InfluxDB: Handle STRING_VIEW datatype (#107812)

This PR fixes an error when reading STRING_VIEW columns by correctly mapping STRING_VIEW in the newField factory and by adding a dedicated test to validate copyData’s handling of both nullable and non‐nullable STRING_VIEW arrays. This enables the Distinct Value Cache feature of InfluxDB v3 Enterprise for use.

pkg/tsdb/influxdb/fsql/arrow.go

@@ -124,7 +124,7 @@ func newFrame(schema *arrow.Schema) *data.Frame {
 
 func newField(f arrow.Field) *data.Field {
 	switch f.Type.ID() {
-	case arrow.STRING:
+	case arrow.STRING, arrow.STRING_VIEW:
 		return newDataField[string](f)
 	case arrow.FLOAT32:
 		return newDataField[float32](f)
@@ -239,6 +239,8 @@ func copyData(field *data.Field, col arrow.Array) error {
 				return err
 			}
 		}
+	case arrow.STRING_VIEW:
+		copyBasic[string](field, array.NewStringViewData(colData))
 	case arrow.STRING:
 		copyBasic[string](field, array.NewStringData(colData))
 	case arrow.UINT8:

pkg/tsdb/influxdb/fsql/arrow_test.go

@@ -469,6 +469,43 @@ func TestCopyData_Float64(t *testing.T) {
 	assert.Equal(t, float64(3.3), *field.CopyAt(2).(*float64))
 }
 
+func TestCopyData_StringView(t *testing.T) {
+	// Non-nullable StringView
+	field := data.NewField("field", nil, []string{})
+	builder := array.NewStringViewBuilder(memory.DefaultAllocator)
+	builder.Append("apple")
+	builder.Append("banana")
+	builder.Append("cherry")
+	arr := builder.NewArray()
+	defer arr.Release()
+
+	svArr := array.NewStringViewData(arr.Data())
+	defer svArr.Release()
+
+	err := copyData(field, svArr)
+	assert.NoError(t, err)
+	assert.Equal(t, "apple", field.CopyAt(0))
+	assert.Equal(t, "banana", field.CopyAt(1))
+	assert.Equal(t, "cherry", field.CopyAt(2))
+
+	// Nullable StringView
+	field = data.NewField("field", nil, []*string{})
+	builder = array.NewStringViewBuilder(memory.DefaultAllocator)
+	builder.Append("dog")
+	builder.AppendNull()
+	builder.Append("cat")
+	arr2 := builder.NewArray()
+	defer arr2.Release()
+	svArr2 := array.NewStringViewData(arr2.Data())
+	defer svArr2.Release()
+
+	err = copyData(field, svArr2)
+	assert.NoError(t, err)
+	assert.Equal(t, "dog", *(field.CopyAt(0).(*string)))
+	assert.Nil(t, field.CopyAt(1))
+	assert.Equal(t, "cat", *(field.CopyAt(2).(*string)))
+}
+
 func TestCustomMetadata(t *testing.T) {
 	schema := arrow.NewSchema([]arrow.Field{
 		{