| <!-- |
| |
| Licensed to the Apache Software Foundation (ASF) under one |
| or more contributor license agreements. See the NOTICE file |
| distributed with this work for additional information |
| regarding copyright ownership. The ASF licenses this file |
| to you under the Apache License, Version 2.0 (the |
| "License"); you may not use this file except in compliance |
| with the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, |
| software distributed under the License is distributed on an |
| "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| KIND, either express or implied. See the License for the |
| specific language governing permissions and limitations |
| under the License. |
| |
| --> |
| |
| # M4 |
| |
| ## M4 |
| |
| ### Usage |
| |
| This function is used to execute the M4 aggregation query using the MAC (merging all chunks) approach. |
| |
| **Name:** M4 |
| |
| **Input Series:** Only supports a single input sequence, the type is INT32 / INT64 / FLOAT / DOUBLE |
| |
| **Parameters:** |
| |
| + `tqs`: The start time (included) of the query time range. |
| + `tqe`: The end time (excluded) of the query time range. |
| + `w`: The number of time spans in the M4 aggregation. |
| |
| **Output Series:** The first, last, bottom, and top points in each time span |
| [tqs+(tqe-tqs)/w*(i-1),tqs+(tqe-tqs)/w*i), i=1,...,w. |
| |
| **Note:** |
| + This function is right now only supported in the branch `research/M4-visualization` right now. |
| + You need to make sure (tqe-tqs) is divisible by w. |
| + You need to add `time>=tqs and time<tqe` in the where clause. |
| |
| ### Examples |
| |
| Input series: |
| |
| ``` |
| +-----------------------------+------------------+ |
| | Time|root.vehicle.d0.s0| |
| +-----------------------------+------------------+ |
| |1970-01-01T08:00:00.001+08:00| 5.0| |
| |1970-01-01T08:00:00.002+08:00| 15.0| |
| |1970-01-01T08:00:00.005+08:00| 10.0| |
| |1970-01-01T08:00:00.008+08:00| 8.0| |
| |1970-01-01T08:00:00.010+08:00| 20.0| |
| |1970-01-01T08:00:00.020+08:00| 20.0| |
| |1970-01-01T08:00:00.025+08:00| 8.0| |
| |1970-01-01T08:00:00.027+08:00| 20.0| |
| |1970-01-01T08:00:00.030+08:00| 40.0| |
| |1970-01-01T08:00:00.033+08:00| 9.0| |
| |1970-01-01T08:00:00.035+08:00| 10.0| |
| |1970-01-01T08:00:00.040+08:00| 20.0| |
| |1970-01-01T08:00:00.045+08:00| 30.0| |
| |1970-01-01T08:00:00.052+08:00| 8.0| |
| |1970-01-01T08:00:00.054+08:00| 18.0| |
| |1970-01-01T08:00:00.120+08:00| 8.0| |
| +-----------------------------+------------------+ |
| ``` |
| |
| SQL for query: |
| |
| ```sql |
| select M4(s0,'tqs'='0','tqe'='100','w'='4') from root.vehicle.d0 where time>=0 and time<100 |
| ``` |
| |
| Output: |
| |
| ``` |
| +-----------------------------+----------------------------------------------------------------------------------+ |
| | Time| M4(root.vehicle.d0.s0, "tqs"="0", "tqe"="100", "w"="4")| |
| +-----------------------------+----------------------------------------------------------------------------------+ |
| |1970-01-01T08:00:00.000+08:00| FirstPoint=(1,5.0), LastPoint=(20,20.0), BottomPoint=(1,5.0), TopPoint=(10,20.0)| |
| |1970-01-01T08:00:00.025+08:00|FirstPoint=(25,8.0), LastPoint=(45,30.0), BottomPoint=(25,8.0), TopPoint=(30,40.0)| |
| |1970-01-01T08:00:00.050+08:00|FirstPoint=(52,8.0), LastPoint=(54,18.0), BottomPoint=(52,8.0), TopPoint=(54,18.0)| |
| |1970-01-01T08:00:00.075+08:00| empty| |
| +-----------------------------+----------------------------------------------------------------------------------+ |
| ``` |
