Sylvain Desbureaux wrote: HSQLDB is not recommended for large wikis; it is merely a small-footprint database that can be used in XWiki distributions to show how XWiki works. In a real setup it is more than needed to use something else. HSQLDB is an in-memory database, so at every moment you have the whole database kept in memory, and when you're using the data, it is stored at least twice, once in the DB app, and once in the XWiki platform. Still, the memory consumption is a bit too high, we should investigate where does all the memory go. There are several reports about HeapMemory exceptions when attaching files. Sergiu