MapInfo - Files locked for Editing

[Will]

We've been getting a few of these errors Cannot Access XXX.DAT for writing" over the last few days progressing to "File is locked for editing" errors as well when we attempt to save edits.

These are master files, native TAB, located on a network drive with access restricted to my coordinator and I. We aren't working on files simultaneously.

This has happened in the past at a previous site that was experiencing internal network capacity and stability issues. Our suspicion is that there are network issues again causing micro-dropouts (other evidence for this includes odd behaviour with Windows explorer closing when viewing network drives and short lived connection error red crosses against network connections). When these dropouts occur MapInfo obviously loses connection to the file but doesn't seem to report an error until a save is attempted.

Wondering if anyone else has experienced this and found the same cause or able to identify another cause. If the network is the problem is there anything that can be done MapInfo side to increase the network tolerance? Just trying to put together some background research before presenting this to IT.

[Warren Vick]

Hello Will,

 

A few years ago, I’ve experienced a period of this happening, but on to local rather than network drives. The culprit was some Time Machine-style passive backup software which was being a little too aggressive and, perhaps, was locking files that it had detected had changed while backing up to a network drive. So, while your problem may be one of network dropouts, do have a think about any software running on your PC which would have any business accessing your table files mid-edit. Backup software, security software, etc. I guess if your problem only shows itself on network table edits, and not local ones, that narrows things down considerably. Try looking at your power settings… for anything other than “full power” mode, Windows may try to put bits of hardware (e.g. network adaptor) to sleep and they sometimes don’t bounce back quick enough. I learned this the hard way too. ☹

 

I hope you resolve your issue soon as it’s definitely an infuriating problem.

 

Regards,

Warren Vick

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[Peter Horsbøll Møller]

Recently a customer of ours was experiences issues refreshing linked database tables.

The error was not exactly like your but in some way similar – refreshing would require Pro to write to the data files.

 

The problem turned out to be linked to their antivirus system, in this case BitDefender.

 

You could consider not checking the data files with your antivirus if that is the source of the problem

 

Peter Horsbøll Møller

Pitney Bowes

[CDR Group]

Hi Will

What version of MapInfo and Windows are you using?

John Ievers

CDR Group
www.cdrgroup.co.uk
Tel: 01433 621282
Fax: 01433 621292
Specialists in Geographic Information Systems

CDR Group is the trading name of Contract Data Research Ltd.
Registered address Eccles House, Eccles Lane, Hope, Hope Valley, S33 6RW.
Registration No. 1972326
VAT No. GB373 3117 67

[911mapper]

I will vote with Peter on anti-virus.

I do not allow [exclude] my AV [avast] past, present & future to have access to any of "my work".

That is app programming, MapInfo/MapBasic, web design, so basically it get "windows" and "program files"

Have seen network cables and bad ports in routers/switches but that being the rare "pull you hair" type with

different symptoms each time. If it is just 1 machine a good cleaning including reseating a cards, just fixed

a $2000 Dell Alianware by checking each memory chip 1 at a time and swapped the 2 and that was enough

to clean contacts.

For network open command windows and use PING [machine address] -t > ping.txt. remove [] and let

it run for a an hour or so while doing heavy work, then stop and analyze the file for any drops/failures.

Just my $0.0175 [was 2 cents]

[Eric Blasenheim]

Will,

What exactly are you doing when you get these errors? That might illuminate things a bit. MapInfo Pro will try to get an exclusive lock on files when you commit your changes.  It can't have any other process even reading the files during this process.

If any other process, MapInfo or anything else, has the .DAT file open for even reading, an error will be displayed and the commit stops.  So it could be the things mentioned here.

If it is occurring while doing something else then that would have to be investigated. 

One tool you can try is Windows Process Explorer which is much more detailed that Task Manager.    You can search for a file or dll and it will show what process is using that file or dll. Now on some systems, anti-virus processes are locked and the tool can't investigate them. Make sure you run the tool as administrator.  It is extremely helpful in identifying opened files. Note that if you are using a network file, the process holding the file might be something running on the server so the process will be a system process that is handling network requests. 

I hope this helps!

Regards,

Eric Blasenheim

Pitney Bowes Software

[rapm...@c031.aone.net.au]

Another vote for AV software interfering.

However I have this nagging thought I ran into a false positive with this error some years ago. Is your table particularly wide, eg many colums of character width 254?

Sometimes edits to tables like this throw odd errors that actually don't really indicate the issue. That being the record you're editing exceeds the maximum size a record can be in a Mapinfo table which I think is 4000 bytes. 

[Brendan Stone]

We've had similar issues in the past.

Last time it happened IT identified it as an issue with the shared drive. Whenever we wrote to the shared drive it instantly mirrored it to several other drives located in different offices. While this sync was happening the file was locked to prevent changes, but usually the sync was instant and completely transparent to the user so didn't cause any issues.

However when there were some networking issues these syncs started to really slow down and in some cases a backlog started to form which meant any files we were working on kept getting locked for hours at a time.

Once the major network issue was resolved, our problems went away - although they do occasionally come back with locks of a few seconds which I put down to a bit of network congestion.

[Will]

Appreciate all the replies. I'll try and address a few of the points raised.

Firstly - this is a decent sized corporation with a somewhat restrictive IT security policy. We do not have admin rights or even any elevated privileges on our own PCs. We do have full admin rights to our GIS server where the files that are locking are being stored. So we are somewhat limited in the investigations we can undertake, we usually collect ideas/solutiosn to our IT problems then hand them over to IT to implement (eventually).

AV - Yes we have Sophos running and this has been a culprit in other problems in the past. I'm informed that it investigates every file on open. Trouble shooting Sophos will likely be a last resort option as IT are very reluctant to relax/alter security for any person, device or drive.

Backup - We do run shadow copies  but that runs pretty infrequently and usually only at 4pm.

Power Mode - I run my laptop at full power and this same problem is occuring on a desktop PC for another user with no power management.

Network Drive syncing - This is an interesting one and something I had not considered. I'll investigate further.

Both computer affected are running MapInfo Pro 16.0.2 on Windows 10.

When we get these errors it is the moment we attempt to save any edits we have made. Last week for example I was realigning water mains against surveyed valve locations, this takes a few hours to do and as a result I progressively the TAB file I'm working on as I complete various runs, this could be anywhere between 1-minute to 20-minutes. There was no guarantee that the lock would happen at either the shorter or longer period between saves.

Eric I will look into running Windows Task Explorer on the server where we have full access.

Cheers,

Will