"Elena Camossi" <elena.camossi@xxxxxxxxx> writes: > Hi list, > > what is the default implementation for GiST index? B-Tree or R-Tree? > That is, if i execute the following SQL command: > > CREATE index ON table USING Gist (column) > > what is the type of the index that is actually built? uhm, GIST. GIST is a particular type of index just like btree. What are you actually trying to do? Do you have a particular problem you're trying to solve? > How can I specify in SQL one of the two implementations provided (e.g. > R-Tree)? R-Tree indexes don't exist in Postgres any more. GIST indexes are very similar only more general. They handle 2D geometric data types like RTree did previously as well as n-dimensional data types and other more exotic things like intarrays and full text search. There are different "kinds" of GIST indexes which you can specify by specifying an operator class with you define the index. But most data types only have a single operator class available to them so that's probably not what you need unless you're trying to do something unusual. An "operator class" defines a set of operators which can be optimized by an index organized the same way and usually correspond to a particular interpretation of the data type. -- Gregory Stark EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your message can get through to the mailing list cleanly
