This makes the following syntax possible:
CREATE CONTINUOUS QUERY mycq ON mydb
RESAMPLE EVERY 1m FOR 1h
BEGIN
SELECT mean(value) INTO cpu_mean FROM cpu GROUP BY time(5m)
END
The RESAMPLE option customizes how often an interval will be sampled and
the duration. The interval is customized with EVERY. Any intervals
within the resampling duration on a multiple of the resample interval
will be updated with the new results from the query.
The duration is customized with FOR. This determines how long an
interval will participate in resampling.
Both options are optional. If RESAMPLE is in the syntax, at least one of
the two needs to be given. The default for both is the interval of the
continuous query.
The service also improves tracking of the last run time and the logic of
when a query for an interval should be run. When determining the oldest
interval to run for a query, the continuous query service determines
what would have been the optimal time to perform the next query based on
the last run time. It then uses this time to determine the oldest
interval that should be run using the resample duration and will
resample all intervals between this time and the current time as opposed
to potentially forgetting about the last run in an interval if the
continuous query service gets delayed for some reason.
This removes the previous config options for customizing continuous
queries since they are no longer relevant and adds a new option of
customizing the run interval. The run interval determines how often the
continuous query service polls for when it should execute a query. This
option defaults to 1s, but can be set to 1m if the least common factor
of all continuous queries' intervals is a higher value (like 1m).
For DERIVATIVE aggregations there was only one check performed: if
aggregation function is given when using group by. However the nested
aggregation function syntax was not checked.
Fixes#4123
When using derivative, it is required that aggregate function is used as
sub-call when grouping by time is used. However, AST parsing used to check
if WHERE-clause contained condition with 'time'.
Fix this by changing check to see if groupByInterval is present.
Modify also related error case tests and add check for
select derivative(...) ... where time > ...
Mark Rushakoff
Jonathan A. Sternberg
Mark Rushakoff
Nathaniel Cook
mengjingleli
Philip O'Toole
Philip O'Toole
Paulo Pires
Paweł Kowalak
Mateusz Dymiński
ch33hau
David Norton
Konstantin Shaposhnikov
linearb
Nick Dawbarn
Cory LaNou
Jason Wilder
Ben Johnson
Jari Sukanen