Group data in InfluxDB with Flux

This page documents an earlier version of InfluxDB. InfluxDB v2.7 is the latest stable version. View this page in the v2.7 documentation.

With Flux, you can group data by any column in your queried data set. “Grouping” partitions data into tables in which each row shares a common value for specified columns. This guide walks through grouping data in Flux and provides examples of how data is shaped in the process.

If you’re just getting started with Flux queries, check out the following:

Group keys

Every table has a group key – a list of columns for which every row in the table has the same value.

Example group key
1. [_start, _stop, _field, _measurement, host]

Grouping data in Flux is essentially defining the group key of output tables. Understanding how modifying group keys shapes output data is key to successfully grouping and transforming data into your desired output.

group() Function

Flux’s group() function defines the group key for output tables, i.e. grouping records based on values for specific columns.

group() example
1. dataStream
2. |> group(columns: ["cpu", "host"])
Resulting group key
1. [cpu, host]

The group() function has the following parameters:

columns

The list of columns to include or exclude (depending on the mode) in the grouping operation.

mode

The method used to define the group and resulting group key. Possible values include by and except.

Example grouping operations

To illustrate how grouping works, define a dataSet variable that queries System CPU usage from the example-bucket bucket. Filter the cpu tag so it only returns results for each numbered CPU core.

Data set

CPU used by system operations for all numbered CPU cores. It uses a regular expression to filter only numbered cores.

1. dataSet = from(bucket: "example-bucket")
2. |> range(start: -2m)
3. |> filter(fn: (r) => r._field == "usage_system" and r.cpu =~ /cpu[0-9*]/)
4. |> drop(columns: ["host"])

This example drops the host column from the returned data since the CPU data is only tracked for a single host and it simplifies the output tables. Don’t drop the host column if monitoring multiple hosts.

1. Table: keys: [_start, _stop, _field, _measurement, cpu]
2. _start:time                      _stop:time           _field:string     _measurement:string              cpu:string                      _time:time                  _value:float
3. ------------------------------  ------------------------------  ----------------------  ----------------------  ----------------------  ------------------------------  ----------------------------
4. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:34:00.000000000Z             7.892107892107892
5. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:34:10.000000000Z                           7.2
6. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:34:20.000000000Z                           7.4
7. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:34:30.000000000Z                           5.5
8. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:34:40.000000000Z                           7.4
9. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:34:50.000000000Z                           7.5
10. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:35:00.000000000Z                          10.3
11. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:35:10.000000000Z                           9.2
12. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:35:20.000000000Z                           8.4
13. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:35:30.000000000Z                           8.5
14. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:35:40.000000000Z                           8.6
15. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:35:50.000000000Z                          10.2
16. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu0  2018-11-05T21:36:00.000000000Z                          10.6

18. Table: keys: [_start, _stop, _field, _measurement, cpu]
19. _start:time                      _stop:time           _field:string     _measurement:string              cpu:string                      _time:time                  _value:float
20. ------------------------------  ------------------------------  ----------------------  ----------------------  ----------------------  ------------------------------  ----------------------------
21. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:34:00.000000000Z            0.7992007992007992
22. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:34:10.000000000Z                           0.7
23. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:34:20.000000000Z                           0.7
24. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:34:30.000000000Z                           0.4
25. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:34:40.000000000Z                           0.7
26. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:34:50.000000000Z                           0.7
27. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:35:00.000000000Z                           1.4
28. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:35:10.000000000Z                           1.2
29. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:35:20.000000000Z                           0.8
30. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:35:30.000000000Z            0.8991008991008991
31. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:35:40.000000000Z            0.8008008008008008
32. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:35:50.000000000Z             0.999000999000999
33. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu1  2018-11-05T21:36:00.000000000Z            1.1022044088176353

35. Table: keys: [_start, _stop, _field, _measurement, cpu]
36. _start:time                      _stop:time           _field:string     _measurement:string              cpu:string                      _time:time                  _value:float
37. ------------------------------  ------------------------------  ----------------------  ----------------------  ----------------------  ------------------------------  ----------------------------
38. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:34:00.000000000Z                           4.1
39. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:34:10.000000000Z                           3.6
40. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:34:20.000000000Z                           3.5
41. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:34:30.000000000Z                           2.6
42. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:34:40.000000000Z                           4.5
43. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:34:50.000000000Z             4.895104895104895
44. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:35:00.000000000Z             6.906906906906907
45. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:35:10.000000000Z                           5.7
46. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:35:20.000000000Z                           5.1
47. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:35:30.000000000Z                           4.7
48. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:35:40.000000000Z                           5.1
49. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:35:50.000000000Z                           5.9
50. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu2  2018-11-05T21:36:00.000000000Z            6.4935064935064934

