Table of Contents
A database administrator frequently wonders, “What is the system doing right now?” This chapter discusses how to find that out.
   Several tools are available for monitoring database activity and
   analyzing performance.  Most of this chapter is devoted to describing
   PostgreSQL's statistics collector,
   but one should not neglect regular Unix monitoring programs such as
   ps, top, iostat, and vmstat.
   Also, once one has identified a
   poorly-performing query, further investigation might be needed using
   PostgreSQL's EXPLAIN command.
   Section 14.1 discusses EXPLAIN
   and other methods for understanding the behavior of an individual
   query.