fp file locking behavior

[Bob Haussmann]

> It was JP Radley who first brought it to my attention that 
> automatic index
> file stamps get changed just by someone entering into a file 
> in clerk. Yes,
> it was long ago, but not more than 23 years or so... I found 
> a reference to
> his notation about this back in some CompuServe stuff in 
> 1985.... and I
> actually remember when he brought this up, thinking that it 
> was odd that the
> stamps should change when no actual modification was made to 
> the file(s).
> This behavior has never caused me a bit of hassle in all those years,
> though.

John--nice memory.  Now that you bring it up, I do remember that
exchange.  I think it was after a major version update.  The question
remains, why would fP need to issue a lock for writing the
index when one is only browsing?  Interestingly, if PFREADONLY is
set, the timestamp is not updated, so this behavior is likely by
design.  Still, in very active files, wouldn't this cause
deadlock/contention issues?  I think that is what we are seeing, and 
why it is so hard to track down.  It has to be two sessions hitting
the same index at the exact same time, and one of those sessions
encountering an index locked for writing.  

Bob Haussmann
Tabor Children's Services, Inc.