The following functions require ordered input but were not guaranteed to
received ordered input:
* `distinct()`
* `sample()`
* `holt_winters()`
* `holt_winters_with_fit()`
* `derivative()`
* `non_negative_derivative()`
* `difference()`
* `moving_average()`
* `elapsed()`
* `cumulative_sum()`
* `top()`
* `bottom()`
These function calls have now been modified to request that their input
be ordered by the query engine. This will prevent the improper output
that could have been caused by multiple series being merged together or
multiple shards being merged together potentially incorrectly when no
time grouping was specified.
Two additional functions were already correct to begin with (so there
are no bugs with these two, but I'm including their names for
completeness).
* `median()`
* `percentile()`
If there were multiple selectors and math, the query engine would
mistakenly think it was the only selector in the query and would not
match their timestamps.
Fixed the query engine to pass whether the selector should be treated as
a selector so queries like `max(value) * 1, min(value) * 1` will match
the timestamps of the result.
The timezone for a query can now be added to the end with something like
`TZ("America/Los_Angeles")` and it will localize the results of the
query to be in that timezone. The offset will automatically be set to
the offset for that timezone and offsets will automatically adjust for
daylight savings time so grouping by a day will result in a 25 hour day
once a year and a 23 hour day another day of the year.
The automatic adjustment of intervals for timezone offsets changing will
only happen if the group by period is greater than the timezone offset
would be. That means grouping by an hour or less will not be affected by
daylight savings time, but a 2 hour or 1 day interval will be.
The default timezone is UTC and existing queries are unaffected by this
change.
When times are returned as strings (when `epoch=1` is not used), the
results will be returned using the requested timezone format in RFC3339
format.
There is a lot of confusion in the code if the range is [start, end) or
[start, end]. This is not made easier because it is acts one way in some
areas and in another way in some other areas, but it is usually [start,
end]. The `time = ?` syntax assumed that it was [start, end) and added
an extra nanosecond to the end time to accomodate for that, but the
range was actually [start, end] and that caused it to include one extra
nanosecond when it shouldn't have.
This change fixes it so exactly one timestamp is selected when `time = ?`
is used.
Jonathan A. Sternberg
Jason Wilder