Datapump import disable_archive_logging will still generate redo?

[Ashish Lunawat]

Hi,

I have a Oracle database version 12.2.0.1 running in noarchivelog mode. I`m
wondering if datapump import parameter TRANSFORM=DISABLE_ARCHIVE_LOGGING:Y
will reduce the redo generated and thus improve the import timing?

I have an import of a LOB table which takes about 10 hours to import about
85GB of data. AWR reports show almost all the time spent on "log file
switch (checkpoint incomplete)" event. There were 3 redo log groups
configured with each member size 200MB.

I increased to 6 groups with each member 1.5GB but I am still getting
these wait events accounting to 94% of the DB time. And now the Avg wait
for these events has gone up to about 34 seconds from 7-8 secs last time.

How can I get rid of the log file switch (checkpoint incomplete) events?
Increase DBwriters? FAST_START_MTTR_TARGET?

Thanks
Regards,
Ashish

[Powell, Mark]

Ashish, Please post the statistics that show 94% of your DB time is spent waiting for the checkpoint to complete.

Also post your dbwr statistics.



Mark Powell
Database Administration
[phone]


________________________________
From: oracle-l-***@freelists.org <oracle-l-***@freelists.org> on behalf of Ashish Lunawat <***@gmail.com>
Sent: Wednesday, September 5, 2018 5:37:09 AM
To: Oracle-L Freelists
Subject: Datapump import disable_archive_logging will still generate redo?

Hi,

I have a Oracle database version 12.2.0.1 running in noarchivelog mode. I`m wondering if datapump import parameter TRANSFORM=DISABLE_ARCHIVE_LOGGING:Y will reduce the redo generated and thus improve the import timing?

I have an import of a LOB table which takes about 10 hours to import about 85GB of data. AWR reports show almost all the time spent on "log file switch (checkpoint incomplete)" event. There were 3 redo log groups configured with each member size 200MB.

I increased to 6 groups with each member 1.5GB but I am still getting these wait events accounting to 94% of the DB time. And now the Avg wait for these events has gone up to about 34 seconds from 7-8 secs last time.

How can I get rid of the log file switch (checkpoint incomplete) events? Increase DBwriters? FAST_START_MTTR_TARGET?

Thanks
Regards,
Ashish




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[Mark J. Bobak]

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