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Setting the TZ Environment Variable on Linux

The Update Checklist for v2015.1 recommends setting the TZ environment variable on Linux platforms and points to the manpage for tzset. This is recommended to improve the performance of Cache’s time-related functions. You can find out more about this here:

https://community.intersystems.com/post/linux-tz-environment-variable-not-being-set-and-impact-caché

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Intro

 

Please note, this article is considered deprecated, check out the new revision over here: https://community.intersystems.com/post/tutorial-websockets

The goal of this post is to discuss working with Websockets in a Caché environment. We are going to have a quick discussion of what websockets are and then talk through an example chat application implemented on top of Websockets.

Last comment 28 January 2019
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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 intended to guide you through the new JSON capabilities that we introduced in Caché 2016.1. JSON has emerged to a serialization format used in many places. The web started it, but nowadays it is utilized everywhere. We've got plenty to cover, so let's get started.

Last comment 11 January 2019
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Now, let’s say you can’t access the terminal or simply you just rather execute it from a web interface. In this article, I will show you how to execute terminal commands from a simple web page.

For example, in the image below you see how we execute $zv on a webpage:

Last comment 13 October 2016
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++Update: August 2, 2018

This article provides a reference architecture as a sample for providing robust performing and highly available applications based on InterSystems Technologies that are applicable to Caché, Ensemble, HealthShare, TrakCare, and associated embedded technologies such as DeepSee, iKnow, Zen and Zen Mojo.

Azure has two different deployment models for creating and working with resources: Azure Classic and Azure Resource Manager. The information detailed in this article is based on the Azure Resource Manager model (ARM).

Last comment 8 July 2016
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This post is dedicated to the task of monitoring a Caché instance using SNMP. Some users of Caché are probably doing it already in some way or another. Monitoring via SNMP has been supported by the standard Caché package for a long time now, but not all the necessary parameters are available “out of the box”. For example, it would be nice to monitor the number of CSP sessions, get detailed information about the use of the license, particular KPI’s of the system being used and such. After reading this article, you will know how to add your parameters to Caché monitoring using SNMP.

Last comment 20 September 2019
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This post will show you an approach to size shared memory requirements for database applications running on InterSystems data platforms including global and routine buffers, gmheap, and locksize as well as some performance tips you should consider when configuring servers and when virtualizing Caché applications. As ever when I talk about Caché I mean all the data platform (Ensemble, HealthShare, iKnow and Caché).


A list of other posts in this series is here

Last comment 22 August 2017
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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):

Last comment 23 August 2019
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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 12 July 2019
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Enterprises need to grow and manage their global computing infrastructures rapidly and efficiently while simultaneously optimizing and managing capital costs and expenses. Amazon Web Services (AWS) and Elastic Compute Cloud (EC2) computing and storage services meet the needs of the most demanding Caché based application by providing
 a highly robust global computing infrastructure.

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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 30 September 2019
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This article, and following two articles of the series, is intended as a user guide for developers or system administrators, who need to work with OAuth 2.0 framework (further referred to as OAUTH for simplicity) in their InterSystems product based applications.

Last comment 27 September 2019
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An installation or upgrade of Caché, Ensemble, or HealthShare on Windows could fail with the titled error if a newer version of the Microsoft Visual C++ Redistributable 2013 (x86) or (x64) is installed instead of version 12.0.30501.

Last comment 14 August 2017
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Class Queries in InterSystems Caché is a useful tool that separates SQL queries from Caché 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!

Last comment 9 December 2016
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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.  

Last comment 13 December 2018
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I am often asked by customers, vendors or internal teams to explain CPU capacity planning for large production databases running on VMware vSphere.

In summary there are a few simple best practices to follow for sizing CPU for large production databases:

  • Plan for one vCPU per physical CPU core.
  • Consider NUMA and ideally size VMs to keep CPU and memory local to a NUMA node.
  • Right-size virtual machines. Add vCPUs only when needed.

Generally this leads to a couple of common questions:

Last comment 8 November 2017
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The Caché System Management Portal includes a robust web-based SQL query tool, but for some applications it’s more convenient to use a dedicated SQL client installed on a user’s PC.

SQuirreL SQL is a well known open source SQL client built in Java, which uses JDBC to connect to a DBMS. As such, we can configure SQuirreL to connect to Caché using the Caché JDBC driver.

Last comment 13 July 2016
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Hello!

This article is a small overview of a tool that helps to understand classes and their structure inside the InterSystems products: from IRIS to Caché, Ensemble, HealthShare.

In short, it visualizes a class or an entire package, shows the relations between classes and provides all the possible information to developers and team leads without making them go to Studio and examine the code there.

If you are learning InterSystems products, reviewing projects a lot or just interested in something new in InterSystems Technology solutions — you are more than welcome to read the overview of ObjectScript Class Explorer!

Last comment 19 July 2019
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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!

Last comment 8 August 2017
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In this article I would like to present the RESTForms project - generic REST API backend for modern web applications.

The idea behind the project is simple -after I wrote several REST APIs I realized that generally, REST API consists of two parts:

  • Work with persistent classes
  • Custom business logic

And, while you'll have to write your own custom business logic, RESTForms provides all things related to working with persistent classes right out of the box.
Use cases

  • You already have a data model in Caché and you want to expose some (or all) of the information in a form of REST API
  • You are developing a new Caché application and you want to provide a REST API
Last comment 17 May 2018
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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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This post provides guidelines for configuration, system sizing and capacity planning when deploying Caché 2015 and later on a VMware ESXi 5.5 and later environment.

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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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I have been meaning to make a post about this topic for a few weeks and the other day an issue came in through the WRC about it so it seems this is a conversation we should be having. I want to begin by taking a few moments to explain "Why Atelier" then we can talk about what this means in the general sense for Studio and Atelier and Caché developers. We have wrestled with what to do with Studio for years. When I moved to Product Management in 2008 this was already a "thing". At the time we could not reach a consensus. Some felt Studio was fine as is.

Last comment 3 March 2016
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This week I am going to look at CPU, one of the primary hardware food groups :) A customer asked me to advise on the following scenario; Their production servers are approaching end of life and its time for a hardware refresh. They are also thinking of consolidating servers by virtualising and want to right-size capacity either bare-metal or virtualized. Today we will look at CPU, in later posts I will explain the approach for right-sizing other key food groups - memory and IO.

So the questions are:

Last comment 30 September 2019
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Hi!

I believe the simplest is (to work with csv delimited by ";"):


set file = ##class(%File).%New( "data.csv" )
    set sc = file.Open( "R" ) 
    if $$$ISERR(sc) quit    ; or do smth

    while 'file.AtEnd {
        set str=file.ReadLine() 
        for i=1:1:$length( str, ";" ) {
            set id=$piece( str, ";" ,i ) 
            write !, id  // or do smth
        }
    }
    do file.Close()

Possible options:

different variants of error handling with sc code.

Embrace while loop into try/catch block.

And what's yours?

Last comment 12 May 2016
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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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