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Dmitry Maslennikov · Aug 25, 2017

To keep your logging data even if transaction rolled back, you should have this changes journaled. Because transaction rollback works by the journal. If it happened to be journaled, it will be rolled back anyway.

And you should remember even you disabled journaling for some database, while system journaling working well. Every change which was made during a transaction will be journaled anyway.

So, how to switch off journaling, for this particular data. 

  • CACHETEMP - you can map this data to database CACHETEMP. This database not journaled even if data changed in a transaction. But the problem is, that data here will be available until server will be stopped.
  • Switch journaling temporary off, just only when logging information should be saved. You can do it with command before save, should be placed in %OnBeforeSave method 
    DO DISABLE^%NOJRN 
    and return journaling back after saving in method %OnAfterSave 
    DO ENABLE^%NOJRN
Dmitry Maslennikov · Aug 23, 2017

This possibility is not alone, it is also possible to have more than one or two databases for one namespace.

There is also mapping, for globals class packages and routines.

One of the reasons to use it is to split different parts of applications. For instance:

  • Let's say, you are a software developing company. Mostly it is enough to deliver to your customer only your compiled code, and it is easy to do it with CACHE.DAT, while a customer has database only with data. So, an update should be quite easy in this case, replace cache.dat, call some update code if needed.
  • Or, you have one application, but should have different data, by some reasons. You can use one database with code, in multiple namespaces. But each namespace will have different databases for Data.

With mapping, you have more flexibilities, like split your code in different databases. If you deliver your code to the customer but gave permission to extend some functionality. In this case, you can put customer's code to another database. Or you can split data to get better performance. If you would have so much count of writing to your database, you can split this data and place this database files to different hardware discs, you may get better writing speed. Or even some part of data in a namespace can be stored on another server and connected through ECP.

So, I can say that even could be more reasons to split data in databases. And always it depends on a project and needs.

You should read this article in the documentation about mapping to get more information about it.

Dmitry Maslennikov · Aug 20, 2017

Every event where I was last time, Global Summit, German Symposium, Evegeny used to promote Developer Community very well. And not only DC but also advertised some open-source projects which are developed on Caché with some support from InterSystems.

I have one more idea, how about to highlight people who made so much for Developer Community, by overall rating or by just last year, no matter. And everybody may see that those people could be useful to answer some questions. Or just for making personal contacts. I know that some of the leaders of DC, already know each other in person, but DC community is growing so fast, and more people joined with their own very useful knowledge. 

What do you think?

Dmitry Maslennikov · Aug 14, 2017

I fixed formatting in your post a little bit just to look it more clear and prettier.

But noticed WHERE% VID instead of  WHERE %VID, and AND% VID instead of AND %VID . And decided that it was an formatter error, which I used, but looks like it was in original SQL as well. 

So, can you add error message? For me, the first query should work, while next one will not work, because %VID will not exist.

Dmitry Maslennikov · Aug 8, 2017

CSP on, can be used either in Directory or Location directive. But you should remember the difference between them. Directory point to the physical path, while Location works with URL. As well as also possible to use DirectoryMatch and LocationMatch, which supports regex.

But with CSP on, all requests will be sent directly to CSPgateway and then to Caché. And if something not working you should check CSPGateway, sometimes it needs to be restarted, usually all parts (depends on configuration, and plus CSPnsd), after some changes in list of CSP Applications

Dmitry Maslennikov · Aug 8, 2017

Why do you think that it may help you? Do you know how much data in your database?

As 5.0 is so old I even not remember how to check the actual size of data in the Database. But I think you can do the integrity check, and in this report, you will have this information in last rows.

And then if you will have less than 10-20% of free space, I think it will not be needed for you. And with this report, you can see how big all globals in this database, and if some useless globals may be unexpectedly exists or have unexpected size. If so, you should check your code, why it could happen and remove it, so you can increase free space, which can be used then for grown useful globals.

If you will have so much free space, which you want to free, you can use ^GBLOCKCOPY, to copy all or only useful globals to the new database.

Dmitry Maslennikov · Aug 1, 2017

As far as I know .abf file format, it is just backup for MSSQL Databases. So, It is not possible and will not possible in any way. And all this conversion will not be such easy. And you should understand that Cubes, that not about data before you should migrate all the data, and create new cubes in Caché with knowledge about, how it was in MS SQL.