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I'm working to build the new data lake of the company and are trying to find the best and the most recent option to work here. So, I found a pretty nice solution to work with EMR + S3 + Athena + Glue.

The process that I did was:

1 - Run Apache Spark script to generate 30 millions rows partitioned by date at S3 stored by Orc.

2 - Run a Athena query to create the external table.

3 - Checked the table at EMR connected with Glue Data Catalog and it worked perfect. Both Spark and Hive were able to access.

4 - Generate another 30 millions rows in other folder partitioned by date. In Orc format

5 - Ran the Glue Crawler that identify the new table. Added to Data Catalog and Athena was able to do the query. But Spark and Hive aren't able to do it. See the exception below:

Spark Caused by: java.lang.ClassCastException: org.apache.hadoop.io.Text cannot be cast to org.apache.hadoop.hive.ql.io.orc.OrcStruct

Hive Error: java.io.IOException: org.apache.hadoop.hive.ql.metadata.HiveException: Error evaluating audit_id (state=,code=0)

I was checking if was any serialisation problem and I found this:

Table created manually (Configuration):

Input format org.apache.hadoop.hive.ql.io.orc.OrcInputFormat

Output format org.apache.hadoop.hive.ql.io.orc.OrcOutputFormat

Serde serialization lib org.apache.hadoop.hive.ql.io.orc.OrcSerde

orc.compress SNAPPY

Table Created with Glue Crawler:

Input format org.apache.hadoop.mapred.TextInputFormat

Output format org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat

Serde serialization lib org.apache.hadoop.hive.ql.io.orc.OrcSerde

So, this is not working to read from Hive or Spark. It works for Athena. I already changed the configurations but with no effect at Hive or Spark.

Anyone faced that problem?

John Rotenstein
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Thiago Baldim
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1 Answers1

4

Well,

After few weeks that I posted this question AWS fixed the problem. As I showed above, the problem was real and that was a bug from Glue.

As it is a new product and still have some problems some times.

But this was solved properly. See the properties of the table now:

ROW FORMAT SERDE 
  'org.apache.hadoop.hive.ql.io.orc.OrcSerde' 
STORED AS INPUTFORMAT 
  'org.apache.hadoop.hive.ql.io.orc.OrcInputFormat' 
OUTPUTFORMAT 
  'org.apache.hadoop.hive.ql.io.orc.OrcOutputFormat'
Thiago Baldim
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