[Zope] SQLSession vs FSSession for ultra-high scalability and speed.

[Pavlos Christoforou]

On Sun, 21 May 2000, chas wrote:

> Hi Folks,
> 
> Sorry if this has been asked before, but can anybody 
> advise on FSSession vs SQLSession for:
> 
> a) Speed.
> b) Scalability.
> 

FSSession does not use ZODB to store data, but stores session pickles
directly on the harddisk. It will also update session info only if there
are modifications to the session object. Given OS file caching I would
not be supprised if FSSession is faster than any RDBMs based solution.
Also note that if you have to support many writes on the Session objects,
a filesystem provides a nice map from users --> files, which then utilizes
the 'high concurrency' provided by the FS. 

OTO an RDBMS maybe a more reliable datastore than the filesystem with
better consistency, recovery tools etc etc.
 
Also check whether SQLSession caches info. It used to hit the RDBMs for
every variable access which was very prohibitive for us, but Anthony
mentioned that he was changing that.

Since performance is going to be a major issue in your design I suggest
you run a small bechmark to test relative performance.

Pavlos