[spacemanmatt]

I wrote an upsert generator a long time ago. It was one of the easier things to work around.

[jeltz]

I have seen quite many broken home-rolled UPSERT implementations, so it is apparently not that easy to get it right. Still not very hard though once you have understood the potential problems involved.

[chrisutz]

Alot of the difficulty was explaining to others that there wasn't an easy way to upsert, and trying to ensure everyone did it the proper way.

[spacemanmatt]

In OSS communities it's a serious problem. At work, it was routine: this is yet another thing that can be more easily screwed up if you don't use a library solution we've provided you.