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Re: Index containing records instead of pointers to the data? - Mailing list pgsql-performance

From Thom Brown
Subject Re: Index containing records instead of pointers to the data?
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Msg-id CAA-aLv5LnrkfUQV1djitxV2vrsiBK=fRinKPn5cxyUey1+4w1g@mail.gmail.com
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In response to Index containing records instead of pointers to the data?  (Stefan Keller <sfkeller@gmail.com>)
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On 18 September 2011 21:18, Stefan Keller <sfkeller@gmail.com> wrote:
> Hi,
>
> Sorry if this is an odd question:
> I assume that Postgres indexes don't store records but only pointers
> to the data.
> This means, that there is always an additional access needed (real table I/O).
> Would an index containing data records make sense?

Yes, it's called a covering index, where the data required to produce
results for the query are entirely contained in the index.  That
should be hopefully coming in 9.2.

See http://wiki.postgresql.org/wiki/Index-only_scans

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Thom Brown
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