feat(bigquery): add ExportDataStatstics to QueryStatistics (#9371)

Fixes https://togithub.com/googleapis/google-cloud-go/issues/8401

bigquery/integration_test.go

@@ -2762,6 +2762,78 @@ func TestIntegration_ExtractExternal(t *testing.T) {
 	}
 }
 
+func TestIntegration_ExportDataStatistics(t *testing.T) {
+	// Create a table, extract it to GCS using EXPORT DATA statement.
+	if client == nil {
+		t.Skip("Integration tests skipped")
+	}
+	ctx := context.Background()
+	schema := Schema{
+		{Name: "name", Type: StringFieldType},
+		{Name: "num", Type: IntegerFieldType},
+	}
+	table := newTable(t, schema)
+	defer table.Delete(ctx)
+
+	// Extract to a GCS object as CSV.
+	bucketName := testutil.ProjID()
+	uri := fmt.Sprintf("gs://%s/bq-export-test-*.csv", bucketName)
+	defer func() {
+		it := storageClient.Bucket(bucketName).Objects(ctx, &storage.Query{
+			MatchGlob: "bq-export-test-*.csv",
+		})
+		for {
+			obj, err := it.Next()
+			if err == iterator.Done {
+				break
+			}
+			if err != nil {
+				t.Logf("failed to delete bucket: %v", err)
+				continue
+			}
+			err = storageClient.Bucket(bucketName).Object(obj.Name).Delete(ctx)
+			t.Logf("deleted object %s: %v", obj.Name, err)
+		}
+	}()
+
+	// EXPORT DATA to GCS object.
+	sql := fmt.Sprintf(`EXPORT DATA 
+		OPTIONS (
+			uri = '%s',
+			format = 'CSV',
+			overwrite = true,
+			header = true,
+			field_delimiter = ';'
+		)
+		AS (
+			SELECT 'a' as name, 1 as num
+			UNION ALL
+			SELECT 'b' as name, 2 as num
+			UNION ALL  
+			SELECT 'c' as name, 3 as num
+		);`,
+		uri)
+	stats, _, err := runQuerySQL(ctx, sql)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	qStats, ok := stats.Details.(*QueryStatistics)
+	if !ok {
+		t.Fatalf("expected query statistics not present")
+	}
+
+	if qStats.ExportDataStatistics == nil {
+		t.Fatal("jobStatus missing ExportDataStatistics")
+	}
+	if qStats.ExportDataStatistics.FileCount != 1 {
+		t.Fatalf("expected ExportDataStatistics to have 1 file, but got %d files", qStats.ExportDataStatistics.FileCount)
+	}
+	if qStats.ExportDataStatistics.RowCount != 3 {
+		t.Fatalf("expected ExportDataStatistics to have 3 rows, got %d rows", qStats.ExportDataStatistics.RowCount)
+	}
+}
+
 func TestIntegration_ReadNullIntoStruct(t *testing.T) {
 	// Reading a null into a struct field should return an error (not panic).
 	if client == nil {

bigquery/job.go

@@ -505,6 +505,30 @@ type QueryStatistics struct {
 
 	// The DDL target table, present only for CREATE/DROP FUNCTION/PROCEDURE queries.
 	DDLTargetRoutine *Routine
+
+	// Statistics for the EXPORT DATA statement as part of Query Job.
+	ExportDataStatistics *ExportDataStatistics
+}
+
+// ExportDataStatistics represents statistics for
+// a EXPORT DATA statement as part of Query Job.
+type ExportDataStatistics struct {
+	// Number of destination files generated.
+	FileCount int64
+
+	// Number of destination rows generated.
+	RowCount int64
+}
+
+func bqToExportDataStatistics(in *bq.ExportDataStatistics) *ExportDataStatistics {
+	if in == nil {
+		return nil
+	}
+	stats := &ExportDataStatistics{
+		FileCount: in.FileCount,
+		RowCount:  in.RowCount,
+	}
+	return stats
 }
 
 // BIEngineStatistics contains query statistics specific to the use of BI Engine.
@@ -1028,6 +1052,7 @@ func (j *Job) setStatistics(s *bq.JobStatistics, c *Client) {
 			DDLTargetTable:                bqToTable(s.Query.DdlTargetTable, c),
 			DDLOperationPerformed:         s.Query.DdlOperationPerformed,
 			DDLTargetRoutine:              bqToRoutine(s.Query.DdlTargetRoutine, c),
+			ExportDataStatistics:          bqToExportDataStatistics(s.Query.ExportDataStatistics),
 			StatementType:                 s.Query.StatementType,
 			TotalBytesBilled:              s.Query.TotalBytesBilled,
 			TotalBytesProcessed:           s.Query.TotalBytesProcessed,