Article
· Jul 22, 2016 16m read
Using Regular Expressions in Caché

1.About this article

Just like Caché pattern matching, Regular Expressions can be used in Caché to identify patterns in text data – only with a much higher expressive power. This article provides a brief introduction into Regular Expressions and what you can do with it in Caché. The information provided herein is based on various sources, most notably the book “Mastering Regular Expressions” by Jeffrey Friedl and of course the Caché online documentation. The article is not intended to discuss all the possibilities and details of regular expressions. Please refer to the information sources listed in chapter 5 if you would like to learn more. If you prefer to read off-line you can also download the PDF version of this article.

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Article
· Nov 11, 2016 2m read
Caché process failures on RHEL V7.2

Caché process failures on RHEL V7.2

InterSystems WRC has investigated several issues of process failure that can be attributed to a recent change in Red Hat Linux.

A new feature implemented in RHEL V7.2 (systemd-219-19.el7.x86_64) can cause O.S. IPC (Inter-process communication) semaphores to be deallocated when a non-system RHEL user logs out (system users, i.e. with a UID number < 1000, are excluded)

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In the previous parts (1, 2) we talked about globals as trees. In this article, we will look at them as sparse arrays.

A sparse array - is a type of array where most values assume an identical value.

In practice, you will often see sparse arrays so huge that there is no point in occupying memory with identical elements. Therefore, it makes sense to organize sparse arrays in such a way that memory is not wasted on storing duplicate values.

In some programming languages, sparse arrays are part of the language - for example, in J, MATLAB. In other languages, there are special libraries that let you use them. For C++, those would be Eigen and the like.

Globals are good candidates for implementing sparse arrays for the following reasons:

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Have some free text fields in your application that you wish you could search efficiently? Tried using some methods before but found out that they just cannot match the performance needs of your customers? Do I have one weird trick that will solve all your problems? Don’t you already know!? All I do is bring great solutions to your performance pitfalls!

As usual, if you want the TL;DR (too long; didn’t read) version, skip to the end. Just know you are hurting my feelings.

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Hi guys!

Portrait of Madame X, Gustave Caillebotte.

One of the features I like in InterSystems ObjectScript is how you can process array transformations in a specific method or a function.

Usually when we say "process an array" we assume a very straightforward algorithm which loops through an array and does something with its entries upon a certain rule.

The trick is how you transfer an array to work with into a function.

One of the nice approaches on how to pass the information about an array is using $Name and Indirection operator.

Below you can find a very simple example which illustrates the thing.

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I needed to know programmatically if last ran failed or not.

After some exploring, here's the code:

ClassMethod isLastTestOk() As %Boolean
{
  set in = ##class(%UnitTest.Result.TestInstance).%OpenId(^UnitTest.Result)
  for i=1:1:in.TestSuites.Count() {
    #dim suite As %UnitTest.Result.TestSuite
    set suite = in.TestSuites.GetAt(i)
    return:suite.Status=0 $$$NO
  }
  quit $$$YES
}

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Article
· Apr 1, 2019 3m read
Closures in ObjectScript

After many sleepless nights it's a pleasure to announce the newer, better, moderner ObjectScript compiler which implemented pretty much everything you ever wanted to have in modern ObjectScript:

  • Design objective of this new compiler is to parse reasonable subset of current ObjectScript syntax which will look readable for stranger, and not scare them with 1 letter syntax. The good start for compiler was the old-good COS Guidelines from here https://github.com/intersystems-ru/cos-guidelines
  • For reasons we mentioned above we do not parse 1 letter syntax. It's declared evil;
  • We do not handle dotted syntax for the same reason - modern syntax with {} is proper replacement for dotted syntax blocks;

But we not only parse the modern ObjectScript syntax, we have implemented finally the long-standing request which we always dreamed about. Closures!

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image

The InterSystems DBMS has a built-in technology for working with non-structured data called iKnow and a full-text search technology called iFind. We decided to take a dive into both and make something useful. As the result, we have DocSearch — a web application for searching in InterSystems documentation using iKnow and iFind.

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Article
· Mar 31, 2019 20m read
How to write the home address right?

How Tax Service, OpenStreetMap, and InterSystems IRIS
could help developers get clean addresses

Pieter Brueghel the Younger, Paying the Tax (The Tax Collector), 1640

In my previous article, we just skimmed the surface of objects. Let's continue our reconnaissance. Today's topic is a tough one. It's not quite BIG DATA, but it's still the data not easy to work with: we're talking about fairly large amounts of data. It won't all fit into RAM at once, and some of it won't even fit on the drive (not due to lack of space, but because there's a lot of junk). The name of our subject is FIAS DB: the Federal Information Address System database - the databases of addresses in Russia. The archive is 5.5 GB. And it's a compressed XML file. After extraction, it will be a full 53 GB (set aside 110 GB for extraction). And when you start to parse and convert it, that 110 GB won't be enough. There won't be enough RAM either.

