Use the <luceneMatchVersion> schema for 3.x Solr versions?

This is suggested as the best practice, but note that because the default merge policy changed in lucene setting the merge policy needs to be set to make it the same for both configs.

The problem here is that people would have to change that value depending on what version of Solr they're actually using, right? Specifying too high a value would make the config fail for older servers while a lower version number would mean that people with the newest servers would all need to change the setting manually to get the best performance (or new features).

Sorry.

I would go for 3.5 and not anything below. Traction started around 3.5 (although 3.4 was the first version that was experimented with and should work equally good afaik)

1.4+ and 3.5+ should be the two main ones that we support.

Why 3.5 and not 3.4:

From the changelog (http://www.lucidimagination.com/blog/2011/11/28/lucenesolr-3-5-released/):

Added a very substantial (3-5X) RAM reduction required to hold the
terms index on opening an IndexReader. (LUCENE-2205)

+ some bug fixes, but this ram fix was very significant.
I would certainly not settle for a version lower than 3.4

I agree with Nick about 3.5+, the memory fix is really huge

Does anyone know which versions the hosted Solr offers provide? If any of those don't have 3.5 yet, that would be bad. (But maybe this is much less of an issue than with PHP? Don't really know.)

I think we can have different versions of the config for different versions of Solr. Having a 1.4.x, 3.x, 4.x directory think is valid. Are there older versions of 3.x that neither module want to support?

We'll definitely do that, but with <luceneMatchVersion> we'd also need different files for 3.0, 3.1, …, and that's not really practical.

So I guess using 3.5 will be fine, but then everyone with a newer server will have to manually correct the setting, right? (It would still work without that, but remove any fixes in the newer versions.)

Any update?

So, let's settle for 3.5. Solr 3.6 will be the latest version of Solr before 4.0 comes out, so we can easily ship with a 3.5 and 3.6 solrconfig, but there are no noticeable improvements that are affecting us in the 3.5 or 3.6 lucene api afaik.