Add VARIABLE_SIZE_LIST

LogicalTypes.md

@@ -256,6 +256,14 @@ The primitive type is a 2-byte `FIXED_LEN_BYTE_ARRAY`.
 
 The sort order for `FLOAT16` is signed (with special handling of NANs and signed zeros); it uses the same [logic](https://github.com/apache/parquet-format#sort-order) as `FLOAT` and `DOUBLE`.
 
+### VARIABLE_SIZE_LIST
+
+The `VARIABLE_SIZE_LIST` annotation represents a variable-size list of elements
+of a primitive data type. It must annotate a `BYTE_ARRAY` primitive type.
+
+The `BYTE_ARRAY` data is interpreted as a variable size sequence of elements of
+the same primitive data type.
+
 ## Temporal Types
 
 ### DATE

src/main/thrift/parquet.thrift

@@ -289,6 +289,9 @@ struct ListType {}    // see LogicalTypes.md
 struct EnumType {}    // allowed for BYTE_ARRAY, must be encoded with UTF-8
 struct DateType {}    // allowed for INT32
 struct Float16Type {} // allowed for FIXED[2], must encoded raw FLOAT16 bytes
+struct VariableSizeListType {     // allowed for BYTE_ARRAY, see LogicalTypes.md
+    1: required Type type;
+}
 
 /**
  * Logical type to annotate a column that is always null.
@@ -397,12 +400,15 @@ union LogicalType {
   8:  TimestampType TIMESTAMP
 
   // 9: reserved for INTERVAL
-  10: IntType INTEGER         // use ConvertedType INT_* or UINT_*
-  11: NullType UNKNOWN        // no compatible ConvertedType
-  12: JsonType JSON           // use ConvertedType JSON
-  13: BsonType BSON           // use ConvertedType BSON
-  14: UUIDType UUID           // no compatible ConvertedType
-  15: Float16Type FLOAT16     // no compatible ConvertedType
+  10: IntType INTEGER                          // use ConvertedType INT_* or UINT_*
+  11: NullType UNKNOWN                         // no compatible ConvertedType
+  12: JsonType JSON                            // use ConvertedType JSON
+  13: BsonType BSON                            // use ConvertedType BSON
+  14: UUIDType UUID                            // no compatible ConvertedType
+  15: Float16Type FLOAT16                      // no compatible ConvertedType
+  // 16: reserved for GEOMETRY
+  // 17: reserved for FIXED_SIZE_LIST
+  18: VariableSizeListType VARIABLE_SIZE_LIST  // no compatible ConvertedType
 }
 
 /**