Tom,
In my experience, in last April, a BBWC solution did not accelerate
PostgreSQL well.
The device which I tried was i-ram by gigabyte
(http://techreport.com/reviews/2006q1/gigabyte-iram/index.x?pg=1 ).
The i-ram showed only a little performance improvement compared to
PostgreSQL with fsync to disk. (However, in then case of PostgreSQL
fsync=off, the performance improvement was great).
Thus I think Sigres is better than BBWC, to the best of my knowledge.
However, I do not know other BBWC technologies such as HP smart array
E200 controller.
(http://h18004.www1.hp.com/products/servers/proliantstorage/arraycontrollers/smartarraye200/index.html)
So, I am sorry if I describe wrong conclusion.
Best Regards,
-- Hideyuki
Tom Lane wrote:
> Gene <genekhart@gmail.com> writes:
>
>> I was curious to see how postgres would perform with wal on a tmpfs vs disk
>> here are some numbers I got from pgbench. Let me know if I did something
>> stupid, this is the first time I've used pgbench. The wal on tmpfs method is
>> not significantly faster.
>>
>
> This comparison is not very useful because you were using battery-backed
> write cache, which gives pretty much all the performance improvement
> that is to be looked for in this area. Try it against a plain vanilla
> disk drive (that's not lying about write complete) and you'll find the
> maximum TPS rate is closely related to the disk's rotation rate.
>
> At the same time though, the existence of BBWC solutions makes me wonder
> why we need another.
>
> regards, tom lane
>
>
>
--
Hideyuki Kawashima (Ph.D), University of Tsukuba,
Graduate School of Systems and Information Engineering
Assistant Professor, TEL: +81-29-853-5322
