fix: regression of dict_id in physical plan proto
#20063
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kumarUjjawal
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brancz
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lgtm, thank you for fixing this!
Thanks for the review! |
alamb
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Thank you @kumarUjjawal
FYI @dispanser
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thanks @kumarUjjawal , appreciated! |
| root_as_message(encoded_schema.ipc_message.as_slice()).map_err( | ||
| |e| { | ||
| Error::General(format!( | ||
| "Error IPC schema message while deserializing ScalarValue::List: {e}" |
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Why the error messages say ScalarValue::List ? (List)
Isn't this used for any nested type ? List, Map, Struct, ...
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Good catch! I will update.
…f-45 Undoing [apache#14227](apache#14227) which introduces a bug in protobuf deserialization by passing a wrong schema to record batch construction of the IPC message containing the dictionary. The associated test and a fix will probably be merged into datafusion as apache#20063 but the test fails in main for completely different reason so the patch cannot be backported and doesn't make sense in the context of df46.
alamb
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Thank you @kumarUjjawal and @brancz
I feel intuitively something could be made much simpler here, but given this fixes the bug and i don't have any specific ideas of how to improve the PR, let's go with this one
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| // IPC dictionary batch IDs are assigned when encoding the schema, but our protobuf |
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I feel like somehow I missing something key -- this seems like a pretty massive overhead to create / decode a single value here.
That being said, it seems like the existing code is also doing the overhead, so maybe it is fine for now 🤔
I wonder if we could pull this logic for creating the schema into its own function to try and reduce the size of the overall method / make it easier to understand
| Ok(()) | ||
| } | ||
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| #[test] |
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With the code change reverted, this test fails like
---- cases::roundtrip_physical_plan::roundtrip_call_null_scalar_struct_dict stdout ----
Error: Plan("General error: Error encoding ScalarValue::List as IPC: Ipc error: no dict id for field item")
I merged up to resolve a conflict |
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Thank you @alamb. I will look into your suggestions. |
Thanks -- let's do it as a follow on PR |
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Which issue does this PR close?
Struct(Dict)data type #20011.Rationale for this change
dict_idis intentionally not preserved protobuf (it’s deprecated in Arrow schema metadata), but Arrow IPC still requires dict IDs for dictionary encoding/decoding.What changes are included in this PR?
Are these changes tested?
Yes added a test for this
Are there any user-facing changes?
No