The LAN which has about a half dozen windows xp professional pcs and one windows 7 professional pc.
A jet/access '97 database file is acting as the database.
The method of acccess is via dao (DAO350.dll) and the front end app is written in vb6.
When an instance is created it immediately opens a global database object which it keeps open for the duration of its lifetime.
The windows 7 machine was acting as the fileserver for the last few months without any glitches.
Within the last week what's happened is that instances of the app will work for a while (say 30 mins) on the xp machines and then will fail on database operations, reporting connection errors (eg disk or network error or unable to find such and such a table.
Instances on the windows 7 machine work normally.
Moving the database file to one of the xp machines has the effect that the app works fine on ALL the xp machines but the error occurs on the windows 7 machine instead.
Just before the problem became apparent a newer version of the app was installed.
Uninstalling and installing the previous version did not solve the problem.
No other network changes that I know of were made although I am not entirely sure about this as the hardware guy did apparently visit about the same time the problems arose, perhaps even to do something concerning online backing up of data. (There is data storage on more than one computer) Apparently he did not go near the win 7 machine.
Finally I know not very much about networks so please forgive me if the information I provide here is superfluous or deficient.
I have tried turning off antivirus on the win 7 machine, restarting etc but nothing seems to work.
It is planned to move our database from jet to sql server express in the future.
I need some suggestions as to the possible causes of this so that I can investigate it further. Any suggestions would be gretly appreciated
UPDATE 08/02/2011
The issue has been resolved by the hardware guy who visited the client today. The problem was that on this particular LAN the IP addresses were allocated dynamically except for the Win 7 machine which had a static IP address.
The static address happened to lie within the range from which the dynamic addresses were being selected. This wasn't a problem until last week when a dynamic address was generated that matched the static one and gave rise to the problems I described above.
Thanks to everyone for their input and thanks for not closing the question.
Having smart knowledgeable people to call on is a great help when you're under pressure from an unhappy customer and the gaps in your own knowledge mean that you can't confidently state that your software is definitely not to blame.
I'd try:
Validate that same DAO and ODBC-drivers is used on both xp- and vista machines.
Is LAN single broadcast domain? If not, rewire. (If routers required make
sure WINS is working)
Upgrade to ms-sql. It could be just a day of well worth work, ;-)
regards,
//t
Related
I have a problem that i have a difficult time explaining, which makes any online search very hard. Here is my dilema.
I'm migrating a VM. The purpose of this machine is to compile send out daily/weekly/monthly reports. I know there are other ways (like Power BI) but this is the situation we are in right now. The older machine has win10 pro and office 365 installed while the new has win10 enterprise version and office 2016 installed. This machine runs 24/7 in the background running specific tasks (via system scheduler app) at given times, that is it's a Virtual machine and has done so without issues since it was created. The reason for the migration is because we need to domain change and bring the machine under a new corporate policy and we don't want to do this on a live server.
We've set it the VM's the same way, same programs and same settings. Everything seams to be running smooth expect for this one thing, and here is the problem i have a hard time to explain or figure out:
MS Access will update the tables and the computer will run the tasks as set but it will not export the data to pdf unless i have a remote desktop connection open. Will not export the pdf's otherwise. MS Access uses a autoexec macro where the pdf export is set with ExportWithFormatting. This works without issues on the old server.
We thought this to be a permission or user specific issue at first but even re-creating the tasks did not work and changing paths. Otherwise also i expect we would have problems with tables updating, specially since it works when you have an active remote desktop conn running.
I'm lost and therefore hoping this community will be able to help or guide me to a solution.
I believe that we found the reason for this. It was caused by windows easy print and the printer drivers of the machine. It worked for some reason differently between the servers. after reinstalling the printer drivers and a few restarts it started working. It exports now from access again.
This is at least solved.
We have multiple applications developed in Visual Foxpro 8.0 running in a data center on Windows 2008 R2 on VMware. We also have a Citrix farm on the same network where users run yet another VFP 8.0 application in Citrix sessions. All applications share the same set of data tables located on a file server (also Windows 2008 R2 VM). Virtual hosts are connected by 10Gb LAN (managed switch).
