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[Java] MapVector written data does not meet expectations #44664

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hawk9821 opened this issue Nov 6, 2024 · 2 comments
Open

[Java] MapVector written data does not meet expectations #44664

hawk9821 opened this issue Nov 6, 2024 · 2 comments

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@hawk9821
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hawk9821 commented Nov 6, 2024

What would you like help with?

    RootAllocator allocator = new RootAllocator(Long.MAX_VALUE);
    Map<String, String> metadata = new HashMap<>();
    metadata.put("K1", "V1");
    metadata.put("K2", "V2");
    Field a = new Field("key", FieldType.notNullable(new ArrowType.Int(32, true)), null);
    Field b = new Field("value", FieldType.nullable(new ArrowType.Int(32,true)), null);
    Schema schema = new Schema(asList(a, b), metadata);
    Field struct = new Field("struct", FieldType.notNullable(new ArrowType.Struct()), schema.getFields());
    StructVector structVector = new StructVector(Field.nullable("struct", struct.getType()), allocator, null);
    MapVector mapVector = new MapVector(Field.nullable("map", structVector.getField().getType()), allocator, null);
    mapVector.initializeChildrenFromFields(Collections.singletonList(struct));
    mapVector.allocateNew();
    
    UnionMapWriter writer = mapVector.getWriter();
    for (int i = 0; i < 10; i++) {
        writer.startMap();
        writer.setPosition(i);
        writer.key().writeInt(i);
        writer.value().writeInt(i * 10);
        writer.endMap();
    }
    writer.setValueCount(10);

when the types of key and value are different, data cannot be written .
Only examples of ListVector are available in the documentation on the official website ,Please provide an example of writing data to MapVector.

image

@hawk9821 hawk9821 changed the title [Java] MapVector write demo [Java] MapVector written data does not meet expectations Nov 6, 2024
@lidavidm
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lidavidm commented Nov 6, 2024

I think this belongs on apache/arrow and not apache/arrow-adbc?

@lidavidm lidavidm transferred this issue from apache/arrow-adbc Nov 6, 2024
@hawk9821
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hawk9821 commented Nov 7, 2024

I think this belongs on apache/arrow and not apache/arrow-adbc?

yes , here are the dependencies , version is 15.0.1

        <dependency>
            <groupId>org.apache.arrow</groupId>
            <artifactId>arrow-vector</artifactId>
            <version>${arrow.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.arrow</groupId>
            <artifactId>arrow-memory-netty</artifactId>
            <version>${arrow.version}</version>
        </dependency>

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