use activerecord-import to upsert only when values have changed

Question

How to use activerecord-import to upsert only when values have changed? Body: I'm using the activerecord-import gem in a Rails 6 app to bulk upsert data into a PostgreSQL database. Here's an example of how I'm using it:

User.import(
  [:id, :name, :age],
  [
    [1, "Alice", 30],
    [2, "Bob", 25]
  ],
  on_duplicate_key_update: {
    conflict_target: [:id],
    columns: [:name, :age]
  }
)

This works as expected for inserting and updating based on id. However, I noticed that even if the values for a given row haven't changed, PostgreSQL still performs an UPDATE. For performance reasons (especially with large datasets), I want to avoid unnecessary updates and only update if any of the fields have actually changed.

Is there a way to do this using activerecord-import? Ideally something like:

WHERE users.name IS DISTINCT FROM EXCLUDED.name OR users.age IS DISTINCT FROM EXCLUDED.age

Can activerecord-import support this kind of conditional update? If so, what would the syntax look like?

prepare data before import

Anton Bogdanov
– Anton Bogdanov

2025-07-16 12:29:10 +00:00
Commented Jul 16 at 12:29 — Anton Bogdanov
– Anton Bogdanov, Commented Jul 16 at 12:29

engineersmnky · Accepted Answer · 2025-07-16 13:56:21Z

3

It appears (Docs) you can supply a condition argument.

:condition

The :condition attribute optionally specifies a WHERE condition on :conflict_action. Only rows for which this expression returns true will be updated. Note that it’s evaluated last, after a conflict has been identified as a candidate to update.

For example (using your proposed condition):

User.import(
  [:id, :name, :age],
  [
    [1, "Alice", 30],
    [2, "Bob", 25]
  ],
  on_duplicate_key_update: {
    conflict_target: [:id],
    columns: [:name, :age]
  }
  condition: "users.name IS DISTINCT FROM EXCLUDED.name OR users.age IS DISTINCT FROM EXCLUDED.age"
)

This condition is a straight pass through SQL String, so any valid WHERE condition should play nicely (Source)

answered Jul 16 at 13:56

engineersmnky

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