Theo Shows Off Dtrace
For a database like PostgreSQL that likes to rely on operating system functionality to keep from re-inventing wheels, figuring out how to get the best information from your operating system is extremly important. As Theo shows us, [http://www.lethargy.org/~jesus/archives/74-PostgreSQL-performance-through-the-eyes-of-DTrace.html dtrace can work wonders] in this department. It’s worth noting too that this is on PostgreSQL 8.1, so he’s just working with operating system level dtrace probes, and not the postgresql specific probes that will be included in 8.2. The beauty of that script is while I can study a system and conclude that your issue is disk bound, this gives real numbers to back up such a claim, which is something every DBA needs from time to time. (Speaking of, anyone have a similar tool as he’s written for Linux?)