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From: Robert Haas on 14 May 2010 14:48 On Fri, May 14, 2010 at 12:03 AM, Takahiro Itagaki <itagaki.takahiro(a)oss.ntt.co.jp> wrote: > We can index multiple scalar values per row with GIN access method, > and also can index single vector value per row with GiST AM. > > Is it worth having a new AM to index multiple vector values per row? > It will be an AM for the missing feature in below: > > | scalar | vector | > ----------------+--------+--------+ > single per row | btree | gist | > multi per row | gin | *HERE* | > > We can call the new AM "gigist". Or, there might be another idea > to support expression indexes for SRF functions, like > =# CREATE TABLE tbl (c circle[]); > =# CREATE INDEX ON tbl USING gist (unnest(c)); > > Comments and ideas welcome. I'm not sure I agree with your characterization of the purpose of GIST. I think of GIST as a mechanism to support index lookups on types that are not totally ordered. Still, I guess I understand the point - I think what you are trying to do is optimize queries of the form, e.g.: SELECT * FROM tbl WHERE [some circle in c overlaps a given box] I don't personally want to do that :-) but I can easily imagine that someone else might. As for adding a new AM, we could certainly do it that way, but we should at least consider the possibility of trying to modify the existing GIST code to handle this case in addition to the things it already does. If that's not possible, then we should think about how to minimize code duplication. I fear that if we're not careful we might end up having to fix a lot of bugs in two places; also, any code that is specific to gigist will certainly get less real-world use than gist itself, so sharing code will help keep our bug counts down. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise Postgres Company -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers |