Long delays over company network

[W. Horton]

Here is a question that I hope someone would be able to help me understand so that I may be able to better program.

I work for a county agency. We have several offices located about 82 miles apart. From our technical services bureau, there may be as many as 16 switches, hubs, routers, etc., between each office. The main database is located in our main office. The remote office is able to access the main database through the county network. We are currently using fractional T1 lines. There are numerous tables within the database. There is one table which is the primary table from which all other tables are updated from. When accessing the database, from the remote office there is a delay of anywhere from 1 to 3 minutes. the main office has only a slight delay. The main table has approximately 250 fields and the .ddm file is approximately 4.4mb. The database has been optimized and each workstation has a copy of the shadow files. I am sure that there are a number of potentials for the delay including indeces being opened but the delay is very frustrating for the remote office. I understand that in using shadow files the request goes to the local drive thaen is redirectoed to the server, but for a script which may be only 30 lines, the delay is difficult to understand. Therefore, perhaps if I understood the way in which A5v4.5 opens and accesses files. Although the database is optimized it still appears that A5 may still be accessing some of the forms from the server instead of the local drive. There is something that is just not working right and I believe that it may be related to the way in which A5 is accessing forms.

Can anyone help with this and I can call to discuss this with anyone that truly has a good working knowledge of the way A5 works internally.

I could really use the help and perhaps this could be a problem that may help others with similar installations over long distances.

Thanks in advance.

warren

[JohnZaleski]

RE: Long delays over company network

There have been a number of threads about different ways to operate remotely. Try doing some searches on words like "remote" "terminal services" "wan" and others.

In a nutshell, A5v4.5 is not client server, so extreme slowdowns should be expected when operating over a Wan without the use of something like Terminal Services, PC Anywhere or other communication software.

Application design including the extensive use of graphics is also a factor, and certainly you would have to be optimized, but I don't think either will overcome the fact that Alpha is not client server at this time.

[W. Horton]

RE: Long delays over company network

Thank you for the reply. I did talk with our technical services bureau and discussed this problem with them. They had suggested the possiblity of using a SQL server but this is costly. Then I was told just how fast this network is; the local system is 100mbit but when it comes to the long haul to the main office, the T1 line is only 1.5mbit, thus providing some insight to such slow responses from the remote office. I had thought and noticed that when certain forms had scripts to switch to and open an index on entry, that that function may be adding to the delay. I did notice that if I assign an index to the form properties, a blue bar would appear across the bottom as the index was being built, that property has been removed. Another thought was that in the way A5 manges the forms in a shadow file, should the fomrs be stored in the .ddm file or some other one. I am referring to the file change that occurred after v1, .alm maybe?? I was thinking that although v4.5 optimizes and creates the .dd* files in the workstation, perhaps it is still reading from the network drive instead. just a thought.

Again, thank you for your thoughts.


Warren

[CALocklin]

RE: Long delays over company network

I have a customer with a similar problem.

Even when "just" running a script that only does data manipulations (copy, append, change, etc.) a 30 second operation at the main office can take about 1/2 hour at the remote office. We were told that it could be improved by upgrading the equipment at the end of the T1 line BUT it would cost about $20,000. (I don't remember what the equipment is called but I can find out if you want me to.)

The only solution we've come up with so far that stays within their budget is to set up a dedicated terminal at the server so users from the remote station can log into it with PCAnywhere via the T1 line when running the database. This basically limits them to one remote user at a time but this is seldom an issue and never a problem - there are only 3 people in the main office who might use it and they are close enough together to talk to each other.

There may be better options than PCAnywhere but they already had it so the price was right.

[W. Horton]

RE: Long delays over company network

Hi Cal

It's been a long time. Thanks for the reply, and yes some scripts seem to take longer than others. A T3 is app 45mbit and would certainly improve the speed but right now the county has it's financial problems and an additional $12,000 per month wasn't in their budget. I think that is what TSB was suggesting as the cost. Unfortunately, we run a government agency and the software is on-line by all of the on-duty personnel during their work hours. At one time we did have a dedicated line via PCAnywhere but having just one terminal to get data just won't work any more. I am still thinking that even with the optimized files on each workstation, it would appear that something is still acceessing the main dictionaries on the server, instead of the workstation, and possibly it is what is causing/adding to the delay. Optimizing did have a very positive impact to time but I had to disconnect 9 of the 11 databases that the main table posts to to help knock down the time. I was told that a SQL server may be an answer but our TSB unit did talk with A5 tech support before we purchased the runtime module and it is unclear if it would solve the problem as the overall line speed is still 1.5mbit. I am kind of wondering if the same problem exists in 5.0, but until we purchase the upgrade, I won't know.

Thanks again for your input.


Warren

[martinwcole]

RE: Long delays over company network

what about using Citrix?

[CALocklin]

RE: Long delays over company network

As Martin suggested, Citrix may be the only answer at this time.

I believe the issue is that the 'computations' must all be done on the local computer. So, even an append operation reads each record of data from the server, takes it to the local station, crunches it (checks to be sure it should be appended, etc.), then sends it back.

At least that's my understanding of why a true client/server system is so much better on networks. All the number crunching is done on the server and only the result is sent to the local workstation.

[W. Horton]

RE: Long delays over company network

Thanks Cal,

Although I am not familiar with Citrix, I will look it up o the net and let TSB know and see just how much it will cost.

Warren

[ROBERT SULLIVAN]

RE: Long delays over company network

If you have windows 2000 server I believe it comes with terminal server capabilities. I use this to trouble shoot clients alpha programs. Almost as fast as being there.

A wide area network needs terminal server or citrix to work with any kind of speed

Bob Sullivan