On Feb 23, 2010, at 2:23 PM, Kevin Grittner wrote:
Here are the values from our two largest and busiest systems (where
we found the pg_xlog placement to matter so much). It looks to me
like a more aggressive bgwriter would help, yes?
cir=> select * from pg_stat_bgwriter ;
-[ RECORD 1 ]------+------------
checkpoints_timed | 125996
checkpoints_req | 16932
buffers_checkpoint | 342972024
buffers_clean | 343634920
maxwritten_clean | 9928
buffers_backend | 575589056
buffers_alloc | 52397855471
cir=> select * from pg_stat_bgwriter ;
-[ RECORD 1 ]------+------------
checkpoints_timed | 125992
checkpoints_req | 16840
buffers_checkpoint | 260358442
buffers_clean | 474768152
maxwritten_clean | 9778
buffers_backend | 565837397
buffers_alloc | 71463873477
Current settings:
bgwriter_delay = '200ms'
bgwriter_lru_maxpages = 1000
bgwriter_lru_multiplier = 4
Any suggestions on how far to push it?
I don't know how far to push it, but you could start by reducing the delay time and observe how that affects performance.