[NSE-576] implement columnar from_unixtime

native-sql-engine/core/src/main/scala/com/intel/oap/expression/ColumnarBinaryExpression.scala

@@ -34,6 +34,7 @@ import scala.collection.mutable.ListBuffer
 
 import com.intel.oap.expression.ColumnarDateTimeExpressions.ColumnarDateDiff
 import com.intel.oap.expression.ColumnarDateTimeExpressions.ColumnarUnixTimestamp
+import com.intel.oap.expression.ColumnarDateTimeExpressions.ColumnarFromUnixTime
 
 /**
  * A version of add that supports columnar processing for longs.
@@ -83,6 +84,8 @@ object ColumnarBinaryExpression {
         new ColumnarDateDiff(left, right)
       case a: UnixTimestamp =>
         new ColumnarUnixTimestamp(left, right)
+      case a: FromUnixTime =>
+        new ColumnarFromUnixTime(left, right)
       case other =>
         throw new UnsupportedOperationException(s"not currently supported: $other.")
     }

native-sql-engine/core/src/main/scala/com/intel/oap/expression/ColumnarDateTimeExpressions.scala

@@ -49,6 +49,7 @@ import org.apache.spark.sql.catalyst.expressions.UnixMicros
 import org.apache.spark.sql.catalyst.expressions.UnixMillis
 import org.apache.spark.sql.catalyst.expressions.UnixSeconds
 import org.apache.spark.sql.catalyst.expressions.UnixTimestamp
+import org.apache.spark.sql.catalyst.expressions.FromUnixTime
 import org.apache.spark.sql.catalyst.expressions.Year
 import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.types.{DateType, IntegerType, LongType, StringType, TimestampType}
@@ -493,6 +494,43 @@ object ColumnarDateTimeExpressions {
     }
   }
 
+  class ColumnarFromUnixTime(left: Expression, right: Expression)
+      extends FromUnixTime(left, right) with
+      ColumnarExpression {
+
+    buildCheck()
+
+    def buildCheck(): Unit = {
+      val supportedTypes = List(TimestampType)
+      if (supportedTypes.indexOf(left.dataType) == -1) {
+        throw new UnsupportedOperationException(
+          s"${left.dataType} is not supported in ColumnarFromUnixTime.")
+      }
+      if (left.dataType == StringType) {
+        right match {
+          case literal: ColumnarLiteral =>
+            val format = literal.value.toString
+            if (format.length > 10) {
+              throw new UnsupportedOperationException(
+                s"$format is not supported in ColumnarFromUnixTime.")
+            }
+          case _ =>
+        }
+      }
+    }
+
+    override def doColumnarCodeGen(args: Object): (TreeNode, ArrowType) = {
+      val (leftNode, leftType) = left.asInstanceOf[ColumnarExpression].doColumnarCodeGen(args)
+      //val (rightNode, rightType) = right.asInstanceOf[ColumnarExpression].doColumnarCodeGen(args)
+      val outType = CodeGeneration.getResultType(dataType)
+
+      val dateNode = TreeBuilder.makeFunction(
+        "castVARCHAR", Lists.newArrayList(leftNode, TreeBuilder.makeLiteral(java.lang.Long.valueOf(10L))), outType)
+
+      (dateNode, outType)
+    }
+  }
+
   class ColumnarDateDiff(left: Expression, right: Expression)
       extends DateDiff(left, right) with ColumnarExpression {