{ "name": "bitmap_estimator", "abstract": "Estimates number of distinct elements in a data set (aggregate and a data type).", "description": "Provides an alternative to COUNT(DISTINCT) aggregate, computing an estimate of number of distinct values, and a data type that may be used within a table (and updated continuously). This implementation is based on self-learning bitmap (see the paper 'Distinct Counting with a Self-Learning Bitmap' by Aiyou Chen and Jin Cao, published in 2009).", "version": "1.3.5", "maintainer": "Tomas Vondra ", "license": "bsd", "prereqs": { "runtime": { "requires": { "PostgreSQL": "9.0.0" } } }, "provides": { "bitmap_counter": { "file": "sql/bitmap_counter--1.3.5.sql", "docfile" : "README.md", "version": "1.3.5" } }, "resources": { "repository": { "url": "https://tvondra@github.com/tvondra/distinct_estimators.git", "web": "http://github.com/tvondra/distinct_estimators", "type": "git" }, "x_blog": "http://www.fuzzy.cz/en/articles/aggregate-functions-for-distinct-estimation/" }, "tags" : ["distinct", "count", "aggregate", "estimate", "bitmap", "self-learning"], "meta-spec": { "version": "1.0.0", "url": "http://pgxn.org/meta/spec.txt" }, "release_status" : "testing" }