Tips & Tricks

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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.

Last comment 6 days ago
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Does anyone NOT use a debugger? I can't remember the last time I did. It's not because I don't dislike them, I just don't need to use them. The main reason for this is because I have a certain development methodology that either produces less bugs, catches them at a unit test level, or makes tracking them down much easier.

Here are my tips...

1. Write your own COS cheat-sheet.

Last comment 5 January 2018
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In this post I would like to talk about the syslog table.  I will cover what it is, how you look at it, what the entries really are, and why it may be important to you.  The syslog table can contain important diagnostic information.  If your system is having any problems, it is important to understand how to look at this table and what information is contained there.

Last comment 9 November 2016
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Caché offers a number of methods for going through a collection and doing something with its elements. The easiest method uses a while-loop and lets you fulfill the task in an imperative manner. The developer needs to take care of the iterator, jumping to the next element and checking if the loop is within the collection.

Last comment 4 July 2017
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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)
Last comment 15 November 2016
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In this post I show strategies for backing up Caché using External Backup with examples of integrating with snapshot based solutions. The majority of solutions I see today are deployed on Linux on VMware so a lot of the post shows how solutions integrate VMware snapshot technology as examples.

Last comment 16 November 2018
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The code of %Z.obj is available on Open Exchange.

During testing your code you are are often confronted with the need to examine
the actual content of an object. Either using ZWRITE or $system.OBJ.Dump()
you get a picture of simple properties as "--- attribute values ---"
while "--- swizzled references ---" are more confusing than informative
and with "--- calculated references ---" you are just left in the lurch.

Last comment 10 June 2019
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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!

Last comment 29 November 2018
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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.

Last comment 9 September 2016
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This is a list of all the posts in the data platforms capacity planning and performance series in order. Also a general list of my other posts. I will update as new posts in the series are added.


Capacity Planning and Performance Series

Generally posts build on previous, but you can also just dive in to subjects that look interesting.

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This post is the direct result of working with an InterSystems customer who came to me with the following problem:

SELECT COUNT(*) FROM MyCustomTable

Takes 0.005 seconds, total 2300 rows.  However:

Last comment 1 November 2016
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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!  

Last comment 5 September 2017
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Note (June 2019): A lot has changed, for the latest details go here

Note (Sept 2018): There have been big changes since this post first appeared, I suggest using the Docker Container version, the project and details for running as a container are still in the same place  published on GitHub so you can download, run - and modify if you need to.

Last comment 12 June 2019
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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.

Last comment 24 July 2017
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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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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.

Last comment 8 December 2018
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In this series of articles, I'd like to present and discuss several possible approaches toward software development with InterSystems technologies and GitLab. I will cover such topics as:

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A feature I recently used in working on ISC internal applications is the ability to send emails on behalf of someone. This is useful when generating system notifications from an application when you want some of them to show up as being from a specific person, perhaps posting comments on a work ticket.

In my case I was updating our facilities work order system for tracking requests. Normally all notification emails are sent from the same noreply email address. I wanted to change that so comments added from the original requester would show up as being from them and stand out. 

Last comment 15 March 2017
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The Management Portal allows you to Export one or more globals to a file that you can then Import into that or another namespace.  However, the Management Portal can only be used to export entire globals.  For exporting selected nodes or subtrees within a global, a different utility is necessary.   This utility is the Export() classmethod in the %Library.Global class, which can export an entire global but also has the ability to export selected nodes or subtrees.

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Caché and InterSystems other products based upon Caché are very reliable. The vast majority of our customers never experience any kind of failure. However, under rare conditions Caché has failed, and in doing so may have produced a core file (called a dump file on Windows and OpenVMS). The core file contains a detailed copy of the state of the process at the instant of its failure, including the processes registers, and memory (including or excluding shared memory depending upon configuration details).

Last comment 9 November 2016
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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:

 

Last comment 1 November 2016
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I'm sure most of you have already familiar with the possibility of using GZIP in InterSystems products. But, the problem is that GZIP working only with one file or stream, and it does not support folders. When you work in Unix systems, there is a possibility how to solve it, using tar compress tool which goes with every Linux system from out of the box. But what to do if you have work on Windows as well, which does not have it. 

I am pleased to offer you my new project isc-tar, which will help you do not care about operating system, and deal with tar files anywhere.

Last comment 18 March 2019
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Hi Community,

This article assumes that you are familiar with Zabbix and SNMP monitoring, if not, there are some very interesting posts on the Community, especially this one (https://community.intersystems.com/post/creating-custom-snmp-oids) which contains a lot of information on how to configure and request an SNMP Cache server.  

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This is the second part of my long post about package managers in operating systems and language distributions. Now, hopefully, we have managed to convince you that convenient package manager and rich 3rd party code repository is one key factor in establishing of a vibrant and fast growing ecosystem. (Another possible reason for ecosystem success is the consistent language design, but it will be topic for another day.)
Last comment 6 February 2017
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After reading Stephen Wilson's article "Windows 7 performs shutdown too fast for Cache to close and so it gets forced down" I've recalled another solution that was based on Local Group Policy, which allows to control extra actions that should occur on computer startup or shutdown. How to add a computer shutdown script is well documented in MS Technet article.

Last comment 27 October 2016
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