Hi Kevin, comments after your comments 2011/12/3 Kevin Grittner <Kevin.Grittner@xxxxxxxxxxxx>: > Ernesto Quiñones wrote: >> Scott Marlowe wrote: >>> Ernesto Quiñones wrote: > >>>> I want to know if it's possible to predict (calculate), how long >>>> a VACUUM FULL process will consume in a table? > > I don't think you said what version of PostgreSQL you're using. > VACUUM FULL prior to version 9.0 is not recommended for most > situations, and can take days or weeks to complete where other > methods of achieving the same end may take hours. If you have > autovacuum properly configured, you will probably never need to run > VACUUM FULL. I'm working with PostgreSQL 8.3 running in Solaris 10, my autovacuum paramaters are: autovacuum on autovacuum_analyze_scale_factor 0,5 autovacuum_analyze_threshold50000 autovacuum_freeze_max_age 200000000 autovacuum_max_workers 3 autovacuum_naptime 1h autovacuum_vacuum_cost_delay -1 autovacuum_vacuum_cost_limit -1 autovacuum_vacuum_scale_factor 0,5 autovacuum_vacuum_threshold 50000 my vacuums parameters are: vacuum_cost_delay 1s vacuum_cost_limit 200 vacuum_cost_page_dirty 20 vacuum_cost_page_hit 1 vacuum_cost_page_miss 10 vacuum_freeze_min_age 100000000 > Ah, well that right there is likely to put you into a position where > you need to do painful extraordinary cleanup like VACUUM FULL. In > most situation the autovacuum defaults are pretty good. Where they > need to be adjusted, the normal things which are actually beneficial > are to change the thresholds to allow more aggressive cleanup or (on > low-powered hardware) to adjust the cost ratios so that performance > is less affected by the autovacuum runs. I have a good performance in my hard disks, I have a good amount of memory, but my cores are very poor, only 1ghz each one. I have some questions here: 1. autovacuum_max_workers= 3 , each work processes is using only one "core" or one "core" it's sharing por 3 workers? 2. when I run a "explain analyze" in a very big table (30millons of rows) , explain returning me 32 millons of rows moved, I am assuming that my statistics are not updated in 2 millons of rows, but, is it a very important number? or maybe, it's a regular result. thanks for your help? -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
