elasticsearch/elasticsearch — Issue #1744: Date Histogram Facet: Add `pre_zone_adjust_large_interval`
Author: kimchy
Created: 2012-02-29 00:52:24+00:00
State: open
Labels: enhancement, v0.19.0.RC4

Will update the docs with its meaning, `pre_zone_adjust_large_interval`. Here is an excerpt:

p. Lets take an example. For @2012-04-01T04:15:30Z@, with a @pre_zone@ of @-08:00@. For @day@ interval, the actual time by applying the time zone and rounding falls under @2012-03-31@, so the returned value will be (in millis) of @2012-03-31T00:00:00Z@ (UTC). For @hour@ interval, applying the time zone results in @2012-03-31T20:15:30@, rounding it results in @2012-03-31T20:00:00@, but, we want to return it in UTC (@post_zone@ is not set), so we convert it back to UTC: @2012-04-01T04:00:00Z@. Note, we are consistent in the results, returning the rounded value in UTC.

p. @post_zone@ simply takes the result, and adds the relevant offset.

p. Sometimes, we want to apply the same conversion to UTC we did above for @hour@ also for @day@ (and up) intervals. We can set @pre_zone_adjust_large_interval@ to @true@, which will apply the same conversion done for @hour@ interval in the example, to @day@ and above intervals (it can be set regardless of the interval, but only kick in when using @day@ and higher intervals).