| This is a tool to convert a nested dataset to an unnested dataset. The source and/or | |
| destination can be the local file system or HDFS. | |
| Structs get converted to a column (with a long name). Arrays and Maps get converted to | |
| a table which can be joined with the parent table on id column. | |
| $ mvn exec:java \ | |
| -Dexec.mainClass=org.apache.impala.infra.tableflattener.Main \ | |
| -Dexec.arguments="file:///tmp/in.parquet,file:///tmp/out,-sfile:///tmp/in.avsc" | |
| $ mvn exec:java \ | |
| -Dexec.mainClass=org.apache.impala.infra.tableflattener.Main \ | |
| -Dexec.arguments="hdfs://localhost:20500/nested.avro,file://$PWD/unnested" | |
| There are various options to specify the type of input file but the output is always | |
| parquet/snappy. | |
| For additional help, use the following command: | |
| $ mvn exec:java \ | |
| -Dexec.mainClass=org.apache.impala.infra.tableflattener.Main -Dexec.arguments="--help" | |
| This is used by testdata/bin/generate-load-nested.sh. |