Access local front-end connected to Azure SQL Server back-end very slow

Solution 1:

Well, the reason why using Azure is slower than running Access connected to a local instance of SQL server is because, well slow is slow!

I mean, if you going to travel 30 miles, you have a choice to walk, or to take a car.

So here is the question you need to know:

Why is walking slower than driving a car?

Answer: Because you are travelling at a slower speed!

So why is using Azure slower the using an instance of SQL server running on your local computer or local network?

Answer: Because the connection speed to Azure is about 100 times slower!

The idea here that you not going to take into account the DIFFERENCE in connection speed is the issue here. It is a disservice to the reading public that may conclude that such a setup (Access front end on a pc to Azure instance of SQL server) is not a viable setup.

So the first issue here is to make a note of your connection speed to the back end database.

A typical office local area network has a speed of 100mbits, or today most are 1gig – even the el-cheapo routers you purchase at Best Buy are now rated at 1gig (1000 mbits).

However, your typical high speed internet is rated at about 5, or 10 mbits. So that is 100 times slower. (Actually 1000/5 = 200 times slower!!!).

That means if something NOW takes 3 seconds on your office network with Access and SQL server? Well then a WAN (over the internet), then you need to multiple the time by the change in your connection speed (this is so simple – yet it seems to escape all!). So, if you lucky, you might have a 5 mbits speed rating for your internet. That means you go

1000 / 5 = 200

You now take the 200 and multiple the existing delay you have of say 3 seconds and you get 600 seconds (that is 10 minutes if you are wondering!). So you going from 3 seconds to 10 minutes!

This kind of comparison in speed would be like walking into a sports shop to purchase a rubber boat to cross the Atlantic. So not taking into account the change in internet speed and wondering why things are slow is the issue here.

You can most certainly use Access to Azure, but you have to realize two simple concepts.

1. a connection and test with a connection that is 50-200 times slower than your LAN is a test that going to run 50 to 200 times slower! The failure to mention and take into considering the MASSIVE DIFFERENCE in your speed connection of your LAN compared to a WAN is the simple issue here.
2. opening a form bound to a large table of data is going to case performance issues.

I was sitting at the bus stop talking to a 90 year old granny lady. I asked her the following:

Have you ever used an instant teller? She said, why yes, I use them all the time.

I then asked here don’t you think it would be bad to have the teller machine download all the peoples accounts while you wait and THEN ask you for your account number?

The old lady stated, of course, that would be silly. I type in my account pin and the machine ONLY downloads my account information – this is practical and obvious.

In other words that old lady realised that downloading a bunch of data BEFORE you the user even types in or does anything is a waste of bandwidth.

So you never want to launch a form bound to a table and THEN ask the user what record to work on. Why have Access download large numbers of records into a form and THEN ask the user or allow the user to navigate to the required record?

Even when using Google, it does not download the whole internet into your web browser page and you then go ctrl+f to search the contents of that web page.

The same concepts should be applied to Access applications. A design that asks for what to work on and then launches a form bound to a table with a "where" clause will thus fix this issue.

So if you have a form (and even a sub form) that displays a customer invoice, you would FIRST ASK FOR the invoice number, and then simply launch that form using a where clause that restricts the form to the ONE invoice!

Keep in mind that you can STILL use that invoice form bound to a table of 1 million rows and ONLY THE ONE record will be pulled down the network connection *if one used the where clause.

So a typical internet connection has adequate speed to run a browser, and also has MORE than adequate bandwidth speed to pull down a few records. Access often gets a bad rap for poor performance, but that is ONLY DUE to Access developers IGNORING the obvious advice that downloading tons of things that you don’t yet need into a form will run slow.

So web based applications, or even desktop applications written in vb.net perform well with SQL Azure running in the cloud over that MUCH slower internet connection because those applications don’t launch forms bound to large datasets WITHOUT FIRST simply allowing the user to request what they need to see and view.

