# 执行计划中的算子 扫描数据类算子（C）
```
mysql> explain select count(*) from t1;
+------------------------------------+----------------+--------------+--------------------------------------+-------------------------------------------------+
| id                                 | estRows        | task         | access object                        | operator info                                   |
+------------------------------------+----------------+--------------+--------------------------------------+-------------------------------------------------+
| StreamAgg_20                       | 1.00           | root         |                                      | funcs:count(Column#11)->Column#6                |
| └─IndexReader_21                   | 1.00           | root         |                                      | index:StreamAgg_8                               |
|   └─StreamAgg_8                    | 1.00           | cop[tikv]    |                                      | funcs:count(1)->Column#11                       |
|     └─IndexFullScan_19             | 2560000.00     | cop[tikv]    | table:t1, index:t1_ind_id(id)        | keep order:false                                |
+------------------------------------+----------------+--------------+--------------------------------------+-------------------------------------------------+
4 rows in set (0.01 sec)
```
-------------------------------------------------------------
Index Full Scan