Re: WIP patch for latestCompletedXid method of computing snapshot xmax

"Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> My desktop machine has a single consumer-grade IDE drive, and even with
> fsync off and synchronous_commit off, it can barely make 190 tps sustained
> pgbench throughput --- it's just disk write bound all the time. On a run
> with 8 clients, 10000 transactions per client, DB scale factor 25, I get
> this distribution of transaction times from CVS HEAD:

Wouldn't you expect to see more of an effect on cpu-bound environments? Is
there any i/o going on while these locks are being held? I suppose there's a
WAL commit record that has to be synced?

Have you tried with a smaller scale factor?

--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com