lance-format / lance-format/lance

Provide adaptor to coerce input schema for append

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arrow rust
Dominant language
Rust
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Description

Sometimes it's challenging to produce the exact same schema for appends. For example, we require dictionary columns to have exactly the same dictionary, but other Arrow systems expect the dictionary to be flexible batch-to-batch. Other examples might be timestamp resolutions, where Python users might not know what resolution their particular system is producing.

We could provide a RecordBatchReader that wraps the input and attempts to coerce data to the correct schema.

We might want to make this default in the Python API.

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Research direction

The proposal names a RecordBatchReader adaptor around append inputs and a possible Python API default, but no files or tests. Start by locating the append path and Python API, then determine how schema coercion should handle dictionary columns and timestamp resolutions. Done should include agreed coercion behavior and coverage for these examples, including whether the adaptor is the default in Python.

Written by the indexing model from the issue text.

Assessment

Tech stack
python, rust
Domain
data-engineering
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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