Mirroring 101

Caché mirroring is a reliable, inexpensive, and easy to implement high availability and disaster recovery solution for Caché and Ensemble-based applications. Mirroring provides automatic failover under a broad range of planned and unplanned outage scenarios, with application recovery time typically limited to seconds. Logical data replication eliminates storage as a single point of failure and a source of data corruption. Upgrades can be executed with little or no downtime.

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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.

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Article
· Oct 24, 2016 4m read
DeepSee Troubleshooting Guide

The goal of this “DeepSee Troubleshooting Guide” is to help you track down and fix problems in your DeepSee project.

If the problem can’t be fixed by following the guidelines, you will at least have enough information to submit a WRC issue with DeepSee Support and provide all the evidence to us, so we can continue the investigation together and resolve it faster!

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Article
· Oct 4, 2016 1m read
How to Parse a URL in Caché

How to parse a URL in Caché:

Let's pretend you are working on a project where you may be retrieving a URL for some purpose and you have the need to be easily able to parse apart that URL to get the various components that make up the URL.

Here's how to do that:

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I wanted to share a little tidbit which is in the Studio documentation (http://docs.intersystems.com/cache20152/csp/docbook/DocBook.UI.Page.cls?...) but many people who have been using the InterSystems Studio for a long time missed the addition of this *very* useful feature, and every time I mention this to an audience I see at least one face light up because of how excited they are to learn about it!

Within Studio, the Output pane (View -> Output) is actually misnamed. It is actually an Input/Output window which can be used to run Caché ObjectScript commands!

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This article will provide tips and tricks on customizing Ensemble business hosts with configurable settings.

Ensemble production Settings are configurable values that control the behavior of a production and its hosts.

The documentation for adding and removing Settings and specifying categories and controls for Settings is provided at the link:

http://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=EGDV_prog#EGDV_prog_settings

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Importance and Collection of Exact Version Information ($zv / $zversion)
The explanation of:
- why collecting $zv is important (The WHY),
- what the components of $zv mean (The WHAT),
- and how to collect $zv (The HOW).
(The Ultimate $zv Guide to the ISC Galaxy in large, friendly letters)
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Article
· Oct 18, 2016 7m read
Macros in the InterSystems Caché

In this article I would like to tell you about macros in InterSystems Caché. A macro is a symbolic name that is replaced with a set of instructions during compilation. A macro can “unfold” in various instruction sets each time it is called, depending on the parameters passed to it and activated scenarios. This can be both static code and the result of ObjectScript execution. Let's take a look at how you can use them in your application.

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Hi, Community!

You know, that when we build hierarchies in DeepSee dimension all the members of lower level should be the part of one member of the higher level.

If not you'll get some empty results in MDX queries with this hierarchy.

With Time dimensions the obvious valid hierarchy is Year->Month->Day, cause every Month consists of one Year and every day consists of one month.

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Problem:

Caché prints to printers in a manner somewhat different from other Windows applications. Caché sends the data directly to the GDI Printer, without the usual interface. This is because the GUI interface can only be shown on a system desktop session and not in web browser and terminal sessions. Some printer drivers have problems with this method of printing.

Is this the problem you are having?

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This short article was motivated by a problem of one of my customers. They use Ensemble to integrate many systems, some of them use just plain files.

So they naturally selected File Outbound Adapter to write into target file. Things were running smoothly for years, until recently, when the volume of data being written to the file reached large size of tens of megabytes. The operation took around half an hour to complete, causing timing problems where subsequent operations within the process had to wait, and third party system was not happy to wait so long.

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Process-private Globals can be used as a data global in storage definition. That way, each process can have its own objects for the class with ppg storage. For example lets define a pool, which can:

  • add elements to a pool (ignoring duplicates)
  • check if an element exists in the pool

Here's the class:

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Article
· Aug 31, 2016 1m read
DeepSee cubes building troubleshooting

Hi!

Sometimes you see that call to DeepSee cube building method:

w ##class(%DeepSee.Utils).%BuildCube("CubeName")

does nothing.

Here are my 2 cents on possible reasons.

1. Run DeepSee Reset method in certain Namespace:

NAMESPACE> w ##class(%DeepSee.Utils).%Reset()

and try again.

2. Make sure, that all the indices in your base class for the cube are rebuilt, rebuild them and run it again:

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I was recently troubleshooting a problem on a Linux (RHEL) instance of 2016.1 at a site. For policy reasons their sysadmins wanted to update the Caché installation so it used network accounts for its cacheusr and iscagent users and groups instead of the locally-created ones that had been set up during original install of Caché.

To do this they ran various commands including chown

Afterwards non-root users couldn't obtain a terminal session using the csession command. Instead they receive this message:

cache: Permission denied

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Article
· Sep 7, 2016 5m read
Running HealthShare XSLTs from Terminal

HealthShare uses a lot of XSLTs. These are used to convert IHE medical documents to SDA (internal HealthShare format) and back to IHE formats, to create summary reports, and to deal with IHE profiles (e.g., patient information query, document provide and register). Customers may customize the XSLTs to customize reports or for other reasons.

For debugging and development, it is very convenient to be able to run an XSLT from Terminal.

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This post is meant to provide a quick possible explanation for a very perplexing problem.

Scenario: You’ve just created your own administrative user in your 2014.1 (or later) instance of Caché. You gave it every possible security role (including %All), so it should in theory be able to do anything within the instance.

You’ve written a very advanced routine with a break command in it for debugging:

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We're developing Ensemble PoC and one day our frontend developer (who doesn't have Ensemble production running) said that Populate just doesn't cut it and he needs to see the real data. He needed only one object, but the problem was - it's a big object. Still, I checked ids of everything related and wrote this command (parts omitted, but you get the idea):

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