Re: Scaling XLog insertion (was Re: Moving more work outside WALInsertLock)

On Fri, Mar 9, 2012 at 7:04 PM, Heikki Linnakangas
<heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
> Here's an updated patch. It now only loops once per segment that a record
> crosses. Plus a lot of other small cleanup.

Thanks! But you forgot to attach the patch.

> I've been doing some performance testing with this, using a simple C
> function that just inserts a dummy WAL record of given size. I'm not totally
> satisfied. Although the patch helps with scalability at 3-4 concurrent
> backends doing WAL insertions, it seems to slow down the single-client case
> with small WAL records by about 5-10%. This is what Robert also saw with an
> earlier version of the patch
> (http://archives.postgresql.org/pgsql-hackers/2011-12/msg01223.php). I
> tested this with the data directory on a RAM drive, unfortunately I don't
> have a server with a hard drive that can sustain the high insertion rate.
> I'll post more detailed results, once I've refined the tests a bit.

I'm also doing performance test. If I get interesting result, I'll post it.

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center