Thanks for your suggestions.
@Flavio
This is very similar to the code I use and yields basically the same problems.
The examples are based on flink-1.0-SNAPSHOT and avro-1.7.6. which is more than
three years old. Do you have a working setup with newer version of avro and
flink?
@Jörn
I tried to do that but I can't see how to get around the AvroParquetInputFormat
(see below). I can pass a schema for projection as a string but then I get a
NullPointerException as there is no ReadSupport class available in
ParquetInputFormat. There is a constructor to instantiate ParquetInputFormat
with a class that extends ReadSupport but I haven't found a suitable one to
pass to the constructor. Do you know of a way around this?
public static void main(String[] args) throws Exception {
ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
Job job = Job.getInstance();
HadoopInputFormat<Void, Customer> hif = new HadoopInputFormat<>(new
ParquetInputFormat(), Void.class,
Customer.class, job);
FileInputFormat.addInputPath((JobConf) job.getConfiguration(), new
org.apache.hadoop.fs.Path(
"/tmp/tpchinput/01/customer_parquet"));
job.getConfiguration().set("parquet.avro.projection",
"{\"type\":\"record\",\"name\":\"Customer\",\"fields\":[{\"name\":\"c_custkey\",\"type\":\"int\"}]}");
env.createInput(hif).print();
}
I am pretty sure that I miss something very basic? Let me know if you need any
additional information.
Thanks ...
> On 24 Apr 2017, at 20:51, Flavio Pompermaier <pomperma...@okkam.it> wrote:
>
> I started from this guide:
>
> https://github.com/FelixNeutatz/parquet-flinktacular
> <https://github.com/FelixNeutatz/parquet-flinktacular>
>
> Best,
> Flavio
>
> On 24 Apr 2017 6:36 pm, "Jörn Franke" <jornfra...@gmail.com
> <mailto:jornfra...@gmail.com>> wrote:
> Why not use a parquet only format? Not sure why you need an avtoparquetformat.
>
> On 24. Apr 2017, at 18:19, Lukas Kircher <lukas.kirc...@uni-konstanz.de
> <mailto:lukas.kirc...@uni-konstanz.de>> wrote:
>
>> Hello,
>>
>> I am trying to read Parquet files from HDFS and having problems. I use Avro
>> for schema. Here is a basic example:
>>
>> public static void main(String[] args) throws Exception {
>> ExecutionEnvironment env =
>> ExecutionEnvironment.getExecutionEnvironment();
>>
>> Job job = Job.getInstance();
>> HadoopInputFormat<Void, Customer> hif = new HadoopInputFormat<>(new
>> AvroParquetInputFormat(), Void.class,
>> Customer.class, job);
>> FileInputFormat.addInputPath((JobConf) job.getConfiguration(), new
>> org.apache.hadoop.fs.Path(
>> "/tmp/tpchinput/01/customer_parquet"));
>> Schema projection = Schema.createRecord(Customer.class.getSimpleName(),
>> null, null, false);
>> List<Schema.Field> fields = Arrays.asList(
>> new Schema.Field("c_custkey", Schema.create(Schema.Type.INT), null,
>> (Object) null)
>> );
>> projection.setFields(fields);
>> AvroParquetInputFormat.setRequestedProjection(job, projection);
>>
>> DataSet<Tuple2<Void, Customer>> dataset = env.createInput(hif);
>> dataset.print();
>> }
>> If I submit this to the job manager I get the following stack trace:
>>
>> java.lang.NoSuchMethodError:
>> org.apache.avro.Schema$Field.<init>(Ljava/lang/String;Lorg/apache/avro/Schema;Ljava/lang/String;Ljava/lang/Object;)V
>> at misc.Misc.main(Misc.java:29)
>>
>> The problem is that I use the parquet-avro dependency (which provides
>> AvroParquetInputFormat) in version 1.9.0 which relies on the avro dependency
>> 1.8.0. The flink-core itself relies on the avro dependency in version 1.7.7.
>> Jfyi the dependency tree looks like this:
>>
>> [INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @
>> flink-experiments ---
>> [INFO] ...:1.0-SNAPSHOT
>> [INFO] +- org.apache.flink:flink-java:jar:1.2.0:compile
>> [INFO] | +- org.apache.flink:flink-core:jar:1.2.0:compile
>> [INFO] | | \- (org.apache.avro:avro:jar:1.7.7:compile - omitted for
>> conflict with 1.8.0)
>> [INFO] | \- org.apache.flink:flink-shaded-hadoop2:jar:1.2.0:compile
>> [INFO] | \- (org.apache.avro:avro:jar:1.7.7:compile - omitted for
>> duplicate)
>> [INFO] \- org.apache.parquet:parquet-avro:jar:1.9.0:compile
>> [INFO] \- org.apache.avro:avro:jar:1.8.0:compile
>>
>> Fixing the above NoSuchMethodError just leads to further problems.
>> Downgrading parquet-avro to an older version creates other conflicts as
>> there is no version that uses avro 1.7.7 like Flink does.
>>
>> Is there a way around this or can you point me to another approach to read
>> Parquet data from HDFS? How do you normally go about this?
>>
>> Thanks for your help,
>> Lukas
>>
>>
>>
