Author Topic: Remote DBMS models  (Read 2536 times)

Adam@Schneider

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Remote DBMS models
« on: November 26, 2014, 02:35:23 pm »
We are hosting our EA models on a server within our corporate network but at a remote site, we have people from all corners of the country accessing the same models on the same server.

We have a response time issue for larger or more complex diagrams (selecting and moving/updating things can take several seconds or more per item). Document generation can also be very slow. The model itself is in SQL server, running EA locally at that site over RDC is very quick. We have tried both direct SQL server (with WAN optimisations) and the cloud service, it seems like the cloud service is little more than additional security, connection management and possibly some caching, the WAN acceleration is also possibly caching, or some optimised requests. None of these really help with interactive use.

I suspect EA is doing lot of things in the background sequentially waiting for the response from one operation before starting the next. Ping times are 35-45 ms, bandwidth is not an issue.

My question is, has anyone encountered and worked through this issue?

It would be really nice if the cloud service implemented a higher level protocol that could at least bundle up lots of updates together so that the number of round trips between the client and server are reduced. Alternatively has anyone used some kind of real time data replication? Is this risky in terms of data integrity (we can put some controls in place such as package locking)?

Geert Bellekens

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Re: Remote DBMS models
« Reply #1 on: November 26, 2014, 06:43:03 pm »
Adam,

I don't think there's much more you can do.
The EA client is very "chatty" with the database server. It sends up to hundreds of small sql queries to the database to get every little piece of information.
So it is not so much the bandwith as the response time that will be the bottleneck when dealing with remote clients.

The only real alternative is to use a central version control system. Then each user can have its local model, and they check-out the parts of the model they want to work on.

Checking in/out takes a while too, but as long as you keep the size of the packages small enough it is a workable solution.

Geert

qwerty

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Re: Remote DBMS models
« Reply #2 on: November 26, 2014, 08:35:33 pm »
Network is a bottleneck and work arounds are always work arounds. You might think of using VC and EAP files for people sitting abroad. But that is on the cost of another latency when packages are checked out. Those can not be edited even if you just want to add a new connector. Another though is a merge process to be set up. That means you distribute work meaningful after making a repository structure that fits. All in all there is no silver bullet. It's hard work in each direction. The easiest and best is to have a good network.

q.

philchudley

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Re: Remote DBMS models
« Reply #3 on: November 27, 2014, 02:32:17 am »
You might want to try using version 11 and the Cloud Services

With this approach you only have one ODBC connection, that is where your DBMS is located and you your users connect to this DBMS via HTTP or HTTPS, and no changes are need to your current DBMS location etc

Hence the response time (in theory) is limited by the Internet connection.

According to Sparx, the Cloud Services has "more intelligent caching, then the multi-user direct LAN / WAN connection

Need a little configuration on the Cloud Services side, but maybe worth a try

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philchudley

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Re: Remote DBMS models
« Reply #4 on: November 27, 2014, 02:34:00 am »
Oooops sorry, should have read your post more carefully, I see you have already tried the Cloud Services,

Please ignore previous post, must be getting late in the day!

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Adam@Schneider

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Re: Remote DBMS models
« Reply #5 on: November 27, 2014, 12:02:10 pm »
Thanks, we might have a look into some kind of replication, testing on something non-production first. 90% of our EA users are new users, we are still getting our repository structure and work method standardised, throwing version control into the mix now might be a bit much for some users.

If I find something that works well I'll update, failing that we might need to set up some kind of co-located server with remote desktop for this kind of thing.

qwerty

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Re: Remote DBMS models
« Reply #6 on: November 27, 2014, 07:39:01 pm »
Good luck with that. It's a difficult task and you should prepare to try out different variants. Having a good configuration manager is definitely a plus.

q.
« Last Edit: November 27, 2014, 07:39:19 pm by qwerty »

Geert Bellekens

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Re: Remote DBMS models
« Reply #7 on: November 28, 2014, 05:44:23 pm »
Quote
Thanks, we might have a look into some kind of replication, testing on something non-production first.
Whatever you do stay far away from the built-in ms-access master-slave replication.
That works, until the point that is doesn't, and then you are in deep sh*t.
There should still be some treads on this forum of people desperately trying to get there model back in a consistent state after a ms-access replication problem.

Geert

Adam@Schneider

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Re: Remote DBMS models
« Reply #8 on: November 28, 2014, 05:49:21 pm »
Thanks, thats probably because MS Access is just a toy :)

We have our model on SQL Server (out of nothing more than familiarity with it) and we have a few experts here who can figure out what kind of replication we should use and how to set that up.