> -----Original Message----- > From: Michael Glaesemann [mailto:grzm@xxxxxxxxxxxxxxx] > Sent: Wednesday, May 09, 2007 12:14 PM > To: Dann Corbit > Cc: Ashish Karalkar; Andrej Ricnik-Bay; Ron Johnson; pgsql- > general@xxxxxxxxxxxxxx > Subject: Re: [GENERAL] Views- Advantages and Disadvantages > > > On May 9, 2007, at 14:02 , Dann Corbit wrote: > > > Views can hide important information from the optimizer (especially > > index information). > > Really? AIUI, views-at least in PostgreSQL-are implemented using > PostgreSQL's rule system: the entire query is rewritten to include > the view query, and the optimizer sees the rewritten query. What the > optimizer sees is the same as if the view were inlined in the > original query. That is a significant achievement, since many database systems do not have that ability.