As for Access and using SharePoint? That setup can be VERY fast, and in fact MUCH faster than SQL Azure, MySQL or any traditional database system because when you using SharePoint tables and Access, then Access automatic syncs a copy of the data local. This setup means your application will continue to run WITHOUT ANY internet connection. The instant the connection is restored, then the data sync can resume.

This means that if you have a table with 15,000 rows and run a report on that data the report can run and launch in an instant with SharePoint back end since a local copy of the data exists in the front end at ALL TIMES! So this setup is VERY well suited an off line mode or in cases that you have a poor and slow internet connections since you as noted always have local copy of the data – only when a record is changed does a sync occur, and that sync can occur independent of Access. So you change one record – and it starts syncing with SharePoint.

However for larger data sets that have to be updated, then SQL server is far better since you can execute a sql update on 10,000 rows and ZERO network traffic and transfer of data need occur to update those 10,000 rows when using SQL server (a pass through query) and when using SharePoint, the 10,000 rows WILL transfer over the network since the local copy requires the rows to be updated. So that massive advantage of using SharePoint for the database backend does not exist for applications that have to update lots of rows or do lots of row update types of data processing.

So the key concepts and take away here:

The high speed internet connection you have is often 10-200 times slower than your typical cheap office (local) network. So that means a 2 second operation will now take 10-200 times longer.

The Access application needs to be optimized to avoid things like loading too many records into a form. So building search forms etc. That FIRST ASK the user what they need to work on is a basic and simple requirement for all good developers and that includes Access developers.

Access and SharePoint can be the BEST option, and such a setup allows the application to run EVEN WHEN there is no internet connection at all. If table sizes are below say 10,000 rows, then this setup can often be ideal. However for applications that have to update lots of rows and for data processing heavy applications this setup is poor since updates to any rows will case data syncing to occur over the network. This setup is also the cheapest, since a single office 365 account with SharePoint support for Access can be had for $6 per month, and that $6 account allows up to 500 free users and those 500 users can even use their Gmail or non-Microsoft account for this setup. And such access applications that do fit within the bounds of SharePoint tables tend to need far less changes and optimizing then using SQL server over the internet.

With SQL server, use of views, pass-tough query and in some cases writing store procedures allows updates and code to run WITHOUT using ANY bandwidth. So one can send a single update query to the server that updates 10,000 rows of data – the only network cost will be the “tiny” amount of bandwidth to send that sql statement.

So while bound forms can be used with SQL Azure running in the cloud, one needs to build software like those do for the web, or vb.net in which they FIRST ask the user what account or customer to work on and THEN launch the UI to display that given data.

So in access, you build a search form say like this:

So at the end of the day, it is important to ignore posts here that suggests Access to SQL in the cloud is not viable. Access with proper designs will work rather well over typical internet connections to SQL server running on Azure.

In fact I seen people use Access to SQL over a 56k modem!

One has to adopt sensible designs in which the data pulled for a given task is restricted – this is a hall mark of all developers – the only issue is Access does NOT enforce this approach while most other developer tools don’t let you hang yourself with things like bound forms to large tables! It not that Access is slow, but Access is slow when you make poor design decisions.

Access to SharePoint can be a real winner – especially for poor bandwidth, spotty bandwidth and even when the connection is lost, the application will continue to run and run faster than 99% of the cases if you were running the same application with a SQL back end. There is a BIG caveat here since only certain types of applications will work well with SharePoint tables. For me to explain the why, how, and when such applications are better is beyond a simple post here, but one simply needs to be aware that SharePoint can be incredible solution, but not for all applications and SQL server can and will be better choice. This SharePoint “better” choice can only be determined on a case by case evaluation of the given type of application in question.

Solution 2:

The problem is simply that Azure SQL Database is not very fast running with small DTUs (Database Transaction Units) compared to, say, an in-house instance of SQL Server hosted on even a moderate modern server.

I've checked it out too, and it requires extremely careful design of queries and filtering - far from what you normally can get away with - to obtain acceptable overall speed. On the other hand, this is a giving experience that will bring focus to potential bottlenecks you otherwise wouldn't encounter before it might be too late.