Re: [jira] [Created] (IOTDB-181) Remove "first_value" and "last_value" in TsDigest

[Xiangdong Huang]

Hi,

+1.

Do not forget to log the changes into format-changelist.md

Best,

---
Xiangdong Huang
School of Software, Tsinghua University

 黄向东
清华大学 软件学院


Jialin Qiao (Jira)  于2019年8月27日周二 上午10:07写道：

> Jialin Qiao created IOTDB-181:
> -
>
>  Summary: Remove "first_value" and "last_value" in TsDigest
>  Key: IOTDB-181
>  URL: https://issues.apache.org/jira/browse/IOTDB-181
>  Project: Apache IoTDB
>   Issue Type: Improvement
> Reporter: Jialin Qiao
>
>
> In TsDigest, we have five statistics: min_value, max_value, sum_value,
> first_value, last_value.
>
> When filtering page or chunk, we use min_value and max_value for a filter
> like "s1>10" or "s1<20".
>
> The sum value can be used in aggregation query "select sum(s1) from
> root...".
>
> However, it is difficult for me to come up with a scenario that uses
> "first_value" and "last_value" to filter data, and they are never used at
> all...
>
> So why not remove them?
>
>
>
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> (v8.3.2#803003)
>

[jira] [Created] (IOTDB-181) Remove "first_value" and "last_value" in TsDigest

[Jialin Qiao (Jira)]

Jialin Qiao created IOTDB-181:
-

 Summary: Remove "first_value" and "last_value" in TsDigest
 Key: IOTDB-181
 URL: https://issues.apache.org/jira/browse/IOTDB-181
 Project: Apache IoTDB
  Issue Type: Improvement
Reporter: Jialin Qiao


In TsDigest, we have five statistics: min_value, max_value, sum_value, 
first_value, last_value.

When filtering page or chunk, we use min_value and max_value for a filter like 
"s1>10" or "s1<20".

The sum value can be used in aggregation query "select sum(s1) from root...".

However, it is difficult for me to come up with a scenario that uses 
"first_value" and "last_value" to filter data, and they are never used at all...

So why not remove them?



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