[BUG]: Tempo drop the interpolated column in Databricks DBR14

[srggrs]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

In Databricks DBR13.3 cluster. This code will return the interpolated column with no problem.

# this table has id, day, ts (timestamp) and signal columns
input_table = spark.table("my_input_table")

assert input_table.columns == ["id", "day", "ts", "signal"], "cols are not the same"

transformed_data = TSDF(input_table, ts_col="ts", partition_cols=["id", "day"])

interpolated = (
    transformed_data.resample(freq="5 minutes", func="mean")
    .interpolate(method="linear")
    .df
)

interpolated.columns == ["id", "day", "ts", "signal"], "cols are not the same"

Expected Behavior

When upgrading to DBR14 I would expect there are no columns dropped and the interpolated dataframe has the same columns as the input one

Steps To Reproduce

1. Set up a compute cluster with DBR13 LTS and one with DBR 14 LTS
2. have an input table with similar columns as above, perharps even just one partition column
3. Run the code above to see the difference between the two enviroments

Cloud

AWS

Version

dbl-tempo==0.1.27

Relevant log output

No response

[tnixon]

Hi @srggrs - thank you for reporting this issue to us. We are currently in process of a major re-write of the Tempo API, and we expect this to be available very soon. We will make sure that this issue does not come up in the new version. If this is a blocker for you, we might be able to try to develop a fix, but right now all our time is focused on the new release.

[R7L208]

Triage — March 2026

Status: Likely fixed on v0.2-integration. The interpolation system was completely rewritten in v0.2 using pandas UDFs instead of the previous window-function approach. The DBR14-specific column-dropping behavior was tied to the old implementation.

Jobs to be done: Verify on DBR14+ that interpolated columns are retained in the output after v0.2 merge.

Effort estimate: 🟢 Small (< 1 day) — repro test on DBR14

Closure path: Close after v0.2 merge + confirmation on DBR14 that the interpolated column appears in the result.