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lockingdbfsmbvisual-foxprodbase

Multiple users accessing VFP App / dbase database over network - slow issues

I'm currently running a VFP9 application that uses a database which is basically a folder of multiple DBF, FPT and CDX files.

Now this database is basically shared on the network (1GB network/switch/PCs) for over 50 users to access.

Now at times we are getting an "attempting to lock" message. I've inspected the hardware with no issues or bottlenecks found. Also at times over 50 people could be accessing or even writing to a specific file within the space of a few seconds.

I've come across potential issues with "Oplocks" in the Lanman area via Google but this doesn't seem to exist in Windows 2008 R2 / Windows 7. Also been reading up on SMB in general but I am at my witts end.

I don't know what to look at next? Maybe I am testing the limits of what a VFP/Dbase system can do?

Could anyone help?

Thanks Ryan

Solution

  • Could be lots of things, and could be perfectly normal Have you source code for the app ?

    " .. over 50 people could be accessing or even writing to a specific file within the space of a few seconds .." means no surprise to me you're getting locking conflicts.

    The Attempting to lock message just means more than one person trying to access the same record (or file if crude locking).

    Have the number of users increased lately ?
    Was the system designed for this volume ? Is it affecting one particular feature of the software (most likely should be), or is it all over the system in several features ?

    The technical limits for VFP are (I think 2 GB per single table) and practically it gets slow when there are millions of records (huge generalisation). Good indexing will help when tables get large

    Is this an intermittent blip on the system (Eg at Lunchtime and evening clock-out times) or is it a continuous or more frequent load on the system ?

    If you have source code you can do a lot, if you haven't you need to figure out which DBFs are being locked (they'll be the ones with lots of records in them and probably big file sizes too, when you look at the directory)

    Do you have VFP itself or is this a compiled EXE ?

    You've lots of options and things you can do, but more info needed.

    Nick