52. Table: keys: [_start, _stop, _field, _measurement, cpu]
53. _start:time                      _stop:time           _field:string     _measurement:string              cpu:string                      _time:time                  _value:float
54. ------------------------------  ------------------------------  ----------------------  ----------------------  ----------------------  ------------------------------  ----------------------------
55. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:34:00.000000000Z            0.5005005005005005
56. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:34:10.000000000Z                           0.5
57. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:34:20.000000000Z                           0.5
58. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:34:30.000000000Z                           0.3
59. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:34:40.000000000Z                           0.6
60. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:34:50.000000000Z                           0.6
61. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:35:00.000000000Z            1.3986013986013985
62. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:35:10.000000000Z                           0.9
63. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:35:20.000000000Z            0.5005005005005005
64. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:35:30.000000000Z                           0.7
65. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:35:40.000000000Z                           0.6
66. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:35:50.000000000Z                           0.8
67. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            usage_system                     cpu                    cpu3  2018-11-05T21:36:00.000000000Z                           0.9

Note that the group key is output with each table: Table: keys: <group-key>.

Group example data set

Group by CPU

Group the dataSet stream by the cpu column.

1. dataSet
2. |> group(columns: ["cpu"])

This won’t actually change the structure of the data since it already has cpu in the group key and is therefore grouped by cpu. However, notice that it does change the group key:

Group by CPU output tables
1. Table: keys: [cpu]
2. cpu:string                      _stop:time                      _time:time                  _value:float           _field:string     _measurement:string                     _start:time
3. ----------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ------------------------------
4. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:00.000000000Z             7.892107892107892            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
5. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:10.000000000Z                           7.2            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
6. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:20.000000000Z                           7.4            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
7. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:30.000000000Z                           5.5            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
8. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:40.000000000Z                           7.4            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
9. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:50.000000000Z                           7.5            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
10. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:00.000000000Z                          10.3            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
11. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:10.000000000Z                           9.2            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
12. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:20.000000000Z                           8.4            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
13. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:30.000000000Z                           8.5            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
14. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:40.000000000Z                           8.6            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
15. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:50.000000000Z                          10.2            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
16. cpu0  2018-11-05T21:36:00.000000000Z  2018-11-05T21:36:00.000000000Z                          10.6            usage_system                     cpu  2018-11-05T21:34:00.000000000Z

18. Table: keys: [cpu]
19. cpu:string                      _stop:time                      _time:time                  _value:float           _field:string     _measurement:string                     _start:time
20. ----------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ------------------------------
21. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:00.000000000Z            0.7992007992007992            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
22. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:10.000000000Z                           0.7            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
23. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:20.000000000Z                           0.7            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
24. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:30.000000000Z                           0.4            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
25. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:40.000000000Z                           0.7            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
26. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:50.000000000Z                           0.7            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
27. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:00.000000000Z                           1.4            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
28. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:10.000000000Z                           1.2            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
29. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:20.000000000Z                           0.8            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
30. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:30.000000000Z            0.8991008991008991            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
31. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:40.000000000Z            0.8008008008008008            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
32. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:50.000000000Z             0.999000999000999            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
33. cpu1  2018-11-05T21:36:00.000000000Z  2018-11-05T21:36:00.000000000Z            1.1022044088176353            usage_system                     cpu  2018-11-05T21:34:00.000000000Z

35. Table: keys: [cpu]
36. cpu:string                      _stop:time                      _time:time                  _value:float           _field:string     _measurement:string                     _start:time
37. ----------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ------------------------------
38. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:00.000000000Z                           4.1            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
39. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:10.000000000Z                           3.6            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
40. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:20.000000000Z                           3.5            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
41. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:30.000000000Z                           2.6            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
42. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:40.000000000Z                           4.5            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
43. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:50.000000000Z             4.895104895104895            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
44. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:00.000000000Z             6.906906906906907            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
45. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:10.000000000Z                           5.7            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
46. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:20.000000000Z                           5.1            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
47. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:30.000000000Z                           4.7            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
48. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:40.000000000Z                           5.1            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
49. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:50.000000000Z                           5.9            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
50. cpu2  2018-11-05T21:36:00.000000000Z  2018-11-05T21:36:00.000000000Z            6.4935064935064934            usage_system                     cpu  2018-11-05T21:34:00.000000000Z

