[IMPALA-3206] Support Decimal type in generated code of Avro scanner

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 2.6.0
• Fix Version/s: Impala 2.7.0
• Component/s: Backend
• Labels: codegen
• Target Version: Product Backlog
• Assignee: Michael Ho
• Reporter: Michael Ho
• Created: 18/Mar/16 01:01
• Updated: 11/Jul/16 20:44
• Resolved: 11/Jul/16 20:44

Description

HdfsAvroScanner::CodegenReadScalar() doesn't have AVRO_DECIMAL in its switch statement so it will not be codegened if AVRO_DECIMAL is in the schema. However, it appears Avro scanner was ready to call ReadAvroDecimal() all along as the following code snippet suggests:

  if (slot_desc != NULL) {
    // Field corresponds to a materialized column, fill in relevant arguments
    write_slot_val = builder->getTrue();
    if (slot_desc->type().type == TYPE_DECIMAL) {
      // ReadAvroDecimal() takes slot byte size instead of slot type
      slot_type_val = builder->getInt32(slot_desc->type().GetByteSize());
    } else {
      slot_type_val = builder->getInt32(slot_desc->type().type);
    }
    Value* slot_val =
        builder->CreateStructGEP(tuple_val, slot_desc->field_idx(), "slot");
    opaque_slot_val =
        builder->CreateBitCast(slot_val, codegen->ptr_type(), "opaque_slot");
  }

We should just add AVRO_DECIMAL to the switch statement and see if things work.