On Mon, Jan 22, 2007 at 07:24:20PM +0000, Heikki Linnakangas wrote: > Kenneth Marshall wrote: > >On Mon, Jan 22, 2007 at 06:42:09PM +0000, Simon Riggs wrote: > >>Hold that thought! Read Heikki's Piggyback VACUUM idea on new thread... > > > >There may be other functions that could leverage a similar sort of > >infrastructure. For example, a long DB mining query could be registered > >with the system. Then as the pieces of the table/database are brought in > >to shared memory during the normal daily DB activity they can be acquired > >without forcing the DB to run a very I/O expensive query when waiting a > >bit for the results would be acceptable. As long as we are thinking > >piggyback. > > Yeah, I had the same idea when we discussed synchronizing sequential > scans. The biggest difference is that with queries, there's often a user > waiting for the query to finish, but with vacuum we don't care so much > how long it takes. > Yes, but with trending and statistical analysis you may not need the exact answer ASAP. An approximate answer based on a fraction of the information would be useful. Also, "what if" queries could be run without impacting the production uses of a database. One might imagine having a query with results that "converge" as the table is processed during normal use. Ken
