Thanks all for the help and insights. I will continue to read up on the details of partitioning and pgpool. best regards, Lars On Thu, Oct 11, 2012 at 2:47 AM, Gavin Flower <GavinFlower@xxxxxxxxxxxxxxxxx> wrote: > On 11/10/12 12:41, Tom Lane wrote: >> >> Gavin Flower <GavinFlower@xxxxxxxxxxxxxxxxx> writes: >>> >>> On 11/10/12 01:03, Lars Helge Øverland wrote: >>>> >>>> My question is: Would it be feasible and/or possible to implement >>>> index only scans in a way that it could take advantage of several, >>>> single-column indexes? For example, a query spanning columns a, b, c >>>> could take advantage of 3 single-column indexes put on columns a, b, >>>> c. >>> >>> Index only scans do use multiple indexes of single fields where >>> appropriate. Here the planner determined it only needed to scan 2 of >>> the 3 relevant single field indexes. >> >> But your example isn't an index-only scan ... it's a plain old bitmap >> scan, and so it does touch the heap. >> >> The difficulty with what Lars proposes is that there's no way to scan >> the different indexes "in sync" --- each one will be ordered according >> to its own column order. In principle I guess we could read out the >> index data and do a join using the ctid's, but it's far from clear that >> such a thing would be worth the trouble. >> >> regards, tom lane > > Thanks for the correction! > > Cheers, > Gavin -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
