fix: write data tail on io.EOF OnInput

query.go

@@ -343,6 +343,19 @@ func (c *Client) sendInput(ctx context.Context, info proto.ColInfoInput, q Query
 		if err := f(ctx); err != nil {
 			if errors.Is(err, io.EOF) {
 				// No more data.
+				if tailRows := q.Input[0].Data.Rows(); tailRows > 0 {
+					// Write data tail on next tick and break.
+					//
+					// This is required to resemble io.Reader behavior.
+					if ce := c.lg.Check(zap.DebugLevel, "Writing tail of input data (not empty and io.EOF)"); ce != nil {
+						ce.Write(
+							zap.Int("rows", tailRows),
+						)
+					}
+					f = nil
+					continue
+				}
+
 				break
 			}
 			// ClickHouse server persists blocks after receive.

query_test.go

@@ -245,7 +245,7 @@ func TestClient_Query(t *testing.T) {
 			OnInput: func(ctx context.Context) error {
 				data = append(data[:0], uint8(total), 2, 3, 4)
 				total++
-				if total > blocks {
+				if total >= blocks {
 					return io.EOF
 				}
 				return nil