#Caché

The release of IBM POWER 8 processors with AIX 7.1 introduced up to 8 SMT threads per processor core (logical or physical). Which SMT level (1, 2, 4, or 8) to use can be confusing and varies based on multiple factors. This article is meant to help with a starting point for your specific application.

Firstly, if running on a version of 2014.x or older, it is advised to use SMT 4 or lower. SMT 8 with those older versions of Cache' has shown a decline in performance and scaling in benchmarking applications.

How we can reduce the size of cache.dat file? Even after deleting the globals of a particular database from management portal size of its  cache.dat file is not reduced.

Myself and the other Technology Architects often have to explain to customers and vendors Caché IO requirements and the way that Caché applications will use storage systems. The following tables are useful when explaining typical Caché IO profile and requirements for a transactional database application with customers and vendors. The original tables were created by Mark Bolinsky.

In future posts I will be discussing more about storage IO so am also posting these tables now as a reference for those articles.

Hi

I'm using %XML.Writer to write XML files from a database source, and I see that it is not encoding carriage return or line feed as 
 and 
 respectively, and is instead leaving them unencode.

What can I do to have them encoded?

Andy

Hi, Community!

Have a question for general discussion.

In ObjectScript we have cls for classes and mac code, which both compile into int code.

Is there any reason when you use mac instead of cls for non-persistent classes?

For me the benefits for cls are:

1. Inheritance and other OOP features

2. Auto-documented code

For mac one visible benefit is easier call in terminal:

do method^Utils(p1,p2)

vs

Introduction

The field test of Caché 2016.2 has been available for quite some time and I would like to focus on one of the substantial features that is new in this version: the document data model. This model is a natural addition to the multiple ways we support for handling data including Objects, Tables and Multidimensional arrays. It makes the platform more flexible and suitable for even more use cases.

I have a couple of new namespaaces/databases that are read-only. I don't remember changing them to read-only, and although my username has %all (I installed the system), I am unable to change the "Always mount as read-only" property.

What am I missing?

Thanks,

Laura

We are building a bunch of rest based services using Ens 2016.2 to serve our browser based application (Angular 4).

Two questions:

1. The initial authentication seems only work if credentials are placed in the url parameters. Trying to use the Authorization header instead, the client code immediately complains about Access-Control-Allow-Origin. How can I resolve this?

2. After initial authentication, what is the proper way to send subsequent rest calls without having to include credential every time?

Database systems have very specific backup requirements that in enterprise deployments require forethought and planning. For database systems, the operational goal of a backup solution is to create a copy of the data in a state that is equivalent to when application is shut down gracefully. Application consistent backups meet these requirements and Caché provides a set of APIs that facilitate the integration with external solutions to achieve this level of backup consistency.

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.

In this article, I would show how you can upload and download files from InterSystems products via http.

The questions about working with files over http arise fairly often on community and I'm usually linking to my FileServer project which demonstrates file upload/download but I'd like to talk a bit more on how we can serve and receive files from InterSystems products.

I try to run below two statements

Set tRS = ##class(%ResultSet).%New("%Dictionary.ClassDefinition:SubclassOf")
​set tSC = tRS.Execute("%Persistent")

and I always get <PROTECT>check+5^%Dictionary.ClassDefinitionQuery.1

The login user is _SYSTEM and should have all the permissions.

I cannot run queries in the $SYSTEM.SQL.Shell(). I would get <PROTECT>%GenerateMetadata+16^%SQL.StatementMetadata.1

However, when I run the query through SMP, everything is fine.

Any idea where could I start to investigate ?

Thanks.

404 Not Found

{
"error": {
 "errors": [
  {
   "domain": "global",
   "reason": "notFound",
   "message": "Not Found"
  }
 ],
 "code": 404,
 "message": "Not Found"
 }
}

I want to do something like the above sample from a Google Storage JSON API. I have a call to Write obj.%ToJSON() followed by return ..ReportHttpStatusCode(..#HTTP404NOTFOUND) however the HTTP Status code is always 200. If I remove the Write obj.%ToJSON() statement it returns a 404 status with no body. How do I return both?

By now it's a commonplace how to implement a basic REST API in Caché and there is good documentation about it here: REST in Caché

A question that comes up from time to time is:

How can I make a parameter in my REST url optional?

Simply put, is it possible to create a URL map in Caché that maps a URL like this: