Is there a way to omit or skip rollback of some data changes during a transaction rollback? Maybe some sort of "autonomous transaction"?

The issue is with error logging in transaction. For example we may have in nested calls the following structure:
TS
<some code>
<error happens>
TRO 1
<error log to database>

but if this code is in another transaction, and that rolls back we lose error data.

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Have very little XML experience and have been able to manually create output. Have a need to take data that I store in a M global (example: ^TML("HDATA", ) and out put it in CCDA XML format.

Are there any examples of M code using the XMLWriter to accomplish this?

Or can anyone provide some guidance 

Any help would be greatly appreciated.

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Globals, these magic swords for storing data, have been around for a while, but not many people can use them efficiently or know about this super-weapon altogether.

If you use globals for tasks where they truly shine, the results may be amazing, either in terms of increased performance or dramatic simplification of the overall solution (1, 2).

Globals offer a special way of storing and processing data, which is completely different from SQL tables. They were first introduced in 1966 in the M(UMPS) programming language, which was initially used in medical databases. It is still used in the same way, but has also been adopted by some other industries where reliability and high performance are top priorities: finance, trading, etc.

Later M(UMPS) evolved into Caché ObjectScript (COS). COS was developed by InterSystems as a superset of M. The original language is still accepted by developers' community and alive in a few implementations. There are several signs of activity around the web: MUMPS Google group, Mumps User's group), effective ISO Standard, etc.

Modern global based DBMS supports transactions, journaling, replication, partitioning. It means that they can be used for building modern, reliable and fast distributed systems.

Globals do not restrict you to the boundaries of the relational model. They give you the freedom of creating data structures optimized for particular tasks. For many applications reasonable use of globals can be a real silver bullet offering speeds that developers of conventional relational applications can only dream of.

Globals as a method of storing data can be used in many modern programming languages, both high- and low-level. Therefore, this article will focus specifically on globals and not the language they once came from.

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Greetings,

If given a global, how can I discover information on that global?  More specifically,  how can I discover how many indices it contains?  ie:  ^G(1,2,3,4,5)   How can I discover that there are 5 subscripts within the Global ^G if I did not already know.

Please advise, and thanks in advance for everyone's time.

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Question
Confused Developer · May 27, 2017
Insert SQL

I am inserting rows in a table. This table is appearing in all namespace as I did global mapping. 

So once I run insert command from a method, it insert the rows. When I run the same insert command from other namespace, it replace the existing data in table. 

Insert command is same in all namespace but the data I m inserting is different. 

 

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Hi, Community!

Is there an option to get an archived file of globals in one command. Say for:

Do $System.OBJ.Export("Class1*D.GBL,Class2*D.GBL","data_gbl.xml")

get something like:

Do $System.OBJ.Export("Data*D.GBL","data_gbl.gz","gzip")

And also to have the convenient one click way to  import it to the namespace via terminal or Control Panel?

If anyone already has this module, share please?

It would be very convenient for import/export/continuous integration purposes cause globals can be really heavy.

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Currently, we have an application running in one namespace ("Database B") that has globals and routines mapped to another database ("Database A"). After enforcing clean up on Database A, we found that 90% of the disk is free. We would like to compact Database A and release the unused space. However, we are running OpenVMS, which seems to be the issue.

For databases consisting of only globals, we are able to use ^GBLOCKCOPY; however, we need to ensure that the routines and mappings are also copied.

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If I were trying to access an index of a global variable, what time complexity would this operation have? My understanding of languages like Java/C++ is that arrays are stored as blocks of memory so that x[15] would have a lookup time complexity of O(1) because it just goes to (address of the array + 15) and retrieves the value stored there.

How does this work in Cache where the index of a variable isn't necessarily an integer value? If I were to have a variable like the following:

x("Adam") = "Red"

x("George") = "Blue"

x("Bryan") = "Green"

etc...

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Can someone direct me to where in the documentation we can find how consumption may be calculated for global storage?

Caché Version2010.1
Operating SystemHP OpenVMS 8.4

EDIT: After receiving some responses, it seems I was unclear in my initial inquiry. I am looking to determine our rate of consumption of storage; however, I am having some difficulty in doing that.

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Currently, namespace Alpha is configured to use database AlphaDB as its global database. How would we go about having namespace Alpha configured to use database AlphaDB for its global database except where global ^Customers(CustomerId) has a CustomerId greater than 10M, which we would like to have it redirected to database BetaDB.

In other words, ^|"AlphaDB"|Customers contains all customers between 1 and 10,000,000; and ^|"BetaDB"|Customers contains all customers greater than 10,000,000. Any help would be appreciated.

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Hello.  When you export and then import a table of data, is the import smart enough to figure out if a row already exists in the new namespace, and if so update the row rather than just save/add the row?

For example, we have a table in DEV, and the same table in QA.  The DEV table has more fields than QA.  When we moved up the class, the field definitions went with the table into QA, so now the table definition is the same in both.

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NewBie's Corner Session 27 Traversing A Global with $Order Part 1

Welcome to NewBie's Corner, a weekly or biweekly post covering basic Caché Material.

Traversing A Global

Perhaps the most difficult concept in Caché/MUMPS is its Global Structure. This session and several that follow it deals with the Global Structure. However, just presenting the material will not guarantee your understanding of it. You must experiment with the data and concepts that are presented.

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We're developing Ensemble PoC and one day our frontend developer (who doesn't have Ensemble production running) said that Populate just doesn't cut it and he needs to see the real data. He needed only one object, but the problem was - it's a big object. Still, I checked ids of everything related and wrote this command (parts omitted, but you get the idea):

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Let's say I have a global named ^a and I need to export its nodes 1, 2, 3, 5 only.

Currently I write something like this:

Write $SYSTEM.OBJ.Export("a(1).gbl,a(2).gbl,a(3).gbl,a(5).gbl", "C:\Users\eduard\Desktop\a.xml")

Is there a way to write it shorter? I want to write global node once and list all the subscripts I need.

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Question
Sebastian Mueller · Aug 25, 2016
Iterate through global

Let's imagine I have a global like this:

^Users(12, "SETTINGS", "IsAllowed") = 1

^Users(41, "SETTINGS", "IsAllowed") = 0

^Users(52, "SETTINGS", "IsAllowed") = 1

Now I would like to check for each user whether they are allowed, therefore I'd need to iterate through the Global. How to do that? It seems that I can't use $Order here like such:

S FF = ""
For {
 S FF=$O(^Users(FF,"SETTINGS","isAllowed"))
 Q:$L(FF)
 W "User ",FF," is allowed",!
}

Is there any other way of doing this? 

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