Suppose you have a key like (page, geo, day) and you want to make rollups/datacube so you can query for all pages, or all geos or all days.
Here is how you do it:
def opts[T](t: T): Seq[Option[T]] = Seq(Some(t), None)
val p: TypedPipe[(String, String, Int)] = ...
p.sumByLocalKeys
| // transcribed from an Apache Spark 1.0 spark-shell session | |
| // using data from http://chriswhong.com/open-data/foil_nyc_taxi/ | |
| // and the QTree algorithm for approximate quantiles over large datasets | |
| // each of the distanceRange and minutesRange calculations below takes about 15 minutes on my four-core SSD-based Macbook Pro | |
| import com.twitter.algebird._ | |
| import com.twitter.algebird.Operators._ | |
| implicit val qtSemigroupD = new QTreeSemigroup[Double](6) | |
| val in = sc.textFile("trip_data") // a directory containing all the trip_data*.csv files downloaded from the above link |
| ADD JAR /opt/cloudera/parcels/CDH/lib/hive/lib/hive-contrib.jar; | |
| ADD JAR /opt/cloudera/parcels/CDH/lib/hive/lib/avro-mapred.jar; | |
| DROP TABLE raw_log; | |
| CREATE EXTERNAL TABLE raw_log( | |
| IP STRING, | |
| timestamp STRING, | |
| URL STRING, | |
| referrer STRING, |
| #!/bin/bash | |
| ## davfs2 installation and Box.com account configuration script for Linux | |
| ## Tested on Ubuntu, Fedora and OpenSuse | |
| ## Update 1.032615 | |
| ## This script must be run as root | |
| if [ ! $UID = 0 ]; then | |
| echo "This script needs super user privileges to run" | |
| echo "run it againg using sudo or login as root" | |
| exit 1 |
As I discussed in Algebra for Analytics, many sketch monoids, such as Bloom filters, HyperLogLog, and Count-min sketch, can be described as a hashing (projection) of items into a sparse space, then using two different commutative monoids to read and write respectively. Finally, the read monoids always have the property that (a + b) <= a, b and the write monoids has the property that (a + b) >= a, b.
##Some questions:
| MIT License | |
| Copyright (c) 2014 Piotr Kuczynski | |
| Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: | |
| The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. | |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWAR |
| groupBy('source) { | |
| _.sortBy('links) | |
| .reverse | |
| .mapStream[(String,Int), (String, Int, Int, Int)] | |
| (('destination, 'links) -> ('destination, 'links, 'rank, 'gap)) { destLinks => | |
| destLinks.scanLeft(None: Option[(String, Int, Int, Int)]) { | |
| (prevRowOut: Option[(String,Int,Int,Int)], thisRow: (String, Int)) => | |
| val (dest, links) = thisRow | |
| prevRowOut match { | |
| case None => Some((dest, links, 1, 0)) // rank 1, gap 0 -- not exactly what you wanted... |
| import com.twitter.scalding._ | |
| import com.twitter.algebird.{ MinHasher, MinHasher32, MinHashSignature } | |
| /** | |
| * Computes similar items (with a string itemId), based on approximate | |
| * Jaccard similarity, using LSH. | |
| * | |
| * Assumes an input data TSV file of the following format: | |
| * | |
| * itemId userId |