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Add deltalake feature #2025
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I would like to be able to register a delta lake deltatable as a table from SQL as part of working on datafusion-tui. For example:
CREATE EXTERNAL TABLE dt
STORED AS DELTATABLE
LOCATION 's3://bucket/schema/table'
From what ive seen this would require adding a FileType and FileFormat for deltatable under deltalake feature, similar to how there is avro feature.
While I understand a delta table isnt exactly a file type / format - i think for the purposes of what were doing with those it meets the definition. Ive played with querying delta tables before and they use register_table as opposed to register_listing_table. So i think we would just need to match based on FileType and then for delta table use register_table instead.
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Enable deltatable FileFormat and FileType as features under deltalake
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Activity
matthewmturner commentedon Mar 16, 2022
@houqp i imagine youll have a view on this.
houqp commentedon Mar 20, 2022
I think you should be able to add deltalake support to datafusion-tui by leveraging the existing table provider directly without touching datafusion core, see: https://github.com/delta-io/delta-rs/blob/main/rust/src/delta_datafusion.rs.
There is no need for adding new filetype or file format because deltalake only uses parquet, which we already support in datafusion.
matthewmturner commentedon Mar 20, 2022
Interesting, ok. I thought there was some more magic going on under the hood (but I hadn't really had chance to look into it) but maybe that only comes into play with some of delta lakes more advanced features like time travel which I don't think is doable without sql extensions.
I'll try it out and get back to you. Thanks!
avantgardnerio commentedon Aug 27, 2022
I think @matthewmturner is on to something. The SQL in this issue is straightforward and makes sense from an intuitive user perspective. Why it doesn't work seems like a limitation of DataFusion:
Our use-case is running a Ballista server, with
delta-rscompiled in, with the intention of allowing users to register tables in locations we can't know at compile time. Unfortunately, I think the wayFileFormats work currently doesn't make this possible?Swoorup commentedon Oct 12, 2024
What's currently remaining for this feature?
matthewmturner commentedon Oct 12, 2024
i dont think deltalake will be added as a "feature" to core datafusion (i.e. this repo) - however, deltalake provides a
TableFactoryProviderthat makes it very easy to register delta tables to a datafusionSessionContext. it's added as a feature in dft if youre interested in playing with it or want to see how to add it to your own application.i am going to close this issue