"Simon Riggs" <[EMAIL PROTECTED]> 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 ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match