Jim Hu wrote:
As I understand it, Lucene indexes and stores the indexes into a set of index files that are kept in memory or are swapped in as needed and does not use the backend database that's running the wiki.
[snip]
But if Lucene sucks up all your free memory, you could get performance problems outside mySQL.
this is not exactly true. Lucene will cache some of the index in memory, but it's only a small amount. you can index a very large wiki (such as the English Wikipedia) using Lucene without running into memory problems.
you will need a reasonable amount of disk space to store the index, of course, and more RAM will allow your OS to cache more of the index files itself, which helps performance.
- river.