I have been replicating for a while now with cloud systems to our in-house server using Universe and before that Unidata. However, one of our clients asked if you could have the publisher be a subscriber too? And could the subscriber be a publisher too?

Posted at: 02-10-2024 10:12

Hi Doug,

A given UniVerse system can be both a publisher and a subscriber. However, a given UniVerse file can either be published or subscribed. But not both. That is, Replication does not support publishing to a subscribed file and having that subscribed file publish to another file. But there is no restriction on a individual UniVerse system having both the role of a publisher and a subscriber. We do have customers using this capability today. 

Thanks,

Neil

So that means if I have two systems running the same files, they cannot update each other? Correct?

Posted 02-12-2024 14:19

If the question is for example whether a CUSTOMER file on System A can publish to the CUSTOMER file on System B. And that the CUSTOMER file on System B could publish back to the CUSTOMER file on System A. You are correct. This can NOT be done. 

If I misunderstood the question, please clarify.

Thanks,

Neil

Now that I understand this. If I have two systems running the same software with a single customer let us say for the sake of argument that the data in each system is unique. Do you set a third system to be a subscriber from those two systems so that all of the data from both will reside in the third system, correct?

Posted:  02-12-2024 17:42

Are you asking if the two publishers could publish to a single file on the subscriber?

While I haven't tried that, not sure Replication would allow the same file to be defined in 2 different replication groups. That is, one for each publisher. Might have to give it a try to confirm the results. 

If replication does not permit a file to be the target of two replicated files, you could set "allow triggers" on one target file and have a trigger write to the other target on the subscriber.

I was thinking more along the lines of having 2 intermediate files be the subscribed files. And each of these would have a trigger or index subroutine writing the updates to a consolidated file. But I see what you are suggesting. Have one file receive the updates normally, and have the second file use a trigger to write updates into the file being replicated normally. That would eliminate an extra file. 

Hi Brian,

The default behavior for a file on the subscriber is that it is read-only for all processes other then the uvrw processes.

However, you can configure the file as SUB_WRITEABLE in repconfig which would remove the read-only restriction.

Thanks,

Neil