Question about failed reindex behavior


I have a question about the behavior of reindex process in case of a failure.

Say we initiate a reindex from index_01, with 100 documents, to a newly created index_02, and the reindex fails somewhere midway with only 50 documents written to index_02.

Does OpenSearch revert writes to index_02 in that case? If not, will OpenSearch ignore already inserted documents, if I re-initiate reindex?

Thanks in advance!

Are you talking about using the Reindex API or something else?

It doesn’t revert documents which already been re-indexed into a new index :smiley:
It will not re-init reindex also :joy:

Make sure you get the taskID so you can know the result like how much time it takes to complete reindex. Which time it starts and detailed information about reindexing action because there is the reason why if it fails also I guess :

Thanks for the reply!
Yes, I’m talking about Reindex API.

Thank you for the reply.

I think you might have misread my question. The question was will OpenSearch ignore documents that were re-indexed into a new index during the failed reindex or will I end up with duplicate records in the new index?

If I’m not wrong, it will not end up with duplicate documents, but normally i was alway delete index before reindex :smiley:

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Yeah, that seems like a safer option! :slight_smile:

Thank you.