Tag Archive for 'kdb+'

kx kdb – 2018 in Review – Changes

kdb Version 3.6 Changes: Enums and linked columns now use 64 bit indices This is a disk-format change, i.e. newly saved data will NOT be backwards compatible. 3.6 will be able to read data in the old format AnyMap – Mapped Nested Types Ability to save unmappable compound objects with >2 billion elements Mapped list […]

KX/FD Shares Fall 30%

First Derivatives Shares have fell back to a price last seen in February 2017: One cause of the fall has been a damning article by ShadowFall. Their main arguments are: First Derivatives was being priced highly as a software company It is not a software company but a consultancy. Previously good years were due to […]

kdb – 2017 in Review

Notable events this year or possibly the previous year due to incoherent memory issues: KX went open on APIs – Improved and open sourced python, R, java and kafka interfaces. Java Driver – Got some new serialization functionality PyQ – KX acquired the rights The fusion/interface/machine-learning team at kdb promise to keep bringing improvements KX […]

kdb lj ij uj joins and upgrading 2.6 to 3.x

A quick post to highlight something a lot of people are bumping into with upgrades. The joins in 3.x for uj/ij and lj all changed how they treat nulls from the keyed table. In particular nulls now by default overwrite existing values. In the past nulls from the joining table did not overwrite and left […]

Drawing the DeathStar bmp with kdb+

This post is a walkthrough of my implementation in Q of the RosettaCode task ‘Death Star’. The code is organized as general-purpose bitmap generator which can be used in other projects, and a client specific to the task of deathstar-drawing. The interface is a function which passes a map of pixel position to pixel value. […]

qStudio kdb+ GUI adds Dark Theme and Chinese Language

Based on user requests we have released a number of new features with qStudio 1.36: Download the latest ->qStudiopreferences Open Results and Charts in New Window To expand a panel into a new window click the “pop-out” icon. This will bring up the result in a new window: UTF-8 Chinese Language Support

Command Line Kdb+ Charts

sqlDashboards are included as a bundle with qStudio, part of that package is a command line utility called sqlChart that allows generating customized sql charts from the command line. Checkout the video to see how you can create a chart based on data from a kdb+ database in 2 minutes: The sqlChart page has all […]

Kdb qSQL vs standard SQL queries

Often at the start of one of our training courses I’m asked why banks use the Kdb Database for their tick data. One well known reason is that kdb is really fast at typical financial time-series queries (due to Kdbs column-oriented architecture). Another reason is that qSQL is extremely expressive and well suited for time-series […]

RSI Relative Strength Index in Kdb

In this tutorial we are going to recreate this example RSI calculation in q, the language of the kdb database. The relative strength index (RSI) is a technical indicator used in the analysis of financial markets. It is intended to chart the current and historical strength or weakness of a stock or market based on […]

jkdb – kdb Java – Running q language code within the java runtime

While doing the project euler programming challenges  it annoyed me how verbose the java answers would have to be compared to kdb. Then I got to wondering if I could create functions like til,mod,where,asc etc. in java and use them to create really short answers. Once I had the basic functions working, I wondered if […]