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:

  1. +-----------------------------+------------------+
  2. |                         Time|root.vehicle.d0.s0|
  3. +-----------------------------+------------------+
  4. |1970-01-01T08:00:00.001+08:00|               5.0|
  5. |1970-01-01T08:00:00.002+08:00|              15.0|
  6. |1970-01-01T08:00:00.005+08:00|              10.0|
  7. |1970-01-01T08:00:00.008+08:00|               8.0|
  8. |1970-01-01T08:00:00.010+08:00|              20.0|
  9. |1970-01-01T08:00:00.020+08:00|              20.0|
  10. |1970-01-01T08:00:00.025+08:00|               8.0|
  11. |1970-01-01T08:00:00.027+08:00|              20.0|
  12. |1970-01-01T08:00:00.030+08:00|              40.0|
  13. |1970-01-01T08:00:00.033+08:00|               9.0|
  14. |1970-01-01T08:00:00.035+08:00|              10.0|
  15. |1970-01-01T08:00:00.040+08:00|              20.0|
  16. |1970-01-01T08:00:00.045+08:00|              30.0|
  17. |1970-01-01T08:00:00.052+08:00|               8.0|
  18. |1970-01-01T08:00:00.054+08:00|              18.0|
  19. |1970-01-01T08:00:00.120+08:00|               8.0|
  20. +-----------------------------+------------------+

SQL for query:

  1. select M4(s0,'tqs'='0','tqe'='100','w'='4') from root.vehicle.d0 where time>=0 and time<100

Output:

  1. +-----------------------------+----------------------------------------------------------------------------------+
  2. |                         Time|                           M4(root.vehicle.d0.s0, "tqs"="0", "tqe"="100", "w"="4")|
  3. +-----------------------------+----------------------------------------------------------------------------------+
  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)|
  5. |1970-01-01T08:00:00.025+08:00|FirstPoint=(25,8.0), LastPoint=(45,30.0), BottomPoint=(25,8.0), TopPoint=(30,40.0)|
  6. |1970-01-01T08:00:00.050+08:00|FirstPoint=(52,8.0), LastPoint=(54,18.0), BottomPoint=(52,8.0), TopPoint=(54,18.0)|
  7. |1970-01-01T08:00:00.075+08:00|                                                                             empty|
  8. +-----------------------------+----------------------------------------------------------------------------------+