Bill Moran wrote:
In response to Edoardo Ceccarelli <eddy@axa.it>:
I have read that autovacuum cannot check to see pg load before launching
vacuum but is there any patch about it? that would sort out the problem
in a good and simple way.
Otherwise, which kind of set of parameters I should put in autovacuum
configuration? I am stuck because in our case the table gets mostly read
and if I set up things as to vacuum the table after a specific amount of
insert/updates, I cannot foresee whether this could happen during
daytime when server is under high load.
How can I configure the vacuum to run after the daily batch insert/update?
It doesn't sound as if your setup is a good match for autovacuum. You
might be better off going back to the cron vacuums. That's the
beauty of Postgres -- it gives you the choice.
If you want to continue with autovac, you may want to experiment with
vacuum_cost_delay and associated parameters, which can lessen the
impact of vacuuming.
The db is constantly monitored during high peak so that we can switch to a backup pg7.3 database that is being vacuumed every night.
This is giving me the opportunity to try it so I tried this:
vacuum_cost_delay = 200
vacuum_cost_page_hit = 5
vacuum_cost_page_miss = 10
vacuum_cost_page_dirty = 20
vacuum_cost_limit = 100
I know these values affect the normal vacuum process but apparently this means setting
#autovacuum_vacuum_cost_delay = -1 # default vacuum cost delay for
# autovac, -1 means use
# vacuum_cost_delay
and
#autovacuum_vacuum_cost_limit = -1 # default vacuum cost limit for
# autovac, -1 means use
# vacuum_cost_limit
for the rest of them I am currently trying the deafults:
#autovacuum_naptime = 60 # time between autovacuum runs, in secs
#autovacuum_vacuum_threshold = 1000 # min # of tuple updates before vacuum
#autovacuum_analyze_threshold = 500 # min # of tuple updates before analyze
#autovacuum_vacuum_scale_factor = 0.4 # fraction of rel size before vacuum
#autovacuum_analyze_scale_factor = 0.2 # fraction of rel size before analyze
Does anybody know which process is actually AUTO-vacuum-ing the db?
So that I can check when is running...
