[Melbourne-pm] An article on session storage in perl weekly newsletter

[Bron Gondwana]

On Tue, Feb 18, 2014, at 03:19 PM, Toby Corkindale wrote:
> On 18/02/14 15:06, Tim Connors wrote:
> > On Tue, 18 Feb 2014, Toby Corkindale wrote:
> >
> >> On 18/02/14 14:22, Tim Connors wrote:
> >> [snip]
> >>> (I still don't get the point of databases.  perl storables were always
> >>> good enough for me and my tens of millions of objects in galaxy simulations)
> >>
> >> How did you manage multiple processes simultaneously wanting access to update
> >> different parts of the same file?
> >>
> >> How did you handle cases where you wanted a process to guarantee that either
> >> all of none of its changes were stored, but never some? (Whilst still allowing
> >> simultaneous access by multiple processes)
> >
> > Filesystem is a database, and atomic renames :P
> 
> So a file per row?
> That must perform amazingly when you want to do something like this 
> across a million tiny files:
> SELECT SUM(x) WHERE y > z
> 
> I guess you have to open every single file in order to flock() them so 
> you get an internally consistent view. How many file handles are your 
> processes allowed?

Nah, just flock a single global lock file for writes.

Bron ( think inside the box )

-- 
  Bron Gondwana
  brong at fastmail.fm