Arup Nanda posted a great blog article about one of the most fundamental, yet misunderstood, behaviors of the Oracle database: the relationship of the COMMIT statement and buffer caches being flushed to disk. I plan to re-read this every day for month. This clip seems apropos:
The article is titled "100 Things You Probably Didn't Know About Oracle Database," and I'm definitely looking forward to the other 99 articles.