Re: Why are we waiting?

On Wed, 2008-02-06 at 19:55, Tom Lane wrote:
> I am wondering if the waits are being
> attributed to the right locks --- I remember such an error in a previous
> set of dtrace results, and some of the other details such as claiming
> shared lock delays but no exclusive lock delays for FirstLockMgrLock
> seem less than credible as well.

Good catch. We've checked the DTrace scripts against the respective
versions of lwlock.h, and the FirstLockMgrLock is off (this is actually
the results for FirstBufMappingLock).

However, this is the last lock in the enum that we trace, the other
lower-numbered lock enums were correctly mapped. (In particular the
ProcArrayLock which we've been puzzled by.)

And also, there was no clog buffer twaking or pg_lock monitoring done
when this benchmark was run, AFAIK.

We'll redo the benchmarks and post new scripts and results.

Staale