Oracle database is on
noarchivelog mode and
tablespace is configured with
nologging option keeping there will not be a situation to recover any data in mind.
Following scenario was occured during ETL process:
- 1st hour AWR showing 15GB per second and 131K per transaction in the Load Profile.
- 1st hour AWR showing 54TB Redo generation logged in the "Instance Activity Statistics"
I am wondering why such a big volume of redo is generated in this context.
Considering following context for excessive redo:
- It's known that dictionary specific tablespace is forced for logging.
- Considering that
NOLOGGINGis not applicable by any mean to any UPDATE operations resulting from the
- NOLOGGING is explicitely specified with CTAS and DMLs like
inserts and used
/*+ APPEND */hint with the insert statement to bypass logging even if nologging options is active in table/tablespace level.
- Can anyone see any other considerations beyond
1, 2 and 3, for generating such big volume REDOs?
- In the context of #2, 54TB(seems that Simply computed by 15G per second X 60 for min X 60 for hr) redo generation is not possible within one hour window. Suspecting some bug with the Oracle AWR report, it should be total redo generated since the Oracle is start up.
- Suspecting bug with the value of redo generated per seconds.
Any constructive answers for above questions and considerations are highly appreciated, so that I could rectify myself if I am wrong.