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.
This is a main instruction for troubleshooting various problems reported in Undo Management. This document provides a brief description of the various issues and a list of diagnostic information to collect before making a service request through Oracle Support.
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)
Various problems related to Undo were reported. See: 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:
a. Undo parameters
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;
Example:
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 states for undo extensions?
SELECT DISTINCT STATUS, SUM(BYTES), COUNT(*) FROM DBA_UNDO_EXTENTS GROUP BY STATUS;
Example:
SQL> SELECT DISTINCT STATUS, SUM(BYTES), COUNT(*) FROM DBA_UNDO_EXTENTS GROUP BY STATUS; STATUS SUM(BYTES) COUNT(*) --------- ---------- ---------- UNEXPIRED 6553600 10 EXPIRED 49283072 152
c. Tuned Retention
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;
Example:
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 14:52:20 20191129 15:02:20 1114 394 0rc4km05kgzb9 0 0 75 79 20191129 14:42:20 20191129 14:52:20 1716 995 0rc4km05kgzb9 0 0 0 2 20191129 14:32:20 20191129 14:42:20 1174 393 0rc4km05kgzb9 0 0 1 14 20191129 14:22:20 20191129 14:32:20 1775 993 0rc4km05kgzb9 0 0 0 6 20191129 14:12:20 20191129 14:22:20 1170 391 0rc4km05kgzb9 0 0 0 83 20191129 14:02:20 20191129 14:12:20 1772 991 0rc4km05kgzb9 0 0 0 11 20191129 13:52:20 20191129 14:02:20 1167 386 0rc4km05kgzb9 0 0 71 78 20191129 13:42:20 20191129 13:52:20 1768 988 0rc4km05kgzb9 0 0 0 6 20191129 13:32:20 20191129 13:42:20 1164 382 0rc4km05kgzb9 0 0 0 22 20191129 13:22:20 20191129 13:32:20 1765 983 0rc4km05kgzb9 0 0 0 11 20191129 13:12:20 20191129 13:22:20 2554 1773 3k9h91mkys9gw 0 0 0 9 20191129 13:02:20 20191129 13:12:20 1951 1170 3k9h91mkys9gw 0 0 3 103 20191129 12:52:20 20191129 13:02:20 1347 566 3k9h91mkys9gw 0 0 109 83 20191129 12:42:20 20191129 12:52:20 1532 751 3k9h91mkys9gw 0 0 2 60 20191129 12:32:20 20191129 12:42:20 1168 386 89km4qj1thh13 0 0 0 13 20191129 12:22:20 20191129 12:32:20 1754 974 0rc4km05kgzb9 0 0 3 31 20191129 12:12:20 20191129 12:22:20 1151 370 0rc4km05kgzb9 0 0 1 80 20191129 12:02:20 20191129 12:12:20 1752 971 0rc4km05kgzb9 0 0 0 12 20191129 11:52:20 20191129 12:02:20 1208 366 0rc4km05kgzb9 0 0 81 77 20191129 11:42:20 20191129 11:52:20 1811 969 0rc4km05kgzb9 0 0 2 7 20191129 11:32:20 20191129 11:42:20 1206 364 0rc4km05kgzb9 0 0 1 16 20191129 11:22:20 20191129 11:32:20 1807 966 0rc4km05kgzb9 0 0 0 10 20191129 11:12:20 20191129 11:22:20 1203 361 0rc4km05kgzb9 0 0 5 157 20191129 11:02:20 20191129 11:12:20 1803 962 0rc4km05kgzb9 0 0 0 12 20191129 10:52:20 20191129 11:02:20 1200 358 0rc4km05kgzb9 0 0 102 95 20191129 10:42:20 20191129 10:52:20 2464 1623 9dzjush42kmfs 0 0 1 7 20191129 10:32:20 20191129 10:42:20 1860 1019 9dzjush42kmfs 0 0 1 49 20191129 10:22:20 20191129 10:32:20 1797 955 0rc4km05kgzb9 0 0 14 216 20191129 10:12:20 20191129 10:22:20 1192 351 0rc4km05kgzb9 0 0 109 228 20191129 10:02:20 20191129 10:12:20 1796 955 0rc4km05kgzb9 0 0 38 481 20191129 09:52:20 20191129 10:02:20 1193 351 0rc4km05kgzb9 0 0 71 942 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
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';
Example:
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"
Provide query output from the "diagnostic information" section of Doc ID 1579081.1