An easy method to count the total number of time-series data

I used workbench to write a large number of data into iotdb, e.g. 50000 devices and 100 sensors for each device. Then I wanted to verify whether the total number of data actually written into iotdb is equal to the number expected.

I used sql statements like "select count(*) from root.test.** group by level =3", but can't get the correct answer which should be 50000\*100. It seems like that result columns over 1000 has been truncated.

What I expect is, when I execute one single sql statement, it can return the correct number of all data in db. In industry, large data is ubiquitous, so a good support for large data might be a common scene.

Now, I used a sql and shell combined way to verify the number, such like "select count(*) from root.test.**.d_${i} group by level =3". Here i ranges from 1 to 50000. And finally add 50000 results together to get the correct number.

首先，复现包含超过 1000 个结果列的单条查询 `select count(*) from root.test.** group by level =3`，并将其与预期的 50000×100 计数进行比较。跟踪查询结果处理过程，确定列在哪个位置被截断。完成标准是：一条 SQL 语句能够返回所报告的大型数据集的完整计数。

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