From 882dc2dc66383d41867f18626443b6e2e81c8ea3 Mon Sep 17 00:00:00 2001
From: Aman Sinha <asinha@maprtech.com>
Date: Sun, 13 Mar 2016 15:42:57 -0700
Subject: [PATCH] DRILL-4503: Write nulls as varchar when all_text_mode is
 enabled.

---
 .../exec/vector/complex/fn/JsonReader.java    |  3 +-
 .../vector/complex/writer/TestJsonReader.java | 52 +++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/exec/java-exec/src/main/java/org/apache/drill/exec/vector/complex/fn/JsonReader.java b/exec/java-exec/src/main/java/org/apache/drill/exec/vector/complex/fn/JsonReader.java
index 16095416a38..24493557445 100644
--- a/exec/java-exec/src/main/java/org/apache/drill/exec/vector/complex/fn/JsonReader.java
+++ b/exec/java-exec/src/main/java/org/apache/drill/exec/vector/complex/fn/JsonReader.java
@@ -402,7 +402,8 @@ private void writeDataAllText(MapWriter map, FieldSelection selection, boolean m
         handleString(parser, map, fieldName);
         break;
       case VALUE_NULL:
-        // do nothing as we don't have a type.
+        // since this method is only called for allTextMode, write nulls as varchar
+        map.varChar(fieldName);
         break;
 
       default:
diff --git a/exec/java-exec/src/test/java/org/apache/drill/exec/vector/complex/writer/TestJsonReader.java b/exec/java-exec/src/test/java/org/apache/drill/exec/vector/complex/writer/TestJsonReader.java
index c088e253d29..62894f1192c 100644
--- a/exec/java-exec/src/test/java/org/apache/drill/exec/vector/complex/writer/TestJsonReader.java
+++ b/exec/java-exec/src/test/java/org/apache/drill/exec/vector/complex/writer/TestJsonReader.java
@@ -597,4 +597,56 @@ public void drill_4032() throws Exception {
     os.close();
     testNoResult("select t.col2.col3 from dfs_test.tmp.drill_4032 t");
   }
+
+  @Test
+  public void drill_4503() throws Exception {
+    try {
+      String dfs_temp = getDfsTestTmpSchemaLocation();
+      File table_dir = new File(dfs_temp, "drill_4503");
+      table_dir.mkdir();
+      BufferedOutputStream os = new BufferedOutputStream(new FileOutputStream(new File(table_dir, "mostlynulls.json")));
+      // Create an entire batch of {non-null-value, null} rows
+      for (int i = 0 ; i < 4096; i++) {
+        os.write("{\"a\": 5, \"b\": null}".getBytes());
+      }
+      // Add a row with {int, string} values
+      os.write("{\"a\": 5, \"b\": \"Hello World\"}".getBytes());
+      os.flush();
+      os.close();
+
+      String query1 = "select a, b, count(*) as cnt from dfs_test.tmp.drill_4503 t group by a, b";
+      // only 1 row with non-null value of b
+      String query2 = "select count(*) as cnt from dfs_test.tmp.drill_4503 t where b is not null";
+      String query3 = "select max(a) as x, max(b) as y from dfs_test.tmp.drill_4503 t";
+
+      testBuilder()
+        .sqlQuery(query1)
+        .ordered()
+        .optionSettingQueriesForTestQuery("alter session set `store.json.all_text_mode` = true")
+        .baselineColumns("a", "b", "cnt")
+        .baselineValues("5", null, 4096L)
+        .baselineValues("5", "Hello World", 1L)
+        .go();
+
+      testBuilder()
+        .sqlQuery(query2)
+        .ordered()
+        .optionSettingQueriesForTestQuery("alter session set `store.json.all_text_mode` = true")
+        .baselineColumns("cnt")
+        .baselineValues(1L)
+        .go();
+
+      testBuilder()
+        .sqlQuery(query3)
+        .ordered()
+        .optionSettingQueriesForTestQuery("alter session set `store.json.all_text_mode` = true")
+        .baselineColumns("x", "y")
+        .baselineValues("5", "Hello World")
+        .go();
+
+    } finally {
+      testNoResult("alter session set `store.json.all_text_mode` = false");
+    }
+  }
+
 }