[openib-general] SA cache design

[Brian Long]

On Wed, 2006-01-11 at 14:21 -0800, Sean Hefty wrote:
> Rimmer, Todd wrote:
> > A relational database is overkill for this function.
> > It will also likely be more complex for end users to setup and debug.
> > The cache setup should be simple.  The solution should be such that
> > just an on/off switch needs to be configured (with a default of on)
> > for most users to get started.
> 
> My take is a little different.  I view the SA as a database that maintains 
> related attributes.
> 
> By supporting relationships between different attributes, we can provide a more 
> powerful, higher performing, and more user-friendly interface to the user.  For 
> example, a single SQL query could return path records given only a node 
> description or service name.  Today, we generate multiple SA queries, their 
> responses, and associated RMPP MADs to obtain the same data.
> 
> I'm not sold on the idea of using a relational database, because of the 
> additional complexity for end-users.  However, I believe it can offer 
> significant advantages over what we could code ourselves.

How much overhead is going to be incurred by using a standard RDBMS
instead of not caching anything?  I'm not completely familiar with the
IB configurations that would benefit from the proposed SA cache, but it
seems to me, adding a RDBMS to anything as fast as IB would actually
slow things down considerably.  Can an RDBMS + SA cache actually be
faster than no cache at all?

/Brian/

-- 
       Brian Long                      |         |           |
       IT Data Center Systems          |       .|||.       .|||.
       Cisco Linux Developer           |   ..:|||||||:...:|||||||:..
       Phone: (919) 392-7363           |   C i s c o   S y s t e m s