[PARQUET-1620] Schema creation from another schema will not be possible - deprecated

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.11.0
• Component/s: parquet-mr
• Labels: usability
• Assignee: Unassigned
• Reporter: Werner Daehn
• Created: 10/Jul/19 19:59
• Updated: 10/Jul/19 19:59

Description

Imagine I have a current schema and want to create a projection schema from that. One option is the schema.Types.*Builder but the more direct version would be to clone the schema itself without children.

List<org.apache.parquet.schema.Type> l = new ArrayList<>();
{{ for (String c : childmappings.keySet()) {}}
  Mapping m = childmappings.get(c);
  l.add(m.getProjectionSchema());
{{ }}}
{{ GroupType gt = new GroupType(schema.getRepetition(), schema.getName(), schema.getOriginalType(), l);}}

 

The last line, the new GroupType(..) constructor is deprecated. We should use the version with the LogicalTypeAnnotation instead. Fine. But how do you get the LogicalTypeAnnotation  from an existing schema?

I feel you should not deprecate these methods and if, provide an extra method to create a Type column from a type column (column alone, without children. Else the projection would have all child columns).

 

Do you agree?