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InterSystems Data Platform includes utilities and tools for system monitoring and alerting, however System Administrators new to solutions built on the InterSystems Data Platform (a.k.a Caché) need to know where to start and what to configure.

This guide shows the path to a minimum monitoring and alerting solution using references from online documentation and developer community posts to show you how to enable and configure the following;

  1. Caché Monitor: Scans the console log and sends emails alerts.

  2. System Monitor: Monitors system status and resources, generating notifications (alerts and warnings) based on fixed parameters and also tracks overall system health.

  3. Health Monitor: Samples key system and user-defined metrics and compares them to user-configurable parameters and established normal values, generating notifications when samples exceed applicable or learned thresholds.

  4. History Monitor: Maintains a historical database of performance and system usage metrics.

  5. pButtons: Operating system and Caché metrics collection scheduled daily.

Remember this guide is a minimum configuration, the included tools are flexible and extensible so more functionality is available when needed. This guide skips through the documentation to get you up and going. You will need to dive deeper into the documentation to get the most out of the monitoring tools, in the meantime, think of this as a set of cheat sheets to get up and running.

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Article
· Mar 2, 2019 6m read
Belated - Advent of Code 2018 Day 1

I know it's late, but I really love the advent of code theme each year to find some project ideas to go out and code something and push myself.

I had the intentions of completing the AOC 2018 before the new year, but I've got 2 young kids (1yo and 4yo), so most nights I just want to sleep.

I've been looking at this on my half hourly commute each day before and after work.

So whilst doing this, I found not many people had posted what they had done and in previous years.

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In this series of articles, I'd like to present and discuss several possible approaches toward software development with InterSystems technologies and GitLab. I will cover such topics as:

  • Git 101
  • Git flow (development process)
  • GitLab installation
  • GitLab Workflow
  • Continuous Delivery
  • GitLab installation and configuration
  • GitLab CI/CD

In the previous article, we covered Git basics, why a high-level understanding of Git concepts is important for modern software development, and how Git can be used to develop software. Still, our focus was on the implementation part of software development, but this part presents:

  • GitLab Workflow - a complete software life cycle process - from idea to user feedback
  • Continuous Delivery - software engineering approach in which teams produce software in short cycles, ensuring that the software can be reliably released at any time. It aims at building, testing, and releasing software faster and more frequently.

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Article
· Feb 8, 2019 2m read
Client Websockets based CSP

The Caché / Ensemble standard distribution contains in namespace SAMPLES
a nice example of a CSP page consuming WebService as a Client.
I have modified it not only to display the replies but to feed them back into a Global.
I used the classic Hyperevent to achieve this. The replies end up as a log in global^WSREPLY.
When there is no input anymore the page closes and goes away.

There are 2 versions with visible and hidden display during operation.
dc.WSCSP.reverseVerbose.cls and dc.WSCSP.reverseHidden.cls

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Article
· Feb 8, 2019 2m read
Client Websockets based on Node.js

It will demonstrate the wide range that is openend by making use
of the power embedded in Node.js and its adapter to Caché, Ensemble, Health,..*
Node / JavaScript have wide reputation to work as a WebSocket client.
By using the Caché adapter it becomes easy to control it and to consume the results as a
Client for WebSocket Servers and to collect the replies in Caché, Ensemble, ..

I used node-v6.16.0-x64.msi and cache610.node as cache.node

You provide a Global for input:

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Intro

Please note, this article is considered deprecated, check out the new revision over here: https://community.intersystems.com/post/tutorial-websockets

The goal of this post is to discuss working with Websockets in a Caché environment. We are going to have a quick discussion of what websockets are and then talk through an example chat application implemented on top of Websockets.

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Headache-free stored objects: a simple example of working with InterSystems Caché objects in ObjectScript and Python

Neuschwanstein Castle

Tabular data storages based on what is formally known as the relational data model will be celebrating their 50th anniversary in June 2020. Here is an official document – that very famous article. Many thanks for it to Doctor Edgar Frank Codd. By the way, the relational data model is on the list of the most important global innovations of the past 100 years published by Forbes.

On the other hand, oddly enough, Codd viewed relational databases and SQL as a distorted implementation of his theory. For general guidance, he created 12 rules that any relational database management system must comply with (there are actually 13 rules). Honestly speaking, there is zero DBMS's on the market that observes at least Rule 0. Therefore, no one can call their DBMS 100% relational :) If you know any exceptions, please let me know.

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