Since mid-July we started seeing random 1104 "Error reading file..." errors on multiple different applications on multiple servers. All of them reference different files on the file server.
The problem started mid-July and it frequency gradually increased. Earlier it was most frequent in the afternoons by 3 pm, now it happens from early morning till late afternoon. It affects EDI servers (these run batch jobs in unattended mode) and Citrix servers and a variety of applications. It occurs when a VFP application (any of them) tries to open a database container file or individual tables most often with USE command but some times executing a SQL Select statement, or when loading a VFP form that opens tables in DataEnvironment
We caught a moment when the same exact error happened on two different servers running different applications at the same exact moment (up to a second). We also saw two different applications running on the same computer erroring out at the same moment.
We replaced the file server with a new virtual machine with no relief (we since changed it back to the old file server ).
We disabled the antivirus.
We updated VMware on all hosts to the latest version.
Sysinternals Process Monitor displays "INVALID_NETWORK_RESPONSE" event when the error occurs.
We captured traffic on both the server side and client side when the error occurred and had it analyzed by a network analysis specialist. He observed a peculiar pattern, where client OS starts retrieving the file in question from the file server AFTER VFP application had thrown an error. It seems that VFP application requests a file from OS, then it either gets an abnormal response or just times out and only after that the OS sends packets requesting the file. Again, this happens sporadically.
OpLocks and SMB2 have been disabled on all computers both on the server and client side of the equation for many years and everything was running smoothly until now...
Any advice would be greatly appreciated.
My first piece of advice would be to re-enable OpLocks and SMB2. There is no reason to mess with either of those items as things stand today and you are losing a huge amount of performance running at SMB1 level.
In my experience these issues have almost always been caused by one of the following.
Antivirus/antimalware software.
Replication or online backup software like MozyPro.
The Windows Search indexing service.
You should consider installing the Windows 7 / Server 2008 R2 Enterprise Hotfix Rollup if you haven't already.
That problem mostly related by SMB2!
Some Antivirus Software!
Windows updates! If you use VFP apps by DBF/DBC file. Do not update your system/OS. That is my personal suggestion. Windows Server 2012+ or Windows 10+ prorbably would big problems at near future.
And the point high probably is:
What is your I/O request per secs? if your IO request bigger than 1000~2000 per secs for a dbf file that is a bottle neck; and your storage device is HDD -> you need to switch/update your HDD to SSD. I suggest m.2 pro series SSD.
I'm having a problem with vfp9 on Windows 7 64-bit. I've found that create sql view is taking 5-6 seconds. These happen instantaneous in XP. When my app starts up, I'm doing a few of these, so in Win 7, my app is taking 30+ seconds longer to start up than in XP. My views look like this:
create sql view MyView remote connection MyConn as select * from MyTable
I've also found that calling dbsetprop is adding another 1-2 seconds in Win 7. Again its instantaneous in XP.
dbsetprop('MyView.MyPk', 'Field', 'KeyField', .T.)
dbsetprop('MyView.MyPk', 'Field', 'Updatable', .T.)
Once created, the views work as they should. No slowness on with platform.
Does anyone have any ideas about what I could try or any info on what is/could be causing this?
Thank you in advance.
I don't know why as I haven't worked with Windows 7 yet with VFP... However, what I would check within VFP and try changing some settings to see if it helps.
From the VFP/IDE menu, go to Tools, then Options. On the multi-tab form, click on the "Remote Data" tab.
I don't know if/what its trying to do, but maybe for testing, make sure the "Records to fetch at a time" is NOT set to "All" (checkbox).
I would also look into SQLSETPROP() function to see if any of those settings might help.
I can't reproduce this on Windows 7 64 bit, either with VFP9 RTM or VFP9 SP2. I don't have a database of any size to work with but on the sample database Northwind the commands you list seem to work instantaneously.
A couple of questions:
Is this reproducible on any machine running Windows 7?
Where is your database? Is it on the local machine, a local network, or the internet?
