Re: more anti-postgresql FUD

On Oct 13, 2006, at 17:13 , Andrew - Supernews wrote:

> On 2006-10-13, Alexander Staubo <alex@purefiction.net> wrote:
>> On my box (Dell PowerEdge 1850, dual Xeon 2.8GHz, 4GB RAM, 10kRPM
>> SCSI, Linux 2.6.15, Ubuntu) I get 1,100 updates/sec, compared to
>> 10,000 updates/sec with MySQL/InnoDB, using a stock installation of
>> both. Insert performance is only around 10% worse than MySQL at
>> around 9,000 rows/sec. Curiously enough, changing shared_buffers,
>> wal_buffers, effective_cache_size and even fsync seems to have no
>> effect on update performance, while fsync has a decent effect on
>> insert performance.
>
> Your disk probably has write caching enabled. A 10krpm disk should be
> limiting you to under 170 transactions/sec with a single connection
> and fsync enabled.

What formula did you use to get to that number? Is there a generic
way on Linux to turn off (controller-based?) write caching?

Alexander.