Re: Apparent deadlock for simultaneous sequential scans

Dear Tom,
>
>
> pgsql-bugs(at)postgresql(dot)org writes:
> > Apparent deadlock for simultaneous sequential scans
>
> > However, if more than one application is run at once, the performance
> > deteriotates drastically.
>
> So is it a deadlock, or a slowdown? How many is "more than one"?

With two processors running the same query, it appears to be a
slowdown. When I look at the system calls, the backends were
executing about one read per second. With six processors running the
same query, it appeared to be a deadlock -- no I/O's were being issued
over the time that I watched.

"More than one" means two or more.

Thanks. --Bob

+----------------------------------+------------------------------------+
| Robert E. Bruccoleri, Ph.D. | Phone: 609 737 6383 |
| President, Congenomics, Inc. | Fax: 609 737 7528 |
| 114 W Franklin Ave, Suite K1,4,5 | email: bruc(at)acm(dot)org |
| P.O. Box 314 | URL: http://www.congen.com/~bruc |
| Pennington, NJ 08534 | |
+----------------------------------+------------------------------------+