为什么bgwriter不运行
select name,setting from pg_settings where name like 'bg%'
"bgwriter_delay";"200"
"bgwriter_lru_maxpages";"100"
"bgwriter_lru_multiplier";"10"
select buffers_clean,buffers_checkpoint,buffers_backend,
(checkPoint_write_time+checkpoint_sync_time)/1000||'s' as "checkPoint_time",
(checkPoints_timed+checkPoints_req) as "checkPoint runs",
buffers_alloc from pg_stat_bgwriter
0;89;1;"0.1s";1;1
buffers_clean 永远是0 ,为什么?