52. Table: keys: [cpu]
53. cpu:string                      _stop:time                      _time:time                  _value:float           _field:string     _measurement:string                     _start:time
54. ----------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ------------------------------
55. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:00.000000000Z            0.5005005005005005            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
56. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:10.000000000Z                           0.5            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
57. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:20.000000000Z                           0.5            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
58. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:30.000000000Z                           0.3            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
59. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:40.000000000Z                           0.6            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
60. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:50.000000000Z                           0.6            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
61. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:00.000000000Z            1.3986013986013985            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
62. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:10.000000000Z                           0.9            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
63. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:20.000000000Z            0.5005005005005005            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
64. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:30.000000000Z                           0.7            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
65. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:40.000000000Z                           0.6            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
66. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:35:50.000000000Z                           0.8            usage_system                     cpu  2018-11-05T21:34:00.000000000Z
67. cpu3  2018-11-05T21:36:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.9            usage_system                     cpu  2018-11-05T21:34:00.000000000Z

The visualization remains the same.

Group by CPU

Group by time

Grouping data by the _time column is a good illustration of how grouping changes the structure of your data.

1. dataSet
2. |> group(columns: ["_time"])

When grouping by _time, all records that share a common _time value are grouped into individual tables. So each output table represents a single point in time.

Group by time output tables
1. Table: keys: [_time]
2. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
3. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
4. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z             7.892107892107892            usage_system                     cpu                    cpu0
5. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            0.7992007992007992            usage_system                     cpu                    cpu1
6. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           4.1            usage_system                     cpu                    cpu2
7. 2018-11-05T21:34:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            0.5005005005005005            usage_system                     cpu                    cpu3

9. Table: keys: [_time]
10. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
11. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
12. 2018-11-05T21:34:10.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           7.2            usage_system                     cpu                    cpu0
13. 2018-11-05T21:34:10.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.7            usage_system                     cpu                    cpu1
14. 2018-11-05T21:34:10.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           3.6            usage_system                     cpu                    cpu2
15. 2018-11-05T21:34:10.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.5            usage_system                     cpu                    cpu3

17. Table: keys: [_time]
18. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
19. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
20. 2018-11-05T21:34:20.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           7.4            usage_system                     cpu                    cpu0
21. 2018-11-05T21:34:20.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.7            usage_system                     cpu                    cpu1
22. 2018-11-05T21:34:20.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           3.5            usage_system                     cpu                    cpu2
23. 2018-11-05T21:34:20.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.5            usage_system                     cpu                    cpu3

25. Table: keys: [_time]
26. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
27. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
28. 2018-11-05T21:34:30.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           5.5            usage_system                     cpu                    cpu0
29. 2018-11-05T21:34:30.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.4            usage_system                     cpu                    cpu1
30. 2018-11-05T21:34:30.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           2.6            usage_system                     cpu                    cpu2
31. 2018-11-05T21:34:30.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.3            usage_system                     cpu                    cpu3

33. Table: keys: [_time]
34. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
35. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
36. 2018-11-05T21:34:40.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           7.4            usage_system                     cpu                    cpu0
37. 2018-11-05T21:34:40.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.7            usage_system                     cpu                    cpu1
38. 2018-11-05T21:34:40.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           4.5            usage_system                     cpu                    cpu2
39. 2018-11-05T21:34:40.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.6            usage_system                     cpu                    cpu3

41. Table: keys: [_time]
42. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
43. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
44. 2018-11-05T21:34:50.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           7.5            usage_system                     cpu                    cpu0
45. 2018-11-05T21:34:50.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.7            usage_system                     cpu                    cpu1
46. 2018-11-05T21:34:50.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z             4.895104895104895            usage_system                     cpu                    cpu2
47. 2018-11-05T21:34:50.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.6            usage_system                     cpu                    cpu3

49. Table: keys: [_time]
50. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
51. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
52. 2018-11-05T21:35:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                          10.3            usage_system                     cpu                    cpu0
53. 2018-11-05T21:35:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           1.4            usage_system                     cpu                    cpu1
54. 2018-11-05T21:35:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z             6.906906906906907            usage_system                     cpu                    cpu2
55. 2018-11-05T21:35:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            1.3986013986013985            usage_system                     cpu                    cpu3

