For a variety of reasons I've started a new blog: http://wwwscope.com/. I probably wont write much Java stuff on there (not that I seem to here, either at the moment), but my intention is that it will contain mostly longer technical content.
I've started off with an analysis of the recently released AOL search logs.
I've got comments enabled over there, so let me know what you think…
The biggest difference between 1.5.0 and 1.7.1 is that 1.7.1 uses two databases at once. In order to support fulltext matching, a new feature, we use a MyISAM database in MySQL with FULLTEXT keys (see http://dev.mysql.com/doc/refman/4.1/en/fulltext-search.html). However, InnoDB is still faster for JOIN's and offers referential integrity, so as a compromise we run two databases and keep them synchronized with MySQL replication (see http://dev.mysql.com/doc/refman/4.1/en/replication.html).
From the Connotea docs