Script - Check Current Undo Configuration and Advise Recommended Setup (Doc ID 1579035.1)
APPLIES TO:
Oracle Database - Enterprise Edition - Version 8.1.7.0 and later
Information in this document applies to any platform.
*** Checked for relevance on 05-Apr-2016 ***
GOAL
This document is intended to check the current undo configuration and provides recommendation based on the previous workload.AUTION
本文档旨在检查当前的 undo 配置，并根据先前的工作量提供建议。
This sample code is provided for diagnosis and troubleshooting purposes only, and is NOT supported by Oracle Support. It has been tested internally, however, we do not guarantee that it will work for you. Ensure that you run it in your test environment before using.
提供: 此示例代码仅用于诊断和故障排除，Oracle Support不支持此示例代码。它已经过内部测试，但是，我们不能保证它会为您服务。使用前，请确保在测试环境中运行它
There are different scripts for database versions post 10g and prior to 10g. Ensure to execute the correct one to get the proper recommendation. Ensure to execute the script as SYS user.
10g之后和10g之前的数据库版本有不同的脚本。确保执行正确的建议以获得正确的建议。确保以SYS用户身份执行脚本。
SOLUTION
For database version 10g and above, use the following script. Ensure to execute the same as SYSDBA.
对于10g及更高版本的数据库，请使用以下脚本。确保执行与SYSDBA相同的操作
RDBMS version 10g and above:
SET SERVEROUTPUT ON
SET LINES 600
ALTER SESSION SET NLS_DATE_FORMAT = 'DD/MM/YYYY HH24:MI:SS';
DECLARE
v_analyse_start_time DATE := SYSDATE - 7;
v_analyse_end_time DATE := SYSDATE;
v_cur_dt DATE;
v_undo_info_ret BOOLEAN;
v_cur_undo_mb NUMBER;
v_undo_tbs_name VARCHAR2(100);
v_undo_tbs_size NUMBER;
v_undo_autoext BOOLEAN;
v_undo_retention NUMBER(5);
v_undo_guarantee BOOLEAN;
v_instance_number NUMBER;
v_undo_advisor_advice VARCHAR2(100);
v_undo_health_ret NUMBER;
v_problem VARCHAR2(1000);
v_recommendation VARCHAR2(1000);
v_rationale VARCHAR2(1000);
v_retention NUMBER;
v_utbsize NUMBER;
v_best_retention NUMBER;
v_longest_query NUMBER;
v_required_retention NUMBER;
BEGIN
select sysdate into v_cur_dt from dual;
DBMS_OUTPUT.PUT_LINE(CHR(9));
DBMS_OUTPUT.PUT_LINE('- Undo Analysis started at : ' || v_cur_dt || ' -');
DBMS_OUTPUT.PUT_LINE('--------------------------------------------------');
v_undo_info_ret := DBMS_UNDO_ADV.UNDO_INFO(v_undo_tbs_name, v_undo_tbs_size, v_undo_autoext, v_undo_retention, v_undo_guarantee);
select sum(bytes)/1024/1024 into v_cur_undo_mb from dba_data_files where tablespace_name = v_undo_tbs_name;
DBMS_OUTPUT.PUT_LINE('NOTE:The following analysis is based upon the database workload during the period -');
DBMS_OUTPUT.PUT_LINE('Begin Time : ' || v_analyse_start_time);
DBMS_OUTPUT.PUT_LINE('End Time : ' || v_analyse_end_time);
DBMS_OUTPUT.PUT_LINE(CHR(9));
DBMS_OUTPUT.PUT_LINE('Current Undo Configuration');
DBMS_OUTPUT.PUT_LINE('--------------------------');
DBMS_OUTPUT.PUT_LINE(RPAD('Current undo tablespace',55) || ' : ' || v_undo_tbs_name);
DBMS_OUTPUT.PUT_LINE(RPAD('Current undo tablespace size (datafile size now) ',55) || ' : ' || v_cur_undo_mb || 'M');
DBMS_OUTPUT.PUT_LINE(RPAD('Current undo tablespace size (consider autoextend) ',55) || ' : ' || v_undo_tbs_size || 'M');
IF V_UNDO_AUTOEXT THEN
DBMS_OUTPUT.PUT_LINE(RPAD('AUTOEXTEND for undo tablespace is',55) || ' : ON');
ELSE
DBMS_OUTPUT.PUT_LINE(RPAD('AUTOEXTEND for undo tablespace is',55) || ' : OFF');
END IF;
DBMS_OUTPUT.PUT_LINE(RPAD('Current undo retention',55) || ' : ' || v_undo_retention);
