[jira] [Created] (IOTDB-5421) Add sampling attributes for M4

["Lei Rui (Jira)" <ji...@apache.org>]

Lei Rui created IOTDB-5421:
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             Summary: Add sampling attributes for M4
                 Key: IOTDB-5421
                 URL: https://issues.apache.org/jira/browse/IOTDB-5421
             Project: Apache IoTDB
          Issue Type: New Feature
            Reporter: Lei Rui


Previously, the M4 function supports two types of attribute inputs (actually two types of sliding windows):
(1) Control the sliding *size* window using attributes {{windowSize}} and {{{}slidingStep{}}}. For example: {{{}select M4(s1,'windowSize'='10','slidingStep'='10') as samples from root.vehicle.d1{}}}.
(2) Control the sliding *time* window using attributes {{{}windowInterval{}}}, {{{}slidingStep{}}}, {{displayWindowBegin}} and {{{}displayWindowEnd{}}}. For example: {{{}select M4(s1,'windowInterval'='25','slidingStep'='25','displayWindowBegin'='0','displayWindowEnd'='100') as samples from root.vehicle.d1{}}}.

As proposes in a real use case (ZhongHe&DWF), the user wants to control M4 behaviors using the following sampling attributes: {{{}samplingInterval{}}}, {{{}samplingThreshold{}}}, {{{}displayWindowBegin{}}}, {{{}displayWindowEnd{}}}. For example: {{{}select M4(s1,'samplingInterval'='5','samplingThreshold'='100','displayWindowBegin'='0','displayWindowEnd'='150') as samples from root.vehicle.d1{}}}.
 * {{{}samplingInterval{}}}: The sampling time interval length. Long data type. {*}Required{*}.
 * {{{}samplingThreshold{}}}: The upper limit of the number of sampling points. Long data type. Optional. If not set, default to 10000.
 * {{{}displayWindowBegin{}}}: The starting position of the window (included). Long data type. {*}Required{*}.
 * {{{}displayWindowEnd{}}}: End time limit (excluded, essentially playing the same role as {{{}WHERE time < displayWindowEnd{}}}). Long data type. {*}Required{*}.

The user-defined sampling time window is a special kind of sliding time window, which is special in that:
 # There is a conversion relationship between the length of the sliding time window {{windowInterval}} and the sampling time interval {{samplingInterval. }}Note that here user *indirectly* controls the window time length {{{}windowInterval{}}}.
 # The sliding step of the sliding time window {{slidingStep}} is fixed to be equal to the window length {{windowInterval}} here, so there is no need for the user to input the {{slidingStep}} parameter.
 # {{displayWindowBegin}} and {{displayWindowEnd}} are required parameters here.



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