
Ask HN: How can a HN comment parent id be higher than it's id? - yehosef
I&#x27;m doing some looking into HN data and I notice times where the parent field is higher than the comment id.  Assuming this is a simple autoincrement id, the comment id should always be higher.<p>Any ideas how this happens?  is this from merging stories? something else?
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gus_massa
Sometimes the mods merge the comments of a story and a close repost. For
example:
[https://news.ycombinator.com/item?id=15137168](https://news.ycombinator.com/item?id=15137168)

I'm not sure if that cover all your cases.

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yehosef
Could be - but I see examples without [dupe] in the title. But that's probably
it.

Its interesting because I see plenty of times where they don't do this..

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gus_massa
It's a manual decision [I guess they have a magical button to do the merge.]
so sometimes they don't find out abbot the dupe or they may decide no to merge
them, so it's quite random and arbitrary, but it looks very difficult to
automate.

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angersock
Parent is updated, perhaps?

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yehosef
I hope not - usually updates don't require a new primary id.

