[InfluxDB] top() and bottom() now returns the time for every point

[jsternberg]

URL for relevant page?

influxdata/influxdb#8289

What products and version are you using?

InfluxDB 1.3.0

top() and bottom() are being modified so they return the actual time numbers always rather than following the standard time grouping rules. That also affects the ordering so they will not always be from greatest to least or least to greatest, they'll be organized by time and then the standard rules we use now.

[rkuchan]

TOP()

• Update example 4:

> SELECT TOP("water_level",3),"location" FROM "h2o_feet" WHERE time >= '2015-08-18T00:00:00Z' AND time <= '2015-08-18T00:54:00Z' GROUP BY time(24m) ORDER BY time DESC
name: h2o_feet

time                 top   location
----                 ---   --------
2015-08-18T00:48:00Z 7.11  coyote_creek
2015-08-18T00:54:00Z 6.982 coyote_creek
2015-08-18T00:54:00Z 2.054 santa_monica
2015-08-18T00:24:00Z 7.635 coyote_creek
2015-08-18T00:30:00Z 7.5   coyote_creek
2015-08-18T00:36:00Z 7.372 coyote_creek
2015-08-18T00:00:00Z 8.12  coyote_creek
2015-08-18T00:06:00Z 8.005 coyote_creek
2015-08-18T00:12:00Z 7.887 coyote_creek

[...]
Notice that the GROUP BY time() clause does not override the points’ original timestamps. See [Issue 1](#**TK **) in the section below for a more detailed explanation of that behavior.

• Update issue 1:

Issue 1: TOP() with a GROUP BY time() clause

Queries with TOP() and a GROUP BY time() clause return the specified
number of points per GROUP BY time() interval.
For
most GROUP BY time() queries,
the returned timestamps mark the start of the GROUP BY time() interval.
GROUP BY time() queries with the TOP() function behave differently;
they maintain the timestamp of the original data point.

Example

The query below returns two points per 18-minute `GROUP BY time()` interval. Notice that the returned timestamps are the points' original timestamps; they are not forced to match the start of the `GROUP BY time()` intervals.

> SELECT TOP("water_level",2) FROM "h2o_feet" WHERE time >= '2015-08-18T00:00:00Z' AND time <= '2015-08-18T00:30:00Z' AND "location" = 'santa_monica' GROUP BY time(18m)

name: h2o_feet
time                   top
----                   ------
                           __
2015-08-18T00:00:00Z  2.064 |
2015-08-18T00:06:00Z  2.116 | <------- Greatest points for the first time interval
                           --
                           __
2015-08-18T00:18:00Z  2.126 |
2015-08-18T00:30:00Z  2.051 | <------- Greatest points for the second time interval
                           --

BOTTOM()

• Update example 4:

> SELECT BOTTOM("water_level",3),"location" FROM "h2o_feet" WHERE time >= '2015-08-18T00:00:00Z' AND time <= '2015-08-18T00:54:00Z' GROUP BY time(24m) ORDER BY time DESC

name: h2o_feet
time                 bottom location
----                 ------ --------
2015-08-18T00:48:00Z 1.991  santa_monica
2015-08-18T00:54:00Z 2.054  santa_monica
2015-08-18T00:54:00Z 6.982  coyote_creek
2015-08-18T00:24:00Z 2.041  santa_monica
2015-08-18T00:30:00Z 2.051  santa_monica
2015-08-18T00:42:00Z 2.057  santa_monica
2015-08-18T00:00:00Z 2.064  santa_monica
2015-08-18T00:06:00Z 2.116  santa_monica
2015-08-18T00:12:00Z 2.028  santa_monica

[...]
Notice that the GROUP BY time() clause does not override the points’ original timestamps. See [Issue 1](#**TK **) in the section below for a more detailed explanation of that behavior.

• Update issue 1:

Issue 1: BOTTOM() with a GROUP BY time() clause

Queries with BOTTOM() and a GROUP BY time() clause return the specified
number of points per GROUP BY time() interval.
For
most GROUP BY time() queries,
the returned timestamps mark the start of the GROUP BY time() interval.
GROUP BY time() queries with the BOTTOM() function behave differently;
they maintain the timestamp of the original data point.

Example

The query below returns two points per 18-minute `GROUP BY time()` interval. Notice that the returned timestamps are the points' original timestamps; they are not forced to match the start of the `GROUP BY time()` intervals.

> SELECT BOTTOM("water_level",2) FROM "h2o_feet" WHERE time >= '2015-08-18T00:00:00Z' AND time <= '2015-08-18T00:30:00Z' AND "location" = 'santa_monica' GROUP BY time(18m)

name: h2o_feet
time                   bottom
----                   ------
                           __
2015-08-18T00:00:00Z  2.064 |
2015-08-18T00:12:00Z  2.028 | <------- Smallest points for the first time interval
                           --
                           __
2015-08-18T00:24:00Z  2.041 |
2015-08-18T00:30:00Z  2.051 | <------- Smallest points for the second time interval
                           --