[openib-general] SA cache design

[Sean Hefty]

Sean Hefty wrote:
> To keep the design as flexible as possible, my plan is to implement the 
> cache in userspace.  The interface to the cache would be via MADs.  
> Clients would send their queries to the sa_cache instead of the SA 
> itself.  The format of the MADs would be essentially identical to those 
> used to query the SA itself.  Response MADs would contain any requested 
> information.  If the cache could not satisfy a request, the sa_cache 
> would query the SA, update its cache, then return a reply.

What I think I really want is a distributed relational database management 
system with an SQL interface and triggers that maintains the SA data...  (select 
* from path_rec where sgid=x and dgid=y and pkey=z)

But without making any assumptions about the SA, a local cache could still use 
an RDMS to store and retrieve the data records.  Would requiring an RDMS on each 
system be acceptable?  If not, then writing a small, dumb pseudo-database as 
part of the sa_cache could provide a lot of flexibility.

- Sean