I wanted to write it as a comment to article of @Evgeny Shvarov . But it happens to be so long, so, decided to post it separately.

Image result for docker clean all images

I would like to add a bit of clarification about how docker uses disk space and how to clean it. I use macOS, so, everything below, is mostly for macOS, but docker commands suit any platform.

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So, one day you're working away at WidgetsDirect, the leading supplier of widget and widget accessories, when your boss asks you to develop the new customer facing portal to allow the client base to access the next generation of Widgets..... and he wants you to use Angular 1.x to read into the department's Caché server.

There's only one problem: You've never used Angular, and don't know how to make it talk to Caché.

This guide is going to walk through the process of setting up a full Angular stack which communicates with a Caché backend using JSON over REST.

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Article
· May 16, 2017 3m read
The COS Faker

Hi Community,

This post is to introduce one of my first project in COS, I created when started to learn the language and until today I'm keeping improve it.

The CosFaker(here on Github) is a pure COS library for generating fake data.

cosFaker vs Populate Utils

So why use cosFaker if caché has the populate data utility?

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Article
· Mar 3, 2016 2m read
Class Projections and Projection Classes

The purpose of this post is to raise the profile of a powerful mechanism that has long been available to us, and to open a discussion about ways in which it can be used or abused.

You can read more detail about the mechanism here. To summarize, your class definition can use the Projection keyword to reference one or more projection classes. A projection class can implement methods that get invoked at key points in the lifecycle of your class.

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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):

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Some key points are emphasized in this article in order to save your time to get linux ldap client in cache working with windows AD (active directory) LDAP server.
The first thing to do is to get successful TLS connection to windows AD.
Raw tcp case is beyond of this article, there is no problem with it, it is trivial.
Windows ldap server uses port 636 for tls and this port can be used to get ldap certificate.
As we will see later there is reason for this.
linux ldap client uses STARTTLS special ldap extension to switch plain tcp to TLS only.

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When using Studio, ODBC or a terminal connection to Caché or Ensemble, you may have wondered how to secure the connection. One option is to add TLS (aka SSL) to your connection. The Caché client applications - TELNET, ODBC and Studio - all understand how to add TLS to the connection. They just need to be configured to do it.

Configuring these clients is easier in 2015.1 and later. I'm going to be discussing this new method. If you're already using the old, legacy method, it will continue to work, but I would recommend you consider switching to the new one.

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At the heart of IRIS and Cache is a very interesting database architecture that we, at M/Gateway Developments, refer to as "Global Storage". If you ever wanted to know more about the fundamentals and capabilities of this underlying database, you might want to read a major analysis we've put together:

https://github.com/robtweed/global_storage

Amongst other things you'll discover that:

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Article
· Apr 20, 2021 3m read
Why gj :: locate?

You may think it isn’t too difficult to get from label+offset^routine to the actual source line responsible for the error. For an expert it isn't that hard... most of the time. But there are enough oddities and special rules that even an expert can get it wrong, whilst spending a lot of time trying to get there.

gj :: locate is the latest tool from George James Software – it debugs any error, class or routine by converting the location of an error in compiled .int code to the corresponding location in your source, and then taking you right there.

Image this scenario…

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In Studio you could open a class directly via it's name, without having to traverse the package tree with multiple clicks until arriving at the desired class.

You would Ctrl + O or (File -> Open) and be able to simply type in the class name, for example:

You press Enter, and viola - the class is opened.

How do you achieve this in VSCode?

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InterSystems states that Caché supports at least three data models – relational, object and hierarchical (globals). On can work with data presented in relational model in a program written on C# the same way one works with any other relational DB. To work with data presented by object model in C# one needs to use .NET Managed Provider or some kind or ORM. And starting with version 2012.2 one can work directly with globals (or use direct access to hierarchical data) via Caché eXTreme for .NET.

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In my previous article, we reviewed possible use-cases for macros, so let’s now proceed to a more comprehensive example of macros usability. In this article we will design and build a logging system.

Logging system

Logging system is a useful tool for monitoring the work of an application that saves a lot of time during debugging and monitoring. Our system would consist of two parts:

  • Storage class (for log records)
  • Set of macros that automatically add a new record to the log

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Article
· Mar 5, 2021 3m read
Using ECP across IRIS and Caché

Migration from Caché to IRIS can be quite a challenge if your code is grown over many years
and probably not so clean structured as you may like it. So you face the need to check your
migrated code against some reference data. A few samples might not be a problem,
but some hundred GB of data for testing might be.

A possible step could be to have your fresh code in IRIS but leave your huge datastore on Caché and connect both environments over ECP. I have created a demo project that gives you the opportunity to try this based on 2 Docker images with IRIS and with Caché connected over ECP.

