Russell Smith wrote:
Strange idea that I haven't researched, Given Vacuum can't be run in a transaction, it is possible at a certain point to quit the current transaction and start another one. There has been much chat and now a TODO item about allowing multiple vacuums to not starve small tables. But if a big table has a long running vacuum the vacuum of the small table won't be effective anyway will it? If vacuum of a big table was done in multiple transactions you could reduce the effect of long running vacuum. I'm not sure how this effects the rest of the system thought.
That was fixed by Hannu Krosing's patch in 8.2 that made vacuum to ignore other vacuums in the oldest xmin calculation.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com