Count distinct by field

[ghost]

Hi i have a large index of tweets and need to know the numbers of distinct authors of a selected tweets (sql: count(distinct user) ), e.g: I make a query fetching facets of tweets that use #elastic and need to know how many different users wrote on it. thank you this functionality is the only one think that mysql get me and elastic not on this project

[jpountz]

This is a feature that we plan to add to the aggregations framework, but it is taking some time because there is some infrastructure that we want to setup in order to be able to implement such an aggregation efficiently. Typically, there are some algorithms that only require hashes of the values in order to estimate the number of unique values and this is something we could leverage (by pre-computing hashes instead of computing them on the fly) to make this aggregation fast.

[davidronk]

We could also use a "distinct" feature. We currently use the elasticsearch-timefacets-plugin to do a distinct date histogram (but we are restricted to a fairly old ES version and would like to upgrade). Could there be a "distinct_value_count" added to the aggregation framework (or something similar)?

[jpountz]

We definitely have plans for this. Since last time I left a comment on this issue, we started doing experiments with an aggregation to compute unique counts under the feature/cardinality_aggregation branch. This is still work in progress and I can't give you any release date for this feature, but we are making progress!

[davidronk]

Awesome, thanks for the update! That will be very helpful!

[jpountz]

Good news, this was just pushed and will be available in Elasticsearch 1.1, see #5426 !

[davidronk]

👍

[ghost]

Great, Thank you

2014-03-13 14:26 GMT-04:30 David Ronk notifications@github.com:

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