IF v_undo_guarantee THEN
DBMS_OUTPUT.PUT_LINE(RPAD('UNDO GUARANTEE is set to',55) || ' : TRUE');
ELSE
dbms_output.put_line(RPAD('UNDO GUARANTEE is set to',55) || ' : FALSE');
END IF;
DBMS_OUTPUT.PUT_LINE(CHR(9));
SELECT instance_number INTO v_instance_number FROM V$INSTANCE;
DBMS_OUTPUT.PUT_LINE('Undo Advisor Summary');
DBMS_OUTPUT.PUT_LINE('---------------------------');
v_undo_advisor_advice := dbms_undo_adv.undo_advisor(v_analyse_start_time, v_analyse_end_time, v_instance_number);
DBMS_OUTPUT.PUT_LINE(v_undo_advisor_advice);
DBMS_OUTPUT.PUT_LINE(CHR(9));
DBMS_OUTPUT.PUT_LINE('Undo Space Recommendation');
DBMS_OUTPUT.PUT_LINE('-------------------------');
v_undo_health_ret := dbms_undo_adv.undo_health(v_analyse_start_time, v_analyse_end_time, v_problem, v_recommendation, v_rationale, v_retention, v_utbsize);
IF v_undo_health_ret > 0 THEN
DBMS_OUTPUT.PUT_LINE('Minimum Recommendation : ' || v_recommendation);
DBMS_OUTPUT.PUT_LINE('Rationale : ' || v_rationale);
DBMS_OUTPUT.PUT_LINE('Recommended Undo Tablespace Size : ' || v_utbsize || 'M');
ELSE
DBMS_OUTPUT.PUT_LINE('Allocated undo space is sufficient for the current workload.');
END IF;
SELECT dbms_undo_adv.best_possible_retention(v_analyse_start_time, v_analyse_end_time) into v_best_retention FROM dual;
SELECT dbms_undo_adv.longest_query(v_analyse_start_time, v_analyse_end_time) into v_longest_query FROM dual;
SELECT dbms_undo_adv.required_retention(v_analyse_start_time, v_analyse_end_time) into v_required_retention FROM dual;
DBMS_OUTPUT.PUT_LINE(CHR(9));
DBMS_OUTPUT.PUT_LINE('Retention Recommendation');
DBMS_OUTPUT.PUT_LINE('------------------------');
DBMS_OUTPUT.PUT_LINE(RPAD('The best possible retention with current configuration is ',60) || ' : ' || v_best_retention || ' Seconds');
DBMS_OUTPUT.PUT_LINE(RPAD('The longest running query ran for ',60) || ' : ' || v_longest_query || ' Seconds');
DBMS_OUTPUT.PUT_LINE(RPAD('The undo retention required to avoid errors is ',60) || ' : ' || v_required_retention || ' Seconds');
END;
/
Sample Output
- Undo Analysis started at : 30/08/2013 11:08:40 - -------------------------------------------------- NOTE:The following analysis is based upon the database workload during the period - Begin Time : 23/08/2013 11:08:40 End Time : 30/08/2013 11:08:40 Current Undo Configuration -------------------------- Current undo tablespace : UNDOTBS2 Current undo tablespace size (datafile size now) : 20M Current undo tablespace size (consider autoextend) : 20M AUTOEXTEND for undo tablespace is : ON Current undo retention : 900 UNDO GUARANTEE is set to : FALSE Undo Advisor Summary --------------------------- Finding 1:Undo Tablespace is under pressure. Recommendation 1:Size undo tablespace to 26 MB Undo Space Recommendation ------------------------- Minimum Recommendation : Size undo tablespace to 26 MB Rationale : Increase undo tablespace size so that long running queries will not fail Recommended Undo Tablespace Size : 26M Retention Recommendation ------------------------ The best possible retention with current configuration is : 9171 Seconds The longest running query ran for : 2543 Seconds The undo retention required to avoid errors is : 2543 Seconds PL/SQL procedure successfully completed.
RDBMS version 9i and below
Script
For 9i and below, please download the script undo_analyse9i.sql.
