Can't shrink MLOG$
Dario Nikolic, November 25, 2016 - 12:22 pm UTC
Hi Connor,
I tryed to shrink table with commands below but:
- it only shrinked from 21GB to 18GB
SELECT S.BYTES/1024/1024/1024 SIZE_GB,S.* FROM DBA_SEGMENTS S WHERE SEGMENT_NAME LIKE 'MLOG$_MASTER_TBL'
- MLOG$ rownumber = 912
select count(*) from MLOG$_MASTER_TBL
;
- MLOG$ extent number = 18512
SELECT count(*) FROM DBA_EXTENTS WHERE SEGMENT_NAME = 'MLOG$_MASTER_TBL';
Commands for shrinking MVLOG
-- compact
ALTER MATERIALIZED VIEW LOG ON MASTER_TBL ENABLE ROW MOVEMENT;
ALTER MATERIALIZED VIEW LOG ON MASTER_TBL _A7 SHRINK SPACE COMPACT;
ALTER MATERIALIZED VIEW LOG ON MASTER_TBL disable ROW MOVEMENT;
-- lower HWM
ALTER MATERIALIZED VIEW LOG ON MASTER_TBL ENABLE ROW MOVEMENT;
ALTER MATERIALIZED VIEW LOG ON MASTER_TBL _A7 SHRINK SPACE;
ALTER MATERIALIZED VIEW LOG ON MASTER_TBL disable ROW MOVEMENT;
November 26, 2016 - 3:25 am UTC
Can you give us a 'describe' on the table and the mview log
bug11072728_mv_refresh_truncate_log
Mikhail Velikikh, November 28, 2016 - 5:05 am UTC
Hello Dario,
I'd been experiencing similar issues in the past till I found the note: Space Not Reclaimed from MLOG$ Segments After MVIEW Refresh (Doc ID 1941137.1)
https://support.oracle.com/CSP/main/article?cmd=show&type=NOT&id=1941137.1 Check out whether it help in your case.
Beware that I have experienced some ORA-00054 errors due to that parameter _bug11072728_mv_refresh_truncate_log in few SQL utilising "FOR UPDATE NOWAIT".
This patch have not caused any other significant drawbacks in my environment.
November 28, 2016 - 6:50 am UTC
Nice input. Hope this helps our original poster.
Dario Nikolic, December 02, 2016 - 8:42 am UTC
Tnx Mikhail. I've forwarded your input to DBA responsible for this database and will review when get feedback from him.