Appologize for kind of takeover but how I'm not seeing this ORA-01628
having below stats (also db 12.1):
SELECT DISTINCT STATUS, SUM(BYTES)/1024/1024/1024 GB, COUNT(*) FROM
DBA_UNDO_EXTENTS GROUP BY STATUS
2 /
Status GB COUNT(*)
--------- ---------- ----------
UNEXPIRED 1601.99518 306973
EXPIRED .745910645 2169
ACTIVE 3.40631104 112
SQL>
SQL> SELECT MAX(TUNED_UNDORETENTION), MAX(MAXQUERYLEN),
MAX(NOSPACEERRCNT), MAX(EXPSTEALCNT) FROM V$UNDOSTAT;
MAX(TUNED_UNDORETENTION) MAX(MAXQUERYLEN) MAX(NOSPACEERRCNT)
MAX(EXPSTEALCNT)
------------------------ ---------------- ------------------
----------------
863546 61543 0 26
SQL> SELECT BEGIN_TIME, END_TIME, TUNED_UNDORETENTION, MAXQUERYLEN,
MAXQUERYID, NOSPACEERRCNT, EXPSTEALCNT, UNDOBLKS, TXNCOUNT FROM V$UNDOSTAT;
BEGIN_TIME Date TUNED_UNDORETENTION MAXQUERYLEN
MAXQUERYID NOSPACEERRCNT EXPSTEALCNT UNDOBLKS TXNCOUNT
------------------- ------------------- ------------------- -----------
------------- ------------- ----------- ---------- ----------
2021-04-21 09:37:14 2021-04-21 09:46:11 863546 2418
fcfpwturkq7dm 0 13 153064 193322
2021-04-21 09:27:14 2021-04-21 09:37:14 863062 1813
fcfpwturkq7dm 0 15 137362 690064
Regards.
Greg
W dniu 2021-04-21 o 12:40, Jonathan Lewis pisze:
That's not a good question.
It doesn't matter what side effects anyone has seen unless you also know what sort of activity their database goes through - so you're asking other people to tell you things about their databases that you should be telling them about your database before you ask the question.
I can think of a couple of /*possible */side effects - but they may be completely irrelevant to you, and if I don't give you a context your next question will probably be to ask for an explanation of how or why the side effects night appear.
a) You waste buffer cache unnecessarily
b) you increase the risk of ORA-01628 max # extents (32765) reached for rollback segment
Regards
Jonathan Lewis
On Tue, 20 Apr 2021 at 05:58, Laurentiu Oprea <laurentiu.oprea06@xxxxxxxxx <mailto:laurentiu.oprea06@xxxxxxxxx>> wrote:
Hello,
DB Version: 12.1
Is someone played around with parameter _rollback_segment_count ?
I`m most interested in what are the side effects of increasing
this parameter.
Thank you.
