HLL Intersections
Why? The intersection of two streams (of user ids) is a particularly important business need in the advertising industry. For instance, if you want to reach suburban moms but the cost of targeting...
View ArticleHyperLogLog++: Google’s Take On Engineering HLL
Matt Abrams recently pointed me to Google’s excellent paper “HyperLogLog in Practice: Algorithmic Engineering of a State of The Art Cardinality Estimation Algorithm” [UPDATE: changed the link to the...
View ArticleOpen Source Release: postgresql-hll
We’re happy to announce the first open-source release of AK’s PostgreSQL extension for building and manipulating HyperLogLog data structures in SQL, postgresql-hll. We are releasing this code under the...
View ArticleDoubling the Size of an HLL Dynamically – Unions
Author’s Note: This post is related to a few previous posts dealing with the HyperLogLog algorithm. See Matt’s overview of the algorithm, and see this post for an overview of “folding” or shrinking...
View ArticleHyperLogLog Engineering: Choosing The Right Bits
Author’s Note: this is just a quick post about an engineering hiccup we ran into while implementing HyperLogLog features that aren’t mentioned in the original paper. We have an introduction to the...
View ArticleSketch of the Day: Probabilistic Counting with Stochastic Averaging (PCSA)
Before there was LogLog, SuperLogLog or HyperLogLog there was Probabilistic Counting with Stochastic Averaging (PCSA) from the seminal work “Probabilistic Counting Algorithms for Data Base...
View ArticleDoubling the Size of an HLL Dynamically – Extra Bits…
Author’s Note: This post is related to a few previous posts on the HyperLogLog algorithm. See Matt’s overview of the algorithm, and see this for an overview of “folding” or shrinking HLLs in order to...
View ArticleOpen Source Release: js-hll
One of the first things that we wanted to do with HyperLogLog when we first started playing with it was to support and expose it natively in the browser. The thought of allowing users to directly...
View ArticleOpen Source Release: java-hll
We’re happy to announce our newest open-source project, java-hll, a HyperLogLog implementation in Java that is storage-compatible with the previously released postgresql-hll and js-hll implementations....
View ArticleHLL talk at SFPUG
I had the pleasure of speaking at the SF PostgreSQL User Group’s meetup tonight about sketching, the history of HLL, and our implementation of HLL as a PG extension. My slides are embedded below and...
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