--undo_analyse9i.sql
SET SERVEROUTPUT ON
SET LINES 600
ALTER SESSION SET NLS_DATE_FORMAT = 'DD/MM/YYYY HH24:MI:SS';
DECLARE
v_begin_time varchar2(30);
v_end_time varchar2(30);
v_max_qry_len number;
v_unto_tbs varchar2(100);
v_cur_undo_ret number;
v_cur_undo_mb number;
v_undo_autoext varchar2(5);
v_cur_dt date;
v_recommended_undo_mb number;
v_analyse_start_time date;
v_analyse_end_time date;
BEGIN
select sysdate
into v_cur_dt
from dual;
select sysdate into v_cur_dt from dual;
DBMS_OUTPUT.PUT_LINE(CHR(10));
DBMS_OUTPUT.PUT_LINE('--------------------------------------------------');
DBMS_OUTPUT.PUT_LINE('- Undo Analysis started at : ' || v_cur_dt || ' -');
DBMS_OUTPUT.PUT_LINE('--------------------------------------------------');
SELECT begin_time,end_time into v_analyse_start_time, v_analyse_end_time
FROM v$undostat WHERE undoblks = (SELECT MAX(undoblks) FROM v$undostat);
DBMS_OUTPUT.PUT_LINE('NOTE:The following analysis is based upon the peak database workload during the period -');
DBMS_OUTPUT.PUT_LINE('Begin Time : ' || v_analyse_start_time);
DBMS_OUTPUT.PUT_LINE('End Time : ' || v_analyse_end_time);
select min(BEGIN_TIME), max(end_time) into v_begin_time, v_end_time from v$undostat;
select max(MAXQUERYLEN) into v_max_qry_len from v$undostat;
select value into v_cur_undo_ret from v$parameter where name = 'undo_retention';
select value into v_unto_tbs from v$parameter where name = 'undo_tablespace';
SELECT ROUND((UR * (UPS * DBS))/1024/1024)
INTO v_recommended_undo_mb
FROM
( select max(MAXQUERYLEN) UR
from v$undostat) ,
(SELECT undoblks/((end_time-begin_time)*86400) AS UPS
FROM v$undostat
WHERE undoblks =
(SELECT MAX(undoblks)
FROM v$undostat)),
(SELECT block_size AS DBS
FROM dba_tablespaces
WHERE tablespace_name =
(SELECT UPPER(value)
FROM v$parameter
WHERE name = 'undo_tablespace'));
select sum(bytes)/1024/1024 into v_cur_undo_mb from dba_data_files where tablespace_name = v_unto_tbs;
SELECT CASE(select count(*) from dba_data_files
where tablespace_name = v_unto_tbs
and autoextensible = 'YES')
WHEN 0 THEN 'OFF'
ELSE 'ON' END
into v_undo_autoext
from dual;
DBMS_OUTPUT.PUT_LINE(CHR(10));
DBMS_OUTPUT.PUT_LINE('----');
DBMS_OUTPUT.PUT_LINE(RPAD('Longest running query ran for : ',40) || ' : ' || v_max_qry_len || ' Seconds');
DBMS_OUTPUT.PUT_LINE(RPAD('Current undo retention is ',40) || ' : ' || v_cur_undo_ret || ' Seconds');
DBMS_OUTPUT.PUT_LINE(RPAD('Current undo tablespace size is ',40) || ' : ' || v_cur_undo_mb || 'M');
DBMS_OUTPUT.PUT_LINE(RPAD('AUTOEXTEND for undo tablespace size is ',40) || ' : ' || v_undo_autoext);
DBMS_OUTPUT.PUT_LINE('----');
DBMS_OUTPUT.PUT_LINE(RPAD('Recommended undo retention is ',40) || ' : ' || TO_CHAR(v_max_qry_len+1) || ' Seconds');
DBMS_OUTPUT.PUT_LINE(RPAD('Recommended undo tablespace size is ',40) || ' : ' || v_recommended_undo_mb || 'M');
select sysdate into v_cur_dt from dual;
DBMS_OUTPUT.PUT_LINE(CHR(10));
DBMS_OUTPUT.PUT_LINE('----------------------------------------------------');
DBMS_OUTPUT.PUT_LINE('- Undo Analysis completed at : ' || v_cur_dt || ' -');
DBMS_OUTPUT.PUT_LINE('----------------------------------------------------');
END;
/
Sample Output
-------------------------------------------------- - Undo Analysis started at : 28/08/2013 11:03:23 - -------------------------------------------------- NOTE:The following analysis is based upon the peak database workload during the period - Begin Time : 27/08/2013 21:56:36 End Time : 27/08/2013 22:06:36 ---- Longest running query ran for : : 1368 Seconds Current undo retention is : 900 Seconds Current undo tablespace size is : 10M AUTOEXTEND for undo tablespace size is : ON ---- Recommended undo retention is : 1369 Seconds Recommended undo tablespace size is : 43M ---------------------------------------------------- - Undo Analysis completed at : 28/08/2013 11:03:23 - ---------------------------------------------------- PL/SQL procedure successfully completed.
REFERENCES
NOTE:877613.1 - AUM Common Analysis/Diagnostic Scripts
NOTE:1580225.1 - What is the Undo Advisor and how to Use it through the DBMS_UNDO_ADV package