There seems to be more scope for speed problems with Windows 7 and Visual FoxPro (and similar) applications, and I think this is down to the different network stack in Windows 7, immature network card drivers, an increased susceptibility to cabling and network switch problems, or any combination of these.
Ensure that all your Windows 7 boxes are on SP1 (and any Server 2008 boxes with shared DBF files also), as this fixes a file corruption issue that affected Visual FoxPro indexes.
Ensure that your network card drivers are 100% up to date. This can make a big difference.
One thing that I have seen which can give a massive improvement to the speed of networked Visual FoxPro applications is the network card driver Interrupt Moderation setting. This is present on Intel, Broadcom and many other NICs, although with possibly slightly different names.
I have personally seen situations where disabling this has changed a networked VFP application from taking 30 seconds to start to about 6 seconds.
Found the solution.
Write caching was being disabled on the drive by the raid controller software included with the machine.
Write caching was enabled under Device Manager > Disk Drive > Properties > Polices. However the software was overriding this setting.
It can be reproduced without the raid software by unchecking it in Windows 7 Polices.
This week I’m going to try and start the move from Windows XP to Windows 7 on my development PC at work. I’ve downloaded the Windows Easy Transfer app for going from XP to Win7; that should take care of My Documents. My concern is all of the development environment. In particular I’m concerned about re-establishing things like my Windows services, which host my WCG services, etc. They use TCP and various ports. Plus there are the various ASP.NET apps that are on my machine. What caveats should I be aware of, before I start this?
I deeply don't recommend you to migrate. If I were you, I'd backup these files, format the PC, reinstall everything back again and re-set up the websites. No matter how much pain that may cause, it's still less pain then the potential one you might get if you use this migration tool rather than doing it properly, which would eventually cause you to do the right way anyway.
I am trying to set up a clean vm I will use in many of my devs. Hopefully I will use it many times and for a long time, so I want to get it right and set it up so performance is as good as possible. I have searched for a list of things to do, but strangely found only older posts, and none here.
My requirements are:
My host is Vista 32b, and guest is Windows2008 64b, using Vmware Workstation.
The VM should also be able to run on a Vmware ESX
I cannot move to other products (VirtualBox etc), but info about performance of each one is welcomed for reference. Anyway I guess most advices would apply to other OSs and other VM products.
I need network connectivity to my LAN
When developing/testing, guest will run several java processes, a DB and perform some file I/O
What I have found so far is:
HOWTO: Squeeze Every Last Drop of Performance Out of Your Virtual PCs: it's and old post, and about Virtual PC, but I guess most things still apply (and also apply to vmware).
I guess it makes a difference to disable all unnecessary services, but the ones mentioned in 1 seem like too few, I specifically always disable Windows Search. Any other service I should disable?
You can try to run the CD/DVD through vLite to remove unwanted crap. I'm not 100% sure if Windows 2008 server is supported but you could give it a try. I've successfully stripped down XP with nLite to about 200MB with only the bare minimum I need for testing software. You might be able to do something similar to Windows 2008 with vLite.
My host is Vista 32b, and guest is
Windows2008 64b,
First mistake. Seriously, why not running 64 bit even on Vista? This would give your VM a good memory space to work with, while now even if it is possible with VmWare it goes through really nasty API's in the Windows layer.
That said, why use Vista as host? Why not directly load a 2008 R2 host, configure it into workstation mode (heck, you even get our friendly AERO if you install all the things the server leaves out per default) and be happy with it?
I guess it makes a difference to
disable all unnecessary services,
Hm, seriously? I run a couple of Hyper-V hosting servers on top of physical domain controllers without any reconfiguration and with good enough (i.e. great) perforamnce. Helps I dont ahve the typical workstation bottleneck (i.e. one overloaded hard disc). I never found a reason to disable any service for squeezing the last performance out.
Guest will run many java processes, a
DB and perform lots of file I/O
Well, get proper hardware for that. I.e. a hardware RAID controller, and a LOT of drives - in accordance with your needs. DB is IO sensitive. VERY sensitive.