[the_mitsuhiko]

The lack of upserts is a problem in postgres, as much as some people say they can get away without them. There are objective concurrency issues with the lack of it, that have been acknowledged by postgres developers when they started work on upserts.

[einhverfr]

> There are objective concurrency issues with the lack of it, that have been acknowledged by postgres developers when they started work on upserts.

These concurrency issues don't fully go away by adding the feature, which is why it is taking time to work out the desired behavior there.

[sendob]

may be a problem, there are workarounds, and workloads where it is not required, but I agree, merge/upsert is a much anticipated enhancement.