fixed a problem with multi index caused by the default value of groupkey #1679
| Job | Run time |
|---|---|
| 1m 24s | |
| 1m 23s | |
| 1m 26s | |
| 1m 26s | |
| 1m 26s | |
| 1m 38s | |
| 1m 38s | |
| 1m 39s | |
| 1m 38s | |
| 1m 39s | |
| 1m 39s | |
| 1m 38s | |
| 1m 40s | |
| 1m 40s | |
| 1m 40s | |
| 1m 42s | |
| 1m 42s | |
| 1m 42s | |
| 1m 43s | |
| 1m 41s | |
| 1m 42s | |
| 1m 42s | |
| 1m 42s | |
| 1m 44s | |
| 1m 43s | |
| 1m 41s | |
| 1m 41s | |
| 1m 42s | |
| 1m 24s | |
| 1m 39s | |
| 48m 44s |