add numRows to segment metadata query response

docs/content/querying/segmentmetadataquery.md

@@ -6,6 +6,7 @@ Segment metadata queries return per segment information about:
 
 * Cardinality of all columns in the segment
 * Estimated byte size for the segment columns if they were stored in a flat format
+* Number of rows stored inside the segment
 * Interval the segment covers
 * Column type of all the columns in the segment
 * Estimated total segment byte size in if it was stored in a flat format
@@ -43,7 +44,8 @@ The format of the result is:
     "dim2" : { "type" : "STRING", "size" : 100000, "cardinality" : 1504 },
     "metric1" : { "type" : "FLOAT", "size" : 100000, "cardinality" : null }
   },
-  "size" : 300000
+  "size" : 300000,
+  "numRows" : 5000000
 } ]
 ```
 

processing/src/main/java/io/druid/query/metadata/SegmentMetadataQueryQueryToolChest.java

@@ -132,7 +132,13 @@ public class SegmentMetadataQueryQueryToolChest extends QueryToolChest<SegmentAn
               columns.put(columnName, rightColumns.get(columnName));
             }
 
-            return new SegmentAnalysis("merged", newIntervals, columns, arg1.getSize() + arg2.getSize());
+            return new SegmentAnalysis(
+                "merged",
+                newIntervals,
+                columns,
+                arg1.getSize() + arg2.getSize(),
+                arg1.getNumRows() + arg2.getNumRows()
+            );
           }
         };
       }

processing/src/main/java/io/druid/query/metadata/SegmentMetadataQueryRunnerFactory.java

@@ -122,7 +122,8 @@ public class SegmentMetadataQueryRunnerFactory implements QueryRunnerFactory<Seg
                     segment.getIdentifier(),
                     Arrays.asList(segment.getDataInterval()),
                     columns,
-                    totalSize
+                    totalSize,
+                    numRows
                 )
             )
         );

processing/src/main/java/io/druid/query/metadata/metadata/SegmentAnalysis.java

@@ -30,13 +30,15 @@ public class SegmentAnalysis
   private final List<Interval> interval;
   private final Map<String, ColumnAnalysis> columns;
   private final long size;
+  private final int numRows;
 
   @JsonCreator
   public SegmentAnalysis(
       @JsonProperty("id") String id,
       @JsonProperty("intervals") List<Interval> interval,
       @JsonProperty("columns") Map<String, ColumnAnalysis> columns,
-      @JsonProperty("size") long size
+      @JsonProperty("size") long size,
+      @JsonProperty("numRows") int numRows
 
   )
   {
@@ -44,6 +46,7 @@ public class SegmentAnalysis
     this.interval = interval;
     this.columns = columns;
     this.size = size;
+    this.numRows = numRows;
   }
 
   @JsonProperty
@@ -70,6 +73,12 @@ public class SegmentAnalysis
     return size;
   }
 
+  @JsonProperty
+  public int getNumRows()
+  {
+    return numRows;
+  }
+
   public String toDetailedString()
   {
     return "SegmentAnalysis{" +
@@ -77,6 +86,7 @@ public class SegmentAnalysis
            ", interval=" + interval +
            ", columns=" + columns +
            ", size=" + size +
+           ", numRows=" + numRows +
            '}';
   }
 
@@ -87,6 +97,7 @@ public class SegmentAnalysis
            "id='" + id + '\'' +
            ", interval=" + interval +
            ", size=" + size +
+           ", numRows=" + numRows +
            '}';
   }
 
@@ -105,6 +116,11 @@ public class SegmentAnalysis
     if (size != that.size) {
       return false;
     }
+
+    if (numRows != that.numRows) {
+      return false;
+    }
+
     if (id != null ? !id.equals(that.id) : that.id != null) {
       return false;
     }
@@ -122,6 +138,7 @@ public class SegmentAnalysis
     result = 31 * result + (interval != null ? interval.hashCode() : 0);
     result = 31 * result + (columns != null ? columns.hashCode() : 0);
     result = 31 * result + (int) (size ^ (size >>> 32));
+    result = 31 * result + (int) (numRows ^ (numRows >>> 32));
     return result;
   }
 }

processing/src/test/java/io/druid/query/metadata/SegmentMetadataQueryQueryToolChestTest.java

@@ -71,7 +71,8 @@ public class SegmentMetadataQueryQueryToolChestTest
                 1,
                 null
             )
-        ), 71982
+        ), 71982,
+        100
     );
 
     Object preparedValue = strategy.prepareForCache().apply(result);

processing/src/test/java/io/druid/query/metadata/SegmentMetadataQueryTest.java

@@ -103,7 +103,8 @@ public class SegmentMetadataQueryTest
                 1,
                 null
             )
-        ), 71982
+        ), 71982,
+        1209
     );
   }