#Caché

Alex Koblov posted today a #CachéHaiku:

Full command names

Make your code more readable

Than compact versions

My haiku:

Caché Globals

Shows you keys to the value

If you $order it

Your variant? ;)

The Art of Mapping Globals to Classes (3 of 3)

If you are looking to breathe new life into an old MUMPS application follow these steps to map your globals to classes and expose all that beautiful data to Objects and SQL.

If the above does not sound familiar to you please start at the beginning with the following:

The Art of Mapping Globals 1

In the previous article, I had just started working with Arduino, and got a meteorological station to show as a result. In this article, let's go further: we will set up authentication via RFID cards and Arduino against the InterSystems Caché application.

One useful feature of our REST framework is the ability for a dispatch class to identify request prefixes and forward them to another dispatch class. This approach of modularizing your URL map will improve code readability, enable you to easily maintain separate versions of an interface, and provide a means to protect API calls that only certain users will be allowed to access.

A group of students at the Chalmers University of Technology (Gothenburg, Sweden) tried different approaches to automatically rating the quality of emergency calls, including iKnow.

Excerpt: "The most impressive results produced by iKnow is its ability to correctly classify 100% of the calls using the Average algorithm. This is quite surprising since iKnow only compares low-level concepts, how words relates to each other."

Some days ago Alberto has written a very interesting article about the usefulness of ObjectGenerators available in Caché.

This article created as side effect of preparations to the longer set of articles about simple, but still handy MapReduce implementation in Caché. I was looking for relatively easy way to pass arguments to (potentially) multiple targets via remote calling facilities. And after several attempts I have realized that we do have very powerful mechanism in the Caché ObjectScript which might be of particular help here – dynamic dispatch for methods and properties.

Question:

How do I get a list of files residing in a certain folder/directory, according to some wildcard/filter.

For example all '*.txt' files in 'C:\Temp'.

Answer:

In CACHE –

You can use the %Library.File's FileSet class query.

Here's some sample code using it (also attached):

When an error occurs in your application, simply logging it might be enough. But for certain errors, you might want to send a notification to people right away. There are three ways to generate custom email notifications from InterSystems IRIS.

** Revised Feb-12, 2018

While this article is about InterSystems IRIS, it also applies to Caché, Ensemble, and HealthShare distributions.

Introduction

Memory is managed in pages. The default page size is 4KB on Linux systems. Red Hat Enterprise Linux 6, SUSE Linux Enterprise Server 11, and Oracle Linux 6 introduced a method to provide an increased page size in 2MB or 1GB sizes depending on system configuration know as HugePages.

At first HugePages required to be assigned at boot time, and if not managed or calculated appropriately could result in wasted resources. As a result various Linux distributions introduced Transparent HugePages with the 2.6.38 kernel as enabled by default. This was meant as a means to automate creating, managing, and using HugePages. Prior kernel versions may have this feature as well however may not be marked as [always] and potentially set to [madvise].

Transparent Huge Pages (THP) is a Linux memory management system that reduces the overhead of Translation Lookaside Buffer (TLB) lookups on machines with large amounts of memory by using larger memory pages. However in current Linux releases THP can only map individual process heap and stack space.

Embedded SQL is a tool that allows us to execute SQL statements in Caché Object Script. For example, to select the name of a person with a particular SSN from the Sample.Person class we can do the following:

Hello

I have noticed that Cache (2016.1 at the time of writing) doesn't come with a systemd startup script for RHEL7.

Here is a small example script I have built.

[Unit]
Description=Intersystems Cache

[Service]
Type=forking
ExecStart=/bin/bash -c '/usr/cachesys/cstart 2>&1 | logger -t cache_start'
ExecStop=/bin/bash -c '/usr/cachesys/cstop quietly 2>&1 | logger -t cache_stop'
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

The file should be placed as /usr/lib/systemd/system/cache.service

I was recently asked whether we have a function to convert LDAP date time stamps into $HOROLOG format or other formats and the answer is not at the moment, but there is a simple method to do the conversion.

Let us look at the facts and figures involved...

1) Active Directory's (AD) date 0 (zero) is 1601-01-01 00:00:00.000 or January 1st, 1601 at midnight (00:00:00)

2) AD timestamps are calculated as the number of 100 nanosecond intervals from date 0

3) 864000000000 is the number of 100 nanosecond intervals per day

Caché Localization Manager

CLM is a tool for localization/internationalization/adding multi-language support to a project based on InterSystems Caché.

Imagine that you have a ready project where all the content is in Russian, and you need to add an English localization to it. You wrap all your strings into resources, translate them into English and call the necessary resource for Russian or English when necessary. Nothing tricky, if you think about it. But what if there are lots of strings and there are mistakes in Russian (or English)? What if you need to localize in more than one language – say, ten? This is exactly the kind of project where you should use CLM. It will help you localize the entire content of your project into the necessary language and retain the possibility to correct entries.