implementation lttb macro function

[Slach]

Would be very cool would be to have an option to use the new lttb function in 23.10 for the downsampling. This could be an option to select in the plugin settings and/or maybe a completely new macro?

https://clickhouse.com/docs/en/sql-reference/aggregate-functions/reference/largestTriangleThreeBuckets

[Slach]

if we will implements $lttb(bucket_numbers, x_field, y_field) AS alias FROM $table WHERE $timeFilter

shall transformed to something like that

SELECT alias.1 AS x_field, alias.2 AS y_field FROM (
  SELECT untuple(arrayJoin(lttb(bucket_numbers)(x_field, y_field))) AS alias FROM $table WHERE $timeFilter
) ORDER BY x_field 

[Slach]

ok. final use case is show downsampled data which will show outliers

also we need to implements

$lttb(auto,x,y)
and calculate auto as
(($__to - $__from) / $__interval_ms )

[Slach]

$lttb(auto,x,y) AS l_alias FROM $table
shall transform to

SELECT l_alias.1 AS x_field, l_alias.2 AS y_field FROM (
  SELECT untuple(arrayJoin(lttb(bucket_numbers)(x_field, y_field))) AS l_alias FROM $table WHERE $timeFilter
) ORDER BY x_field