Re: Exact index overhead - Mailing list pgsql-performance

From Scott Marlowe
Subject Re: Exact index overhead
Date
Msg-id dcc563d10804190948o573612d0r51e3792574962b99@mail.gmail.com
Whole thread Raw
In response to Re: Exact index overhead  (Gunther Mayer <gunther.mayer@googlemail.com>)
List pgsql-performance
On Thu, Apr 17, 2008 at 9:42 AM, Gunther Mayer
<gunther.mayer@googlemail.com> wrote:
> Pavan Deolasee wrote:
>

> > 2. The existing block should have enough free space to accommodate the
> > new version
> > A less than 100 fillfactor may help you given your rate of updates.
> >
> >
>  I see, as soon as a new block is required for the new version the index
> pointer needs updating too, I understand now. But at least in the common
> case of space being available the index overhead is reduced to zero. I can
> live with that.

Quick clarification, it's the table, not the index that has to have
free space for the new row version.  This rewards good normalization
practices (narrower rows) and a lower fill factor.

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