I'd have to add my two cents and strongly disagree with this guy. I work for a Berkshire Hathaway company and had database speed issues for a variety of reasons. I suggested using Elasticsearch for this as well as other benefits, and it's been absolutely fantastic. There are a few small things I think it could improve upon but overall it is like nothing else out there.

---
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB