EDIT: This article has been updated with up-to-date information about the Port project, which now includes a tutorial for basic usage.

The Port project is something that I've introduced more than two years ago but I hadn't enough room to elaborate a tutorial on how to use it till now.


First, the motivation:

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Our team is reworking an application to use REST services that use the same database as our current ZEN application. One of the new REST endpoints uses a query that ran very slowly when first implemented. After some analysis, we found that an index on one of the fields in the table greatly improved performance (a query that took 35 seconds was now taking a fraction of a second).

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Object Synchronization is a feature that has been around for a while, since Caché days, but I wanted to explore a bit more how it works. I've always thought that database automatic synchronization is complex by nature but, for some particular scenarios shouldn't be so hard. So I considered a very simple use case (OK, perhaps the typical one, I'm not discovering anything... but if it's common and it works, it's good wink ).

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Article
· Jul 18, 2017 2m read
Old/New Dynamic SQL Cheat Sheet

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:

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Article
· Jul 31, 2019 2m read
Anti CSRF Methods

IRIS provides us with anti login CSRF attack mitigation, however this is not the same as a CSRF attack, as login attacks only occur on the login form. There are currently no built-in tools to mitigate CSRF attacks on api calls and other forms, so this is a step in mitigating these attacks.

See the following link from OWASP for the definition of a CSRF attack:

https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)

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Article
· May 31, 2017 28m read
Cogs Library

Cogs Library

Over the next few months I will be releasing a number of open source libraries and tools to the Caché community.

Most of the code has evolved from previous production grade solutions over the years and I am collating it together under a single overarching library package that I am calling Cogs.

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Article
· Jul 26, 2019 3m read
Dynamic SQL to Dynamic Object

Hello community! I have to work with queries using all kinds of methods like embedded sql and class queries. But my favorite is dynamic sql, simply because of how easy it is to manipulate them at runtime. The downside to writing a lot of these is the maintenance of the code and interacting with the output in a meaningful way.

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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!

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In this article I'll describe how to set up web services and/or REST services using EWD 3.

Since EWD 3 is designed to be modular, you can construct the environment that exactly meets your needs, but for much of the time you'll probably find that the pre-built EWD 3 ewd-xpress super-module does most of what you need because it hooks together all the core EWD 3 and other building-blocks you'll need:

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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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