RE: Read-only lock on RPM db

["Shawn Weber" <Shawn Weber cnet com>]

> Hmmm, this smells like rpm-4.0.4 or earlier. That the case?

Yes, this particular build server is running version 4.0.4.  

> The solution will be to participate in the locking scheme 
> that rpm uses, basically shared/exclusive fcntl locks on 
> /var/lib/rpm/Packages.

How would I find out what specific process(es) has a shared/exclusive
fcntl lock on /var/lib/rpm/Packages?

TIA,
Shawn


> -----Original Message-----
> From: rpm-list-bounces@redhat.com 
> [mailto:rpm-list-bounces@redhat.com] On Behalf Of Jeff Johnson
> Sent: Tuesday, August 24, 2004 3:23 PM
> To: RPM Package Manager
> Subject: Re: Read-only lock on RPM db
> 
> 
> On Tue, Aug 24, 2004 at 02:49:11PM -0700, Shawn Weber wrote:
> > We have an automated third-party tool that builds a tree of 
> code, called
> > CruiseControl which some of you might be familiar with.   
> Occasionally,
> > an automated build will fail when trying to acquire a 
> read-only lock 
> > on the rpm database.
> > 
> 
> Probably because another process has an exclusive fcntl lock.
> 
> > The error message itself looks something like this in the logs:
> > 
> > error: cannot get shared lock on /var/lib/rpm/Packages
> > error: cannot open Packages index using db3 - Operation not 
> permitted
> > (1)
> 
> Hmmm, this smells like rpm-4.0.4 or earlier. That the case?
> 
> > 
> > The main problem is that this error confuses a developer, since the 
> > error message that our automated build system 
> (CruiseControl) returns 
> > is rather cryptic and the detailed build log must usually 
> be inspected 
> > to determine that this is the root cause of the problem.
> > 
> > Does anyone know what can be done to alleviate this error from 
> > occasionally occuring, such as explicitly locking and unlocking the 
> > db?
> > 
> 
> The solution will be to participate in the locking scheme 
> that rpm uses, basically shared/exclusive fcntl locks on 
> /var/lib/rpm/Packages.
> 
> The first step, however, is gonna be to understand what 
> process has the exclusive lock, as you will not be able to 
> get a shared lock until the exclusive lock is relinquished.
> 
> Alternatively, use Berkeley DB concurrent access locks, been 
> in "production" rpm since rpm-4.1 (currently rpm-4.3.2 
> something) several years now, and
> (mostly) avoids fcntl locks entirely.
> 
> 73 de Jeff
> 
> -- 
> Jeff Johnson	ARS N3NPQ
> jbj@redhat.com (jbj@jbj.org)
> Chapel Hill, NC
> 
> 
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