主说明：自动Undo管理的故障排除指南(Doc ID 1579081.1)

Master Note: Troubleshooting guide for Automatic Undo Management (Doc ID 1579081.1)

APPLIES TO:

Oracle Database - Enterprise Edition - Version 9.2.0.1 to 12.1.0.1 [Release 9.2 to 12.1]
Information in this document applies to any platform.

PURPOSE

This is a Master Note for troubleshooting the various issues reported on Undo Management. This document provides a brief explanation for the various issues and the list of diagnostic information to be collected before raising a Service Request with Oracle Support.

这是一个主要说明，用于对Undo Management中报告的各种问题进行故障排除。本文档简要说明了各种问题，并在通过Oracle Support提出服务请求之前要收集的诊断信息列表。

TROUBLESHOOTING STEPS

There are various Undo related issues reported. Refer : Assistant: Get Assistance to Understand and Solve Oracle Undo Management issues (Doc ID 1575667.2)

报告了各种与Undo相关的问题。请参阅：Assistant: Get Assistance to Understand and Solve Oracle Undo Management issues (Doc ID 1575667.2)

1- Please provide the following diagnostic information if the issue persists: 如果问题仍然存在，请提供以下诊断信息：

a. Undo parameters Undo参数

select nam.ksppinm NAME, val.KSPPSTVL VALUE

  from x$ksppi nam, x$ksppsv val

 where nam.indx = val.indx

   and (nam.ksppinm like '%undo%' or

       nam.ksppinm in ('_first_spare_parameter', '_smu_debug_mode'))

 order by 1;

示例：

col NAME for a35

col VALUE for a50

select nam.ksppinm NAME, val.KSPPSTVL VALUE

  from x$ksppi nam, x$ksppsv val

 where nam.indx = val.indx

   and (nam.ksppinm like '%undo%' or

       nam.ksppinm in ('_first_spare_parameter', '_smu_debug_mode'))

 order by 1;

NAME                                VALUE

----------------------------------- --------------------------------------------------

_collect_undo_stats                 TRUE

_disable_undo_tablespace_alerts     FALSE

_enable_default_undo_threshold      TRUE

_first_spare_parameter

_flush_undo_after_tx_recovery       TRUE

_gc_undo_affinity                   TRUE

_gc_undo_block_disk_reads           TRUE

_highthreshold_undoretention        4294967294

_in_memory_undo                     TRUE

_lm_spare_undo                      0

_optimizer_undo_changes             FALSE

_optimizer_undo_cost_change         11.2.0.4

_smon_undo_seg_rescan_limit         10

_smu_debug_mode                     0

_undo_autotune                      TRUE

_undo_block_compression             TRUE

_undo_debug_mode                    0

_undo_debug_usage                   0

_verify_undo_quota                  FALSE

undo_management                     AUTO

undo_retention                      900

undo_tablespace                     UNDOTBS1

22 rows selected.

b. What are the various statuses for Undo Extents? Undo Extents的各种状态是什么？

SELECT DISTINCT STATUS, SUM(BYTES)/1024/1024 MB, COUNT(*) FROM DBA_UNDO_EXTENTS GROUP BY STATUS;

示例：

SQL> SELECT DISTINCT STATUS, SUM(BYTES)/1024/1024 MB, COUNT(*) FROM DBA_UNDO_EXTENTS GROUP BY STATUS;

STATUS            MB   COUNT(*)

--------- ---------- ----------

ACTIVE       2162.25        408

EXPIRED     18233.75      16146

UNEXPIRED   27083.25      21389

c. Tuned Retention 调整保留

SELECT MAX(TUNED_UNDORETENTION), MAX(MAXQUERYLEN), MAX(NOSPACEERRCNT), MAX(EXPSTEALCNT) FROM V$UNDOSTAT;

SELECT BEGIN_TIME, END_TIME, TUNED_UNDORETENTION, MAXQUERYLEN, MAXQUERYID, NOSPACEERRCNT, EXPSTEALCNT, UNDOBLKS, TXNCOUNT FROM V$UNDOSTAT;

示例：

SQL> SELECT BEGIN_TIME, END_TIME, TUNED_UNDORETENTION, MAXQUERYLEN, MAXQUERYID, NOSPACEERRCNT, EXPSTEALCNT, UNDOBLKS, TXNCOUNT FROM V$UNDOSTAT;

BEGIN_TIME        END_TIME          TUNED_UNDORETENTION MAXQUERYLEN MAXQUERYID    NOSPACEERRCNT EXPSTEALCNT   UNDOBLKS   TXNCOUNT

----------------- ----------------- ------------------- ----------- ------------- ------------- ----------- ---------- ----------

20191129 15:22:20 20191129 15:27:42                1420         699 0rc4km05kgzb9             0           0          0          4

20191129 15:12:20 20191129 15:22:20                1118         397 0rc4km05kgzb9             0           0          1         83

20191129 15:02:20 20191129 15:12:20                1717         997 0rc4km05kgzb9             0           0          0         13

... ...

20191129 09:42:20 20191129 09:52:20                1795         953 0rc4km05kgzb9             0           3        129        654

20191129 09:32:20 20191129 09:42:20                1190         348 0rc4km05kgzb9             0          10       5446        540

36 rows selected.

d. The size details and auto-extend setting for the UNDO Tablespace UNDO表空间的大小详细信息和自动扩展设置

COL AUTOEXTENSIBLE FORMAT A14

SELECT FILE_ID, BYTES/1024/1024 AS "BYTES (MB)", MAXBYTES/1024/1024 AS "MAXBYTES (MB)", AUTOEXTENSIBLE FROM DBA_DATA_FILES WHERE TABLESPACE_NAME='&UNDOTBS';

示例：

SQL> COL AUTOEXTENSIBLE FORMAT A14

SQL> SELECT FILE_ID, BYTES/1024/1024 AS "BYTES (MB)", MAXBYTES/1024/1024 AS "MAXBYTES (MB)", AUTOEXTENSIBLE FROM DBA_DATA_FILES WHERE TABLESPACE_NAME='&UNDOTBS';

Enter value for undotbs: UNDOTBS1

   FILE_ID BYTES (MB) MAXBYTES (MB) AUTOEXTENSIBLE

---------- ---------- ------------- --------------

         3         70    32767.9844 YES

e. Upload the alert log file from the startup.

2- Provide the query outputs from the "diagnostic information" section of Doc ID 1579081.1"

提供来自Doc ID 1579081.1的"diagnostic information"部分的查询输出