From: khaines@...
Date: 2006-08-31T01:23:44+09:00
Subject: Re: problem using pstore with multi-users

On Thu, 31 Aug 2006, James Edward Gray II wrote:

>> pstore doesn't itself do any locking of any sort.
>
> I don't think that's accurate.  Here's part of the transaction() method for 
> PStore.  Note the calls to flock():
>
>  def transaction(read_only=false)  # :yields:  pstore
>    # ...
>
>      unless read_only
>        file = File.open(@filename, File::RDWR | File::CREAT)
>        file.binmode
>        file.flock(File::LOCK_EX)
>        commit_new(file) if FileTest.exist?(new_file)
>        content = file.read()
>      else
>        begin
>          file = File.open(@filename, File::RDONLY)
>          file.binmode
>          file.flock(File::LOCK_SH)
>          content = (File.read(new_file) rescue file.read())
>        rescue Errno::ENOENT
>          content = ""
>        end
>      end

Well now, that's really interesting, because I never had anything but 
misery when I tried using pstore in a context where two threads or 
processes would try to access the same file at the same time.  This has me 
very curious as to why.

Fiddlesticks!


Kirk Haines