In the light of IndexTank being open sourced by LinkedIn, here is a post in which Gautam Rege compares IndexTank with Thinking Sphinx and WebSolr. Feature-wise IndexTank has some advantages over Solr and almost none when compared wtih Thinking Sphinx.
When I first set out needing full text searching, I used Solr. It was pretty good though re-indexing took ages and to ensure consistency, I had to re-index every day via cron. Then I found Thinking Sphinx – and loved it because it managed delta indexes! Wow – no more daily re-index cron jobs. Even the re-indexing was way quicker.
The big issue with both Solr and TS was that it required tight integration with models and my database. For example – in TS, if a relationship was changed, I had to ensure to trigger the parent / child delta index in order to ensure it gets indexed too. Both TS and Solr add methods to ActiveRecord, which I find a little annoying. These nuances gets my code too dependent on TS or Solr and switching from them to something else becomes a big pain!
Original title and link: IndexTank vs Thinking Sphinx vs WebSolr (NoSQL database©myNoSQL)