... |
| 1qq2h1qkxkaha | 2939541073 | 776 | 1.71 | latch: cache buffers chains | 1.02 | TABLE ACCESS - FULL | 0.83 | select round(sum(t.current_fac... |
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Top SQL with Top Row Sources
| SQL ID | PlanHash | Sampled # of Executions | % Activity | Row Source | % RwSrc | Top Event | % Event | SQL Text |
| 2xg4n5sj1sx5h | 2047223008 | 5066 | 11.18 | TABLE ACCESS - FULL | 4.70 | CPU + Wait for CPU | 2.35 | select * from (select a.bis_pr... |
| ? | ? | ? | ? | TABLE ACCESS - FULL | 3.90 | latch: cache buffers chains | 2.30 | |
| ? | ? | ? | ? | TABLE ACCESS - FULL | 1.13 | latch: cache buffers chains | 0.66 | |
| 19gkjf4r3zkpw | 2939541073 | 1013 | 2.23 | TABLE ACCESS - FULL | 1.73 | latch: cache buffers chains | 1.00 | select round(sum(t.current_fac... |
| 6qhrc4ax6zr1a | 2939541073 | 960 | 2.12 | TABLE ACCESS - FULL | 1.59 | latch: cache buffers chains | 0.96 | select round(sum(t.current_fac... |
| 6nmdjjxfv7aqp | 2939541073 | 847 | 1.87 | TABLE ACCESS - FULL | 1.39 | latch: cache buffers chains | 0.78 | select round(sum(t.current_fac... |
| 1qq2h1qkxkaha | 2939541073 | 776 | 1.71 | TABLE ACCESS - FULL | 1.34 | latch: cache buffers chains | 0.83 | select round(sum(t.current_fac... |
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從這里分析，可以看到2xg4n5sj1sx5h的SQL引發(fā)了性能瓶頸，因為短短的20分鐘內(nèi)執(zhí)行了5066次，而且誘發(fā)了latch: cache buffers chains以及TABLE ACCESS – FULL全表掃描，所以針對這個sql，分析后，建立優(yōu)化索引：
createindex IDX_PROJECT_ID_BRRQon BIS_REPORT_RENT_QUICK(BIS_PROJECT_ID, SEQUNCE_NO, YEAR, MONTH);
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之后繼續(xù)觀察cpu負(fù)載，已經(jīng)降低了一半，但是還不夠，還沒有達(dá)到正常值，而看ash報告已經(jīng)不能提供幫助了。接下來我們需要更加全面的awr報告。
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2、Awr看以下個主要方向
（1）SQL ordered by Sharable Memory
（2）SQL ordered by CPU Tim
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3、先看SQL ordered by Sharable Memory
- Only Statements with Sharable Memory greater than 1048576 are displayed
| Sharable Mem (b) | Executions | % Total | SQL Id | SQL Module | SQL Text |
| 5,890,119 | 19 | 0.04 | 8jfndnfr9hct8 | ? | select * from ( select * from ... |
| 4,980,367 | 3 | 0.04 | 3gnf4zamgyb7x | ? | select * from ( select * from ... |
| 3,816,036 | 8 | 0.03 | 277rt4gknr76h | ? | update POWERDESK.cont_ledger s... |
| 2,966,255 | 21 | 0.02 | f2b3a59mdr7wb | ? | select * from ( select * from ... |
| 2,694,091 | 12 | 0.02 | a8y6k4gt09xxn | ? | select * from ( select * from ... |
| 2,316,487 | 21 | 0.02 | amyymj7a06gum | ? | select * from ( select * from ... |
| 2,003,767 | 18 | 0.01 | 7z4hxbs26uz8d | ? | select * from ( select * from ... |
| 2,003,743 | 6 | 0.01 | 96264xfwmxcm7 | ? | select * from ( select * from ... |
| 1,979,443 | 12 | 0.01 | a8y6k4gt09xxn | ? | select * from ( select * from ... |
| 1,626,167 | 18 | 0.01 | 7z4hxbs26uz8d | ? | select * from ( select * from ... |
| 1,354,011 | 9 | 0.01 | g371ncnjwg9zx | ? | select * from ( select * from ... |
| 1,325,857 | 1,827 | 0.01 | fm2hxa2nb9gzx | ? | select count(*) from ( select ... |
| 1,303,125 | 192 | 0.01 | dq8xug6mzj7dj | ? | select count(*) from (select r... |
| 1,277,136 | 11 | 0.01 | 1jubuhx6cdxw8 | ? | select sum(rent_square) from( ... |
| 1,147,400 | 4 | 0.01 | 6gj7zqb64m29q | ? | select count(*) from ( select ... |
| 1,135,232 | 4 | 0.01 | 6gj7zqb64m29q | ? | select count(*) from ( select ... |
| 1,126,672 | 1 | 0.01 | 242g0k9qdh0q0 | ? | select sum(rent_square) from( ... |
