Date range queries going too slow for you?  SQL Performance got you down?  I have one weird trick that might just help you out! (SQL Developers hate this!)*

If you have a class that records timestamps when the data is added, then that data will be in sequence with your IDKEY values - that is, TimeStamp< TimeStampif and only if ID1 < IDfor all IDs and TimeStamp values in table - then you can use this knowledge to increase performance for queries against TimeStamp ranges.  Consider the following table:

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It has been noticed that some customers running JAVA programs (for example, FOP) on AIX would see the server eventually running low then out of memory. Customer would notice the system pages heavily and user experience becomes bad. And the server would crash when out of memory.


When the problem happens, we can see in ipcs a lot of shared memory segment marked for deletion (Capital D at the beginning of MODE section). This means they will not disappear until the last process attached to the segment detaches it.


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Peter Everett · Sep 22, 2016 3m read
Windows write caching

(This article was reviewed in February 2021.  It is still relevant to Caché-based installations and similarly applies to IRIS-based installations.)

This article discusses the Windows write caching setting which can leave systems vulnerable to data loss or corruption in the event of power loss or operating system crash.  The setting is on by default in some Windows configurations.

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Hi Dev Community,

My team is currently working on a project where we need to post pdf documents to a 3rd party REST API.

The API specifies a field in the JSON request message to contain the 'physical content' of the file as an array of bytes, example of the JSON request as follows - data truncated for readability purposes:

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Leo Makowski · Jul 15, 2016 5m read
Zinsert and friends: Coding in terminal

              While Studio and Atelier are useful development interfaces, there are occasionally situations where a quick edit needs to be made to code and only terminal access is available.  A useful set of tools to do this are the zload, zprint, zinsert, zremove, and zsave commands.  These are abbreviated to zl, zp, zi, zr, and zs respectively.  While each of these commands has its own page in documentation, this article will synthesize that information with examples to provide instruction for their combined use.

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somehow my installation on win10 canceled during finish. "Installation of Caché finished" showed up for 20 minutes and canceled with an error I didn't saved.

Every file and service was installed but never registered as successfull installation. Now I try to reinstall it but the installer shows me everytime "Another installation is already in progress. Please finish the second installation first".

The unfinished installation is broken. I can't startup Caché from launcher. So I deleted everything in c:/intersystems

Things I already tried:

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Neerav Adam Verma · Mar 5, 2019
PrimaryKey vs Idkey

Just wondering an Insight in the difference between these two indexes

IdKey / PrimaryKey

Property Identifier As %Integer

Index Index1 on Identifier [Idkey]

Index Index2 on Identifier [PrimaryKey]

What's the difference?

1. If I don't have Index1 and only have Index2,  then cache does still make its own id.
So how and why  do I ever use the PrimaryKey.  In Joins ??

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InterSystems has identified an issue with product distributions containing Certificate Authority certificates that expire at the end of 2020. This issue does not affect system operation or system security in any way, although it does generate alerts about expiring certificates in the cconsole.log or messages.log files.

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Hi, guys,

One of my clients was required by the hospital to name their webservice operation as Action_Subject, ie. Get_PatientInfo

When I define the web method as "Get_PatientInfo" as below,

/// MyApp.MyService
Class MyApp.MyService Extends %SOAP.WebService [ ProcedureBlock ]

/// Name of the WebService.
Parameter SERVICENAME = "MyService";

/// TODO: change this to actual SOAP namespace.
/// SOAP Namespace for the WebService
Parameter NAMESPACE = "";

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Hi, guys,

I'm working on zen report to display an examination report for a client.

They stored order information in several tables. Examination findings and diagnosis were recorded in a html page and codes of the page was stored in another table. We need to put them together in one single report.

So far we can only read the html codes from that table  which is a whole page since it start from label <html> and have <header>. We know that if we are using javascript we can display the page by assigning the codes to innerHtml property of an iframe object.

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InterSystems has corrected a defect that can cause a build-up of orphaned processes consuming system resources. In extreme cases, this can cause a system to become unresponsive.

This defect affects the following versions:

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I am currently working on an Upgrade to HealthShare 2019.1.1. As described in the steps once the upgrade was complete to run $system.OBJ.Upgrade(). When I run $system.OBJ.Upgrade() , it is not finding any classes to update. However I am getting an Error 5116 on one of my Productions...

Class dictionary version for '%1' is out of date, please run upgrade utility $system.OBJ.Upgrade()


so if I am running $system.OBJ.upgrade() why isn't it updating this production as it should?

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Let Say I have 
Class Carrier Extends %Persistent

Property Employee As Array of Class Employees

Class Employees Extends %SerialObject

Property Name As %String

Property Address As Array of Class AddressDetail

Class AddressDetail Extends %SerialObject

Property Street1 As %String

Property Street2 As %String

I can get value for Employee Name  as Employee_Name.

But I want to Get Value of Address Street1 and Street2 of Class AddressDetail using SQL Query
How can I get that?

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InterSystems has corrected several critical defects that can result in data integrity issues. These defects were identified and corrected within a short time, so InterSystems has simplified the upgrade process by consolidating them into a single package. The effects of encountering these defects may not always be visible.

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