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#Caché

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InterSystems Caché is a multi-model DBMS and application server. See more details here.

Documentation.

APM normally focuses on the activity of the application but gathering information about system usage gives you important background information that helps understand and manage the performance of your application so I am including the IRIS History Monitor in this series.

In this article I will briefly describe how you start the IRIS or Caché History Monitor to build a record of the system level activity to go with the application activity and performance information you gather. I will also give examples of SQL to access the information.

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Article
· Feb 13, 2017 14m read
Creating custom SNMP OIDs

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.

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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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The DeclarativeCOS project is a heartfelt cry about programming in the COS language.

The purpose of the project is to draw attention of the public to improving the inner core of COS.

The idea of the project is the support of a laconic syntax for cycles and collections.

So what is this laconic something that I have come up with? Welcome to the examples below!

Examples

The key concept underlying the project is the declarative approach to writing code. You need to specify WHAT should be used and HOW.

Open Exchange app
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EDIT: This article has been updated with up-to-date information about the Port project, which now includes a tutorial for basic usage.

The Port project is something that I've introduced more than two years ago but I hadn't enough room to elaborate a tutorial on how to use it till now.


First, the motivation:

Open Exchange app
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Article
· Jul 18, 2017 2m read
Old/New Dynamic SQL Cheat Sheet

The newer dynamic SQL classes (%SQL.Statement and %StatementResult) perform better than %ResultSet, but I did not adopt them for some time because I had learned how to use %ResultSet. Finally, I made a cheat sheet, which I find useful when writing new code or rewriting old code. I thought other people might find it useful.

First, here is a somewhat more verbose adaptation of my cheat sheet:

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Article
· May 31, 2017 28m read
Cogs Library

Cogs Library

Over the next few months I will be releasing a number of open source libraries and tools to the Caché community.

Most of the code has evolved from previous production grade solutions over the years and I am collating it together under a single overarching library package that I am calling Cogs.

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In the previous parts (1, 2) we talked about globals as trees. In this article, we will look at them as sparse arrays.

A sparse array - is a type of array where most values assume an identical value.

In practice, you will often see sparse arrays so huge that there is no point in occupying memory with identical elements. Therefore, it makes sense to organize sparse arrays in such a way that memory is not wasted on storing duplicate values.

In some programming languages, sparse arrays are part of the language - for example, in J, MATLAB. In other languages, there are special libraries that let you use them. For C++, those would be Eigen and the like.

Globals are good candidates for implementing sparse arrays for the following reasons:

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image

The InterSystems DBMS has a built-in technology for working with non-structured data called iKnow and a full-text search technology called iFind. We decided to take a dive into both and make something useful. As the result, we have DocSearch — a web application for searching in InterSystems documentation using iKnow and iFind.

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Recently, a partner company started to develop an Angular client for their Cache application. Together, we decided to leverage the power of Caché dynamic objects to exchange JSON encoded data between client and server parts. However, we realized that currently there is a gap in Cache JSON implementation that prevents simple use of traditional registered and persistent classes to exposed their data with the same ease as with XML. I wrote a small JSON adapter, that does the job and bridgers the gap. It's purpose is simple expose data described by a regular Cache class in a one-to-one fashion to a %DynamicObject. On the other hand, when a serialized JSON data comes in, it can be easily deserialized into dynamic object and subsequently bound to regular class by the newly created adapter.

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Article
· Nov 23, 2017 12m read
Where is my global stored?

It's well-known that namespace global mapping helps us to write code independent on database storage details (Caché instance name, directory path). But sometimes we can face problems accessing an unsubscripted global which has subscript level mapping (SLM) defined. Most of such cases are evident and associated with administrative tasks that should be done on database level, but some of them can confuse even an experienced developer. Just to start:

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or "Bonus Breakage"

In our last lesson, we added a relationship between 2 persistent classes. We are clearly going to need to start creating REST Services to expose CRUD operations for each of these classes, but before we do that, we should really finish defining our linkages. We added code to our Widget toJSON to spool off related Accessory data, so we should really do the reciprocal and allow Accessories to return all Widgets that are compatible.

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or "Didn't you say you would cover Persistent Objects in Part 5, Chris?"

Yes, that was the plan. This is a pretty important topic, so it get's its own Article

Up until now, we've display widget JSON that has been created by a basic loop. Clearly this isn't of much value. Now we have our stack connected together, and we can see that the data is flowing to the Welcome page, it's time to complete the stack and start feeding our service from "real" data.

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Apache Spark has rapidly become one of the most exciting technologies for big data analytics and machine learning. Spark is a general data processing engine created for use in clustered computing environments. Its heart is the Resilient Distributed Dataset (RDD) which represents a distributed, fault tolerant, collection of data that can be operated on in parallel across the nodes of a cluster. Spark is implemented using a combination of Java and Scala and so comes as a library that can run on any JVM.

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Article
· Jun 12, 2017 1m read
Setting the Windows service account

I recently helped a site investigate a problem that appeared after they upgraded their Windows instance of Caché from 2015.1 to 2017.1. A terminal session launched from the server's desktop cube was unable to run OS-level commands using the $ZF(-1) function. For instance, using the no-op command "REM" as follows:

write $zf(-1,"rem")

was returning -1, indicating that the Windows command could not be issued.

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This is the first article of a series diving into visualization tools and analysis of time series data. Obviously we are most interested in looking at performance related data we can gather from the Caché family of products. However, as we'll see down the road, we are absolutely not limited to that. For now we are exploring python and the libraries/tools available within that ecosystem.

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This series of articles aims to address the following topics:

  • Creation of a web application based on REST pages;
  • Overview of some tools for tracing (debugging) HTTP requests;
  • Switching from hyperevents to... hyperevents;
  • Integration with jQuery File Upload;
  • Conversion of JSON from the {id:1,parentId:1} format to the {id:1,children:[{}]} format for tree visualization;
  • Integration with jQuery EasyUI (using datagrid and tree as examples);
  • Other topics.

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It is often necessary to sort the results of a query on a string field containing a combination of alphabetic and numeric characters. In cases like this the default string collation may not always return the data in the expected sequence.

An example of this may be where a select from Samples.Person should order the results by the street address, but firstly ordered by the street number part as numeric, and then by the street name.

The default query will return the results as follows:

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