| 1,064,607 | 3,723 | 0.01 | 7sum7dh4hcmbh | ? | select * from ( select jbpmtas... |
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看到有fm2hxa2nb9gzx這條sql記錄，執(zhí)行次數(shù)比較多，有優(yōu)化的空間：
| SELECT ? COUNT(*) FROM ? (SELECT ??? res.*, ??? 1 rec_status ? FROM ??? Res_Approve_Info res ? WHEREEXISTS ??? (SELECT ????? 1 ??? FROM ????? Res_Approve_User u ??? WHERE u.res_Approve_Info_Id = res.res_Approve_Info_Id ????? AND u.user_Cd = :1) ?????? ??? UNION ??? SELECT ????? res.*, ????? 9 rec_status ??? FROM ????? Res_Approve_Info res ??? WHEREEXISTS ????? (SELECT ??????? 1 ????? FROM ??????? Res_Approve_User u, ??????? Res_Accredit_Info a ????? WHERE u.res_Approve_Info_Id = res.res_Approve_Info_Id ??????? AND U.USER_CD = A.USER_CD ??????? AND A.ACC_USER_CD = :2)) res ? WHERE1 = 1 ??? AND res.status_cd = '1' |
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解決辦法，添加索引：
createindex IXU_RES_USER_CD_2 on RES_APPROVE_USER(USER_CD);
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4、再看SQL ordered by CPU Time
- Resources reported for PL/SQL code includes the resources used by all SQL statements called by the code.
- %Total - CPU Time as a percentage of Total DB CPU
- %CPU - CPU Time as a percentage of Elapsed Time
- %IO - User I/O Time as a percentage of Elapsed Time
- Captured SQL account for 23.1% of Total CPU Time (s): 11,858
- Captured PL/SQL account for 0.0% of Total CPU Time (s): 11,858
| CPU Time (s) | Executions | CPU per Exec (s) | %Total | Elapsed Time (s) | %CPU | %IO | SQL Id | SQL Module | SQL Text |
| 146.67 | 11,055 | 0.01 | 1.24 | 192.16 | 76.33 | 0.00 | 4198t22zum3dr | ? | select t1.module_cd, count(t1.... |
| 140.39 | 65 | 2.16 | 1.18 | 300.45 | 46.73 | 0.00 | a8s9kjk7mk6yc | ? | select nvl(sum(nvl(sales_money... |
| 133.99 | 63 | 2.13 | 1.13 | 365.39 | 36.67 | 0.00 | 15uv0hbq9dmm7 | ? | select nvl(sum(nvl(sales_money... |
| 130.97 | 65 | 2.01 | 1.10 | 286.23 | 45.75 | 0.00 | bhnjxfa4av3kw | ? | select nvl(sum(nvl(sales_money... |
| 127.93 | 4,215 | 0.03 | 1.08 | 157.88 | 81.03 | 0.00 | aajc7r9y7z1qs | ? | select * from ( select this_.d... |
| 124.72 | 63 | 1.98 | 1.05 | 317.81 | 39.24 | 0.00 | 1na6hypkn1q2f | ? | select nvl(sum(nvl(sales_money... |
| 112.56 | 347 | 0.32 | 0.95 | 444.87 | 25.30 | 0.00 | cpw6nx6gdv937 | ? | select sum(rent_square) from( ... |
| 110.81 | 19,013 | 0.01 | 0.93 | 156.71 | 70.71 | 0.00 | ckkvz3r38xa4k | ? | select * from ( select kmpush0... |
| 103.00 | 19,013 | 0.01 | 0.87 | 136.82 | 75.28 | 0.00 | 8n23w37kwdn3p | ? | select count(*) as col_0_0_ fr... |
| 97.71 | 7,400 | 0.01 | 0.82 | 130.32 | 74.98 | 0.00 | f1z0k5gx90tqz | ? | select (case when t1.module_cd... |
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依據(jù)以上awr統(tǒng)計分析cpu time（s）得出的結(jié)論，點擊進(jìn)去，找出sql記錄，并給出優(yōu)化方案如下：
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屬于sql寫法不規(guī)范的優(yōu)化：
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| 4198t22zum3dr | select t1.module_cd, count(t1.jbpm_task_id) num from jbpm_task t1, jbpm_task_candidate t2 where t1.jbpm_task_id=t2.jbpm_task_id and (t2.user_cd=:1 or t2.user_cd like :2 ) group by t1.module_cd order by decode(t1.module_cd, 'mesMeetingInfo', '0', 'resApprove', '1', 'planTarget', '2') asc | 優(yōu)化建議： 將order by后面的decode(t1.module_cd, 'mesMeetingInfo', '0', 'resApprove', '1', 'planTarget', '2') asc移到from前面，在外層做order by操作 |
