On Thursday 22 March 2007 16:12, Alvaro Herrera wrote: > Dimitri escribió: > > On Thursday 22 March 2007 14:52, Alvaro Herrera wrote: > > > Dimitri escribió: > > > > Folks, > > > > > > > > is there any constrains/problems/etc. to run several vacuum processes > > > > in parallel while each one is 'vaccuming' one different table? > > > > > > No, no problem. Keep in mind that if one of them takes a very long > > > time, the others will not be able to remove dead tuples that were > > > killed while the long vacuum was running -- unless you are in 8.2. > > > > Yes, I'm using the last 8.2.3 version. So, will they *really* processing > > in parallel, or will block each other step by step? > > They won't block. Wow! Excellent! :) So, in this case why not to add 'parallel' option integrated directly into the 'vacuumdb' command? In my case I have several CPU on the server and quite powerful storage box which is not really busy with a single vacuum. So, my idea is quite simple - speed-up vacuum with parallel execution (just an algorithm): -------------------------------------------------------------------------- PLL=parallel_degree select tab_size, tabname, dbname from ... order by tab_size desc; vacuumdb -d $dbname -t $tabname 2>&1 > /tmp/vac.$dbname.$tabname.log & while (pgrep vacuumdb | wc -l ) >= $PLL sleep 1 end end wait -------------------------------------------------------------------------- biggest tables are vacuumed first, etc. But of course it will be much more cool to have something like: vacuumdb -a -P parallel_degree What do you think? ;) Rgds, -Dimitri
