"Tom Lane" <[EMAIL PROTECTED]> writes: > Why? What you're really trying to determine, I think, is the I/O load > imposed by the bgwriter, and pages-per-second seems a pretty natural > way to think about that; percentage of shared buffers not so much.
What I'm saying is that pages/s will vary from system to system. Busier systems will have higher i/o rates. So a system with a DBA on a system with a higher rate will want to adjust the bgwriter sleep time lower than the DBA on a system where bgwriter isn't doing much work. In particular I'm worried about what happens on a very busy cpu-bound system where adjusting the sleep times would result in it deciding to not sleep at all. On such a system sleeping for even 10ms might be too long. But we probably don't want to make the default even as low as 10ms. Anyways, if we have a working patch that works the other way around we could experiment with that and see if there are actual situations where sleeping for 0ms is necessary. Perhaps a mixture of the two approaches will be necessary anyways because of the granularity issue. -- Gregory Stark EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
