Re: WAL CPU overhead/optimization (was Master-slave visibility order)

On 09/03/2013 05:27 PM, Robert Haas wrote:
> On Thu, Aug 29, 2013 at 8:22 PM, Ants Aasma <ants(at)cybertec(dot)at> wrote:
>> I might give it a shot later this cycle as I have familiarized my self
>> with the problem domain anyway. I understand the appeal of staying
>> with what we have, but this would cap the speedup at 4x and has large
>> caveats with the extra lookup tables. A 28x speedup might be worth the
>> extra effort.
> I agree. However, on the flip side, a bird in the hand is worth two
> in the bush. A patch that just does the same thing faster is likely
> to be less controversial than changing the algorithm, and does not
> preclude changing the algorithm later.
>
Has anybody looked at the recent i5/i7 added hrdware support for CRC32 ?

http://www.strchr.com/crc32_popcnt

From number there it is probably still slower than xxhash, but it might
be worth doing as
an interim optimisation.

Cheers

--
Hannu Krosing
PostgreSQL Consultant
Performance, Scalability and High Availability
2ndQuadrant Nordic OÜ