Re: [PROPOSAL] Covering + unique indexes. - Mailing list pgsql-hackers

From Teodor Sigaev
Subject Re: [PROPOSAL] Covering + unique indexes.
Date
Msg-id 55F718B1.8030306@sigaev.ru
Whole thread Raw
In response to Re: [PROPOSAL] Covering + unique indexes.  (Thomas Munro <thomas.munro@enterprisedb.com>)
List pgsql-hackers
> It surprised me that you can INCLUDE extra columns on non-UNIQUE
> indexes, since you could just add them as regular indexed columns for
> the same effect.  It looks like when you do that in SQL Server, the
> extra columns are only stored on btree leaf pages and so can't be used
> for searching or ordering.  I don't know how useful that is or if we
> would ever want it... but I just wanted to note that difference, and
Agree

> that the proposed UNIQUE ON FIRST n COLUMNS syntax and catalog change
> can't express that. Proposal suggests to work only with unique index by exactly your 
reasons above.


-- 
Teodor Sigaev                      E-mail: teodor@sigaev.ru                                      WWW:
http://www.sigaev.ru/



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