57. Table: keys: [_time]
58. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
59. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
60. 2018-11-05T21:35:10.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           9.2            usage_system                     cpu                    cpu0
61. 2018-11-05T21:35:10.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           1.2            usage_system                     cpu                    cpu1
62. 2018-11-05T21:35:10.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           5.7            usage_system                     cpu                    cpu2
63. 2018-11-05T21:35:10.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.9            usage_system                     cpu                    cpu3

65. Table: keys: [_time]
66. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
67. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
68. 2018-11-05T21:35:20.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           8.4            usage_system                     cpu                    cpu0
69. 2018-11-05T21:35:20.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.8            usage_system                     cpu                    cpu1
70. 2018-11-05T21:35:20.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           5.1            usage_system                     cpu                    cpu2
71. 2018-11-05T21:35:20.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            0.5005005005005005            usage_system                     cpu                    cpu3

73. Table: keys: [_time]
74. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
75. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
76. 2018-11-05T21:35:30.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           8.5            usage_system                     cpu                    cpu0
77. 2018-11-05T21:35:30.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            0.8991008991008991            usage_system                     cpu                    cpu1
78. 2018-11-05T21:35:30.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           4.7            usage_system                     cpu                    cpu2
79. 2018-11-05T21:35:30.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.7            usage_system                     cpu                    cpu3

81. Table: keys: [_time]
82. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
83. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
84. 2018-11-05T21:35:40.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           8.6            usage_system                     cpu                    cpu0
85. 2018-11-05T21:35:40.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            0.8008008008008008            usage_system                     cpu                    cpu1
86. 2018-11-05T21:35:40.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           5.1            usage_system                     cpu                    cpu2
87. 2018-11-05T21:35:40.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.6            usage_system                     cpu                    cpu3

89. Table: keys: [_time]
90. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
91. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
92. 2018-11-05T21:35:50.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                          10.2            usage_system                     cpu                    cpu0
93. 2018-11-05T21:35:50.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z             0.999000999000999            usage_system                     cpu                    cpu1
94. 2018-11-05T21:35:50.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           5.9            usage_system                     cpu                    cpu2
95. 2018-11-05T21:35:50.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.8            usage_system                     cpu                    cpu3

97. Table: keys: [_time]
98. _time:time                     _start:time                      _stop:time                  _value:float           _field:string     _measurement:string              cpu:string
99. ------------------------------  ------------------------------  ------------------------------  ----------------------------  ----------------------  ----------------------  ----------------------
100. 2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                          10.6            usage_system                     cpu                    cpu0
101. 2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            1.1022044088176353            usage_system                     cpu                    cpu1
102. 2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z            6.4935064935064934            usage_system                     cpu                    cpu2
103. 2018-11-05T21:36:00.000000000Z  2018-11-05T21:34:00.000000000Z  2018-11-05T21:36:00.000000000Z                           0.9            usage_system                     cpu                    cpu3

Because each timestamp is structured as a separate table, when visualized, all points that share the same timestamp appear connected.

Group by time

With some further processing, you could calculate the average CPU usage across all CPUs per point of time and group them into a single table, but we won’t cover that in this example. If you’re interested in running and visualizing this yourself, here’s what the query would look like:

1. dataSet
2. |> group(columns: ["_time"])
3. |> mean()
4. |> group(columns: ["_value", "_time"], mode: "except")

Group by CPU and time

Group by the cpu and _time columns.

1. dataSet
2. |> group(columns: ["cpu", "_time"])

This outputs a table for every unique cpu and _time combination:

Group by CPU and time output tables

``` 1. Table: keys: [_time, cpu] 2. _time:time cpu:string _stop:time _value:float _field:string _measurement:string _start:time 3. ------------------------------ ---------------------- ------------------------------ ---------------------------- ---------------------- ---------------------- ------------------------------ 4. 2018-11-05T21:34:00.000000000Z cpu0 2018-11-05T21:36:00.000000000Z 7.892107892107892 usage_system cpu 2018-11-05T21:34:00.000000000Z

  1. Table: keys: [_time, cpu]
  2. _time:time cpu:string _stop:time _value:float _field:string _measurement:string _start:time

  3. 2018-11-05T21:34:00.000000000Z cpu1 2018-11-05T21:36:00.000000000Z 0.7992007992007992 usa

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