Simon Riggs wrote: > On Mon, 2010-02-22 at 08:51 +0200, Heikki Linnakangas wrote: >> Gokulakannan Somasundaram wrote: > >>> May i get a little clarification on this issue? Will we be supporting >>> the IOT feature in postgres in future? >> What seems like the best path to achieve the kind of performance >> benefits that IOTs offer is allowing index-only-scans using the >> visibility map. > > I don't agree with that. Could you explain why you think that would be > the case? It would be a shame to have everybody think you can solve a > problem if it turned out not to be the case.
I'm thinking of a scan based on the index key. With an index-organised-table, you can skip the heap access because the heap and the index are the same structure. An index-only-scan likewise allows you to skip the heap access. I grant you that an index-organised-table can have other benefits, like reduced disk space usage (which is good cache efficiency), or less random I/O required for updates. The question was if PostgreSQL will be supporting index-organised-tables in the future. The answer is "not in the foreseeable future". No-one has come up with a plausible plan for how to do it, and no-one working on it at the moment. I don't want to discourage thinking about pie-in-the-sky features. There's many tricks like column-oriented storage, compression, index-organised-tables etc. that would be nice to have. Whether any particular feature is worthwhile in the end, the devil is in the details. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
