[lug] /etc/mail/access rebuilding collisions (was how to handle open ...)

[vlad]

Hello back.  I should have read the whole thread before posting, my 
apologies.    My previous post was just a one liner, but yes, there's 
much better ways of doing it :)

In regards to your query, the problem I was seeing was rebuilding  
/etc/mail/access.db on one of our mail servers.  During busy times, it's 
automatically rebuilt quite often.  I *think* what is happening is that 
sendmail tries to read it during a makemap rebuild and doesn't realize 
it's in the process of being hashed.  The effects are missed entries 
that sendmail doesn't read in.  The libc version is 2.2.4, but I have 
two different versions of Redhat where one doesn't appear to have a 
problem and the other does.  I haven't had a chance to really dive too 
deep into it, but if there's a commonly known piece of information I'm 
missing, I'd love to hear it.  I've tried recompiling sendmail with and 
without flock and couldn't tell a difference (makemap, etc. too of course).

I see sendmail 8.12.11 is out and I haven't tested this one yet, but the 
race condition mentioned in the release notes doesn't seem to be the 
problem described above (however I have experienced that one as well).

Sorry for the late reply.

Cheers

v

rm at fabula.de wrote:

> [snip]
>
>>1.  I've had problems with locking libs in earlier versions of Linux.  
>>Can't remember if it was flock or fcntl, but I'd check out the problems 
>>with each if you're running around RH 7.2-7.3.
>>    
>>
>
>both are in libc and used in rather critical applications. What exactly
>where the problems?
>
>  
>
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