[elephant-devel] QDBM Support

[Robert L. Read]

On Thu, 2008-02-14 at 22:34 -0500, John DeSoi wrote:
> SQLite seems like it would be the ideal database for this project  
> since it is easy to embed in an application and has no license  
> hassles. I don't really know anything about BDB, but I'm surprised
> the  
> performance of a properly indexed SQL database can't get close to
> it.  
> If the performance with SQLite is poor, has it been verified to be  
> only a SQLite issue and not something related to CLSQL?
> 
> 

I think SQLite is faster than PostGres on our test suite.  It is my
understanding that this is perhaps possible because it provides much
weaker concurrency control.

I wouldn't say that the CL-SQL backend on top of Postgres or SQLite3 has
really been studied for performance.  In writing it, my primary goal was
to make the tests work as the did for BDB.  This of course is valuable
for migrating from one backend to the other.

Since that time, Ian and I have agreed that in fact the tests are little
too strong, and that we should allow some uncertainty in certain results
which are currently demanded by the tests but are really just an
artifact of the way BDB works.  However, the work to change the tests
has not been done, and the basic CL-SQL system that tries so hard to
imitate BDB (mostly in the ordering of indices) has not been changed
either.