Solr Deduplication use of overWriteDupes flag

[Amit Agrawal <aa...@gmail.com>]

Hello,

I had a configuration where I had "overwriteDupes"=false. I added few
duplicate documents. Result: I got duplicate documents in the index.

When I changed to "overwriteDupes"=true, the duplicate documents started
overwriting the older documents.

Question 1: How do I achieve, [add if not there, fail if duplicate is
found] i.e. mimic the behaviour of a DB which fails when trying to insert a
record which violates some unique constraint. I thought that
"overwriteDupes"=false would do that, but apparently not.

Question2: Is there some documentation around overwriteDupes? I have
checked the existing Wiki; there is very little explanation of the flag
there.

Thanks,

-Amit