Review feedback, split into FixedSizeListType and VariableSizeListType

Author: rok

LogicalTypes.md

@@ -259,13 +259,21 @@ The sort order for `FLOAT16` is signed (with special handling of NANs and signed
 ### FIXED_SIZE_LIST
 
 The `FIXED_SIZE_LIST` annotation represents a fixed-size list of elements
-of a primitive data type. It must annotate a `binary` primitive type.
+of a primitive data type. It must annotate a `FIXED_LEN_BYTE_ARRAY` primitive type.
 
-The `binary` data is interpreted as a sequence of elements of
-the same primitive data type.
+The `FIXED_LEN_BYTE_ARRAY` data is interpreted as a fixed size sequence of
+elements of the same primitive data type.
 
 The sort order used for `FIXED_SIZE_LIST` is undefined.
 
+### 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

@@ -289,7 +289,13 @@ 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 FixedSizeListType {} // see LogicalTypes.md
+struct FixedSizeListType {        // allowed for FIXED_LEN_BYTE_ARRAY[num_values * width of type],
+    1: required Type type;        // see LogicalTypes.md
+    2: required i32 num_values;
+}
+struct VariableSizeListType {     // allowed for BYTE_ARRAY, see LogicalTypes.md
+    1: required Type type;
+}
 
 /**
  * Logical type to annotate a column that is always null.
@@ -398,14 +404,15 @@ 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: FixedSizeListType FIXED_SIZE_LIST // no compatible ConvertedType
+  17: FixedSizeListType FIXED_SIZE_LIST        // no compatible ConvertedType
+  18: VariableSizeListType VARIABLE_SIZE_LIST  // no compatible ConvertedType
 }
 
 /**