parquet-cli unable to read UUID values
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Description
I am finding that parquet-cli throws when trying to read UUID values.
Attached to this bug report is a parquet file with 2 columns, message encoded as byte-array and number encoded as fixed length byte array (UUID). This file was written by my .net implementation of parquet specification. The file has one row worth of data and is readable by parquet-cpp.
Schema as read by parquet-cli:
message root
{ required binary Message (STRING); required fixed_len_byte_array(16) Number (UUID); }
Values as read by parquet-cpp:
— Values —
Message |Number |
First record |215 48 212 219 218 57 169 67 166 116 7 79 44 227 50 17 |
Here is the exception stack from parquet-cli when trying to read uuid values:
```java
Caused by: org.apache.parquet.io.ParquetDecodingException: The requested schema is not compatible with the file schema. incompatible types: required binary Number (STRING) != required fixed_len_byte_array(16) Number (UUID)
at org.apache.parquet.io.ColumnIOFactory$ColumnIOCreatorVisitor.incompatibleSchema(ColumnIOFactory.java:101)
at org.apache.parquet.io.ColumnIOFactory$ColumnIOCreatorVisitor.visit(ColumnIOFactory.java:93)
at org.apache.parquet.schema.PrimitiveType.accept(PrimitiveType.java:602)
at org.apache.parquet.io.ColumnIOFactory$ColumnIOCreatorVisitor.visitChildren(ColumnIOFactory.java:83)
at org.apache.parquet.io.ColumnIOFactory$ColumnIOCreatorVisitor.visit(ColumnIOFactory.java:57)
at org.apache.parquet.schema.MessageType.accept(MessageType.java:55)
at org.apache.parquet.io.ColumnIOFactory.getColumnIO(ColumnIOFactory.java:162)
at org.apache.parquet.hadoop.InternalParquetRecordReader.checkRead(InternalParquetRecordReader.java:135)
at org.apache.parquet.hadoop.InternalParquetRecordReader.nextKeyValue(InternalParquetRecordReader.java:225)
```
I debugged parquet-cli code and found that parquet-cli is trying to project the UUID as a string and later on that throws as these types are not compatible?
Source code references:
At AvroReadSupport.java, line 97
~~~~~~~~~~~~
String requestedProjectionString = configuration.get(AVRO_REQUESTED_PROJECTION);
if (requestedProjectionString != null)
{ Schema avroRequestedProjection = new Schema.Parser().parse(requestedProjectionString); projection = new AvroSchemaConverter(configuration).convert(avroRequestedProjection); }
~~~~~~~~~~~~
Debugger values for
requestedProjectionString=
{"type":"record","name":"root","fields":[
{"name":"Message","type":"string"}
,\{"name":"Number","type":{"type":"string","logicalType":"uuid"}}]}
[Note that `Number` now has a type of `string` and a logicalType of `uuid`]
At ColumnIOFactory.java line 93
~~~~~~~~~~~~
incompatibleSchema(primitiveType, currentRequestedType);
~~~~~~~~~~~~
Debugger values for
primitiveType = required fixed_len_byte_array(16) Number (UUID)
currentRequestedType = required binary Number (STRING)
and this will throw.
If I skip over the projection code in AvroReadSupport, parquet-cli is able to read my file.
I am not sure if the bug is in parquet-cli or parquet-mr or in the library I used to encode this file. The fact that parquet-cpp is able to read it gives me some confidence to say that the problem is either in parquet-cli or parquet-mr.
Please point me in the right direction if I could verify this UUID roundtripping purely from parquet-mr itself in form of an unit-test. Happy to contribute tests or fix if needed.
**Reporter**: [Balaji K](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=gamaken)
#### Original Issue Attachments:
- [guid.parquet](https://issues.apache.org/jira/secure/attachment/13042816/guid.parquet)
**Note**: *This issue was originally created as [PARQUET-2140](https://issues.apache.org/jira/browse/PARQUET-2140). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*
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Research direction
Start with AvroReadSupport.java around the requested projection conversion and ColumnIOFactory.java around the incompatible-schema check. Reproduce the failure with the attached guid.parquet file or a parquet-mr unit test using the UUID schema shown in the report. Done means parquet-cli or the relevant parquet-mr read path can read the fixed_len_byte_array UUID without the schema incompatibility exception.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- java
- Domain
- data-engineering
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100