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Article
· Mar 4, 2021 1m read
What is accuracy, accuracy, recall

Accuracy rate is a measure of our prediction results, and it is a measure of how many of the predicted positive samples are actually positive.
The recall rate is for our original sample, and it shows how many positive examples in the sample were correctly predicted.
Accuracy = Predicted correctly/All
If we want to be able to retrieve as much content as possible, this is the pursuit of "recall ratio", namely A/(A+C), the bigger the better.

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While the integrity of Caché and InterSystems IRIS databases is completely protected from the consequences of system failure, physical storage devices do fail in ways that corrupt the data they store. For that reason, many sites choose to run regular database integrity checks, particularly in coordination with backups to validate that a given backup could be relied upon in a disaster.

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Index to Articles

Hi All

It's been 6 weeks since my original article sad
- - - - -but I have been busy on this project

I have been looking at/thinking about a replacement for ZEN for around 12 months but only really started in depth 4 months ago.
Also been in IT for long enough that I can "get a feel" for a product/technology and make decisions accordingly without going into great detail.
Any new technology has a learning curve and I don't want to waste time and effort on something that won't fly.
And, as always, I am looking to minimise the learning curve as I want to concentrate on delivering business benefit.

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Article
· Sep 10, 2020 3m read
How To Create "Write-Only" Code

One of the leading benefits of ObjectScript is the speed and efficiency it allows for an experienced developer. Let's look at an example of how you can benefit from ObjectScript today.

Suppose you have a class that stores the names of your users. We'll call the class Data.User, and give it a string property Name. Next, we will need a method to create a new user or update an existing one. A naive, simplistic approach might look like this example:

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As we all well know, InterSystems IRIS has an extensive range of tools for improving the scalability of application systems. In particular, much has been done to facilitate the parallel processing of data, including the use of parallelism in SQL query processing and the most attention-grabbing feature of IRIS: sharding. However, many mature developments that started back in Caché and have been carried over into IRIS actively use the multi-model features of this DBMS, which are understood as allowing the coexistence of different data models within a single database. For example, the HIS qMS database contains both semantic relational (electronic medical records) as well as traditional relational (interaction with PACS) and hierarchical data models (laboratory data and integration with other systems). Most of the listed models are implemented using SP.ARM's qWORD tool (a mini-DBMS that is based on direct access to globals). Therefore, unfortunately, it is not possible to use the new capabilities of parallel query processing for scaling, since these queries do not use IRIS SQL access.

Meanwhile, as the size of the database grows, most of the problems inherent to large relational databases become right for non-relational ones. So, this is a major reason why we are interested in parallel data processing as one of the tools that can be used for scaling.

In this article, I would like to discuss those aspects of parallel data processing that I have been dealing with over the years when solving tasks that are rarely mentioned in discussions of Big Data. I am going to be focusing on the technological transformation of databases, or, rather, technologies for transforming databases.

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Developing a Full-Stack JavaScript web app with Caché requires you to bring together the right building blocks. Previously, I outlined the basic steps to install and connect Node.js to Caché and make it's powerful multi-model database capabilites available for use with Node.js. You can use Caché as a NoSQL-, document- (with unique key-level access!), SQL- and object-database with Node.js. When developing JavaScript applications, you'll see how powerful this combination is and makes Caché a perfect fit for Node.js.

In the first part of this article series I will show how to get started with the React framework, one of the most popular frameworks currently taking over front-end development. In the next parts you'll learn how to connect a basic web app to a Caché back-end.

You'll see, it's very easy to get started with this technology - you can even compare the amount of basic knowledge you need to COS because you only need to know a few basic concepts to start!

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Article
· Feb 5, 2016 11m read
Class Queries in InterSystems IRIS

Class Queries in InterSystems IRIS (and Cache, Ensemble, HealthShare) is a useful tool that separates SQL queries from Object Script code. Basically, it works like this: suppose that you want to use the same SQL query with different arguments in several different places.In this case you can avoid code duplication by declaring the query body as a class query and then calling this query by name. This approach is also convenient for custom queries, in which the task of obtaining the next row is defined by a developer. Sounds interesting? Then read on!

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$LIST string format and %DynamicArray and %DynamicObject classes

IRIS, and previously Cache, contain several different ways to create a sequence containing a mixture of data values. A data sequence that has been available for many years is the $LIST string. Another more recent data sequence is the %DynamicArray class, which along with the %DynamicObject class, is part of the IRIS support for JSON string representation. These two sequences involve very different tradeoffs.

$LIST String Format

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Presenter: Anton Umnikov
Task: Identify your slowest SQL queries and tune them for better performance
Approach: Use InterSystems’ query profiling and analysis tools. Discuss how system configuration can affect performance

This session will show you how you identify the weakest link in your application SQL and introduce you to the fine art of tuning those queries. To do this we will take a look at InterSystems query profiling and analysis tools, as well as how system configuration can impact SQL performance.

Problem: Obscurity on how our SQL engine works

Content related to this session, including slides, video and additional learning content can be found here.

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