Non-filepro files

[Jeff Harrison]

--- On Mon, 10/13/08, Nancy Palmquist <nlp at vss3.com> wrote:

> From: Nancy Palmquist <nlp at vss3.com>
> Subject: Non-filepro files
> To: "filePro List" <filepro-list at lists.celestial.com>
> Date: Monday, October 13, 2008, 3:22 PM
> Fellow FilePro experts,
> 
> I have a non-filepro file that is used to collect changed
> records and only 
> writes free records,  each night the file is reset and
> starts collecting changes 
> for the next day.
> 
> I am wondering how the filePro locking is managed for a
> non-filepro kind of file.
> 
> lookup file r=free -n
> or to lock a free record do you have to add the -p
> 
> lookup file r=free -np
> 
> Two processes are writing records to this file and I think
> I noticed that a 
> record here and there are missing, seemingly written over
> by another process.
> 
> Both the processes were using -n without the -p for
> locking.  I always 
> understood that r=free was automatically locking, but now I
> wonder if 
> non-filepro Files are different somehow.
> 
> I noticed that in other cases where I have not noticed any
> lost records, I was 
> using -np  on the lookup FREE.
> 
> Many, many records are written to this file from many
> processes.  I am concerned 
> I am really missing more data than I am noticing.
> 
> (This is data that is not lost it just slows down the cycle
> when it is not 
> written to this temporary change file.  I want to get all
> the new data and post 
> it to the web as it is received. Each night the entire file
> is refreshed, but 
> this gets the data added all day so it is not 24 hours
> old.)
> 
> I am expecting a record for each order processed and
> noticed I miss a few 
> everyday, that did all the other things it should have but
> there is not a record 
> in this file.  Nothing crashed, nothing is broken, it just
> looks like a record 
> was written over the record by another process.
> 
> Any thoughts would be useful.
> 
> Someone is going to ask me what OS is writing this file and
> here is the answer, 
> both Linux and Windows write records into this file.  That
> is why I used 
> NON-filepro format.  There are no indexes.  The data part
> of the file is in a 
> folder that is shared by both systems.  It works great as a
> way to pass data 
> between the systems.  The only reason I noticed is that I
> run a process on this 
> one shared file that marks off orders to indicate they were
> processed on the 
> other platform.  I noticed a few are not marked off and
> wondered why.
> 
> 
> Nancy
> -- 

I had asked this same question a while back, and Ken's answer was that you do not need to add a -p to a free record lookup.  Filepro automatically locks the record.  

No doubt the problem relates to the way you are sharing the file between two systems - whatever you are using is not respecting the lock I would guess.

Jeff Harrison
jeffaharrison at yahoo.com