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Posted to dev@avro.apache.org by "Doug Cutting (JIRA)" <ji...@apache.org> on 2011/09/20 20:41:17 UTC
[jira] [Commented] (AVRO-891) Exception when attempting to read
modified schema containing deleted field
[ https://issues.apache.org/jira/browse/AVRO-891?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13108920#comment-13108920 ]
Doug Cutting commented on AVRO-891:
-----------------------------------
When you read you should use 'new SpecificDatumReader<Record>(Record.class)' to pass the new schema to the reader. Otherwise it assumes the same schema that's used to write should be used to read. Does that help?
> Exception when attempting to read modified schema containing deleted field
> --------------------------------------------------------------------------
>
> Key: AVRO-891
> URL: https://issues.apache.org/jira/browse/AVRO-891
> Project: Avro
> Issue Type: Bug
> Components: java
> Affects Versions: 1.5.4
> Environment: OSX 10.7
> Reporter: Alex Holmes
>
> An AvroRuntimeException exception is thrown when attempting to read an Avro file serialized with an older version of a schema containing a field which has been subsequently removed in the newer schema.
> *Exception*
> {code}
> Exception in thread "main" org.apache.avro.AvroRuntimeException: Bad index
> at Record.put(Unknown Source)
> at org.apache.avro.generic.GenericData.setField(GenericData.java:463)
> at org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:166)
> at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:138)
> at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:129)
> at org.apache.avro.file.DataFileStream.next(DataFileStream.java:233)
> at org.apache.avro.file.DataFileStream.next(DataFileStream.java:220)
> at Read.readFromAvro(Unknown Source)
> at Read.main(Unknown Source)
> {code}
> *Steps to reproduce*
> # Generate code for schema v1 and v2
> # Write an Avro file with the v1 code-generated Record class using the DataFileWriter and SpecificDatumWriter
> # (informational only) Read the Avro file using the v1 code-generated Record class using DataFileStream and SpecificDatumReader (output follows)
> {code}
> Record@2ec791b9[name=r1,id=1]
> Record@bd86fd3[name=r2,id=2]
> {code}
> # Read the Avro file using the v2 code-generated Record class using DataFileStream and SpecificDatumReader
> *Schema details*
> v1 schema:
> {code}
> {"name": "Record", "type": "record",
> "fields": [
> {"name": "name", "type": "string"},
> {"name": "id", "type": "int"}
> ]
> }
> {code}
> v2 schema:
> {code}
> {"name": "Record", "type": "record",
> "fields": [
> {"name": "name", "type": "string"}
> ]
> }
> {code}
> *Write code*
> {code}
> public static Record createRecord(String name, int id) {
> Record record = new Record();
> record.name = name;
> record.id = id;
> return record;
> }
> public static void writeToAvro(OutputStream outputStream)
> throws IOException {
> DataFileWriter<Record> writer =
> new DataFileWriter<Record>(new SpecificDatumWriter<Record>());
> writer.create(Record.SCHEMA$, outputStream);
> writer.append(createRecord("r1", 1));
> writer.append(createRecord("r2", 2));
> writer.close();
> outputStream.close();
> }
> {code}
> *Read code*
> {code}
> public static void readFromAvro(InputStream is) throws IOException {
> DataFileStream<Record> reader = new DataFileStream<Record>(
> is, new SpecificDatumReader<Record>());
> for (Record a : reader) {
> System.out.println(ToStringBuilder.reflectionToString(a));
> }
> IOUtils.cleanup(null, is);
> IOUtils.cleanup(null, reader);
> }
> {code}
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