Hi Michael, Histogram aggregations return buckets that are a multiple of the interval, you are getting this weird offset because not all months have exactly 30 days. Setting "interval" to "month" should fix the issue?
On Thu, Oct 16, 2014 at 6:03 PM, Michael Herold <[email protected]> wrote: > I'm trying to use elasticsearch to give me 30-day statistics for a given > collection of models (pertinent fields are a date in *created_at* and an > integer in *value*). Currently, I have this query/aggregation: > > { > "query": { > "match_all": {} > }, > "aggregations": { > "date_histogram": { > "field": "created_at", > "interval": "30d", > "min_doc_count": 0, > "extended_bounds": { > "min": 1381881600000, // Dynamically generated for 365 days ago > (This is 2013-10-16 00:00:00 +0000) > "max": 1413503999000 // Dynamically generated for end of today > (This is 2014-10-16 23:59:59 +0000) > } > }, > "aggregations": { > "stats": { > "extended_stats": { > "field": "value" > } > } > } > } > } > > It's working as expected, except for one thing: the buckets don't line up > as expected. For some reason, *the last bucket always starts on > 2014-10-07 00:00:00 +0000, regardless of what data is in elasticsearch*. > I have tried this aggregation on a bunch of different date ranges, > including: > > - 1 model instance per day for the past 30 days > - 1 model instance per day for the past 365 days > - 1 model instance total, for a *created_at* of 2014-09-30 > - 1 model instance total, for a *created_at* of 2014-10-15 > - 1 model instance total, for a *created_at* of 2014-10-16 > - 1 model instance total, for a *created_at* of 2014-10-31 > > I have also tried to adjust the *extended bounds*, which doesn't shift > the bucket dates at all. > > The result is that the last bucket is always giving a date of 2014-10-07. > This throws off the statistics because the last bucket isn't a full 30 days > of material, whereas the rest of buckets are. > > *My questions:* > > *- Why are the buckets always pivoting around October 7th? *My > expectation is that it pivots around 30 days prior to > *extend_bounds["max"]*. > *- Is there a way to tune this?* > > Thank you in advance for any help you can give. > > -- > You received this message because you are subscribed to the Google Groups > "elasticsearch" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elasticsearch/87fe5659-50c5-4870-8139-12a680b94c9e%40googlegroups.com > <https://groups.google.com/d/msgid/elasticsearch/87fe5659-50c5-4870-8139-12a680b94c9e%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- Adrien Grand -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/elasticsearch/CAL6Z4j5STokXP_R_DMKbFeijxC-vsc6Y2-AOrZGHbon7AwLqFg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
