HIVE-27562: Iceberg: Fetching virtual columns failing.

iceberg/iceberg-handler/src/main/java/org/apache/iceberg/mr/mapreduce/IcebergInputFormat.java

@@ -534,12 +534,12 @@ private static Schema readSchema(Configuration conf, Table table, boolean caseSe
       }
 
       String[] selectedColumns = InputFormatConfig.selectedColumns(conf);
-      if (selectedColumns == null) {
-        return table.schema();
-      }
+      readSchema = table.schema();
 
-      readSchema = caseSensitive ? table.schema().select(selectedColumns) :
-          table.schema().caseInsensitiveSelect(selectedColumns);
+      if (selectedColumns != null) {
+        readSchema =
+            caseSensitive ? readSchema.select(selectedColumns) : readSchema.caseInsensitiveSelect(selectedColumns);
+      }
 
       if (InputFormatConfig.fetchVirtualColumns(conf)) {
         return IcebergAcidUtil.createFileReadSchemaWithVirtualColums(readSchema.columns(), table);

iceberg/iceberg-handler/src/test/queries/positive/query_iceberg_virtualcol.q

@@ -2,8 +2,17 @@ drop table if exists tbl_ice;
 create external table tbl_ice(a int, b string) partitioned by (c int) stored by iceberg stored as orc tblproperties ('format-version'='2');
 insert into tbl_ice values (1, 'one', 50), (2, 'two', 50), (3, 'three', 50), (4, 'four', 52), (5, 'five', 54), (111, 'one', 52), (333, 'two', 56);
 
+select tbl_ice.ROW__POSITION from tbl_ice;
+
 select a, c, tbl_ice.PARTITION__SPEC__ID, tbl_ice.PARTITION__HASH, tbl_ice.ROW__POSITION from tbl_ice
 order by tbl_ice.PARTITION__HASH, tbl_ice.ROW__POSITION desc;
 
 select a, c, tbl_ice.PARTITION__SPEC__ID, tbl_ice.PARTITION__HASH, tbl_ice.ROW__POSITION from tbl_ice
 sort by tbl_ice.PARTITION__HASH, tbl_ice.ROW__POSITION desc;
+
+
+-- create a table with more than 4 columns
+create table ice01 (a int, b int, c int, d int, e int) stored by iceberg tblproperties ('format-version'='2');
+insert into ice01 values (1,2,3,4,5), (6,7,8,9,10);
+
+select ice01.ROW__POSITION from ice01;

iceberg/iceberg-handler/src/test/results/positive/query_iceberg_virtualcol.q.out

@@ -20,6 +20,21 @@ POSTHOOK: query: insert into tbl_ice values (1, 'one', 50), (2, 'two', 50), (3,
 POSTHOOK: type: QUERY
 POSTHOOK: Input: _dummy_database@_dummy_table
 POSTHOOK: Output: default@tbl_ice
+PREHOOK: query: select tbl_ice.ROW__POSITION from tbl_ice
+PREHOOK: type: QUERY
+PREHOOK: Input: default@tbl_ice
+PREHOOK: Output: hdfs://### HDFS PATH ###
+POSTHOOK: query: select tbl_ice.ROW__POSITION from tbl_ice
+POSTHOOK: type: QUERY
+POSTHOOK: Input: default@tbl_ice
+POSTHOOK: Output: hdfs://### HDFS PATH ###
+0
+1
+2
+0
+1
+0
+0
 PREHOOK: query: select a, c, tbl_ice.PARTITION__SPEC__ID, tbl_ice.PARTITION__HASH, tbl_ice.ROW__POSITION from tbl_ice
 order by tbl_ice.PARTITION__HASH, tbl_ice.ROW__POSITION desc
 PREHOOK: type: QUERY
@@ -54,3 +69,29 @@ POSTHOOK: Output: hdfs://### HDFS PATH ###
 4	52	0	83	0
 5	54	0	85	0
 333	56	0	87	0
+PREHOOK: query: create table ice01 (a int, b int, c int, d int, e int) stored by iceberg tblproperties ('format-version'='2')
+PREHOOK: type: CREATETABLE
+PREHOOK: Output: database:default
+PREHOOK: Output: default@ice01
+POSTHOOK: query: create table ice01 (a int, b int, c int, d int, e int) stored by iceberg tblproperties ('format-version'='2')
+POSTHOOK: type: CREATETABLE
+POSTHOOK: Output: database:default
+POSTHOOK: Output: default@ice01
+PREHOOK: query: insert into ice01 values (1,2,3,4,5), (6,7,8,9,10)
+PREHOOK: type: QUERY
+PREHOOK: Input: _dummy_database@_dummy_table
+PREHOOK: Output: default@ice01
+POSTHOOK: query: insert into ice01 values (1,2,3,4,5), (6,7,8,9,10)
+POSTHOOK: type: QUERY
+POSTHOOK: Input: _dummy_database@_dummy_table
+POSTHOOK: Output: default@ice01
+PREHOOK: query: select ice01.ROW__POSITION from ice01
+PREHOOK: type: QUERY
+PREHOOK: Input: default@ice01
+PREHOOK: Output: hdfs://### HDFS PATH ###
+POSTHOOK: query: select ice01.ROW__POSITION from ice01
+POSTHOOK: type: QUERY
+POSTHOOK: Input: default@ice01
+POSTHOOK: Output: hdfs://### HDFS PATH ###
+0
+1