[elephant-devel] BDB vs postmodern

[lists at infoway.net]

Hi all,

I don't mean to start a war here or put any work down. However, I just  
needed some clarification/direction into which way the data stores  
work is going.

 From the documentation I've read, the BDB data store only supports  
BDB version 4.5 (or up to 4.5), so further work done in 4.6 and above  
is not leveraged. I don't know if there is any effort to continue  
evolving the BDB data store. Any comments?

Also, from what I've been reading on the list, it seems the postmodern  
data store is more active. Granted is a more recent data store and may  
need more work to get to where the BDB data store has gotten after all  
this time (just speculation since I haven't really used the postmodern  
data store). However, from what I've read, the postmodern seems to use  
Postgres as the backend but not in a Object-Relational mode but rather  
as plain storing of "btree pages". So, in essence, what I understand  
is that operating on this data store requires elephant to read/write  
"pages" or "btrees" in Postgres and once in memory, they may be  
treated similar to how the BDB engine works (don't mean to mock  
postmodern with my lack of knowledge).

So, putting licensing issues aside, what is the real difference/ 
advantage of one data store over the other? In a recent email I read  
by Alex, he mentions he's going to work on improving performance on  
the postmodern data store. So, even after that improves and  
performance is matched with that of BDB, is there an advantage of one  
data store over the other?

Since Postgres does allow for features such as replication,  
clustering, and fail-over with multiple active simultaneous client  
connections, does this mean that I could have multiple (separate) lisp  
clients using elephant connecting to a separate Postgres cluster with  
no concurrency issues?

Thanks,
Waldo