Lok,
>> Ora-01628 max extent 32765 reached for rollback segment
If you are running out of space on your rollback segments, then you are
not actually using direct path insert, APPEND or APPEND_VALUES hint
notwithstanding. The only undo you should be generating is for the DDL,
not the DML, and that should not max out anything.
Long story short: you really can not effectively perform direct-path
APPEND insert directly to that "live" table or partition with indexes.
In your case, you need to perform the direct-path insert to a
hash-partitioned table of the same logical "shape" as the list partition
you are targeting, then build indexes to match the main table when you
are done loading, and then finally use ALTER TABLE ... EXCHANGE
PARTITION to swap it all with the "live" partition(s) in the main
table. If it helps, HERE
<http://evdbt.com/download/presentation-scaling-to-infinity-partitioning-data-warehouses-on-oracle-database/>is
a presentation on this technique and HERE
<http://evdbt.com/download/paper-scaling-to-infinity-partitioning-data-warehouses-on-oracle-database-2/>is
a corresponding white paper on the technique. Also, HERE
<http://evdbt.com/download/exchpart-sql/>is a PL/SQL package called
EXCHPART which contains procedures to automate the moves mentioned in
the white paper and presentation. Please don't consider EXCHPART as
anything more than a template, it is not intended as working code,
particularly when it must be adapted for your local coding culture and
standards. Hopefully it is a good start?
Oh also, there is no such thing as a NOLOGGING hint; nologging is an
attribute on the table or partition which is effective only with
direct-path insert operations, never with conventional-path INSERT,
UPDATE, or DELETE operations.
Hope this helps...
Thanks!
-Tim
On 3/27/2021 10:37 PM, Lok P wrote:
Hi Listers, we have one process in which we load ~50million daily (using direct path insert.. INSERT APPEND ) to a target table which holds ~20billion rows(~1TB in size)) and is list -hash composite partitioned. ~2 list partition and ~2048 hash subpartitions. It has 4 indexes out of those one is a composite primary key comprising of 5 columns.We have that data load job failing since ~15-20 days without notice and it thus accumulated ~billion rows and the load process is now failing with (Ora-01628 max extent 32765 reached for rollback segment).
So we thought of running it in a bulk collect method(append_values hint) and commit in chunks of ~1million. But during that process we endup seeing the data load is significantly slower , it was inserting ~1million rows in ~40minutes. And we were not able to understand the reason but the wait events were all showing "cell single block physical read" and the object was the target load object. Means it was the INSERt which was struggling. So we now endup having partial data loaded to the target i.e. around ~40-50million loaded to the target. And as it has a primary key , we have to delete the ~40-50million rows from the target table and then reload it.
I was thinking if we should do the delete in bulk method with a chunk of 1million , but again that will happen in a single thread and will be significantly slow. So what is the best way to have those ~40-50million data deleted from the target table(which holds a total ~20billion rows)?
And then I was also thinking , if we could make the index unusable and perform the delete and then data load(which would happen with almost zero UNDo in absence of INDEXes) , but then in that case it seems that DELETE will need the PK index to fetch the rowids so we cant get rid of the PK index then. So what is the best approach to go for the delete and data load here without breaking data consistency in the target table?
So wanted to understand what is the best/faster approach to go for delete and data load in this situation?
Regards
Lok
