Re: WIP patch for latestCompletedXid method of computing snapshot xmax

Markus,

> I've just completed two dbt2 test runs on a mid-level system, with 4GB
> RAM and a 7 disk SATA RAID 1+0 w/ BBU. Once with code as of 2007/09/05
> 18:00 (which is *before* the first lazy xid commit) and once with cvs
> HEAD (2007/09/08  +latestCompletedXid.patch.

Hmmm.  Your results are withing the margin of error for DBT2, so they show no 
real difference.  What we need for this is a heavy-read workload, though; on 
a workload like DBT2 (which is mostly writes) I wouldn't expect lazy-XID to 
help much.

I'll see if I can find something appropriate.  Maybe Jan's TPC-W 
implementation?

-- 
Josh Berkus
PostgreSQL @ Sun
San Francisco