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Re: Covering Indexes

From: Thomas Munro <munro(at)ip9(dot)org>
To: Rob Wultsch <wultsch(at)gmail(dot)com>
Cc: "David E(dot) Wheeler" <david(at)justatheory(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Covering Indexes
Date: 2012-06-30 10:12:09
Message-ID: CADLWmXV-oDoD8+A+0n+xv3uE8n86jTTxfQtfMsm8-XXXQTC_JQ@mail.gmail.com (view raw or flat)
Thread:
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On 28 June 2012 14:02, Rob Wultsch <wultsch(at)gmail(dot)com> wrote:
> On Thu, Jun 28, 2012 at 8:16 AM, David E. Wheeler <david(at)justatheory(dot)com> wrote:
>> I'm particularly intrigued by "covering indexes". For example:
>>
>>    CREATE INDEX cover1 ON table1(a,b) COVERING(c,d);
>
> IRC MS SQL also allow unindexed columns in the index.

For what it's worth, DB2 also has this feature, written roughly the
same way as MS SQL Server: CREATE INDEX cover1 ON table1(a, b) INCLUDE
(c, d).

http://pic.dhe.ibm.com/infocenter/db2luw/v9r7/index.jsp?topic=/com.ibm.db2.luw.sql.ref.doc/doc/r0000919.html

Oracle doesn't seem to have this feature (and the SQL standard doesn't
mention indexes at all).

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