This is a posting about a particular feature of Caché which I find useful but is probably not well known or used. I am referring to the feature of Language Extensions.

This feature allows you to extend the commands, special variables and functions available in Caché Object Script with commands, special variables and functions of your own. This functionality also applies to other languages the Caché supports at the server, including Caché Basic and Multivalue Basic.

Why would I need or want to add new commands ?

The MONITOR process (also called the Caché Monitor) scans the messages in your cconsole.log file and sends you emails based on the severity of those messages. The MONITOR is configured using the ^MONMGR utility in terminal.

The MONITOR should not be confused with the similarly named System Monitor, which checks a variety of system health and performance metrics and can log messages regarding them to the cconsole.log, where they can then be scanned by the MONITOR.

This is the second article in a series on iKnow demo applications, showcasing how the concepts and context provided through iKnow's unique bottom-up approach can be used to implement relevant use cases and help users be more productive in their daily tasks. Last week's article discussed the Knowledge Portal, a straightforward tool to browse iKnow indexing results.

This week, we'll look into the Set Analysis demo, a slightly more advanced application where you'll be using the concepts identified by iKnow to organize your content into sets of documents. The original version of this demo was developed by Danny Wijnschenk & Alain Houf for an academy session at GS2015, but the app has evolved significantly since then.

Imagine that your .NET project uses the Caché DBMS and you need a fully-functional and reliable authorization system. Writing such a system from scratch would not make much sense, and you will clearly want to use something that already exists in .NET, e.g. ASP.NET Identity. By default, however, this framework supports only its native DBMS – MS SQL. Our task was to create an adaptor that would let us quickly and easily port Identity to the InterSystems Caché DBMS. This work resulted in creation of the ASP.NET Identity Caché Provider.

One of the topics that comes up often when managing Ensemble productions is disk space:

The database (the CACHE.DAT file) grows in a rate that was unexpected; or the Journal files build up at a fast pace; or the database grows continuously though the system has a scheduled purge of the Ensemble runtime data.

It would have been better if these kind of phenomena would have been observed and accounted for yet at the development and testing stage rather than on a live system.

For this purpose I created a basic framework that could aid in this task.

I saw someone recently refer to ECP as magic. It certainly seems so, and there is a lot of very clever engineering to make it work. But the following sequence of diagrams is a simple view of how data is retrieved and used across a distributed architecture.

For more more on ECP including capacity planning follow this link: Data Platforms and Performance - Part 7 ECP for performance, scalability and availability

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.

The attached file contains two $system.Event examples that processes work asynchronously using persistent queues:

• Events_Simple.prj.xml
• Events_PubSub.prj.xml - updated this example has been published on https://github.com/intersystems-ib/cache-iat-pubsub

Events_Simple

This is a very basic example that creates some worker processes and then enqueue messages to them using $system.Event.

To install the Python binding on Windows one must follow the instructions in the following:

https://blogs.msdn.microsoft.com/pythonengineering/2016/04/11/unable-to-...

The reason is that ActiveState Python version 2.7.X is built with Visual Studio 2008 and Microsoft provides Visual Studio 2008, which one must install, so that Python C extensions can be built.

I have posted to aid others in diagnosing problem with SSL/TLS connections to superserver port from .NET client executable.

The cache instance this appeared on is quite old - 2011 - so I do not know if Intersystems have added a better error message in a later version

The actual fault was due to the certificate in the %SuperServer SSL/TLS configuration having expired.

The unhelpful message that appeared in the .NET client included the following partial stack trace.

Development productivity? Isn’t it kind of an oxymoron? Anyhow, we all dream a magic tool which does the tedious job of the software development and leave the intuitive or creative part on the developer. Atelier is the next generation tool of InterSystems aiming to boost the productivity of Caché/ Ensemble based software development. Atelier is based on the popular Eclipse IDE platform, which makes available the “infinite” pool of third party tools for Caché developers. Those tools can truly boost the productivity. This short article gives some examples how third party plug-ins can help developing for Caché. It is an absolute beginner’s guide, beginner to Eclipse but experienced to Caché.

Today my customer ask me a question about how to write the MDX with a summary row however this row with different aggregate functions for each column.

We know in DeepSee analyzer has pivot table option "Summary", user can select sum, avg ... aggregate functions to get the summary row/column. However we can not specify different aggregate function for each measure column.

Here show the example to use All level and IIF function achieve that. see the example (Holefood cube in Sample namespace) below

WITH MEMBER measures.[with avg summary info] AS

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