DRILL-2338: Fix Decimal38/Decimal28 vector's get() to copy the scale …

…and precision into the holder

exec/java-exec/src/main/codegen/templates/FixedValueVectors.java

@@ -394,26 +394,18 @@ public StringBuilder getAsStringBuilder(int index) {
     <#elseif (minor.class == "Decimal28Sparse") || (minor.class == "Decimal38Sparse") || (minor.class == "Decimal28Dense") || (minor.class == "Decimal38Dense")>
 
     public void get(int index, ${minor.class}Holder holder) {
-
         holder.start = index * ${type.width};
-
         holder.buffer = data;
-
-        /* The buffer within the value vector is little endian.
-         * For the dense representation though, we use big endian
-         * byte ordering (internally). This is because we shift bits to the right and
-         * big endian ordering makes sense for this purpose.  So we have to deal with
-         * the sign bit for the two representation in a slightly different fashion
-         */
         holder.scale = getField().getScale();
         holder.precision = getField().getPrecision();
     }
 
     public void get(int index, Nullable${minor.class}Holder holder) {
         holder.isSet = 1;
         holder.start = index * ${type.width};
-
         holder.buffer = data;
+        holder.scale = getField().getScale();
+        holder.precision = getField().getPrecision();
     }
 
       @Override

exec/java-exec/src/test/java/org/apache/drill/exec/physical/impl/writer/TestParquetWriter.java

@@ -21,6 +21,7 @@
 
 import java.io.UnsupportedEncodingException;
 import java.lang.reflect.Array;
+import java.math.BigDecimal;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -360,6 +361,30 @@ public void testParquetReadWebReturns() throws Exception {
     compareParquetReadersColumnar("wr_returning_customer_sk", "dfs.`/tmp/web_returns`");
   }
 
+  @Test
+  public void testWriteDecimal() throws Exception {
+    String outputTable = "decimal_test";
+    Path path = new Path("/tmp/" + outputTable);
+    if (fs.exists(path)) {
+      fs.delete(path, true);
+    }
+    String ctas = String.format("use dfs.tmp; " +
+        "create table %s as select " +
+        "cast('1.2' as decimal(38, 2)) col1, cast('1.2' as decimal(28, 2)) col2 " +
+        "from cp.`employee.json` limit 1", outputTable);
+
+    test(ctas);
+
+    BigDecimal result = new BigDecimal("1.20");
+
+    testBuilder()
+        .unOrdered()
+        .sqlQuery(String.format("select col1, col2 from %s ", outputTable))
+        .baselineColumns("col1", "col2")
+        .baselineValues(result, result)
+        .go();
+  }
+
   public void runTestAndValidate(String selection, String validationSelection, String inputTable, String outputFile) throws Exception {
 
     Path path = new Path("/tmp/" + outputFile);