"Simon Riggs" <simon@2ndquadrant.com> wrote:
> > > With the default
> > > value of scan_recycle_buffers(=0), VACUUM seems to use all of buffers in pool,
> > > just like existing sequential scans. Is this intended?
> >
> New test version enclosed, where scan_recycle_buffers = 0 doesn't change
> existing VACUUM behaviour.
This is a result with scan_recycle_buffers.v3.patch. I used normal VACUUM
with background load using slowdown-ed pgbench in this instance. I believe
the patch is useful in normal cases, not only for VACUUM FREEZE.
N | time | WAL flush(*)
-----+--------+----------- 0 | 112.8s | 44.3% 1 | 148.9s | 52.1% 8 | 105.1s | 17.6% 16 | 96.9s | 8.7% 32 | 103.9s
| 6.3% 64 | 89.4s | 6.6%128 | 80.0s | 3.8%
Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center
