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1. Re: HANDLECOLLISIONS Impact
ORASCN Nov 7, 2019 5:57 AM (in response to 3415172)1 person found this helpfulHi KK,
HANDLECOLLISIONS should be used only during the course of Initial Load and not during the Normal or Online replication. Using this parameter will lead to a data integrity issue or data mismatch issue between the source and target.
When the HANDLECOLLISIONS parameter is set, data is processed as follows : -
Missing updates are ignored.
Missing deletes are ignored.
Duplicate inserts are turned into updates.
PK updates will be inserted
Regards,
Veera
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2. Re: HANDLECOLLISIONS Impact
3415172 Nov 15, 2019 6:19 AM (in response to ORASCN)Hi Veera, Can you please have some examples to understand above 4 categories when its active continuously. -- Regards, KK
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3. Re: HANDLECOLLISIONS Impact
3415172 Nov 15, 2019 7:23 AM (in response to ORASCN)Hi veera,
Few examples i can think of at this moment are:
Missing Updates - Source has data from inception(like from 10 yrs) but replication only has data from past 3 years(as per requirement for example). And, now any update that happened on data beyond 3 yrs will be missing update as 3years beyond data won't exists in target;
Missing Deletes - Same as above but source operation is delete;
Duplicate inserts - any tables doesn't have keys at source;
PK updates will be inserted - any example on this please..
-- Regards,
KK
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4. Re: HANDLECOLLISIONS Impact
ORASCN Nov 17, 2019 8:01 AM (in response to 3415172)Hi KK,
Duplicate inserts - any tables doesn't have keys at source;
-----When initial load is not done correctly. If you have the record in the Target and not in the Source and when you try to insert that record in the source, you hit this error.
PK updates will be inserted - any example on this please..
------- When PK column is getting updated for a record in the source and that particular record is not available in the target, then you will hit this scenario.
Also, when you don't have PK or UI for a table, then OGG will consider all the columns as PK columns. In this case, you will hit the above.
Regards,
Veera