Best Practices

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ObjectScript has at least three ways of handling errors (status codes, exceptions, SQLCODE, etc.). Most of the system code uses statuses but exceptions are easier to handle for a number of reasons. Working with legacy code you spend some time translating between the different techniques. I use these snippets a lot for reference. Hopefully they're useful to others as well.

 

Last comment 4 days ago
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InterSystems IRIS 2019.1 has been out for a while and I would like to cover some enhancements for handling JSON which might have gone unnoticed. Dealing with JSON as a serialization format is an important part of building modern applications, especially when you interact with REST endpoints.

Last comment 1 October 2019
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In this post I show strategies for backing up Caché using External Backup with examples of integrating with snapshot based solutions. The majority of solutions I see today are deployed on Linux on VMware so a lot of the post shows how solutions integrate VMware snapshot technology as examples.

Last comment 30 September 2019
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This week I am going to look at CPU, one of the primary hardware food groups :) A customer asked me to advise on the following scenario; Their production servers are approaching end of life and its time for a hardware refresh. They are also thinking of consolidating servers by virtualising and want to right-size capacity either bare-metal or virtualized. Today we will look at CPU, in later posts I will explain the approach for right-sizing other key food groups - memory and IO.

So the questions are:

Last comment 30 September 2019
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This article, and following two articles of the series, is intended as a user guide for developers or system administrators, who need to work with OAuth 2.0 framework (further referred to as OAUTH for simplicity) in their InterSystems product based applications.

Last comment 27 September 2019
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This post is dedicated to the task of monitoring a Caché instance using SNMP. Some users of Caché are probably doing it already in some way or another. Monitoring via SNMP has been supported by the standard Caché package for a long time now, but not all the necessary parameters are available “out of the box”. For example, it would be nice to monitor the number of CSP sessions, get detailed information about the use of the license, particular KPI’s of the system being used and such. After reading this article, you will know how to add your parameters to Caché monitoring using SNMP.

Last comment 20 September 2019
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Date range queries going too slow for you?  SQL Performance got you down?  I have one weird trick that might just help you out! (SQL Developers hate this!)*

If you have a class that records timestamps when the data is added, then that data will be in sequence with your IDKEY values - that is, TimeStamp< TimeStampif and only if ID1 < IDfor all IDs and TimeStamp values in table - then you can use this knowledge to increase performance for queries against TimeStamp ranges.  Consider the following table:

Last comment 6 September 2019
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Here are a few examples of conversions and operations you might need, along with links to documentation where you can learn more.

At the time I wrote this, Eastern Daylight Time was in effect for my Caché system.

How Caché keeps the time and date

Caché has a simple time format, with a longer range of recognized dates compared to some other technologies.

The current time is maintained in a special variable $HOROLOG ($H):

Last comment 23 August 2019
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The newer dynamic SQL classes (%SQL.Statement and %StatementResult) perform better than %ResultSet, but I did not adopt them for some time because I had learned how to use %ResultSet. Finally, I made a cheat sheet, which I find useful when writing new code or rewriting old code. I thought other people might find it useful.

First, here is a somewhat more verbose adaptation of my cheat sheet:

Last comment 15 August 2019
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Estimated reading time: 6 minutes
 

Hello everyone,

I was first introduced to TDD almost 9 year ago, and I immediately fell in love with it. 
Nowadays it's become very popular but, unfortunately, I see that many companies don't use it. Moreover, many developers don't even know what it is exactly or how to use it, mainly beginners.

 

 

Last comment 9 August 2019
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As a developer, you have probably spent at least some time writing repetetive code. You may have even found yourself wishing you could generate the code programmatically. If this sounds familiar, this article is for you!

We'll start with an example. Note: the following examples use the %DynamicObject interface, which requires Caché 2016.2 or later. If you are unfamiliar with this class, check out the documentation here: Using JSON in Caché. It's really cool!

Last comment 26 July 2019
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Hello!

This article is a small overview of a tool that helps to understand classes and their structure inside the InterSystems products: from IRIS to Caché, Ensemble, HealthShare.

In short, it visualizes a class or an entire package, shows the relations between classes and provides all the possible information to developers and team leads without making them go to Studio and examine the code there.

If you are learning InterSystems products, reviewing projects a lot or just interested in something new in InterSystems Technology solutions — you are more than welcome to read the overview of ObjectScript Class Explorer!

Last comment 19 July 2019
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The topic of for/while loop performance in Caché ObjectScript came up in discussion recently, and I'd like to share some thoughts/best practices with the rest of the community. While this is a basic topic in itself, it's easy to overlook the performance implications of otherwise-reasonable approaches.

Last comment 12 July 2019
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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.

Last comment 17 June 2019
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InterSystems supports use of the InterSystems IRIS Docker images it provides on Linux only. Rather than executing containers as native processes, as on Linux platforms, Docker for Windows creates a Linux VM running under Hyper-V, the Windows virtualizer, to host containers. These additional layers add complexity that prevents InterSystems from supporting Docker for Windows at this time.

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Note (June 2019): A lot has changed, for the latest details go here

Note (Sept 2018): There have been big changes since this post first appeared, I suggest using the Docker Container version, the project and details for running as a container are still in the same place  published on GitHub so you can download, run - and modify if you need to.

Last comment 12 June 2019
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Hi all. Today we are going to upload a ML model into IRIS Manager and test it.

Note: I have done the following on Ubuntu 18.04, Apache Zeppelin 0.8.0, Python 3.6.5.

Introduction

These days many available different tools for Data Mining enable you to develop predictive models and analyze the data you have with unprecedented ease. InterSystems IRIS Data Platform provide a stable foundation for your big data and fast data applications, providing interoperability with modern DataMining tools. 

Last comment 17 May 2019
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The last time that I created a playground for experimenting with machine learning using Apache Spark and an InterSystems data platform,  see Machine Learning with Spark and Caché, I installed and configured everything directly on my laptop: Caché, Python, Apache Spark, Java, some Hadoop libraries, to name a few. It required some effort, but eventually it worked.

Last comment 17 May 2019
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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.

Last comment 10 May 2019
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Intro

Most server-client communication on the web is based on a request and response structure. The client sends a request to the server and the server responds to this request. The WebSocket protocol provides a two-way channel of communication between a server and client, allowing servers to send messages to clients without first receiving a request. For more information on the WebSocket protocol and its implementation in InterSystems IRIS, see the links below.

Last comment 26 April 2019
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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
}

Last comment 13 April 2019
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Database systems have very specific backup requirements that in enterprise deployments require forethought and planning. For database systems, the operational goal of a backup solution is to create a copy of the data in a state that is equivalent to when application is shut down gracefully.  Application consistent backups meet these requirements and Caché provides a set of APIs that facilitate the integration with external solutions to achieve this level of backup consistency.

Last comment 18 March 2019
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