Absurd Shared Memory Limits

Today, I fixed a problem.  Or at least, I think I fixed it.  Time will tell.  But Thom Brown seems pretty happy, and so does Dan Farina.  So let me tell you about it.  Here's the executive summary: assuming the patch I committed today holds up, PostgreSQL 9.3 will largely eliminate the need to fiddle with operating system shared memory limits.

perf: the good, the bad, the ugly

For the past few months, I've spent a good deal of time using the Linux utility perf to profile PostgreSQL.  On the whole, I've been favorably impressed.  Before I started using perf, trying to profile generally meant using oprofile or gprof.  Unfortunately, both of those tools have serious problems.