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| bhnjxfa4av3kw | select nvl(sum(nvl(sales_money, 0)), 0) from bis_sales_day where to_char(sales_date, 'yyyy-MM')='2016-06' and bis_cont_id in (select bis_cont_id from bis_cont bc where cont_type_cd in ('1', '2') and ((bc.status_cd = '2' and '2016-06' >= to_char(bc.cont_start_date, 'yyyy-MM') and to_char(bc.cont_to_fail_date, 'yyyy-MM')>='2016-06') or (bc.status_cd in ('1', '3') and '2016-06' >= to_char(bc.cont_start_date, 'yyyy-MM') and to_char(bc.cont_end_date, 'yyyy-MM')>='2016-06')) and bc.bis_project_id in (select bis_project_id from bis_project where is_business_project ='1' ) and bc.store_type='1' ) | 優(yōu)化建議： 將where后面 in的子查詢判斷字句變成 exists判斷。 |
| 15uv0hbq9dmm7 | select nvl(sum(nvl(sales_money, 0)), 0) from bis_sales_day where to_char(sales_date, 'yyyy-MM')='2016-07' and bis_cont_id in (select bis_cont_id from bis_cont bc where cont_type_cd in ('1', '2') and ((bc.status_cd = '2' and '2016-07' >= to_char(bc.cont_start_date, 'yyyy-MM') and to_char(bc.cont_to_fail_date, 'yyyy-MM')>='2016-07') or (bc.status_cd in ('1', '3') and '2016-07' >= to_char(bc.cont_start_date, 'yyyy-MM') and to_char(bc.cont_end_date, 'yyyy-MM')>='2016-07')) and bc.bis_project_id in (select bis_project_id from bis_project where is_business_project ='1' ) and bc.store_type in ('1', '2') ) | 優(yōu)化建議： 將where后面 in的子查詢判斷字句變成 exists判斷。 |
| bhnjxfa4av3kw | select nvl(sum(nvl(sales_money, 0)), 0) from bis_sales_day where to_char(sales_date, 'yyyy-MM')='2016-06' and bis_cont_id in (select bis_cont_id from bis_cont bc where cont_type_cd in ('1', '2') and ((bc.status_cd = '2' and '2016-06' >= to_char(bc.cont_start_date, 'yyyy-MM') and to_char(bc.cont_to_fail_date, 'yyyy-MM')>='2016-06') or (bc.status_cd in ('1', '3') and '2016-06' >= to_char(bc.cont_start_date, 'yyyy-MM') and to_char(bc.cont_end_date, 'yyyy-MM')>='2016-06')) and bc.bis_project_id in (select bis_project_id from bis_project where is_business_project ='1' ) and bc.store_type='1' ) | 優(yōu)化建議： 將where后面 in的子查詢判斷字句變成 exists判斷。 |
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屬于sql中添加索引的優(yōu)化：
| aajc7r9y7z1qs | select * from ( select this_.dly_note_id as dly1_396_0_, this_.created_center_cd as created2_396_0_, this_.created_date as created3_396_0_, this_.created_dept_cd as created4_396_0_, this_.created_position_cd as created5_396_0_, this_.creator as creator396_0_, this_.note_biz_type_cd as note7_396_0_, this_.note_content as note8_396_0_, this_.note_title as note9_396_0_, this_.record_version as record10_396_0_, this_.remark as remark396_0_, this_.send_mail_flg as send12_396_0_, this_.seq as seq396_0_, this_.tip_end_date as tip14_396_0_, this_.tip_flg as tip15_396_0_, this_.tip_period_cd as tip16_396_0_, this_.tip_start_date as tip17_396_0_, this_.tip_type_cd as tip18_396_0_, this_.updated_center_cd as updated19_396_0_, this_.updated_date as updated20_396_0_, this_.updated_dept_cd as updated21_396_0_, this_.updated_position_cd as updated22_396_0_, this_.updator as updator396_0_ from POWERDESK.dly_note this_ where this_.creator=:1 order by this_.seq asc ) where rownum <= :2 | 優(yōu)化方案，添加索引：createindex IDX_CREATOR on DLY_NOTE (creator); ? |
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在添加好IDX_CREATOR、IXU_RES_USER_CD_2 這2個索引后，cpu負(fù)載已經(jīng)再次降低了一半，雖然沒有到正常值，但是已經(jīng)接近最低級別的告警線，暫時數(shù)據(jù)庫脫離危險了，就等其它的幾個需要修改sql的優(yōu)化繼續(xù)完成后，cpu負(fù)載基本就可以恢復(fù)到正常值了。
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所以，一般oracle服務(wù)器負(fù)載飆升，90%都是由不規(guī)范的sql、性能差的sql造成的，而ash和awr分析報告是我們解決的最有效的途徑。
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