Re: [WIP] Double-write with Fast Checksums

>              9.2 + DW patch
>              -----------------------------------
>              FPW off  FPW on  DW on/FPW off
>              CK on    CK on   CK on
> one disk:     11078   10394    3296  [1G shared_buffers, 8G RAM]
> sep log disk: 13605   12015    3412
>
> one disk:      7731    6613    2670  [1G shared_buffers, 2G RAM]
> sep log disk:  6752    6129    2722
>

On my single Hard disk test with write cache turned off I see
different results than what Dan sees..
DBT2 50-warehouse, 1hr steady state with shared_buffers 1G,
checkpoint_segments=128 as common settings on 8GB RAM)
(checkpoints were on for all cases) with 8 Core .

FPW off: 3942.25 NOTPM
FPW on: 3613.37 NOTPM
DW on : 3479.15 NOTPM

I retried it with 2 core also and get similar results. So high
evictions does have slighly higher penalty than FPW.

My run somehow did not collect the background writer stats so dont
have that comparison for these runs but have fixed it for the next
runs.

Regards,
Jignesh