What's the purpose of defining timestamp_add_sql in all the adapters?

[vergenzt]

It seems to be redundant with defining a <adapter>__dateadd macro implementation, and I can't figure out why it's needed. (I'm working on a new dbt adapter and am trying to understand the purpose.)

I did a Github code search to try to find references to adapter.timestamp_add_sql and all I could find were implementations in nearly all adapters, and tests code that references it. Is testing the sole purpose? Can we consolidate and try to use the dbt.dateadd macro in testing instead of requiring adapters to define this method to generate SQL?

[0trm]

Yes, testing is its only use. The one caller is generate_update_clause in dbt/tests/util.py, behind update_rows, which BaseSnapshotTimestamp and BaseSnapshotCheckCols in dbt-tests-adapter use to bump a timestamp column between snapshot runs. Nothing in dbt-core or dbt-adapters calls it at run time, and it has no @available decorator, so macros can't reach it as adapter.timestamp_add_sql either (the Jinja adapter wrapper only exposes _available_ methods).

For a new adapter you don't have to define it. BaseAdapter ships a default:

def timestamp_add_sql(self, add_to: str, number: int = 1, interval: str = "hour") -> str:
    return f"{add_to} + interval '{number} {interval}'"

Override it only if your database rejects + interval '1 hour' and you run those two snapshot tests. Checked on dbt-core 1.12.5, dbt-tests-adapter 1.20.0 and dbt-adapters at 1c56acf.

• BaseAdapter.timestamp_add_sql
• generate_update_clause in dbt/tests/util.py
• update_rows with add_timestamp in the snapshot test