The root cause turned out to be mundane – I’ve forgotten to open the database
as read only before migrating it to PDB over a database link. That was
necessary, because the database was in NOARCHIVELOG mode.
Best regards,
Nenad
From: oracle-l-bounce@xxxxxxxxxxxxx <oracle-l-bounce@xxxxxxxxxxxxx> On Behalf
Of Mladen Gogala
Sent: Freitag, 26. November 2021 21:57
To: oracle-l@xxxxxxxxxxxxx
Subject: Re: nonlogged blocks despite force logging
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On 11/26/21 10:37, Noveljic Nenad wrote:
What might be the explanation for non-logged blocks if logging is forced on the
database level?
SQL> select count(*) from v$nonlogged_block ;
COUNT(*)
----------
17
SQL> select force_logging from v$database ;
FORCE_LOGGING
---------------------------------------
YES
The non-logged blocks belong to a LOB segment:
1* select segment_name,segment_type from dba_extents where file_id = 11 and
137828 between block_id and block_id + blocks -1
SQL> /
SEGMENT_NAME SEGMENT_TYPE
------------------------------ ------------------
SYS_LOB0000006331C00004$$ LOBSEGMENT
It started happening after migrating from 19.7 non-cdb to 19.13 multi-tenant.
Best regards,
Nenad
____________________________________________________
Based on your description and the very low number of unlogged blocks, I would
say, you've encountered the following bug:
[Click to add to
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Bug 9766652 - If a lob column is modified to 'cache reads' or 'nocache', the
logging attribute for the lob index may be unexpectedly changed to 'nologging'
(Doc ID 9766652.8)
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________________________________
Of course, I cannot be sure, you will probably have to open a SR with Oracle
Support.
Regards
--
Mladen Gogala
Database Consultant
Tel: (347) 321-1217
https://dbwhisperer.wordpress.com
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